Journal articles on the topic 'Right PPC'
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1
He, Xiaofei, Yue Lan, Guangqing Xu, Yurong Mao, Zhenghong Chen, Dongfeng Huang, and Zhong Pei. "Frontoparietal regions may become hypoactive after intermittent theta burst stimulation over the contralateral homologous cortex in humans." Journal of Neurophysiology 110, no. 12 (December 15, 2013): 2849–56. http://dx.doi.org/10.1152/jn.00369.2013.
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Brain injury to the dorsal frontoparietal networks, including the posterior parietal cortex (PPC) and dorsolateral prefrontal cortex (DLPFC), commonly cause spatial neglect. However, the interaction of these different regions in spatial attention is unclear. The aim of the present study was to investigate whether hyperexcitable neural networks can cause an abnormal interhemispheric inhibition. The Attention Network Test was used to test subjects following intermittent theta burst stimulation (iTBS) to the left or right frontoparietal networks. During the Attention Network Test task, all subjects tolerated each conditioning iTBS without any obvious iTBS-related side effects. Subjects receiving real-right-PPC iTBS showed significant enhancement in both alerting and orienting efficiency compared with those receiving either sham-right-PPC iTBS or real-left-PPC iTBS. Moreover, subjects exposed to the real-right-DLPFC iTBS exhibited significant improvement in both alerting and executive control efficiency, compared with those exposed to either the sham-right-DLPFC or real-left-DLPFC conditioning. Interestingly, compared with subjects exposed to the sham-left-PPC stimuli, subjects exposed to the real-left-PPC iTBS had a significant deficit in the orienting index. The present study indicates that iTBS over the contralateral homologous cortex may induce the hypoactivity of the right PPC through interhemispheric competition in spatial orienting attention.
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Hartmann, Matthias, Sarah Singer, Branislav Savic, René M. Müri, and Fred W. Mast. "Anodal High-definition Transcranial Direct Current Stimulation over the Posterior Parietal Cortex Modulates Approximate Mental Arithmetic." Journal of Cognitive Neuroscience 32, no. 5 (May 2020): 862–76. http://dx.doi.org/10.1162/jocn_a_01514.
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The representation and processing of numerosity is a crucial cognitive capacity. Converging evidence points to the posterior parietal cortex (PPC) as primary “number” region. However, the exact role of the left and right PPC for different types of numerical and arithmetic tasks remains controversial. In this study, we used high-definition transcranial direct current stimulation (HD-tDCS) to further investigate the causal involvement of the PPC during approximative, nonsymbolic mental arithmetic. Eighteen healthy participants received three sessions of anodal HD-tDCS at 1-week intervals in counterbalanced order: left PPC, right PPC, and sham stimulation. Results showed an improved performance during online parietal HD-tDCS (vs. sham) for subtraction problems. Specifically, the general tendency to underestimate the results of subtraction problems (i.e., the “operational momentum effect”) was reduced during online parietal HD-tDCS. There was no difference between left and right stimulation. This study thus provides new evidence for a causal involvement of the left and right PPC for approximate nonsymbolic arithmetic and advances the promising use of noninvasive brain stimulation in increasing cognitive functions.
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Collignon, Olivier, Marco Davare, Anne G. De Volder, Colline Poirier, Etienne Olivier, and Claude Veraart. "Time-course of Posterior Parietal and Occipital Cortex Contribution to Sound Localization." Journal of Cognitive Neuroscience 20, no. 8 (August 2008): 1454–63. http://dx.doi.org/10.1162/jocn.2008.20102.
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It has been suggested that both the posterior parietal cortex (PPC) and the extrastriate occipital cortex (OC) participate in the spatial processing of sounds. However, the precise time-course of their contribution remains unknown, which is of particular interest, considering that it could give new insights into the mechanisms underlying auditory space perception. To address this issue, we have used event-related transcranial magnetic stimulation (TMS) to induce virtual lesions of either the right PPC or right OC at different delays in subjects performing a sound lateralization task. Our results confirmed that these two areas participate in the spatial processing of sounds. More precisely, we found that TMS applied over the right OC 50 msec after the stimulus onset significantly impaired the localization of sounds presented either to the right or to the left side. Moreover, right PPC virtual lesions induced 100 and 150 msec after sound presentation led to a rightward bias for stimuli delivered on the center and on the left side, reproducing transiently the deficits commonly observed in hemineglect patients. The finding that the right OC is involved in sound processing before the right PPC suggests that the OC exerts a feedforward influence on the PPC during auditory spatial processing.
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Schintu, Selene, Elisa Martín-Arévalo, Michael Vesia, Yves Rossetti, Romeo Salemme, Laure Pisella, Alessandro Farnè, and Karen T. Reilly. "Paired-Pulse Parietal-Motor Stimulation Differentially Modulates Corticospinal Excitability across Hemispheres When Combined with Prism Adaptation." Neural Plasticity 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/5716179.
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Rightward prism adaptation ameliorates neglect symptoms while leftward prism adaptation (LPA) induces neglect-like biases in healthy individuals. Similarly, inhibitory repetitive transcranial magnetic stimulation (rTMS) on the right posterior parietal cortex (PPC) induces neglect-like behavior, whereas on the left PPC it ameliorates neglect symptoms and normalizes hyperexcitability of left hemisphere parietal-motor (PPC-M1) connectivity. Based on this analogy we hypothesized that LPA increases PPC-M1 excitability in the left hemisphere and decreases it in the right one. In an attempt to shed some light on the mechanisms underlying LPA’s effects on cognition, we investigated this hypothesis in healthy individuals measuring PPC-M1 excitability with dual-site paired-pulse TMS (ppTMS). We found a left hemisphere increase and a right hemisphere decrease in the amplitude of motor evoked potentials elicited by paired as well as single pulses on M1. While this could indicate that LPA biases interhemispheric connectivity, it contradicts previous evidence that M1-only MEPs are unchanged after LPA. A control experiment showed that input-output curves were not affected by LPAper se. We conclude that LPA combined with ppTMS on PPC-M1 differentially alters the excitability of the left and right M1.
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Mevorach, Carmel, Glyn W. Humphreys, and Lilach Shalev. "Reflexive and Preparatory Selection and Suppression of Salient Information in the Right and Left Posterior Parietal Cortex." Journal of Cognitive Neuroscience 21, no. 6 (June 2009): 1204–14. http://dx.doi.org/10.1162/jocn.2009.21088.
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Attentional cues can trigger activity in the parietal cortex in anticipation of visual displays, and this activity may, in turn, induce changes in other areas of the visual cortex, hence, implementing attentional selection. In a recent TMS study [Mevorach, C., Humphreys, G. W., & Shalev, L. Opposite biases in salience-based selection for the left and right posterior parietal cortex. Nature Neuroscience, 9, 740–742, 2006b], it was shown that the posterior parietal cortex (PPC) can utilize the relative saliency (a nonspatial property) of a target and a distractor to bias visual selection. Furthermore, selection was lateralized so that the right PPC is engaged when salient information must be selected and the left PPC when the salient information must be ignored. However, it is not clear how the PPC implements these complementary forms of selection. Here we used on-line triple-pulse TMS over the right or left PPC prior to or after the onset of global/local displays. When delivered after the onset of the display, TMS to the right PPC disrupted the selection of the more salient aspect of the hierarchical letter. In contrast, left PPC TMS delivered prior to the onset of the stimulus disrupted responses to the lower saliency stimulus. These findings suggest that selection and suppression of saliency, rather than being “two sides of the same coin,” are fundamentally different processes. Selection of saliency seems to operate reflexively, whereas suppression of saliency relies on a preparatory phase that “sets up” the system in order to effectively ignore saliency.
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Murphy, Aidan P., David A. Leopold, Glyn W. Humphreys, and Andrew E. Welchman. "Lesions to right posterior parietal cortex impair visual depth perception from disparity but not motion cues." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1697 (June 19, 2016): 20150263. http://dx.doi.org/10.1098/rstb.2015.0263.
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The posterior parietal cortex (PPC) is understood to be active when observers perceive three-dimensional (3D) structure. However, it is not clear how central this activity is in the construction of 3D spatial representations. Here, we examine whether PPC is essential for two aspects of visual depth perception by testing patients with lesions affecting this region. First, we measured subjects' ability to discriminate depth structure in various 3D surfaces and objects using binocular disparity. Patients with lesions to right PPC ( N = 3) exhibited marked perceptual deficits on these tasks, whereas those with left hemisphere lesions ( N = 2) were able to reliably discriminate depth as accurately as control subjects. Second, we presented an ambiguous 3D stimulus defined by structure from motion to determine whether PPC lesions influence the rate of bistable perceptual alternations. Patients' percept durations for the 3D stimulus were generally within a normal range, although the two patients with bilateral PPC lesions showed the fastest perceptual alternation rates in our sample. Intermittent stimulus presentation reduced the reversal rate similarly across subjects. Together, the results suggest that PPC plays a causal role in both inferring and maintaining the perception of 3D structure with stereopsis supported primarily by the right hemisphere, but do not lend support to the view that PPC is a critical contributor to bistable perceptual alternations. This article is part of the themed issue ‘Vision in our three-dimensional world’.
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Maggio, C. Di, C. Massullo, C. Imperatori, O. Palazzolo, B. Farina, M. Brinciotti, M. Ferrara, V. Guidetti, and A. Terrinoni. "Triple network in adolescents with borderline personality disorder, early traumatic experiences and dissociative symptoms: An eloreta study." European Psychiatry 64, S1 (April 2021): S140. http://dx.doi.org/10.1192/j.eurpsy.2021.384.
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IntroductionTriple Network Model (TNM), which considers the dynamic interaction between Default Mode (DMN), Salience (SN), and Central Executive (CEN) networks, explains clinical features in mental disorders from a neurophysiological perspective. Some studies highlight the increased connectivity in TNM in adults with Borderline Personality Disorder (BPD), but little is known about adolescents.ObjectivesThe aim of our preliminary study was to investigate TN functional connectivity (FC) in BPD adolescents with a history of traumatic experiences, and its correlation with dissociative symptoms.Methods15 BPD adolescents (DSM-5 criteria) with early traumatic experiences were compared to 15 healthy controls, matched for sex and age. Dissociation Questionnaire (DIS-Q) was administered. Eyes-closed resting-state (RS) EEG recordings were performed (19 electrodes; 10- 20 system) and analyzed using Exact Low-Resolution Electromagnetic Tomography software (eLORETA). FC was computed for all frequency bands and 9 Regions of Interest for TNM.ResultsBPD adolescents showed a hyper-connection between CEN and DMN [dorso-lateral prefrontal cortex (dlPFC) and posterior cingulate cortex (PCC); PCC and left posterior parietal cortex (PPC)] and within the CEN (left and right PPC). The strength of PCC-dlPFC and left-right PPC connections was correlated with dissociative symptoms severity.ConclusionsFC alterations can already be identified in BPD adolescents, supporting the need for early diagnosis. Normally DMN and CEN show opposite functioning. In our BPD adolescents, the absence of this “anti-correlation” reflects the typical confusion between internal and external mental states, which clarify their difficulties in metacognition or mentalization. Moreover, in dissociative symptoms, two CEN nodes are also involved, not only DMN as previously described.DisclosureNo significant relationships.
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Matsuda, Masayuki, Yoshiro Kai, Suzuka Harada, Kentaro Suzuki, Shigeto Hontsu, and Shigeo Muro. "Duodenal Metastasis of Pulmonary Pleomorphic Carcinoma: A Case Report." Case Reports in Oncology 14, no. 3 (October 21, 2021): 1511–15. http://dx.doi.org/10.1159/000519664.
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Pulmonary pleomorphic carcinoma (PPC) is a rare subtype of lung sarcomatoid carcinoma that has a poor prognosis, and no standard therapy has been established. Here, we report the case of a 74-year-old man with PCC who showed rare duodenal metastasis. He was referred to our hospital with a mass shadow in the right lung. The patient was diagnosed with PPC clinical stage II B on the basis of immunohistochemical staining from bronchoscopy, and the tumor proportion score of programmed death-ligand 1 was 80%. He did not want any treatment. A year and a half later, progressive anemia was detected. The primary tumor was stable; however, abdominal computed tomography and esophagogastroduodenoscopy revealed a duodenal tumor with stenosis. He was diagnosed with duodenal metastasis from PPC, and he underwent gastrojejunal bypass surgery to prevent bowel obstruction. After surgery, he received pembrolizumab for chemotherapy. However, owing to the progression of peritoneum dissemination, he died 2 months later due to the onset of melena.
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Magis-Weinberg, Lucía, Ruud Custers, and Iroise Dumontheil. "Rewards Enhance Proactive and Reactive Control in Adolescence and Adulthood." Social Cognitive and Affective Neuroscience 14, no. 11 (November 1, 2019): 1219–32. http://dx.doi.org/10.1093/scan/nsz093.
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Abstract Cognitive control allows the coordination of cognitive processes to achieve goals. Control may be sustained in anticipation of goal-relevant cues (proactive control) or transient in response to the cues themselves (reactive control). Adolescents typically exhibit a more reactive pattern than adults in the absence of incentives. We investigated how reward modulates cognitive control engagement in a letter-array working memory (WM) task in 30 adolescents (12–17 years) and 20 adults (23–30 years) using a mixed block- and event-related functional magnetic resonance imaging design. After a Baseline run without rewards, participants performed a Reward run where 50% trials were monetarily rewarded. Accuracy and reaction time (RT) differences between Reward and Baseline runs indicated engagement of proactive control, which was associated with increased sustained activity in the bilateral anterior insula (AI), right dorsolateral prefrontal cortex (PFC) and right posterior parietal cortex (PPC). RT differences between Reward and No reward trials of the Reward run suggested additional reactive engagement of cognitive control, accompanied with transient activation in bilateral AI, lateral PFC, PPC, supplementary motor area, anterior cingulate cortex, putamen and caudate. Despite behavioural and neural differences during Baseline WM task performance, adolescents and adults showed similar modulations of proactive and reactive control by reward.
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Rounis, Elisabeth, Kielan Yarrow, and John C. Rothwell. "Effects of rTMS Conditioning over the Fronto-parietal Network on Motor versus Visual Attention." Journal of Cognitive Neuroscience 19, no. 3 (March 2007): 513–24. http://dx.doi.org/10.1162/jocn.2007.19.3.513.
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Many studies have shown that visuospatial orienting attention depends on a network of frontal and parietal areas in the right hemisphere. Rushworth et al. [Rushworth, M. F., Krams, M., & Passingham, R. E. The attentional role of the left parietal cortex: The distinct lateralization and localization of motor attention in the human brain. Journal of Cognitive Neuroscience, 13, 698–710, 2001] have recently provided evidence for a left-lateralized network of parietal areas involved in motor attention. Using two variants of a cued reaction time (RT) task, we set out to investigate whether high-frequency repetitive transcranial magnetic stimulation (rTMS; 5 Hz) delivered “off-line” in a virtual lesion paradigm over the right or left dorsolateral prefrontal cortex (DLPFC) or the posterior parietal cortex (PPC) would affect performance in a motor versus a visual attention task. Although rTMS over the DLPFC on either side did not affect RT performance on a spatial orienting task, it did lead to an increase in the RTs of invalidly cued trials in a motor attention task when delivered to the left DLPFC. The opposite effect was found when rTMS was delivered to the PPC: In this case, conditioning the right PPC led to increased RTs in invalidly cued trials located in the left hemispace, in the spatial orienting task. rTMS over the PPC on either side did not affect performance in the motor attention task. This double dissociation was evident in the first 10 min after rTMS conditioning. These results enhance our understanding of the networks associated with attention. They provide evidence of a role for the left DLPFC in the mechanisms of motor preparation, and confirm Mesulam's original proposal for a right PPC dominance in spatial attention [Mesulam, M. M. A cortical network for directed attention and unilateral neglect. Annals of Neurology, 10, 309–325, 1981].
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Duecker, Felix, Teresa Schuhmann, Nina Bien, Christianne Jacobs, and Alexander T. Sack. "Moving Beyond Attentional Biases: Shifting the Interhemispheric Balance between Left and Right Posterior Parietal Cortex Modulates Attentional Control Processes." Journal of Cognitive Neuroscience 29, no. 7 (July 2017): 1267–78. http://dx.doi.org/10.1162/jocn_a_01119.
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The concept of interhemispheric competition has been very influential in attention research, and the occurrence of biased attention due to an imbalance in posterior parietal cortex (PPC) is well documented. In this context, the vast majority of studies have assessed attentional performance with tasks that did not include an explicit experimental manipulation of attention, and, as a consequence, it remains largely unknown how these findings relate to core attentional constructs such as endogenous and exogenous control and spatial orienting and reorienting. We here addressed this open question by creating an imbalance between left and right PPC with transcranial direct current stimulation, resulting in right-hemispheric dominance, and assessed performance on three experimental paradigms that isolate distinct attentional processes. The comparison between active and sham transcranial direct current stimulations revealed a highly informative pattern of results with differential effects across tasks. Our results demonstrate the functional necessity of PPC for endogenous and exogenous attentional control and, importantly, link the concept of interhemispheric competition to core attentional processes, thus moving beyond the notion of biased attention after noninvasive brain stimulation over PPC.
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Riemer, Martin, Darren Rhodes, and Thomas Wolbers. "Systematic Underreproduction of Time Is Independent of Judgment Certainty." Neural Plasticity 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/6890674.
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We recently proposed that systematic underreproduction of time is caused by a general judgment bias towards earlier responses, instead of reflecting a genuine misperception of temporal intervals. Here we tested whether this bias can be explained by the uncertainty associated with temporal judgments. We applied transcranial magnetic stimulation (TMS) to inhibit neuronal processes in the right posterior parietal cortex (PPC) and tested its effects on time discrimination and reproduction tasks. The results show increased certainty for discriminative time judgments after PPC inhibition. They suggest that the right PPC plays an inhibitory role for time perception, possibly by mediating the multisensory integration between temporal stimuli and other quantities. Importantly, this increased judgment certainty had no influence on the degree of temporal underreproduction. We conclude that the systematic underreproduction of time is not caused by uncertainty for temporal judgments.
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Nakayama, Takashin, Kohei Hashimoto, Takeshi Kiriyama, and Keita Hirano. "Optimal imaging conditions for the diagnosis of pleuroperitoneal communication." BMJ Case Reports 12, no. 3 (March 2019): e228940. http://dx.doi.org/10.1136/bcr-2018-228940.
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A 70-year-old woman with end-stage renal disease caused by a polycystic kidney disease developed massive right-sided pleural effusion 10 days after the initiation of peritoneal dialysis (PD). Although pleuroperitoneal communication (PPC) was suspected, computed tomographic peritoneography on usual breath holding did not show leakage. Therefore, we instructed her to strain with maximal breathing, which caused a jet of contrast material to stream from the peritoneal cavity into the right pleural cavity and allowed the identification of the exact site of the diaphragm defect. Following the thoracoscopic closure of the defect, she was discharged without recurrence of hydrothorax on PD. Hydrothorax due to PPC is a rare complication of PD. Notably, numerous previous modalities used to diagnose PPC lack sufficient sensitivity. Thus, an approach to spread the pressure gradient between the peritoneal cavity and the pleural cavity on imaging may improve this insufficient sensitivity.
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Roy, Lucia B., Roland Sparing, Gereon R. Fink, and Maike D. Hesse. "Modulation of attention functions by anodal tDCS on right PPC." Neuropsychologia 74 (July 2015): 96–107. http://dx.doi.org/10.1016/j.neuropsychologia.2015.02.028.
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Vesia, Michael, Jachin A. Monteon, Lauren E. Sergio, and J. D. Crawford. "Hemispheric Asymmetry in Memory-Guided Pointing During Single-Pulse Transcranial Magnetic Stimulation of Human Parietal Cortex." Journal of Neurophysiology 96, no. 6 (December 2006): 3016–27. http://dx.doi.org/10.1152/jn.00411.2006.
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Dorsal posterior parietal cortex (PPC) has been implicated through single-unit recordings, neuroimaging data, and studies of brain-damaged humans in the spatial guidance of reaching and pointing movements. The present study examines the causal effect of single-pulse transcranial magnetic stimulation (TMS) over the left and right dorsal posterior parietal cortex during a memory-guided “reach-to-touch” movement task in six human subjects. Stimulation of the left parietal hemisphere significantly increased endpoint variability, independent of visual field, with no horizontal bias. In contrast, right parietal stimulation did not increase variability, but instead produced a significantly systematic leftward directional shift in pointing (contralateral to stimulation site) in both visual fields. Furthermore, the same lateralized pattern persisted with left-hand movement, suggesting that these aspects of parietal control of pointing movements are spatially fixed. To test whether the right parietal TMS shift occurs in visual or motor coordinates, we trained subjects to point correctly to optically reversed peripheral targets, viewed through a left–right Dove reversing prism. After prism adaptation, the horizontal pointing direction for a given visual target reversed, but the direction of shift during right parietal TMS did not reverse. Taken together, these data suggest that induction of a focal current reveals a hemispheric asymmetry in the early stages of the putative spatial processing in PPC. These results also suggest that a brief TMS pulse modifies the output of the right PPC in motor coordinates downstream from the adapted visuomotor reversal, rather than modifying the upstream visual coordinates of the memory representation.
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Kwinn, Michael J., Julia Coxen, and Jason A. Wolter. "Getting the Last Stop Right: An Analysis of the Fort Campbell Personnel Processing Center." Industrial and Systems Engineering Review 2, no. 1 (July 8, 2014): 1–14. http://dx.doi.org/10.37266/iser.2014v2i1.pp1-14.
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This project proposes to develop an improved system to process Soldiers at the Personnel Processing Center (PPC) located at Fort Campbell, Kentucky. This processing center is the final pre-deployment requirement prior to missions in support of the Global War on Terror. The PPC services the 101st Airborne Division and Fort Campbell’s tenant units and receives a high volume of Soldiers for processing. It is in the interest of Soldiers, their families, and senior leadership to process deploying troops accurately and rapidly. The current system, though functioning and meeting the Army’s needs, has inherent inefficiencies that limit its capacities and ability to maximize utilization.
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Pisella, L., N. Alahyane, A. Blangero, F. Thery, S. Blanc, and D. Pelisson. "Right-hemispheric dominance for visual remapping in humans." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1564 (February 27, 2011): 572–85. http://dx.doi.org/10.1098/rstb.2010.0258.
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We review evidence showing a right-hemispheric dominance for visuo-spatial processing and representation in humans. Accordingly, visual disorganization symptoms (intuitively related to remapping impairments) are observed in both neglect and constructional apraxia. More specifically, we review findings from the intervening saccade paradigm in humans—and present additional original data—which suggest a specific role of the asymmetrical network at the temporo-parietal junction (TPJ) in the right hemisphere in visual remapping: following damage to the right dorsal posterior parietal cortex (PPC) as well as part of the corpus callosum connecting the PPC to the frontal lobes, patient OK in a double-step saccadic task exhibited an impairment when the second saccade had to be directed rightward . This singular and lateralized deficit cannot result solely from the patient's cortical lesion and, therefore, we propose that it is due to his callosal lesion that may specifically interrupt the interhemispheric transfer of information necessary to execute accurate rightward saccades towards a remapped target location. This suggests a specialized right-hemispheric network for visuo-spatial remapping that subsequently transfers target location information to downstream planning regions, which are symmetrically organized.
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Zmigrod, Sharon. "The Role of the Parietal Cortex in Multisensory and Response Integration: Evidence from Transcranial Direct Current Stimulation (tDCS)." Multisensory Research 27, no. 2 (2014): 161–72. http://dx.doi.org/10.1163/22134808-00002449.
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The question of how the brain forms unified representations from multisensory data that are processed in distinct cortical regions is known in the literature as ‘the binding problem’. In the last decade, several studies have suggested possible neural mechanisms and brain regions that might be involved in integration processes. One of the brain regions that is implicated with multisensory perception is the posterior parietal cortex (PPC). Evidence from patients with parietal lesions suggests the involvement of the PPC in coherent perception. Here, we investigated the role of the PPC in multisensory feature integration through experimental manipulation of non-invasive brain stimulation with healthy participants using transcranial direct current stimulation (tDCS). In different sessions, healthy participants received anodal, cathodal, or sham stimulation (2 mA, 20 min) over the right PPC while performing an audio-visual event-file task. The results underscore two interesting observations. Firstly, there was a significant difference in integration effects between features from different modalities in the anodal stimulation compared to sham, suggesting interference of the multisensory integration processes during the brain stimulation. And secondly, after anodal stimulation, the unattended feature became more likely to be integrated with the response feature compared to the other conditions, presumably through an interference of attentional processes. Hence, these findings emphasize the role of the right PPC in multisensory integration. Furthermore, from a methodological perspective, tDCS can be used as an experimental tool by creating a temporary, reversible disruption in cognitive processes in order to explore the mechanisms underlying cognitive functions.
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van Koningsbruggen, Martijn G., Marius V. Peelen, Eilir Davies, and Robert D. Rafal. "Neural Control of Voluntary Eye Closure: A Case Study and an fMRI Investigation of Blinking and Winking." Behavioural Neurology 25, no. 2 (2012): 103–9. http://dx.doi.org/10.1155/2012/282686.
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The current paper describes a rare case of a patient who suffered from unilateral apraxia of eye closure as a result of a bilateral stroke. Interestingly, the patient’s ability to voluntarily close both eyelids (i.e. blinking) was not affected, indicating that different neural mechanisms control each type of eye closure. The stroke caused damage to a large part of the right frontal cortex, including the motor cortex, pre-motor cortex and the frontal eye field (FEF). The lesion in the left hemisphere was restricted to the FEF. In order to further study the neural mechanisms of eye closure, we conducted an fMRI study in a group of neurological healthy subjects. We found that all areas of the oculomotor cortex were activated by both left and right winking, including the FEF, supplementary eye field (SEF), and posterior parietal cortex (PPC). Blinking activated FEF and SEF, but not PPC. Both FEF and PPC were significantly more active during winking than blinking. Together, these results provide evidence for a critical role of the FEF in voluntary unilateral eye closure.
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Carroll, Thomas, Maie El-Sourady, Mohana Karlekar, and Ashley Richeson. "Primary Palliative Care Education Programs: Review and Characterization." American Journal of Hospice and Palliative Medicine® 36, no. 6 (November 18, 2018): 546–49. http://dx.doi.org/10.1177/1049909118809947.
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Background: Primary palliative care (PPC) education programs have arisen in response to the recognition that all clinicians need to have a basic set of knowledge and skills to provide excellent care to all patients. PPC education programs appear to vary widely, making it difficult for potential learners to find the right program to fit their needs. We have cataloged and categorized a snapshot of PPC education programs across the United States to serve as a resource for those seeking training, and for educators interested in starting or optimizing such programs. Methods: Medical and commercial search engines (MSEs and CSEs, respectively) were used to generate a list of PPC education programs in the United States. Programs were contacted to supplement information available online, and then categorized based on intended learner, certification/degree conferred upon completion, and other characteristics. Results: There was little overlap between the PPC education programs found through MSEs and CSEs. Programs found via CSEs varied with respect to intended learners, pedagogy, content, and cost. Among the minority of programs that confer a certification/degree upon completion, there is no consensus as to what these signify. Conclusions: The wide variety of PPC education programs is both a challenge to and strength of the field. We hope that this report will serve as a call to develop a standard PPC education taxonomy to help define essential components of all PPC programs, while also leaving sufficient room for programs to serve the unique needs of their local learners and patient populations.
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Gonzalez, Alex, J. Benjamin Hutchinson, Melina R. Uncapher, Janice Chen, Karen F. LaRocque, Brett L. Foster, Vinitha Rangarajan, Josef Parvizi, and Anthony D. Wagner. "Electrocorticography reveals the temporal dynamics of posterior parietal cortical activity during recognition memory decisions." Proceedings of the National Academy of Sciences 112, no. 35 (August 17, 2015): 11066–71. http://dx.doi.org/10.1073/pnas.1510749112.
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Theories of the neurobiology of episodic memory predominantly focus on the contributions of medial temporal lobe structures, based on extensive lesion, electrophysiological, and imaging evidence. Against this backdrop, functional neuroimaging data have unexpectedly implicated left posterior parietal cortex (PPC) in episodic retrieval, revealing distinct activation patterns in PPC subregions as humans make memory-related decisions. To date, theorizing about the functional contributions of PPC has been hampered by the absence of information about the temporal dynamics of PPC activity as retrieval unfolds. Here, we leveraged electrocorticography to examine the temporal profile of high gamma power (HGP) in dorsal PPC subregions as participants made old/new recognition memory decisions. A double dissociation in memory-related HGP was observed, with activity in left intraparietal sulcus (IPS) and left superior parietal lobule (SPL) differing in time and sign for recognized old items (Hits) and correctly rejected novel items (CRs). Specifically, HGP in left IPS increased for Hits 300–700 ms poststimulus onset, and decayed to baseline ∼200 ms preresponse. By contrast, HGP in left SPL increased for CRs early after stimulus onset (200−300 ms) and late in the memory decision (from 700 ms to response). These memory-related effects were unique to left PPC, as they were not observed in right PPC. Finally, memory-related HGP in left IPS and SPL was sufficiently reliable to enable brain-based decoding of the participant’s memory state at the single-trial level, using multivariate pattern classification. Collectively, these data provide insights into left PPC temporal dynamics as humans make recognition memory decisions.
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Cazzoli, Dario, René M. Müri, Christopher Kennard, and Clive R. Rosenthal. "The Role of the Right Posterior Parietal Cortex in Letter Migration between Words." Journal of Cognitive Neuroscience 27, no. 2 (February 2015): 377–86. http://dx.doi.org/10.1162/jocn_a_00713.
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When briefly presented with pairs of words, skilled readers can sometimes report words with migrated letters (e.g., they report hunt when presented with the words hint and hurt). This and other letter migration phenomena have been often used to investigate factors that influence reading such as letter position coding. However, the neural basis of letter migration is poorly understood. Previous evidence has implicated the right posterior parietal cortex (PPC) in processing visuospatial attributes and lexical properties during word reading. The aim of this study was to assess this putative role by combining an inhibitory TMS protocol with a letter migration paradigm, which was designed to examine the contributions of visuospatial attributes and lexical factors. Temporary interference with the right PPC led to three specific effects on letter migration. First, the number of letter migrations was significantly increased only in the group with active stimulation (vs. a sham stimulation group or a control group without stimulation), and there was no significant effect on other error types. Second, this effect occurred only when letter migration could result in a meaningful word (migration vs. control context). Third, the effect of active stimulation on the number of letter migrations was lateralized to target words presented on the left. Our study thus demonstrates that the right PPC plays a specific and causal role in the phenomenon of letter migration. The nature of this role cannot be explained solely in terms of visuospatial attention, rather it involves an interplay between visuospatial attentional and word reading-specific factors.
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Bolognini, Nadia, Luca Zigiotto, Maíra Izzadora Souza Carneiro, and Giuseppe Vallar. "“How Did I Make It?”: Uncertainty about Own Motor Performance after Inhibition of the Premotor Cortex." Journal of Cognitive Neuroscience 28, no. 7 (July 2016): 1052–61. http://dx.doi.org/10.1162/jocn_a_00950.
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Optimal motor performance requires the monitoring of sensorimotor input to ensure that the motor output matches current intentions. The brain is thought to be equipped with a “comparator” system, which monitors and detects the congruence between intended and actual movement; results of such a comparison can reach awareness. This study explored in healthy participants whether the cathodal transcranial direct current stimulation (tDCS) of the right premotor cortex (PM) and right posterior parietal cortex (PPC) can disrupt performance monitoring in a skilled motor task. Before and after tDCS, participants underwent a two-digit sequence motor task; in post-tDCS session, single-pulse TMS (sTMS) was applied to the right motor cortex, contralateral to the performing hand, with the aim of interfering with motor execution. Then, participants rated on a five-item questionnaire their performance at the motor task. Cathodal tDCS of PM (but not sham or PPC tDCS) impaired the participants' ability to evaluate their motor performance reliably, making them unconfident about their judgments. Congruently with the worsened motor performance induced by sTMS, participants reported to have committed more errors after sham and PPC tDCS; such a correlation was not significant after PM tDCS. In line with current computational and neuropsychological models of motor control and awareness, the present results show that a mechanism in the PM monitors and compares intended versus actual movements, evaluating their congruence. Cathodal tDCS of the PM impairs the activity of such a “comparator,” disrupting self-confidence about own motor performance.
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Kirimoto, Hikari, Tatsunori Watanabe, Nami Kubo, Shota Date, Toru Sunagawa, Tatsuya Mima, Katsuya Ogata, Hisato Nakazono, Shozo Tobimatsu, and Antonio Oliviero. "Influence of Static Magnetic Field Stimulation on the Accuracy of Tachystoscopically Presented Line Bisection." Brain Sciences 10, no. 12 (December 18, 2020): 1006. http://dx.doi.org/10.3390/brainsci10121006.
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Transcranial static magnetic stimulation (tSMS) has been known to reduce human cortical excitability. Here, we investigated whether tSMS would modulate visuo-spatial cognition in healthy humans. Subjects performed a visuo-spatial task requiring judgements about the symmetry of pre-bisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 150 ms on a computer monitor. Task performance was examined before, immediately after, and 10 min after tSMS/sham stimulation of 20 min over the posterior parietal cortex (PPC: P4 from the international 10–20 system) or superior temporal gyrus (STG: C6). Nine out of 16 subjects misjudged pre-bisected lines by consistently underestimating the length of the right-side segment (judging lines to be exactly pre-bisected when the transector was located to the left of the midpoint, or judging the left-side segment to be longer when the transector was located at the midpoint). In these subjects showing a leftward bias, tSMS over the right STG reduced the magnitude of the leftward bias. This did not occur with tSMS over the right PPC or sham stimulation. In the remaining right-biased subjects, no intervention effect was observed with any stimulation. Our findings indicate that application of tSMS over the right STG modulates visuo-spatial cognition in healthy adults.
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Chalah, Moussa A., Naji Riachi, Rechdi Ahdab, Alaa Mhalla, Mohamed Abdellaoui, Alain Créange, Jean-Pascal Lefaucheur, and Samar S. Ayache. "Effects of left DLPFC versus right PPC tDCS on multiple sclerosis fatigue." Journal of the Neurological Sciences 372 (January 2017): 131–37. http://dx.doi.org/10.1016/j.jns.2016.11.015.
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Ogawa, Kenji, and Toshio Inui. "Reference Frame of Human Medial Intraparietal Cortex in Visually Guided Movements." Journal of Cognitive Neuroscience 24, no. 1 (January 2012): 171–82. http://dx.doi.org/10.1162/jocn_a_00132.
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Visually guided reaching involves the transformation of a spatial position of a target into a body-centered reference frame. Although involvement of the posterior parietal cortex (PPC) has been proposed in this visuomotor transformation, it is unclear whether human PPC uses visual or body-centered coordinates in visually guided movements. We used a delayed visually guided reaching task, together with an fMRI multivoxel pattern analysis, to reveal the reference frame used in the human PPC. In experiments, a target was first presented either to the left or to the right of a fixation point. After a delay period, subjects moved a cursor to the position where the target had previously been displayed using either a normal or a left–right reversed mouse. The activation patterns of normal sessions were first used to train the classifier to predict movement directions. The activity patterns of the reversed sessions were then used as inputs to the decoder to test whether predicted directions correspond to actual movement directions in either visual or body-centered coordinates. When the target was presented before actual movement, the predicted direction in the medial intraparietal cortex was congruent with the actual movement in the body-centered coordinates, although the averaged signal intensities were not significantly different between two movement directions. Our results indicate that the human medial intraparietal cortex uses body-centered coordinates to encode target position or movement directions, which are crucial for visually guided movements.
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Abwainy, Ala'a, Fawzi Babiker, Saghir Akhtar, and Ibrahim F. Benter. "Endogenous angiotensin-(1-7)/Mas receptor/NO pathway mediates the cardioprotective effects of pacing postconditioning." American Journal of Physiology-Heart and Circulatory Physiology 310, no. 1 (January 1, 2016): H104—H112. http://dx.doi.org/10.1152/ajpheart.00121.2015.
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The aim of the present study was to investigate the role of the ANG-(1–7) receptor (Mas) and nitric oxide (NO) in pacing postconditiong (PPC)-mediated cardioprotection against ischemia-reperfusion injury. Cardiac contractility and hemodynamics were assessed using a modified Langendorff system, cardiac damage was assessed by measuring infarct size and creatinine kinase levels, and levels of phosphorylated and total endothelial NO synthase (eNOS) were determined by Western blot analysis. Isolated hearts were subjected to 30 min of regional ischemia, produced by fixed position ligation of the left anterior descending coronary artery, followed by 30 min of reperfusion ( n = 6). Hearts were also subjected to PPC (three cycles of 30 s of left ventricular pacing alternated with 30 s of right atrial pacing) and/or treated during reperfusion with ANG-(1–7), NG-nitro-l-arginine methyl ester, or the Mas antagonist (d-Ala7)-ANG I/II (1–7). The PPC-mediated improvement in cardiac contractility and hemodyanamics, cardiac damage, and eNOS phosphorylation were significantly attenuated upon treatment with (d-Ala7)-ANG I/II (1–7) or NG-nitro-l-arginine methyl ester. Treatment with ANG-(1–7) improved cardiac function and reduced infarct size and creatinine kinase levels; however, the effects of ANG-(1–7) were not additive with PPC. In conclusion, these data provide novel insights into the cardioprotective mechanisms of PPC in that they involve the Mas receptor and eNOS and further suggest a potential therapeutic role for ANG-(1–7) in cardiac ischemic injury.
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Tozahro, Ni'mah, and Afrizal Nursin. "LAST PLANNER SYSTEM (LPS) IMPLEMENTATION ON JAKARTA-CIKAMPEK II ELEVATED TOLL ROAD PROJECT." Applied Research on Civil Engineering and Environment (ARCEE) 2, no. 01 (August 27, 2020): 17–22. http://dx.doi.org/10.32722/arcee.v2i01.2859.
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In construction industry, its implementation of the construction has its own constraints. A good management or project management system is needed to minimize the risk of these constraints. The latest project management concept that has proven more effective and efficient is Last Planner System method. This study aims to investigate how the implementation of Last Planner System works on Jakarta-Cikampek II Elevated Toll Road Project. With the evaluation of weekly job evaluations using PPC (Percent Plan Completed) and Pareto Variance Constraint analysis, the constraint issues of this project will be identified. Then they are followed up to find the right solution in handling the constraints. The research method is done by conducting literature study, problem formulation, followed by implementing LPS method, which is through work flow control such as phase and pull plan, lookahead plan, constrain analysis, daily huddles, PPC (Percent Plan Completed) calculation, Pareto Chart analysis with data variation of issues that have been obtained. The results show that the average PPC weekly project is 83.04% and the most influential reason that must be concerned its priority is submittals.
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Ogawa, Kenji, and Toshio Inui. "Lateralization of the Posterior Parietal Cortex for Internal Monitoring of Self- versus Externally Generated Movements." Journal of Cognitive Neuroscience 19, no. 11 (November 2007): 1827–35. http://dx.doi.org/10.1162/jocn.2007.19.11.1827.
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Internal monitoring or state estimation of movements is essential for human motor control to compensate for inherent delays and noise in sensorimotor loops. Two types of internal estimation of movements exist: self-generated movements, and externally generated movements. We used functional magnetic resonance imaging to investigate differences in brain activity for internal monitoring of self- versus externally generated movements during visual occlusion. Participants tracked a sinusoidally moving target with a mouse cursor. On some trials, vision of either target (externally generated) or cursor (self-generated) movement was transiently occluded, during which subjects continued tracking by estimating current position of either the invisible target or cursor on screen. Analysis revealed that both occlusion conditions were associated with increased activity in the presupplementary motor area and decreased activity in the right lateral occipital cortex compared to a control condition with no occlusion. Moreover, the right and left posterior parietal cortex (PPC) showed greater activation during occlusion of target and cursor movements, respectively. This study suggests lateralization of the PPC for internal monitoring of internally versus externally generated movements, fully consistent with previously reported clinical findings.
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Yang, Jie. "Measurement and Feature Analysis of Plantar Pressure Center in Athletes under Different Exercise Modes." Instrumentation Mesure Métrologie 19, no. 5 (November 15, 2020): 399–403. http://dx.doi.org/10.18280/i2m.190511.
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Walking and running, two essential exercises in daily training for athletes, are major causes to foot injuries. The plantar pressure center (PPC) can accurately reflect the gait process, and effectively measure the function of foot. This paper measures the PPC trajectories of a total of 45 athletes during the support period of walking and running, and analyzes their regularities under different exercise modes. The time percentage of PPC trajectory and foot progression angle were selected as the main observation indices. The support period under each exercise mode was divided into four phases: the initial contact phase (ICP), the forefoot contact phase (FFCP), the foot flat phase (FFP), and the forefoot push off phase (FFPOP). The statistical analysis shows that: Under the running mode, the time of the heel landing on the ground and the relative load on the heel decrease with the growing speed. Under the same exercise mode, the left and right feet differ slightly in the PPC trajectory; the foot progression angle peaks in FFPOP and minimizes in FFP. In ICP and FFPOP, the foot progression angle under running is smaller than that under walking; in FFP and FFCP, the foot progression angle under running is larger than that under walking. The research results provide the scientific basis for the reasonable arrangement of athlete training.
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García-Quintero, Ximena, Angélica Claros-Hulbert, María Elena Tello-Cajiao, Jhon Edwar Bolaños-Lopez, María Isabel Cuervo-Suárez, Martha Gabriela García Durán, Wendy Gómez-García, Michael McNeil, and Justin N. Baker. "Using EmPalPed—An Educational Toolkit on Essential Messages in Palliative Care and Pain Management in Children—As a Strategy to Promote Pediatric Palliative Care." Children 9, no. 6 (June 6, 2022): 838. http://dx.doi.org/10.3390/children9060838.
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Background: Most children needing palliative care (PC) live in low- and middle-income countries. In Colombia, pediatric palliative care (PPC) knowledge among healthcare professionals (HCPs) is lacking as PPC is not included in the educational curricula of healthcare programs. Therefore, specific training that improves knowledge of HCPs and access to PC for children and their families is needed. To address this gap, we organized and conducted the Essential Messages in Palliative Care and Pain Management in Children (EmPalPed), an educational toolkit to increase awareness and promote essential knowledge in PPC for low- and middle-income countries. Methodology: The EmPalPed toolkit consisted of a 5-h virtual workshop with small working groups of HCPs caring for children with life-threatening conditions such as cancer. The toolkit was organized along five key domains: (1) PC as it relates to the concept of quality of life (QoL), (2) effective communication, (3) addressing pain management as a top priority, (4) providing end-of-life care, and (5) access to high-quality PC as a fundamental human right. The workshop activities included different educational strategies and tools (e.g., a pocket guide for pain assessment and management, a PPC booklet, a quick guide for communicating bad news, role playing, and discussions of clinical cases). Results: A total of 145 HCPs from 22 centers were trained. The post-test analysis for HCPs showed that attitude and knowledge about communication (p < 0.001), pain assessment (p < 0.001), first-line opioid of choice in children (p < 0.001), and palliative sedation (p < 0.001) had positive and statistically significant changes from the pre-test analysis. Discussion: This study supported the notion that the EmPalPed educational toolkit is an effective mechanism for raising awareness regarding PPC as well as providing training in many of the key aspects of PPC. The EmPalPed training approach should be studied beyond this setting, and the impact should be measured longitudinally.
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Serino, Andrea, Elisa Canzoneri, and Alessio Avenanti. "Fronto-parietal Areas Necessary for a Multisensory Representation of Peripersonal Space in Humans: An rTMS Study." Journal of Cognitive Neuroscience 23, no. 10 (October 2011): 2956–67. http://dx.doi.org/10.1162/jocn_a_00006.
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A network of brain regions including the ventral premotor cortex (vPMc) and the posterior parietal cortex (PPc) is consistently recruited during processing of multisensory stimuli within peripersonal space (PPS). However, to date, information on the causal role of these fronto-parietal areas in multisensory PPS representation is lacking. Using low-frequency repetitive TMS (rTMS; 1 Hz), we induced transient virtual lesions to the left vPMc, PPc, and visual cortex (V1, control site) and tested whether rTMS affected audio–tactile interaction in the PPS around the hand. Subjects performed a timed response task to a tactile stimulus on their right (contralateral to rTMS) hand while concurrent task-irrelevant sounds were presented either close to the hand or 1 m far from the hand. When no rTMS was delivered, a sound close to the hand reduced RT-to-tactile targets as compared with when a far sound was presented. This space-dependent, auditory modulation of tactile perception was specific to a hand-centered reference frame. Such a specific form of multisensory interaction near the hand can be taken as a behavioral hallmark of PPS representation. Crucially, virtual lesions to vPMc and PPc, but not to V1, eliminated the speeding effect due to near sounds, showing a disruption of audio–tactile interactions around the hand. These findings indicate that multisensory interaction around the hand depends on the functions of vPMc and PPc, thus pointing to the necessity of this human fronto-parietal network in multisensory representation of PPS.
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de Graaf, Tom A., Alard Roebroeck, Rainer Goebel, and Alexander T. Sack. "Brain Network Dynamics Underlying Visuospatial Judgment: An fMRI Connectivity Study." Journal of Cognitive Neuroscience 22, no. 9 (September 2010): 2012–26. http://dx.doi.org/10.1162/jocn.2009.21345.
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Previous functional imaging research has consistently indicated involvement of bilateral fronto-parietal networks during the execution of visuospatial tasks. Studies with TMS have suggested that the right hemispheric network, but not the left, is functionally relevant for visuospatial judgments. However, very little is still known about the interactions within these fronto-parietal networks underlying visuospatial processing. In the current study, we investigated task modulation of functional connectivity (instantaneous correlations of regional time courses), and task-specific effective connectivity (direction of influences), within the right fronto-parietal network activated during visuospatial judgments. Ten healthy volunteers performed a behaviorally controlled visuospatial judgment task (ANGLE) or a control task (COLOR) in an fMRI experiment. Visuospatial task-specific activations were found in posterior parietal cortex (PPC) and middle/inferior frontal gyrus (MFG). Functional connectivity within this network was task-modulated, with significantly higher connectivity between PPC and MFG during ANGLE than during COLOR. Effective connectivity analysis for directed influence revealed that visuospatial task-specific projections within this network were predominantly in a frontal-to-parietal direction. Moreover, ANGLE-specific influences from thalamic nuclei to PPC were identified. Exploratory effective connectivity analysis revealed that closely neighboring clusters, within visuospatial regions, were differentially involved in the network. These neighboring clusters had opposite effective connectivity patterns to other nodes of the fronto-parietal network. Our data thus reveal that visuospatial judgments are supported by massive fronto-parietal backprojections, thalamo-parietal influence, and multiple stages, or loops, of information flow within the visuospatial network. We speculate on possible functional contributions of the various network nodes and informational loops in a neurocognitive model.
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Vesia, Michael, Xiaogang Yan, Denise Y. Henriques, Lauren E. Sergio, and J. D. Crawford. "Transcranial Magnetic Stimulation Over Human Dorsal–Lateral Posterior Parietal Cortex Disrupts Integration of Hand Position Signals Into the Reach Plan." Journal of Neurophysiology 100, no. 4 (October 2008): 2005–14. http://dx.doi.org/10.1152/jn.90519.2008.
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Posterior parietal cortex (PPC) has been implicated in the integration of visual and proprioceptive information for the planning of action. We previously reported that single-pulse transcranial magnetic stimulation (TMS) over dorsal–lateral PPC perturbs the early stages of spatial processing for memory-guided reaching. However, our data did not distinguish whether TMS disrupted the reach goal or the internal estimate of initial hand position needed to calculate the reach vector. To test between these hypotheses, we investigated reaching in six healthy humans during left and right parietal TMS while varying visual feedback of the movement. We reasoned that if TMS were disrupting the internal representation of hand position, visual feedback from the hand might still recalibrate this signal. We tested four viewing conditions: 1) final vision of hand position; 2) full vision of hand position; 3) initial and final vision of hand position; and 4) middle and final vision of hand position. During the final vision condition, left parietal stimulation significantly increased endpoint variability, whereas right parietal stimulation produced a significant leftward shift in both visual fields. However, these errors significantly decreased with visual feedback of the hand during both planning and control stages of the reach movement. These new findings demonstrate that 1) visual feedback of hand position during the planning and early execution of the reach can recalibrate the perturbed signal and, importantly, and 2) TMS over dorsal–lateral PPC does not disrupt the internal representation of the visual goal, but rather the reach vector, or more likely the sense of initial hand position that is used to calculate this vector.
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McMackin, Roisin, Stefan Dukic, Emmet Costello, Marta Pinto-Grau, Antonio Fasano, Teresa Buxo, Mark Heverin, et al. "Localization of Brain Networks Engaged by the Sustained Attention to Response Task Provides Quantitative Markers of Executive Impairment in Amyotrophic Lateral Sclerosis." Cerebral Cortex 30, no. 9 (April 21, 2020): 4834–46. http://dx.doi.org/10.1093/cercor/bhaa076.
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Abstract Objective: To identify cortical regions engaged during the sustained attention to response task (SART) and characterize changes in their activity associated with the neurodegenerative condition amyotrophic lateral sclerosis (ALS). Methods: High-density electroencephalography (EEG) was recorded from 33 controls and 23 ALS patients during a SART paradigm. Differences in associated event-related potential peaks were measured for Go and NoGo trials. Sources active during these peaks were localized, and ALS-associated differences were quantified. Results: Go and NoGo N2 and P3 peak sources were localized to the left primary motor cortex, bilateral dorsolateral prefrontal cortex (DLPFC), and lateral posterior parietal cortex (PPC). NoGo trials evoked greater bilateral medial PPC activity during N2 and lesser left insular, PPC and DLPFC activity during P3. Widespread cortical hyperactivity was identified in ALS during P3. Changes in the inferior parietal lobule and insular activity provided very good discrimination (AUROC > 0.75) between patients and controls. Activation of the right precuneus during P3 related to greater executive function in ALS, indicative of a compensatory role. Interpretation: The SART engages numerous frontal and parietal cortical structures. SART–EEG measures correlate with specific cognitive impairments that can be localized to specific structures, aiding in differential diagnosis.
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Giovanello, Kelly S., Felipe De Brigard, Jaclyn Hennessey Ford, Daniel I. Kaufer, James R. Burke, Jeffrey N. Browndyke, and Kathleen A. Welsh-Bohmer. "Event-Related Functional Magnetic Resonance Imaging Changes during Relational Retrieval in Normal Aging and Amnestic Mild Cognitive Impairment." Journal of the International Neuropsychological Society 18, no. 5 (May 24, 2012): 886–97. http://dx.doi.org/10.1017/s1355617712000689.
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AbstractThe earliest cognitive deficits observed in amnestic mild cognitive impairment (aMCI) appear to center on memory tasks that require relational memory (RM), the ability to link or integrate unrelated pieces of information. RM impairments in aMCI likely reflect neural changes in the medial temporal lobe (MTL) and posterior parietal cortex (PPC). We tested the hypothesis that individuals with aMCI, as compared to cognitively normal (CN) controls, would recruit neural regions outside of the MTL and PPC to support relational memory. To this end, we directly compared the neural underpinnings of successful relational retrieval in aMCI and CN groups, using event-related functional magnetic resonance imaging (fMRI), holding constant the stimuli and encoding task. The fMRI data showed that the CN, compared to the aMCI, group activated left precuneus, left angular gyrus, right posterior cingulate, and right parahippocampal cortex during relational retrieval, while the aMCI group, relative to the CN group, activated superior temporal gyrus and supramarginal gyrus for this comparison. Such findings indicate an early shift in the functional neural architecture of relational retrieval in aMCI, and may prove useful in future studies aimed at capitalizing on functionally intact neural regions as targets for treatment and slowing of the disease course. (JINS, 2012, 18, 1–12)
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Schintu, Selene, Michael Freedberg, Stephen J. Gotts, Catherine A. Cunningham, Zaynah M. Alam, Sarah Shomstein, and Eric M. Wassermann. "Prism Adaptation Modulates Connectivity of the Intraparietal Sulcus with Multiple Brain Networks." Cerebral Cortex 30, no. 9 (April 21, 2020): 4747–58. http://dx.doi.org/10.1093/cercor/bhaa032.
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Abstract Prism adaptation (PA) alters spatial cognition according to the direction of visual displacement by temporarily modifying sensorimotor mapping. Right-shifting prisms (right PA) improve neglect of left visual field in patients, possibly by decreasing activity in the left hemisphere and increasing it in the right. Left PA shifts attention rightward in healthy individuals by an opposite mechanism. However, functional imaging studies of PA are inconsistent, perhaps because of differing activation tasks. We measured resting-state functional connectivity (RSFC) in healthy individuals before and after PA. When contrasted, right versus left PA decreased RSFC in the spatial navigation network defined by the right posterior parietal cortex (PPC), hippocampus, and cerebellum. Within-PA-direction comparisons showed that right PA increased RSFC in subregions of the PPCs and between the PPCs and the right middle frontal gyrus and left PA decreased RSFC between these regions. Both right and left PA decreased RSFC between the PPCs and bilateral temporal areas. In summary, right PA increases connectivity in the right frontoparietal network and left PA produces essentially opposite effects. Furthermore, right, compared with left, PA modulates RSFC in the right hemisphere navigation network.
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Chalah, M. A., A. Créange, J. P. Lefaucheur, and S. S. Ayache. "P071 tDCS effects over the left DLPFC versus the right PPC in multiple sclerosis fatigue." Clinical Neurophysiology 128, no. 3 (March 2017): e39-e40. http://dx.doi.org/10.1016/j.clinph.2016.10.196.
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Yordanova, Bilyana B., Lyudmil D. Krastev, and Nikolay Iv Ivantchev. "FACTORIAL STRUCTURE AND PSYCHOMETRIC PROPERTIES OF ATTITUDES TO ECONOMIC DEPENDENCE OR INDEPENDENCE IN A SAMPLE OF BULGARIAN CITIZENS." Problems of Psychology in the 21st Century 8, no. 1 (April 20, 2014): 26–35. http://dx.doi.org/10.33225/ppc/14.08.26.
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Rising interactions of asymmetrical exchange as a consequence of unequal access to economic resources create status differences between people. In that way some people are provided with authority benefits while the others are in dependent position. The situation of economic dependence arises when the object is seen by the subject like a unique source for personal needs gratification. The degree of dependence is right proportional to the object’s subjective significance for a particular person, group, organization, etc. This statement provokes the problem of dependence as a psychological phenomenon that defines personal behavior and the character of interactions in respect of actual needs gratification. Contrary, economic independence is associated with these resources that are the result of personal incomes, property, and capital dividends. Key words: attitudes, dependence, independence, psychometric properties, structure.
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Gaviria Morales, Elizabeth, Marco Guidi, Tomas Peterka, Andrea Rabufetti, Roland Blum, and Carlo Mainetti. "Primary Cutaneous Cryptococcosis due to Cryptococcus neoformans in an Immunocompetent Host Treated with Itraconazole and Drainage: Case Report and Review of the Literature." Case Reports in Dermatology 13, no. 1 (February 4, 2021): 89–97. http://dx.doi.org/10.1159/000512289.
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<i>Cryptococcus neoformans</i> is an opportunistic germ, usually causing infections in immunocompromised patients. The main sources of infection with <i>C. neoformans</i> are excrement from birds, decomposing wood, fruit, and vegetables. Primary cutaneous cryptococcosis (PCC) is a clinical entity, differing from secondary cutaneous cryptococcosis and systematic infection. We report the case of an immunocompetent 60-year-old woman with PCC due to <i>C. neoformans</i> in her right thumb. She reported an accidental injury caused by a rose thorn while she was gardening. Clinical examination showed the presence of an erythematous ulcerated nodule with elevated borders, suppuration, and central necrosis. Skin histology examination showed cutaneous and subcutaneous fibrinoid necrosis with bleeding, abscess, neutrophil-rich cellular infiltration, and the presence of PAS-, Grocott- and mucin-positive spores. The mycological culture showed milky and creamy colonies of <i>C. neoformans</i> after 3 days. As there was no previous history of pulmonary cryptococcosis, we diagnosed PPC. We treated the patient surgically with accurate debridement of nonvital tissues in the right thumb. In addition, we started itraconazole treatment 100 mg twice daily for 6 months, which led to rapid clinical improvement without relapse. PCC is a rare infection that can present with quite unspecific clinical pictures including acneiform lesions, purpura, vesicles, nodules, abscesses, ulcers, granulomas, pustules, draining sinuses, and cellulitis. Prolonged systemic antifungal therapy is necessary in order to get a healing result without relapse. We summarize all the cases of PCC in immunocompetent patients published so far in the literature.
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Kumar, Adarsh, Gaurav Panthi, Rechu Divakar, and Pratik K. Mutha. "Mechanistic determinants of effector-independent motor memory encoding." Proceedings of the National Academy of Sciences 117, no. 29 (July 9, 2020): 17338–47. http://dx.doi.org/10.1073/pnas.2001179117.
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Coordinated, purposeful movements learned with one effector generalize to another effector, a finding that has important implications for tool use, sports, performing arts, and rehabilitation. This occurs because the motor memory acquired through learning comprises representations that are effector-independent. Despite knowing this for decades, the neural mechanisms and substrates that are causally associated with the encoding of effector-independent motor memories remain poorly understood. Here we exploit intereffector generalization, the behavioral signature of effector-independent representations, to address this crucial gap. We first show in healthy human participants that postlearning generalization across effectors is principally predicted by the level of an implicit mechanism that evolves gradually during learning to produce a temporally stable memory. We then demonstrate that interfering with left but not right posterior parietal cortex (PPC) using high-definition cathodal transcranial direct current stimulation impedes learning mediated by this mechanism, thus potentially preventing the encoding of effector-independent memory components. We confirm this in our final experiment in which we show that disrupting left PPC but not primary motor cortex after learning has been allowed to occur blocks intereffector generalization. Collectively, our results reveal the key mechanism that encodes an effector-independent memory trace and uncover a central role for the PPC in its representation. The encoding of such motor memory components outside primary sensorimotor regions likely underlies a parsimonious neural organization that enables more efficient movement planning in the brain, independent of the effector used to act.
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Buneo, Christopher A., and Richard A. Andersen. "Integration of target and hand position signals in the posterior parietal cortex: effects of workspace and hand vision." Journal of Neurophysiology 108, no. 1 (July 1, 2012): 187–99. http://dx.doi.org/10.1152/jn.00137.2011.
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Previous findings suggest the posterior parietal cortex (PPC) contributes to arm movement planning by transforming target and limb position signals into a desired reach vector. However, the neural mechanisms underlying this transformation remain unclear. In the present study we examined the responses of 109 PPC neurons as movements were planned and executed to visual targets presented over a large portion of the reaching workspace. In contrast to previous studies, movements were made without concurrent visual and somatic cues about the starting position of the hand. For comparison, a subset of neurons was also examined with concurrent visual and somatic hand position cues. We found that single cells integrated target and limb position information in a very consistent manner across the reaching workspace. Approximately two-thirds of the neurons with significantly tuned activity (42/61 and 30/46 for left and right workspaces, respectively) coded targets and initial hand positions separably, indicating no hand-centered encoding, whereas the remaining one-third coded targets and hand positions inseparably, in a manner more consistent with the influence of hand-centered coordinates. The responses of both types of neurons were largely invariant with respect to the presence or absence of visual hand position cues, suggesting their corresponding coordinate frames and gain effects were unaffected by cue integration. The results suggest that the PPC uses a consistent scheme for computing reach vectors in different parts of the workspace that is robust to changes in the availability of somatic and visual cues about hand position.
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Albanese, M. C., E. G. Duerden, V. Bohotin, P. Rainville, and G. H. Duncan. "Differential Effects of Cognitive Demand on Human Cortical Activation Associated With Vibrotactile Stimulation." Journal of Neurophysiology 102, no. 3 (September 2009): 1623–31. http://dx.doi.org/10.1152/jn.91295.2008.
Full textAbstract:
This event-related functional MRI study examines the neural correlates of vibrotactile sensation within the context of different psychophysical demands. Nine subjects received vibrotactile stimuli on the right volar forearm during detection, localization, and passive tasks. In the detection task, subjects indicated the offset (end) of each stimulus by pressing a response key with their left hand. In the localization task, subjects identified the location of the stimulus (“distal?” or “proximal?”) by pressing the appropriate response key 4 s after the end of the stimulus. In the passive task, subjects received the same vibrotactile stimuli, but no response was required. Analysis of stimulus-evoked activity compared with the resting baseline period revealed significant bilateral secondary somatosensory cortex activation for all three tasks. However, only in the offset-detection and localization tasks was stimulus-evoked activation observed in other expected areas of tactile processing, such as contralateral primary somatosensory cortex neighboring the posterior parietal cortex (SI/PPC) and in bilateral anterior insular cortex (aIC). During the localization task, we identified vibrotactile-evoked activation in the right aIC, which was maintained after the termination of the stimulus. Results suggest that vibrotactile-related activation within SI/PPC and aIC is enhanced by the increased levels of attention and cognitive demands required by the detection and localization tasks. Activation of aIC not only during vibrotactile stimulation, but also during the poststimulus delay in the localization trials, is consistent with the growing literature linking this area with the perception and short-term memory of tactile information.
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Manobanda-Narvaez, J. S., Y. E. Calizaya-Milla, and J. Saintila. "Chemical composition and acceptability of peanut paste (Arachis hypogaea L.) based on proteins isolated from legumes." Food Research 6, no. 2 (April 17, 2022): 345–53. http://dx.doi.org/10.26656/fr.2017.6(2).251.
Full textAbstract:
Protein-calorie malnutrition represents one of the public health problems in the world. A total of three mixtures of peanut paste were formulated with legume protein isolate at 5% each, peanut paste and lentil protein isolate (PPL), peanut paste and pea protein isolate (PPP), and peanut paste and chickpea protein isolate (PPC). To evaluate the composition of the mixtures; moisture, crude protein, total fat, ash, crude fibre, and carbohydrates were determined according to the Association of Official Analytical Chemists, Official methods of analysis (AOAC). Acceptability was assessed using the Just-About-Right scale. A hierarchical cluster analysis was performed. It was found that PPP reported higher values in protein (30.65 g) and fat (48.25 g). The scores were significantly higher for the PPP and PPC mixtures for the attributes texture (p<0.001), flavour (p<0.05), and smell (p<0.001). The general acceptability of the mixtures received scores >8.7. It was found that the addition of legume protein isolated at a level of 5% increased the nutritional value of the peanut paste. In addition, it obtained good acceptability for sensory attributes.
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Pecchinenda, Anna, Francesca De Luca, Bianca Monachesi, Manuel Petrucci, Mariella Pazzaglia, Fabrizio Doricchi, and Michal Lavidor. "Contributions of the Right Prefrontal and Parietal Cortices to the Attentional Blink: A tDCS Study." Symmetry 13, no. 7 (July 6, 2021): 1208. http://dx.doi.org/10.3390/sym13071208.
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The AB refers to the performance impairment that occurs when visual selective attention is overloaded through the very rapid succession of two targets (T1 and T2) among distractors by using the rapid serial visual presentation task (RSVP). Under these conditions, performance is typically impaired when T2 is presented within 200–500 ms from T1 (AB). Based on neuroimaging studies suggesting a role of top-down attention and working memory brain hubs in the AB, here we potentiated via anodal or sham tDCS the activity of the right DLPFC (F4) and of the right PPC (P4) during an AB task. The findings showed that anodal tDCS over the F4 and over P4 had similar effects on the AB. Importantly, potentiating the activity of the right frontoparietal network via anodal tDCS only benefitted poor performers, reducing the AB, whereas in good performers it accentuated the AB. The contribution of the present findings is twofold: it shows both top-down and bottom-up contributions of the right frontoparietal network in the AB, and it indicates that there is an optimal level of excitability of this network, resulting from the individual level of activation and the intensity of current stimulation.
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Muri, R. M., A. I. Vermersch, S. Rivaud, B. Gaymard, and C. Pierrot-Deseilligny. "Effects of single-pulse transcranial magnetic stimulation over the prefrontal and posterior parietal cortices during memory-guided saccades in humans." Journal of Neurophysiology 76, no. 3 (September 1, 1996): 2102–6. http://dx.doi.org/10.1152/jn.1996.76.3.2102.
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1. We used single-pulse transcranial magnetic stimulation (TMS) to explore the temporal organization of the cortical control of memory-guided saccades in eight humans. The posterior parietal cortex (PPC) or the dorsolateral prefrontal cortex (DPFC), which are both known to be involved in the control of such saccades, were stimulated on the right side at different time intervals after the presentation of a flashed lateral visual target. The memorization delay was 2,000 ms. Single pulses were applied at 160, 260, and 360 ms after the flashed target, during the period of 700 and 1,500 ms, and finally at 2,100 ms, i.e., 100 ms after the extinguishing of the central fixation point. The effects of TMS were evaluated by calculating the percentage of error in amplitude (PEA) and latency of memory-guided saccades. The PEA was determined for the primary saccade (motor aspect) and the final eye position, i.e., after the end saccade (mnemonic aspect). Stimulation over the occipital cortex at the same time intervals served as control experiments. 2. After PPC stimulation, a significant increase in the PEA of the primary saccade and final eye position existed for contralateral saccades, compared with the PEA without stimulation, when stimulation was applied 260 ms after target presentation, but not at other time intervals. There was no significant effect on ipsilateral saccades. Latency was significantly increased bilaterally when stimulation was performed 2,100 ms after target presentation. 3. After prefrontal stimulation, a significant increase in the PEA of the primary saccade and final eye position existed for contralateral saccades, when stimulation was applied between 700 and 1,500 ms after target presentation, but not at other time intervals. There was no significant effect on ipsilateral saccades. Latency was not affected by prefrontal TMS at any stimulation times. 4. Occipital stimulation resulted in no significant effect on the PEA and latency of ipsilateral or contralateral saccades, in particular including the application at 260 ms after target presentation or during the memorization phase. 5. From these results it may be concluded that the observed effects of TMS on saccade accuracy were specific to the stimulated region and specific to the stimulation time. The PPC seems to be involved in the preparation of saccade amplitude, during the early phase of the paradigm, i.e., the sensorimotor processing period, whereas the DPFC could play a role during the later phase of the paradigm, i.e., the memorization period. Therefore in humans these results support the experimental findings suggesting that sensorimotor integration is controlled by the PPC and spatial memory by the DPFC. Furthermore, our results suggest that the PPC, although not the DPFC, plays a role in saccade triggering.
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Stoet, Gijsbert, and Lawrence H. Snyder. "Correlates of Stimulus-Response Congruence in the Posterior Parietal Cortex." Journal of Cognitive Neuroscience 19, no. 2 (February 2007): 194–203. http://dx.doi.org/10.1162/jocn.2007.19.2.194.
Full textAbstract:
Primate behavior is flexible: The response to a stimulus often depends on the task in which it occurs. Here we study how single neurons in the posterior parietal cortex (PPC) respond to stimuli which are associated with different responses in different tasks. Two rhesus monkeys performed a task-switching paradigm. Each trial started with a task cue instructing which of two tasks to perform, followed by a stimulus requiring a left or right button press. For half the stimuli, the associated responses were different in the two tasks, meaning that the task context was necessary to disambiguate the incongruent stimuli. The other half of stimuli required the same response irrespective of task context (congruent). Using this paradigm, we previously showed that behavioral responses to incongruent stimuli are significantly slower than to congruent stimuli. We now demonstrate a neural correlate in the PPC of the additional processing time required for incongruent stimuli. Furthermore, we previously found that 29% of parietal neurons encode the task being performed (task-selective cells). We now report differences in neuronal timing related to congruency in task-selective versus task nonselective cells. These differences in timing suggest that the activity in task nonselective cells reflects a motor command, whereas activity in task-selective cells reflects a decision process.
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Hinkley, Leighton B. N., Leah A. Krubitzer, Jeff Padberg, and Elizabeth A. Disbrow. "Visual-Manual Exploration and Posterior Parietal Cortex in Humans." Journal of Neurophysiology 102, no. 6 (December 2009): 3433–46. http://dx.doi.org/10.1152/jn.90785.2008.
Full textAbstract:
Areas of human posterior parietal cortex (PPC) specialized for processing sensorimotor information associated with visually locating an object, reaching to grasp, and manually exploring that object were examined using functional MRI. Cortical activation was observed in response to three tasks: 1) saccadic eye movements, 2) visually guided reaching to grasp, and 3) manual shape discrimination. During saccadic eye movements, cortical fields within the lateral and rostral superior parietal lobe (SPL) and the caudal SPL and parieto-occipital boundary were active. During visually guided reaching to grasp, regions of cortex within the postcentral sulcus (PoCS) and rostral intraparietal sulcus (IPS) were active, as well as the caudal SPL of the left hemisphere and the medial and caudal IPS of the right hemisphere. Cortical regions at the junction of the IPS and PoCS and an area in the medial SPL were active bilaterally during shape manipulation. Only a few regions were most active during a single motor behavior, whereas several areas were highly active during two or more tasks. Hemispheric asymmetries in activation patterns were observed during visually guided reaching to grasp. The gross areal organization of human PPC is likely similar to the pattern previously described in nonhuman primates, including multifunctional regions and asymmetric processing of some manual abilities.
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Kuhl, Ulrike, Sarah Sobotta, and Michael A. Skeide. "Mathematical learning deficits originate in early childhood from atypical development of a frontoparietal brain network." PLOS Biology 19, no. 9 (September 30, 2021): e3001407. http://dx.doi.org/10.1371/journal.pbio.3001407.
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Mathematical learning deficits are defined as a neurodevelopmental disorder (dyscalculia) in the International Classification of Diseases. It is not known, however, how such deficits emerge in the course of early brain development. Here, we conducted functional and structural magnetic resonance imaging (MRI) experiments in 3- to 6-year-old children without formal mathematical learning experience. We followed this sample until the age of 7 to 9 years, identified individuals who developed deficits, and matched them to a typically developing control group using comprehensive behavioral assessments. Multivariate pattern classification distinguished future cases from controls with up to 87% accuracy based on the regional functional activity of the right posterior parietal cortex (PPC), the network-level functional activity of the right dorsolateral prefrontal cortex (DLPFC), and the effective functional and structural connectivity of these regions. Our results indicate that mathematical learning deficits originate from atypical development of a frontoparietal network that is already detectable in early childhood.
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Awoyale, Wasiu, Emmanuel Alamu, Emmanuel Irondi, Busie Maziya-Dixon, and Abebe Menkir. "Impact of packaging material and storage condition on retention of provitamin A carotenoids and xanthophylls in yellow-seeded maize flour." Functional Foods in Health and Disease 8, no. 10 (October 31, 2018): 462. http://dx.doi.org/10.31989/ffhd.v8i10.535.
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Background: Pro-vitamin A carotenoid (pVAC) rich foods are those foods that contain substance which can be converted within the human body into retinol. These foods also contribute to the reduction of vitamin A deficiency diseases. Yellow-seeded maize flour is a pVAC rich food. Identifying the right packaging materials and storage conditions that retain pVAC in this food is essential for their health benefits. Traditionally, maize flour is stored with different packaging materials to increase its shelf life. For example, previous studies have shown how during storage in different food matrices, carotenoids, including maize grains, are highly susceptible to degradation by temperature, light, and oxygen. Therefore, in this study we investigated the effect of storage packaging materials (polypropylene woven sacks-PWS, high-density polyethylene bags-HDPE, and polyvinyl plastic containers-PPC) and storage condition (temperature and relative humidity) on retaining pVAC in yellow-seed maize flour.Methods: The yellow-seeded maize grains were collected and ground into flour. The maize flour was divided into portions (200 g). Each portion was packed and sealed in PWS, HDPE, and PPC. The control samples (12 pieces) were stored on top of the storage box. The packed samples were stored in both the upper (12 samples) and lower (12 samples) compartment of a storage wooden box. The interior of the upper part was lightened with aluminum foil and fitted with fluorescent tube to increase the light intensity. The lower compartment was darkened with gloss black painting. The flour samples were stored for 28 days. Samples were collected for pVAC and xanthophylls analyses at 7 day intervals using standard methods.Results: The results demonstrated how packaging in PPC and storing in a dark compartment resulted in the highest total pVAC (92.39%) and total xanthophylls (89.44%) retention and retinol equivalent (RE) (0.40 µg/g). In contrast, packaging in HDPE and storing in lighted compartment resulted in the lowest pVAC (44.92%) and total xanthophylls (46.76%) retention and RE (0.19 µg/g).Conclusions: Packaging yellow-seeded maize flour in PPC and storing in the dark may be recommended for maximum retention of carotenoids in yellow-seeded maize flour since, as the packaging material and storage condition resulted in the highest pVAC retention and retinol equivalent.Keywords: Yellow-seeded maize; Carotenoids; Packaging materials; Storage conditions; Retinol equivalent