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Halička, Juraj, Erik Sahatqija, Michal Krasňanský, Karolína Kapitánová, Monika Fedorová y Peter Žiak. "Visual Training in Virtual Reality in Adult Patients With Anisometric Amblyopia". Czech and Slovak Ophthalmology 76, n.º 1 (5 de diciembre de 2019): 24–28. http://dx.doi.org/10.31348/2020/3.
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Purpose: Amblyopia is one of the most common childhood disease. The average prevalence of amblyopia in children is estimated at 2-5 %. It arises during the child development until the age of six, if not treated then, it persist throught adulthood. The aim of our work is to retrospectively analyze the results of treatment of anisometropic amblyopia using dichoptical training in virtual reality in adult amblyopic patients. Materials and Methods: Our group consisted of 84 amblyopic patients with anisometropic amblyopia with an average age of 33.8 ± 9.4 years. Patients played a video game twice a week in the Oculus Rift 3D virtual reality. Together they completed 8 visual trainings, with one training lasting 60 minutes. Before and after the training we evaluated the best corrected visual acuity (BCVA). Discussion: Throughout the group, we observed an improvement of 0.1 BCVA from 0.48 to 0.58 Sloan table (p <0.05). 17% of patients before training and 31% after visual training reached BCVA better or equal to 0.9. The overall response rate was 56% in adult patients (n = 47). Conclusion: Our results suggest that a certain degree of residual neuro-plasticity in the visual cortex can be revealed in the adult brain, thereby improve visual acuity in adult amblyopic patients.
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Jeon, Seong Taek, Daphne Maurer y Terri L. Lewis. "The Effect of Video Game Training on the Vision of Adults with Bilateral Deprivation Amblyopia". Seeing and Perceiving 25, n.º 5 (7 de julio de 2012): 493–520. http://dx.doi.org/10.1163/18784763-00002391.
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Amblyopia is a condition involving reduced acuity caused by abnormal visual input during a critical period beginning shortly after birth. Amblyopia is typically considered to be irreversible during adulthood. Here we provide the first demonstration that video game training can improve at least some aspects of the vision of adults with bilateral deprivation amblyopia caused by a history of bilateral congenital cataracts. Specifically, after 40 h of training over one month with an action video game, most patients showed improvement in one or both eyes on a wide variety of tasks including acuity, spatial contrast sensitivity, and sensitivity to global motion. As well, there was evidence of improvement in at least some patients for temporal contrast sensitivity, single letter acuity, crowding, and feature spacing in faces, but not for useful field of view. The results indicate that, long after the end of the critical period for damage, there is enough residual plasticity in the adult visual system to effect improvements, even in cases of deep amblyopia caused by early bilateral deprivation.
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Sauvan, Lauren, Natacha Stolowy, Danièle Denis, Frédéric Matonti, Frédéric Chavane, Robert F. Hess y Alexandre Reynaud. "Contribution of Short-Time Occlusion of the Amblyopic Eye to a Passive Dichoptic Video Treatment for Amblyopia beyond the Critical Period". Neural Plasticity 2019 (28 de agosto de 2019): 1–12. http://dx.doi.org/10.1155/2019/6208414.
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Dichoptic movie viewing has been shown to significantly improve visual acuity in amblyopia in children. Moreover, short-term occlusion of the amblyopic eye can transiently increase its contribution to binocular fusion in adults. In this study, we first asked whether dichoptic movie viewing could improve the visual function of amblyopic subjects beyond the critical period. Secondly, we tested if this effect could be enhanced by short-term monocular occlusion of the amblyopic eye. 17 subjects presenting stable functional amblyopia participated in this study. 10 subjects followed 6 sessions of 1.5 hour of dichoptic movie viewing (nonpatched group), and 7 subjects, prior to each of these sessions, had to wear an occluding patch over the amblyopic eye for two hours (patched group). Best-corrected visual acuity, monocular contrast sensitivity, interocular balance, and stereoacuity were measured before and after the training. For the nonpatched group, mean amblyopic eye visual acuity significantly improved from 0.54 to 0.46 logMAR (p<0.05). For the patched group, mean amblyopic eye visual acuity significantly improved from 0.62 to 0.43 logMAR (p<0.05). Stereoacuity improved significantly when the data of both groups were combined. No significant improvement was observed for the other visual functions tested. Our training procedure combines modern video technologies and recent fundamental findings in human plasticity: (i) long-term plasticity induced by dichoptic movie viewing and (ii) short-term adaptation induced by temporary monocular occlusion. This passive dichoptic movie training approach is shown to significantly improve visual acuity of subjects beyond the critical period. The addition of a short-term monocular occlusion to the dichoptic training shows promising trends but was not significant for the sample size used here. The passive movie approach combined with interocular contrast balancing even over such a short period as 2 weeks has potential as a clinical therapy to treat amblyopia in older children and adults.
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Hernández-Rodríguez, Carlos J., David P. Piñero, Ainhoa Molina-Martín, León Morales-Quezada, Dolores de Fez, Luis Leal-Vega, Juan F. Arenillas y María Begoña Coco-Martín. "Stimuli Characteristics and Psychophysical Requirements for Visual Training in Amblyopia: A Narrative Review". Journal of Clinical Medicine 9, n.º 12 (9 de diciembre de 2020): 3985. http://dx.doi.org/10.3390/jcm9123985.
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Active vision therapy using perceptual learning and/or dichoptic or binocular environments has shown its potential effectiveness in amblyopia, but some doubts remain about the type of stimuli and the mode and sequence of presentation that should be used. A search was performed in PubMed, obtaining 143 articles with information related to the stimuli used in amblyopia rehabilitation, as well as to the neural mechanisms implied in such therapeutic process. Visual deficits in amblyopia and their neural mechanisms associated are revised, including visual acuity loss, contrast sensitivity reduction and stereopsis impairment. Likewise, the most appropriate stimuli according to the literature that should be used for an efficient rehabilitation of the amblyopic eye are described in detail, including optotypes, Gabor’s patches, random-dot stimuli and Vernier’s stimuli. Finally, the properties of these stimuli that can be modified during the visual training are discussed, as well as the psychophysical method of their presentation and the type of environment used (perceptual learning, dichoptic stimulation or virtual reality). Vision therapy using all these revised concepts can be an effective option for treating amblyopia or accelerating the treatment period when combining with patching. It is essential to adapt the stimuli to the patient’s individual features in both monocular and binocular training.
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Gupta, Reena, Richa Jangra, Gaurav Dubey, Ramesh Hooda y Nirmal Parmar. "Efficacy of vision therapy in impaired stereoscopic depth with intermittent exotropia (true divergence excess) with unilateral amblyopia: a case report". International Journal Of Community Medicine And Public Health 7, n.º 2 (28 de enero de 2020): 773. http://dx.doi.org/10.18203/2394-6040.ijcmph20200466.
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Divergence excess (DE) can be described clinically as exotropia at far greater than the near deviation by at least 10 prism dioptres (PD). We are reporting a rare case of 25-year-old female visited in the eye department for a routine eye check-up with a history of decreased vision in one eye. On examination, it was detected as a case of unilateral amblyopia with intermittent exotropia of true divergence excess with high accommodative-convergence over accommodation (AC/A) ratio. The patient was asymptomatic from exo-deviation due to the presence of binocular vision and good fusional reserve. The patient was started on active conventional vision therapy along with occlusion therapy. Post 16 weeks of constant therapy, a vision assessment with complete squint assessment along with binocular vision tests were performed. The result interprets to support the use of active conventional vision therapy as an integral part of the clinical treatment of amblyopia and intermittent exotropia. The rate of recovery of several monocular functions monitored during the vision therapy period provides the evidence of neural plasticity at multiple sites in the visual pathway in this adult amblyope. Therefore, if an ordered plan is being followed for the management of the patient of unilateral amblyopia and divergence excess, it can yield long-lasting improvement in visual acuity and binocular functions of any age.
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Lagas, Alice K., Joanna M. Black, Bruce R. Russell, Robert R. Kydd y Benjamin Thompson. "The Effect of Combined Patching and Citalopram on Visual Acuity in Adults with Amblyopia: A Randomized, Crossover, Placebo-Controlled Trial". Neural Plasticity 2019 (9 de junio de 2019): 1–10. http://dx.doi.org/10.1155/2019/5857243.
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Nonhuman animal models have demonstrated that selective serotonin reuptake inhibitors (SSRIs) can enhance plasticity within the mature visual cortex and enable recovery from amblyopia. The aim of this study was to test the hypothesis that the SSRI citalopram combined with part-time patching of the fellow fixing eye would improve amblyopic eye visual acuity in adult humans. Following a crossover, randomized, double-blind, placebo-controlled design, participants completed two 2-week blocks of fellow fixing eye patching. One block combined patching with citalopram (20 mg/day) and the other with a placebo tablet. The blocks were separated by a 2-week washout period. The primary outcome was change in amblyopic eye visual acuity. Secondary outcomes included stereoacuity and electrophysiological measures of retinal and cortical function. Seven participants were randomized, fewer than our prespecified sample size of 20. There were no statistically significant differences in amblyopic eye visual acuity change between the active (mean±SD change=0.08±0.16 logMAR) and the placebo (mean change=−0.01±0.03 logMAR) blocks. No treatment effects were observed for any secondary outcomes. However, 3 of 7 participants experienced a 0.1 logMAR or greater improvement in amblyopic eye visual acuity in the active but not the placebo blocks. These results from a small sample suggest that larger-scale trials of SSRI treatment for adult amblyopia may be warranted. Considerations for future trials include drug dose, treatment duration, and recruitment challenges. This study was preregistered as a clinical trial (ACTRN12611000669998).
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Marsh, Eric y Robert Baker. "Normal and Adapted Visuooculomotor Reflexes in Goldfish". Journal of Neurophysiology 77, n.º 3 (1 de marzo de 1997): 1099–118. http://dx.doi.org/10.1152/jn.1997.77.3.1099.
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Marsh, Eric and Robert Baker. Normal and adapted visuooculomotor reflexes in goldfish. J. Neurophysiol. 77: 1099–1118. Under normal physiological conditions, whole field visual motion generally occurs in response to either active or passive self-motion. In the laboratory, selective movement of the visual surround produces an optokinetic response (OKR) that acts primarily to support the vestibuloocular reflex (VOR). During visual world motion, however, the OKR can be viewed as operating independently over frequency and amplitude ranges insufficient for vestibular activation. The goal of the present study was to characterize this isolated behavior of the OKR in goldfish as an essential step for studying central neuronal correlates of visual-vestibular interactions and the mechanisms underlying oculomotor adaptation. After presentation of either binocular sinusoidal or step visual stimuli, conjugate eye movements were elicited with an amplitude and phase profile similar to that of other vertebrates. An early and a delayed component were measured with different dynamics that could be altered independently by visual training. The ensuing visuomotor plasticity was robust and exhibited five major characteristics. First, the gain of both early and delayed components of the OKR increased >100%. Second, eye velocity decreased 0.5–2.0 s before the change in direction of stimulus velocity. Third, on lengthening the duration of a constant velocity visual stimulus (e.g., from 8 to 16 s), eye velocity decreased toward 0°/s. This behavior was correlated with the direction and period as opposed to the frequency of the visual stimulus (“period tuning”). Fourth, visual stimulus training increased VOR eye velocity with a ratio of 0.6 to 1 to that measured for the OKR. Fifth, after OKR adaptation, eye velocity consistently oscillated in a conjugate, symmetrical fashion at 2.4 Hz in the light, whereas in the dark, a rhythmical low-amplitude eye velocity occurred at the visual training frequency. We conclude that the frequency and amplitude of visual stimuli for eliciting the goldfish OKR are well suited for complementing the VOR. Unlike most mammals, OKR adaptive modifications significantly alter VOR gain, whereas the effects of VOR training are much less on OKR gain. These observations suggest that both distributed circuits and discrete neuronal populations control visuo- and vestibulomotor performance. Finally, the existence of a rhythmic, “period tuned” visuomotor behavior provides a unique opportunity to examine the neuronal mechanisms of adaptive plasticity.
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Cybulska-Klosowicz, Anita, François Tremblay, Wan Jiang, Stéphanie Bourgeon, El-Mehdi Meftah y C. Elaine Chapman. "Differential effects of the mode of touch, active and passive, on experience-driven plasticity in the S1 cutaneous digit representation of adult macaque monkeys". Journal of Neurophysiology 123, n.º 3 (1 de marzo de 2020): 1072–89. http://dx.doi.org/10.1152/jn.00014.2019.
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This study compared the receptive field (RF) properties and firing rates of neurons in the cutaneous hand representation of primary somatosensory cortex (areas 3b, 1, and 2) of 9 awake, adult macaques that were intensively trained in a texture discrimination task using active touch (fingertips scanned over the surfaces using a single voluntary movement), passive touch (surfaces displaced under the immobile fingertips), or both active and passive touch. Two control monkeys received passive exposure to the same textures in the context of a visual discrimination task. Training and recording extended over 1–2 yr per animal. All neurons had a cutaneous receptive field (RF) that included the tips of the stimulated digits (D3 and/or D4). In area 3b, RFs were largest in monkeys trained with active touch, smallest in those trained with passive touch, and intermediate in those trained with both; i.e., the mode of touch differentially modified the cortical representation of the stimulated fingers. The same trends were seen in areas 1 and 2, but the changes were not significant, possibly because a second experience-driven influence was seen in areas 1 and 2, but not in area 3b: smaller RFs with passive exposure to irrelevant tactile inputs compared with recordings from one naive hemisphere. We suggest that added feedback during active touch and higher cortical firing rates were responsible for the larger RFs with behavioral training; this influence was tempered by periods of more restricted sensory feedback during passive touch training in the active + passive monkeys. NEW & NOTEWORTHY We studied experience-dependent sensory cortical plasticity in relation to tactile discrimination of texture using active and/or passive touch. We showed that neuronal receptive fields in primary somatosensory cortex, especially area 3b, are largest in monkeys trained with active touch, smallest in those trained with passive touch, and intermediate in those trained using both modes of touch. Prolonged, irrelevant tactile input had the opposite influence in areas 1 and 2, favoring smaller receptive fields.
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Stefano Filho, Carlos Alberto, Romis Attux y Gabriela Castellano. "Motor imagery practice and feedback effects on functional connectivity". Journal of Neural Engineering 18, n.º 6 (1 de diciembre de 2021): 066048. http://dx.doi.org/10.1088/1741-2552/ac456d.
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Abstract Objective. The use of motor imagery (MI) in motor rehabilitation protocols has been increasingly investigated as a potential technique for enhancing traditional treatments, yielding better clinical outcomes. However, since MI performance can be challenging, practice is usually required. This demands appropriate training, actively engaging the MI-related brain areas, consequently enabling the user to properly benefit from it. The role of feedback is central for MI practice. Yet, assessing which underlying neural changes are feedback-specific or purely due to MI practice is still a challenging effort, mainly due to the difficulty in isolating their contributions. In this work, we aimed to assess functional connectivity (FC) changes following MI practice that are either extrinsic or specific to feedback. Approach. To achieve this, we investigated FC, using graph theory, in electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data, during MI performance and at resting-state (rs), respectively. Thirty healthy subjects were divided into three groups, receiving no feedback (control), ‘false’ feedback (sham) or actual neurofeedback (active). Participants underwent 12–13 hands-MI EEG sessions and pre- and post-MI training fMRI exams. Main results. Following MI practice, control participants presented significant increases in degree and in eigenvector centrality for occipital nodes at rs-fMRI scans, whereas sham-feedback produced similar effects, but to a lesser extent. Therefore, MI practice, by itself, seems to stimulate visual information processing mechanisms that become apparent during basal brain activity. Additionally, only the active group displayed decreases in inter-subject FC patterns, both during MI performance and at rs-fMRI. Significance. Hence, actual neurofeedback impacted FC by disrupting common inter-subject patterns, suggesting that subject-specific neural plasticity mechanisms become important. Future studies should consider this when designing experimental NFBT protocols and analyses.
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Tyler, Sarah C., Federica Contò y Lorella Battelli. "Rapid Improvement on a Temporal Attention Task within a Single Session of High-frequency Transcranial Random Noise Stimulation". Journal of Cognitive Neuroscience 30, n.º 5 (mayo de 2018): 656–66. http://dx.doi.org/10.1162/jocn_a_01235.
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This study explored the modulatory effects of high-frequency transcranial random noise stimulation (tRNS) on visual sensitivity during a temporal attention task. We measured sensitivity to different onset asynchronies during a temporal order judgment task as a function of active stimulation relative to sham. While completing the task, participants were stimulated bilaterally for 20 min over either the TPJ or the human middle temporal area. We hypothesized that tRNS over the TPJ, which is critical to the temporal attention network, would selectively increase cortical excitability and induce cognitive training-like effects on performance, perhaps more so in the left visual field [Matthews, N., & Welch, L. Left visual field attentional advantage in judging simultaneity and temporal order. Journal of Vision, 15, 1–13, 2015; Romanska, A., Rezlescu, C., Susilo, T., Duchaine, B., & Banissy, M. J. High-frequency transcranial random noise stimulation enhances perception of facial identity. Cerebral Cortex, 25, 4334–4340, 2015]. In Experiment 1, we measured the performance of participants who judged the order of Gabors temporally imbedded in flickering discs, presented with onset asynchronies ranging from −75 msec (left disc first) to +75 msec (right disc first). In Experiment 2, we measured whether each participant's temporal sensitivity increased with stimulation by using temporal offsets that the participant initially perceived as simultaneous. We found that parietal cortex stimulation temporarily increased sensitivity on the temporal order judgment task, especially in the left visual field. Stimulation over human middle temporal area did not alter cortical excitability in a way that affected performance. The effects were cumulative across blocks of trials for tRNS over parietal cortex but dissipated when stimulation ended. We conclude that single-session tRNS can induce temporary improvements in behavioral sensitivity and that this shows promising insight into the relationship between cortical stimulation and neural plasticity.
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Black, Bryan J., Aswini Kanneganti, Alexandra Joshi-Imre, Rashed Rihani, Bitan Chakraborty, Justin Abbott, Joseph J. Pancrazio y Stuart F. Cogan. "Chronic recording and electrochemical performance of Utah microelectrode arrays implanted in rat motor cortex". Journal of Neurophysiology 120, n.º 4 (1 de octubre de 2018): 2083–90. http://dx.doi.org/10.1152/jn.00181.2018.
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Multisite implantable electrode arrays serve as a tool to understand cortical network connectivity and plasticity. Furthermore, they enable electrical stimulation to drive plasticity, study motor/sensory mapping, or provide network input for controlling brain-computer interfaces. Neurobehavioral rodent models are prevalent in studies of motor cortex injury and recovery as well as restoration of auditory/visual cues due to their relatively low cost and ease of training. Therefore, it is important to understand the chronic performance of relevant electrode arrays in rodent models. In this report, we evaluate the chronic recording and electrochemical performance of 16-channel Utah electrode arrays, the current state-of-the-art in pre-/clinical cortical recording and stimulation, in rat motor cortex over a period of 6 mo. The single-unit active electrode yield decreased from 52.8 ± 10.0 ( week 1) to 13.4 ± 5.1% ( week 24). Similarly, the total number of single units recorded on all electrodes across all arrays decreased from 106 to 15 over the same time period. Parallel measurements of electrochemical impedance spectra and cathodic charge storage capacity exhibited significant changes in electrochemical characteristics consistent with development of electrolyte leakage pathways over time. Additionally, measurements of maximum cathodal potential excursion indicated that only a relatively small fraction of electrodes (10–35% at 1 and 24 wk postimplantation) were capable of delivering relevant currents (20 µA at 4 nC/ph) without exceeding negative or positive electrochemical potential limits. In total, our findings suggest mainly abiotic failure modes, including mechanical wire breakage as well as degradation of conducting and insulating substrates. NEW & NOTEWORTHY Multisite implantable electrode arrays serve as a tool to record cortical network activity and enable electrical stimulation to drive plasticity or provide network feedback. The use of rodent models in these fields is prevalent. We evaluated chronic recording and electrochemical performance of 16-channel Utah electrode arrays in rat motor cortex over a period of 6 mo. We primarily observed abiotic failure modes suggestive of mechanical wire breakage and/or degradation of insulation.
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Leal Vega, L., D. P. Piñero, C. J. Hernández Rodríguez, A. Molina Martín, L. Morales-Quezada, A. I. Vallelado Álvarez, J. F. Arenillas Lara y M. B. Coco Martín. "Study protocol for a randomized controlled trial of the NEIVATECH virtual reality system to improve visual function in children with anisometropic amblyopia". BMC Ophthalmology 22, n.º 1 (7 de junio de 2022). http://dx.doi.org/10.1186/s12886-022-02466-z.
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Abstract Background Interest in developing alternative methods for the treatment of amblyopia has long been a topic of interest among clinicians and researchers, as prescribed occlusion and penalization therapies do not always provide an effective response and are associated with a high risk of recurrence and non-compliance. Here, we present the protocol of a small-scale RCT to evaluate the safety and clinical efficacy of a novel VR-based system designed to provide binocular vision training to children with anisometropic amblyopia. Methods We aim to recruit a total of 60 children with anisometropic amblyopia aged 5-17 years with no previous treatment for amblyopia other than refractive correction from the pediatric ophthalmology units of the University Clinical Hospital of Valladolid and the Vithas Medimar International Hospital of Alicante. Children who meet the eligibility criteria and consent to participate will be randomly assigned to a three-month intervention group of 18 half-hour in-office therapy sessions with the NEIVATECH system (group A) or to a parallel group receiving 2 hours of conventional patching per day at home for the same period of time (group B). Assessments of visual function will be carried out before the intervention and at 1, 2 and 3 months, with changes in distance BCVA being the primary outcome measure to be considered. Patient safety, compliance, satisfaction and acceptance to treatment will also be assessed after therapy as other valuable outcome measures. In addition, a rsfMRI scan will be performed on a subgroup of 5 patients from each group at the pre-intervention visit and at the post-intervention visit to test the effects of both therapies on neural plasticity in the visual cortex. Discussion The NEIVATECH system has been conceived as a serious game designed to provide binocular vision training to anisometropic amblyopic children by complementing the concepts of perceptual learning, dichoptic training and gamification in an immersive VR environment. We hope that this novel approach may lead to greater improvements in vision performance than those provided so far by conventional patching in anisometropic amblyopic children. Trial registration This protocol was registered with ClinicalTrials.gov (NCT04819386) on 29 March 2021.
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Jiang, Huai, Terrence R. Stanford, Benjamin A. Rowland y Barry E. Stein. "Association Cortex Is Essential to Reverse Hemianopia by Multisensory Training". Cerebral Cortex, 31 de mayo de 2021. http://dx.doi.org/10.1093/cercor/bhab138.
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Abstract Hemianopia induced by unilateral visual cortex lesions can be resolved by repeatedly exposing the blinded hemifield to auditory–visual stimuli. This rehabilitative “training” paradigm depends on mechanisms of multisensory plasticity that restore the lost visual responsiveness of multisensory neurons in the ipsilesional superior colliculus (SC) so that they can once again support vision in the blinded hemifield. These changes are thought to operate via the convergent visual and auditory signals relayed to the SC from association cortex (the anterior ectosylvian sulcus [AES], in cat). The present study tested this assumption by cryogenically deactivating ipsilesional AES in hemianopic, anesthetized cats during weekly multisensory training sessions. No signs of visual recovery were evident in this condition, even after providing animals with up to twice the number of training sessions required for effective rehabilitation. Subsequent training under the same conditions, but with AES active, reversed the hemianopia within the normal timeframe. These results indicate that the corticotectal circuit that is normally engaged in SC multisensory plasticity has to be operational for the brain to use visual–auditory experience to resolve hemianopia.
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Pratviel, Yvan, Veronique Deschodt-Arsac, Florian Larrue y Laurent M. Arsac. "Reliability of the Dynavision task in virtual reality to explore visuomotor phenotypes". Scientific Reports 11, n.º 1 (12 de enero de 2021). http://dx.doi.org/10.1038/s41598-020-79885-9.
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AbstractDaily-life behaviors strongly rely on visuomotor integration, a complex sensorimotor process with obvious plasticity. Visual-perceptive and visual-cognitive functions are degraded by neurological disorders and brain damage, but are improved by vision training, e.g. in athletes. Hence, developing tools to evaluate/improve visuomotor abilities has found echo among psychologists, neurophysiologists, clinicians and sport professionals. Here we implemented the Dynavision visuomotor reaction task in virtual reality (VR) to get a flexible tool to place high demands on visual-perceptive and visual-cognitive processes, and explore individual abilities in visuomotor integration. First, we demonstrated high test–retest reliability for the task in VR among healthy physically-active students (n = 64, 32 females). Second, the capture of head movements thanks to the VR-headset sensors provided new and reliable information on individual visual-perceptual strategies, which added significant value to explore visuomotor phenotypes. A factor analysis of mixed data and hierarchical clustering on principal components points to head movements, video-games practice and ball-tracking sports as critical cues to draw visuomotor phenotypes among our participants. We conclude that the visuomotor task in VR is a reliable, flexible and promising tool. Since VR nowadays can serve e.g. to modulate multisensorial integration by creating visual interoceptive-exteroceptive conflicts, or placing specifically designed cognitive demand, much could be learned on complex integrated visuomotor processes through VR experiments. This offers new perspectives for post brain injury risk evaluation, rehabilitation programs and visual-cognitive training.
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Mikos, Ania, Brigitta Malagurski, Franziskus Liem, Susan Mérillat y Lutz Jäncke. "Object-Location Memory Training in Older Adults Leads to Greater Deactivation of the Dorsal Default Mode Network". Frontiers in Human Neuroscience 15 (26 de febrero de 2021). http://dx.doi.org/10.3389/fnhum.2021.623766.
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Substantial evidence indicates that cognitive training can be efficacious for older adults, but findings regarding training-related brain plasticity have been mixed and vary depending on the imaging modality. Recent years have seen a growth in recognition of the importance of large-scale brain networks on cognition. In particular, task-induced deactivation within the default mode network (DMN) is thought to facilitate externally directed cognition, while aging-related decrements in this neural process are related to reduced cognitive performance. It is not yet clear whether task-induced deactivation within the DMN can be enhanced by cognitive training in the elderly. We previously reported durable cognitive improvements in a sample of healthy older adults (age range = 60–75) who completed 6 weeks of process-based object-location memory training (N = 36) compared to an active control training group (N = 31). The primary aim of the current study is to evaluate whether these cognitive gains are accompanied by training-related changes in task-related DMN deactivation. Given the evidence for heterogeneity of the DMN, we examine task-related activation/deactivation within two separate DMN branches, a ventral branch related to episodic memory and a dorsal branch more closely resembling the canonical DMN. Participants underwent functional magnetic resonance imaging (fMRI) while performing an untrained object-location memory task at four time points before, during, and after the training period. Task-induced (de)activation values were extracted for the ventral and dorsal DMN branches at each time point. Relative to visual fixation baseline: (i) the dorsal DMN was deactivated during the scanner task, while the ventral DMN was activated; (ii) the object-location memory training group exhibited an increase in dorsal DMN deactivation relative to the active control group over the course of training and follow-up; (iii) changes in dorsal DMN deactivation did not correlate with task improvement. These results indicate a training-related enhancement of task-induced deactivation of the dorsal DMN, although the specificity of this improvement to the cognitive task performed in the scanner is not clear.
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Toovey, Benjamin Robert William, Florian Kattner y Torsten Schubert. "Cross-Modal Transfer Following Auditory Task-Switching Training in Old Adults". Frontiers in Psychology 12 (25 de febrero de 2021). http://dx.doi.org/10.3389/fpsyg.2021.615518.
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Maintaining and coordinating multiple task-sets is difficult and leads to costs, however task-switching training can reduce these deficits. A recent study in young adults demonstrated that this training effect occurs at an amodal processing level. Old age is associated with reduced cognitive plasticity and further increases the performance costs when mixing multiple tasks. Thus, cognitive aging might be a limiting factor for inducing cross-modal training effects in a task-switching environment. We trained participants, aged 62–83 years, with an auditory task-switching paradigm over four sessions (2880 total trials), to investigate whether training-related reductions in task-switching costs would also manifest in an untrained visual modality version of the task. Two control groups trained with single tasks (active control) or not trained (passive control) allowed us to identify improvements specific to task-switching training. To make statistical evaluations of any age differences in training and cross-modal transfer, the data from the Kattner cohort were incorporated into the present analysis. Despite the tendency for older adults to respond more cautiously, task-switching training specifically led to a mixing cost reduction in both trained and untrained modalities, the magnitude of which was statistically similar regardless of age. In line with a growing body of research, we failed to observe any far transfer effects in measures of inhibition, working memory or fluid intelligence. Overall, we conclude that any apparent cognitive limitations associated with aging do not prevent cognitive control processes which support set-shifting from improving at an amodal level.
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Szturm, Tony, Tiffany A. Kolesar, Bhuvan Mahana, Andrew L. Goertzen, Douglas E. Hobson, Jonathan J. Marotta, Antonio P. Strafella y Ji Hyun Ko. "Changes in Metabolic Activity and Gait Function by Dual-Task Cognitive Game-Based Treadmill System in Parkinson’s Disease: Protocol of a Randomized Controlled Trial". Frontiers in Aging Neuroscience 13 (4 de junio de 2021). http://dx.doi.org/10.3389/fnagi.2021.680270.
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Balance and gait impairments, and consequently, mobility restrictions and falls are common in Parkinson’s disease (PD). Various cognitive deficits are also common in PD and are associated with increased fall risk. These mobility and cognitive deficits are limiting factors in a person’s health, ability to perform activities of daily living, and overall quality of life. Community ambulation involves many dual-task (DT) conditions that require processing of several cognitive tasks while managing or reacting to sudden or unexpected balance challenges. DT training programs that can simultaneously target balance, gait, visuomotor, and cognitive functions are important to consider in rehabilitation and promotion of healthy active lives. In the proposed multi-center, randomized controlled trial (RCT), novel behavioral positron emission tomography (PET) brain imaging methods are used to evaluate the molecular basis and neural underpinnings of: (a) the decline of mobility function in PD, specifically, balance, gait, visuomotor, and cognitive function, and (b) the effects of an engaging, game-based DT treadmill walking program on mobility and cognitive functions. Both the interactive cognitive game tasks and treadmill walking require continuous visual attention, and share spatial processing functions, notably to minimize any balance disturbance or gait deviation/stumble. The ability to “walk and talk” normally includes activation of specific regions of the prefrontal cortex (PFC) and the basal ganglia (site of degeneration in PD). The PET imaging analysis and comparison with healthy age-matched controls will allow us to identify areas of abnormal, reduced activity levels, as well as areas of excessive activity (increased attentional resources) during DT-walking. We will then be able to identify areas of brain plasticity associated with improvements in mobility functions (balance, gait, and cognition) after intervention. We expect the gait-cognitive training effect to involve re-organization of PFC activity among other, yet to be identified brain regions. The DT mobility-training platform and behavioral PET brain imaging methods are directly applicable to other diseases that affect gait and cognition, e.g., cognitive vascular impairment, Alzheimer’s disease, as well as in aging.