Articles de revues : « Visual dorsal stream »

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Kaas, Jon H., et Mary K. L. Baldwin. « The Evolution of the Pulvinar Complex in Primates and Its Role in the Dorsal and Ventral Streams of Cortical Processing ». Vision 4, n^o 1 (30 décembre 2019) : 3. http://dx.doi.org/10.3390/vision4010003.

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Current evidence supports the view that the visual pulvinar of primates consists of at least five nuclei, with two large nuclei, lateral pulvinar ventrolateral (PLvl) and central lateral nucleus of the inferior pulvinar (PIcl), contributing mainly to the ventral stream of cortical processing for perception, and three smaller nuclei, posterior nucleus of the inferior pulvinar (PIp), medial nucleus of the inferior pulvinar (PIm), and central medial nucleus of the inferior pulvinar (PIcm), projecting to dorsal stream visual areas for visually directed actions. In primates, both cortical streams are highly dependent on visual information distributed from primary visual cortex (V1). This area is so vital to vision that patients with V1 lesions are considered “cortically blind”. When the V1 inputs to dorsal stream area middle temporal visual area (MT) are absent, other dorsal stream areas receive visual information relayed from the superior colliculus via PIp and PIcm, thereby preserving some dorsal stream functions, a phenomenon called “blind sight”. Non-primate mammals do not have a dorsal stream area MT with V1 inputs, but superior colliculus inputs to temporal cortex can be more significant and more visual functions are preserved when V1 input is disrupted. The current review will discuss how the different visual streams, especially the dorsal stream, have changed during primate evolution and we propose which features are retained from the common ancestor of primates and their close relatives.

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Bernardino, Inês, José Rebola, Reza Farivar, Eduardo Silva et Miguel Castelo-Branco. « Functional Reorganization of the Visual Dorsal Stream as Probed by 3-D Visual Coherence in Williams Syndrome ». Journal of Cognitive Neuroscience 26, n^o 11 (novembre 2014) : 2624–36. http://dx.doi.org/10.1162/jocn_a_00662.

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Object and depth perception from motion cues involves the recruitment of visual dorsal stream brain areas. In 3-D structure-from-motion (SFM) perception, motion and depth information are first extracted in this visual stream to allow object categorization, which is in turn mediated by the ventral visual stream. Such interplay justifies the use of SFM paradigms to understand dorsal–ventral integration of visual information. The nature of such processing is particularly interesting to be investigated in a neurological model of cognitive dissociation between dorsal (impaired) and ventral stream (relatively preserved) processing, Williams syndrome (WS). In the current fMRI study, we assessed dorsal versus ventral stream processing by using a performance-matched 3-D SFM object categorization task. We found evidence for substantial reorganization of the dorsal stream in WS as assessed by whole-brain ANOVA random effects analysis, with subtle differences in ventral activation. Dorsal reorganization was expressed by larger medial recruitment in WS (cuneus, precuneus, and retrosplenial cortex) in contrast with controls, which showed the expected dorsolateral pattern (caudal intraparietal sulcus and lateral occipital cortex). In summary, we found a substantial reorganization of dorsal stream regions in WS in response to simple visual categories and 3-D SFM perception, with less affected ventral stream. Our results corroborate the existence of a medial dorsal pathway that provides the substrate for information rerouting and reorganization in the presence of lateral dorsal stream vulnerability. This interpretation is consistent with recent findings suggesting parallel routing of information in medial and lateral parts of dorsal stream.

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Mitchell, Teresa V., et Helen J. Neville. « Asynchronies in the Development of Electrophysiological Responses to Motion and Color ». Journal of Cognitive Neuroscience 16, n^o 8 (octobre 2004) : 1363–74. http://dx.doi.org/10.1162/0898929042304750.

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Recent reports have documented greater plasticity in the dorsal visual stream as compared with the ventral visual stream. This study sought to test the hypothesis that this greater plasticity may be related to a more protracted period of development in the dorsal as compared with the ventral stream. Age-related effects on event-related potentials (ERPs) elicited by motion and color stimuli, designed to activate the two visual streams, were assessed in healthy individuals aged 6 years through adulthood. Although significant developmental effects were observed in amplitudes of ERPs to both color and motion stimuli, marked latency effects were observed only in response to motion. These results provide support for the hypothesis that the dorsal stream displays a longer developmental time course across the early school years than the ventral stream. Implications for neural and behavioral plasticity are discussed.

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Njemanze, Philip, Mathias Kranz et Peter Brust. « Fourier Analysis of Cerebral Metabolism of Glucose : Gender Differences in Mechanisms of Color Processing in the Ventral and Dorsal Streams in Mice ». Forecasting 1, n^o 1 (30 septembre 2018) : 135–56. http://dx.doi.org/10.3390/forecast1010010.

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Conventional imaging methods could not distinguish processes within the ventral and dorsal streams. The application of Fourier time series analysis was helpful to segregate changes in the ventral and dorsal streams of the visual system in male and female mice. The present study measured the accumulation of [18F]fluorodeoxyglucose ([18F]FDG) in the mouse brain using small animal positron emission tomography and magnetic resonance imaging (PET/MRI) during light stimulation with blue and yellow filters, compared to during conditions of darkness. Fourier analysis was performed using mean standardized uptake values (SUV) of [18F]FDG for each stimulus condition to derive spectral density estimates for each condition. In male mice, luminance opponency occurred by S-peak changes in the sub-cortical retino-geniculate pathways in the dorsal stream supplied by ganglionic arteries in the left visual cortex, while chromatic opponency involved C-peak changes in the cortico-subcortical pathways in the ventral stream perfused by cortical arteries in the left visual cortex. In female mice, there was resonance phenomenon at C-peak in the ventral stream perfused by the cortical arteries in the right visual cortex during luminance processing. Conversely, chromatic opponency caused by S-peak changes in the subcortical retino-geniculate pathways in the dorsal stream supplied by the ganglionic arteries in the right visual cortex. In conclusion, Fourier time series analysis uncovered distinct mechanisms of color processing in the ventral stream in males, while in female mice color processing was in the dorsal stream. It demonstrated that computation of colour processing as a conscious experience could have a wide range of applications in neuroscience, artificial intelligence and quantum mechanics.

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Goodale, Mel. « Pointing the way to a unified theory of action and perception ». Behavioral and Brain Sciences 20, n^o 4 (décembre 1997) : 749–50. http://dx.doi.org/10.1017/s0140525x9732161x.

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Deictic coding offers a useful model for understanding the interactions between the dorsal and ventral streams of visual processing in the cerebral cortex. By extending Ballard et al.'s ideas on teleassistance, I show how dedicated low-level visuomotor processes in the dorsal stream might be engaged for the services of high-level cognitive operations in the ventral stream.

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Zachariou, Valentinos, Roberta Klatzky et Marlene Behrmann. « Ventral and Dorsal Visual Stream Contributions to the Perception of Object Shape and Object Location ». Journal of Cognitive Neuroscience 26, n^o 1 (janvier 2014) : 189–209. http://dx.doi.org/10.1162/jocn_a_00475.

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Growing evidence suggests that the functional specialization of the two cortical visual pathways may not be as distinct as originally proposed. Here, we explore possible contributions of the dorsal “where/how” visual stream to shape perception and, conversely, contributions of the ventral “what” visual stream to location perception in human adults. Participants performed a shape detection task and a location detection task while undergoing fMRI. For shape detection, comparable BOLD activation in the ventral and dorsal visual streams was observed, and the magnitude of this activation was correlated with behavioral performance. For location detection, cortical activation was significantly stronger in the dorsal than ventral visual pathway and did not correlate with the behavioral outcome. This asymmetry in cortical profile across tasks is particularly noteworthy given that the visual input was identical and that the tasks were matched for difficulty in performance. We confirmed the asymmetry in a subsequent psychophysical experiment in which participants detected changes in either object location or shape, while ignoring the other, task-irrelevant dimension. Detection of a location change was slowed by an irrelevant shape change matched for difficulty, but the reverse did not hold. We conclude that both ventral and dorsal visual streams contribute to shape perception, but that location processing appears to be essentially a function of the dorsal visual pathway.

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Kristensen, Stephanie, Frank E. Garcea, Bradford Z. Mahon et Jorge Almeida. « Temporal Frequency Tuning Reveals Interactions between the Dorsal and Ventral Visual Streams ». Journal of Cognitive Neuroscience 28, n^o 9 (septembre 2016) : 1295–302. http://dx.doi.org/10.1162/jocn_a_00969.

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Visual processing of complex objects is supported by the ventral visual pathway in the service of object identification and by the dorsal visual pathway in the service of object-directed reaching and grasping. Here, we address how these two streams interact during tool processing, by exploiting the known asymmetry in projections of subcortical magnocellular and parvocellular inputs to the dorsal and ventral streams. The ventral visual pathway receives both parvocellular and magnocellular input, whereas the dorsal visual pathway receives largely magnocellular input. We used fMRI to measure tool preferences in parietal cortex when the images were presented at either high or low temporal frequencies, exploiting the fact that parvocellular channels project principally to the ventral but not dorsal visual pathway. We reason that regions of parietal cortex that exhibit tool preferences for stimuli presented at frequencies characteristic of the parvocellular pathway receive their inputs from the ventral stream. We found that the left inferior parietal lobule, in the vicinity of the supramarginal gyrus, exhibited tool preferences for images presented at low temporal frequencies, whereas superior and posterior parietal regions exhibited tool preferences for images present at high temporal frequencies. These data indicate that object identity, processed within the ventral stream, is communicated to the left inferior parietal lobule and may there combine with inputs from the dorsal visual pathway to allow for functionally appropriate object manipulation.

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Cahill, Kyle, Timothy Jordan et Mukesh Dhamala. « Connectivity in the Dorsal Visual Stream Is Enhanced in Action Video Game Players ». Brain Sciences 14, n^o 12 (28 novembre 2024) : 1206. http://dx.doi.org/10.3390/brainsci14121206.

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Action video games foster competitive environments that demand rapid spatial navigation and decision-making. Action video gamers often exhibit faster response times and slightly improved accuracy in vision-based sensorimotor tasks. Background/Objectives: However, the underlying functional and structural changes in the two visual streams of the brain that may be contributing to these cognitive improvements have been unclear. Methods: Using functional and diffusion MRI data, this study investigated the differences in connectivity between gamers who play action video games and nongamers in the dorsal and ventral visual streams. Results: We found that action video gamers have enhanced functional and structural connectivity, especially in the dorsal visual stream. Specifically, there is heightened functional connectivity—both undirected and directed—between the left superior occipital gyrus and the left superior parietal lobule during a moving-dot discrimination decision-making task. This increased connectivity correlates with response time in gamers. The structural connectivity in the dorsal stream, as quantified by diffusion fractional anisotropy and quantitative anisotropy measures of the axonal fiber pathways, was also enhanced for gamers compared to nongamers. Conclusions: These findings provide valuable insights into how action video gaming can induce targeted improvements in structural and functional connectivity between specific brain regions in the visual processing pathways. These connectivity changes in the dorsal visual stream underpin the superior performance of action video gamers compared to nongamers in tasks requiring rapid and accurate vision-based decision-making.

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Hirayama, Kazumi, et Katsuhiko Takeda. « What is the dorsal visual stream doing ? » Higher Brain Function Research 35, n^o 2 (2015) : 197–98. http://dx.doi.org/10.2496/hbfr.35.197.

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Madary, Michael. « The dorsal stream and the visual horizon ». Phenomenology and the Cognitive Sciences 10, n^o 4 (15 juillet 2011) : 423–38. http://dx.doi.org/10.1007/s11097-011-9214-2.

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Chen, Qi, Ralph Weidner, Peter H. Weiss, John C. Marshall et Gereon R. Fink. « Neural Interaction between Spatial Domain and Spatial Reference Frame in Parietal–Occipital Junction ». Journal of Cognitive Neuroscience 24, n^o 11 (novembre 2012) : 2223–36. http://dx.doi.org/10.1162/jocn_a_00260.

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On the basis of double dissociations in clinical symptoms of patients with unilateral visuospatial neglect, neuropsychological research distinguishes between different spatial domains (near vs. far) and different spatial reference frames (egocentric vs. allocentric). In this fMRI study, we investigated the neural interaction between spatial domains and spatial reference frames by constructing a virtual three-dimensional world and asking participants to perform either allocentric or egocentric judgments on an object located in either near or far space. Our results suggest that the parietal–occipital junction (POJ) not only shows a preference for near-space processing but is also involved in the neural interaction between spatial domains and spatial reference frames. Two dissociable streams of visual processing exist in the human brain: a ventral perception-related stream and a dorsal action-related stream. Consistent with the perception–action model, both far-space processing and allocentric judgments draw upon the ventral stream whereas both near-space processing and egocentric judgments draw upon the dorsal stream. POJ showed higher neural activity during allocentric judgments (ventral) in near space (dorsal) and egocentric judgments (dorsal) in far space (ventral) as compared with egocentric judgments (dorsal) in near space (dorsal) and allocentric judgments (ventral) in far space (ventral). Because representations in the dorsal and ventral streams need to interact during allocentric judgments (ventral) in near space (dorsal) and egocentric judgments (dorsal) in far space (ventral), our results imply that POJ is involved in the neural interaction between the two streams. Further evidence for the suggested role of POJ as a neural interface between the dorsal and ventral streams is provided by functional connectivity analysis.

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Dwivedi, Kshitij, Michael F. Bonner, Radoslaw Martin Cichy et Gemma Roig. « Unveiling functions of the visual cortex using task-specific deep neural networks ». PLOS Computational Biology 17, n^o 8 (13 août 2021) : e1009267. http://dx.doi.org/10.1371/journal.pcbi.1009267.

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The human visual cortex enables visual perception through a cascade of hierarchical computations in cortical regions with distinct functionalities. Here, we introduce an AI-driven approach to discover the functional mapping of the visual cortex. We related human brain responses to scene images measured with functional MRI (fMRI) systematically to a diverse set of deep neural networks (DNNs) optimized to perform different scene perception tasks. We found a structured mapping between DNN tasks and brain regions along the ventral and dorsal visual streams. Low-level visual tasks mapped onto early brain regions, 3-dimensional scene perception tasks mapped onto the dorsal stream, and semantic tasks mapped onto the ventral stream. This mapping was of high fidelity, with more than 60% of the explainable variance in nine key regions being explained. Together, our results provide a novel functional mapping of the human visual cortex and demonstrate the power of the computational approach.

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Ray, Dipanjan, Nilambari Hajare, Dipanjan Roy et Arpan Banerjee. « Large-scale Functional Integration, Rather than Functional Dissociation along Dorsal and Ventral Streams, Underlies Visual Perception and Action ». Journal of Cognitive Neuroscience 32, n^o 5 (mai 2020) : 847–61. http://dx.doi.org/10.1162/jocn_a_01527.

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Visual dual-stream theory posits that two distinct neural pathways of specific functional significance originate from primary visual areas and reach the inferior temporal (ventral) and posterior parietal areas (dorsal). However, there are several unresolved questions concerning the fundamental aspects of this theory. For example, is the functional dissociation between ventral and dorsal stream driven by features in input stimuli or is it driven by categorical differences between visuoperceptual and visuomotor functions? Is the dual stream rigid or flexible? What is the nature of the interactions between the two streams? We addressed these questions using fMRI recordings on healthy human volunteers and employing stimuli and tasks that can tease out the divergence between visuoperceptual and visuomotor variants of dual-stream theory. fMRI scans were repeated after seven practice sessions that were conducted in a non-MRI environment to investigate the effects of neuroplasticity. Brain activation analysis supports an input-based functional dissociation and existence of context-dependent neuroplasticity in dual-stream areas. Intriguingly, premotor cortex activation was observed in the position perception task and distributed deactivated regions were observed in all perception tasks, thus warranting a network-level analysis. Dynamic causal modeling analysis incorporating activated and deactivated brain areas during perception tasks indicates that the brain dynamics during visual perception and actions could be interpreted within the framework of predictive coding. Effectively, the network-level findings point toward the existence of more intricate context-driven functional networks selective of “what” and “where” information rather than segregated streams of processing along ventral and dorsal brain regions.

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Goodale, Melvyn A. « Real action in a virtual world ». Behavioral and Brain Sciences 24, n^o 5 (octobre 2001) : 984–85. http://dx.doi.org/10.1017/s0140525x01350112.

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O'Regan & Noë run into some difficulty in trying to reconcile their “seeing as acting” proposal with the perception and action account of the functions of the two streams of visual projections in the primate cerebral cortex. I suggest that part of the problem is their reluctance to acknowledge that the mechanisms in the ventral stream may play a more critical role in visual awareness and qualia than mechanisms in the dorsal stream.

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Himmelbach, Marc, et Hans-Otto Karnath. « Dorsal and Ventral Stream Interaction : Contributions from Optic Ataxia ». Journal of Cognitive Neuroscience 17, n^o 4 (avril 2005) : 632–40. http://dx.doi.org/10.1162/0898929053467514.

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In monkeys and humans, two functionally specialized cortical streams of visual processing emanating from V1 have been proposed: a dorsal, action-related system and a ventral, perception-related pathway. Traditionally, a separate organization of the two streams is assumed; the extent of functional interaction is unknown. After lesions of the dorsal stream in patients with optic ataxia, it has recently been shown that the ventral perception-related system might contribute to visuo-motor processing if movements rely on remembered target positions. The ventral pathway thus seemed to participate in goal-directed movements, a function that previously has been assigned exclusively to the dorsal stream. We wondered whether different types of pointing movements are controlled by switching between two separated cortical pathways or whether a variable interaction of interconnected systems should be assumed. Our study investigated two acute stroke patients with optic ataxia following lesions of the dorsal stream in a delayed pointing task. The delays ranged from 0 to 10 sec. The patients' pointing error decreased in a linear manner with the length of time. The finding suggests a gradual change between dorsal and ventral control of reaching behavior, rather than a sudden switch between two separated cortical processing streams. Although our observations with two patients require further validation, the results suggest that the ventral and dorsal systems interact closely in the sensorimotor control of reaching behavior.

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Jackson, Stephen R. « Is the visual dorsal stream really very visual after all ? » Cognitive Neuroscience 1, n^o 1 (26 février 2010) : 68–69. http://dx.doi.org/10.1080/17588920903513177.

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Chieffi, Sergio. « Dysfunction of Magnocellular/dorsal Processing Stream in Schizophrenia ». Current Psychiatry Research and Reviews 15, n^o 1 (2 mai 2019) : 26–36. http://dx.doi.org/10.2174/1573400515666190119163522.

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Background: Patients with schizophrenia show not only cognitive, but also perceptual deficits. Perceptual deficits may affect different sensory modalities. Among these, the impairment of visual information processing is of particular relevance as demonstrated by the high incidence of visual disturbances. In recent years, the study of neurophysiological mechanisms that underlie visuo-perceptual, -spatial and -motor disorders in schizophrenia has increasingly attracted the interest of researchers. Objective: The study aims to review the existent literature on magnocellular/dorsal (occipitoparietal) visual processing stream impairment in schizophrenia. The impairment of relatively early stages of visual information processing was examined using experimental paradigms such as backward masking, contrast sensitivity, contour detection, and perceptual closure. The deficits of late processing stages were detected by examining visuo-spatial and -motor abilities. Results: Neurophysiological and behavioral studies support the existence of deficits in the processing of visual information along the magnocellular/dorsal pathway. These deficits appear to affect both early and late stages of visual information processing. Conclusion: The existence of disturbances in the early processing of visual information along the magnocellular/dorsal pathway is strongly supported by neurophysiological and behavioral observations. Early magnocellular dysfunction may provide a substrate for late dorsal processing impairment as well as higher-level cognition deficits.

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Milner, A. D. « Is visual processing in the dorsal stream accessible to consciousness ? » Proceedings of the Royal Society B : Biological Sciences 279, n^o 1737 (28 mars 2012) : 2289–98. http://dx.doi.org/10.1098/rspb.2011.2663.

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There are two highly interconnected clusters of visually responsive areas in the primate cortex. These two clusters have relatively few interconnections with each other, though those interconnections are undoubtedly important. One of the two main clusters (the dorsal stream) links the primary visual cortex (V1) to superior regions of the occipito-parietal cortex, while the other (the ventral stream) links V1 to inferior regions of the occipito-temporal cortex. According to our current understanding of the functional anatomy of these two systems, the dorsal stream's principal role is to provide real-time ‘bottom-up’ visual guidance of our movements online. In contrast, the ventral stream, in conjunction with top-down information from visual and semantic memory, provides perceptual representations that can serve recognition, visual thought, planning and memory offline. In recent years, this interpretation, initially based chiefly on studies of non-human primates and human neurological patients, has been well supported by functional MRI studies in humans. This perspective presents empirical evidence for the contention that the dorsal stream governs the visual control of movement without the intervention of visual awareness.

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Wokke, Martijn E., H. Steven Scholte et Victor A. F. Lamme. « Opposing Dorsal/Ventral Stream Dynamics during Figure-ground Segregation ». Journal of Cognitive Neuroscience 26, n^o 2 (février 2014) : 365–79. http://dx.doi.org/10.1162/jocn_a_00497.

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The visual system has been commonly subdivided into two segregated visual processing streams: The dorsal pathway processes mainly spatial information, and the ventral pathway specializes in object perception. Recent findings, however, indicate that different forms of interaction (cross-talk) exist between the dorsal and the ventral stream. Here, we used TMS and concurrent EEG recordings to explore these interactions between the dorsal and ventral stream during figure-ground segregation. In two separate experiments, we used repetitive TMS and single-pulse TMS to disrupt processing in the dorsal (V5/HMT+) and the ventral (lateral occipital area) stream during a motion-defined figure discrimination task. We presented stimuli that made it possible to differentiate between relatively low-level (figure boundary detection) from higher-level (surface segregation) processing steps during figure-ground segregation. Results show that disruption of V5/HMT+ impaired performance related to surface segregation; this effect was mainly found when V5/HMT+ was perturbed in an early time window (100 msec) after stimulus presentation. Surprisingly, disruption of the lateral occipital area resulted in increased performance scores and enhanced neural correlates of surface segregation. This facilitatory effect was also mainly found in an early time window (100 msec) after stimulus presentation. These results suggest a “push–pull” interaction in which dorsal and ventral extrastriate areas are being recruited or inhibited depending on stimulus category and task demands.

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Mascheretti, Sara, Denis Peruzzo, Chiara Andreola, Martina Villa, Tommaso Ciceri, Vittoria Trezzi, Cecilia Marino et Filippo Arrigoni. « Selecting the Most Relevant Brain Regions to Classify Children with Developmental Dyslexia and Typical Readers by Using Complex Magnocellular Stimuli and Multiple Kernel Learning ». Brain Sciences 11, n^o 6 (28 mai 2021) : 722. http://dx.doi.org/10.3390/brainsci11060722.

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Increasing evidence supports the presence of deficits in the visual magnocellular (M) system in developmental dyslexia (DD). The M system is related to the fronto-parietal attentional network. Previous neuroimaging studies have revealed reduced/absent activation within the visual M pathway in DD, but they have failed to characterize the extensive brain network activated by M stimuli. We performed a multivariate pattern analysis on a Region of Interest (ROI) level to differentiate between children with DD and age-matched typical readers (TRs) by combining full-field sinusoidal gratings, controlled for spatial and temporal frequencies and luminance contrast, and a coherent motion (CM) sensitivity task at 6%-CML6, 15%-CML15 and 40%-CML40. ROIs spanning the entire visual dorsal stream and ventral attention network (VAN) had higher discriminative weights and showed higher act1ivation in TRs than in children with DD. Of the two tasks, CM had the greatest weight when classifying TRs and children with DD in most of the ROIs spanning these streams. For the CML6, activation within the right superior parietal cortex positively correlated with reading skills. Our approach highlighted the dorsal stream and the VAN as highly discriminative areas between children with DD and TRs and allowed for a better characterization of the “dorsal stream vulnerability” underlying DD.

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Pelekanos, Vassilis, Marieke Mur et Katherine R. Storrs. « Extracting Object Identity : Ventral or Dorsal Visual Stream ? » Journal of Neuroscience 36, n^o 24 (15 juin 2016) : 6368–70. http://dx.doi.org/10.1523/jneurosci.1102-16.2016.

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Tankus, Ariel, et Itzhak Fried. « Visuomotor Coordination and Motor Representation by Human Temporal Lobe Neurons ». Journal of Cognitive Neuroscience 24, n^o 3 (mars 2012) : 600–610. http://dx.doi.org/10.1162/jocn_a_00160.

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The division of cortical visual processing into distinct dorsal and ventral streams is a key concept in primate neuroscience [Goodale, M. A., & Milner, A. D. Separate visual pathways for perception and action. Trends in Neurosciences, 15, 20–25, 1992; Steele, G., Weller, R., & Cusick, C. Cortical connections of the caudal subdivision of the dorsolateral area (V4) in monkeys. Journal of Comparative Neurology, 306, 495–520, 1991]. The ventral stream is usually characterized as a “What” pathway, whereas the dorsal stream is implied in mediating spatial perception (“Where”) and visually guided actions (“How”). A subpathway emerging from the dorsal stream and projecting to the medial-temporal lobe has been identified [Kravitz, D. J., Saleem, K. S., Baker, C. I., & Mishkin, M. A new neural framework for visuospatial processing. Nature Reviews Neuroscience, 12, 217–230, 2011; Cavada, C., & Goldman-Raiuc, P. S. Posterior parietal cortex in rhesus monkey: I. Parcellation of areas based on distinctive limbic and sensory cortico-cortical connections. Journal of Comparative Neurology, 287, 393–421, 1989]. The current article studies the coordination of visual information typically associated with the dorsal stream (“Where”), with planned movements, focusing on the temporal lobe. We recorded extracellular activity from 565 cells in the human medial-temporal and frontal lobes while 13 patients performed cued hand movements with visual feedback (visuomotor task), without feedback (motor task), or observed visual feedback without motor movement (visual-only task). We discovered two different neural populations in the human medial-temporal lobe. One consists of motor-like neurons representing hand position, speed or acceleration during the motor task but not during the visuomotor or visual tasks. The other is specific to the parahippocampal gyrus (an area known to process visual motion [Gur, M., & Snodderly, D. M. Direction selectivity in V1 of alert monkeys: Evidence for parallel pathways for motion processing. Journal of Physiology, 585, 383–400, 2007; Sato, N., & Nakamura, K. Visual response properties of neurons in the parahippocampal cortex of monkeys. Journal of Neurophysiology, 90, 876–886, 2003]) and encodes speed, acceleration, or direction of hand movements, but only during the visuomotor task: neither during visual-only nor during motor tasks. These findings suggest a functional basis for the anatomical subpathway between the dorsal stream and the medial-temporal lobe. Similar to the recent expansion of the motor control process into the sensory cortex [Matyas, F., Sreenivasan, V., Marbach, F., Wacongne, C., Barsy, B., Mateo, C., et al. Motor control by sensory cortex. Science, 330, 1240–1243, 2010], our findings render the human medial-temporal lobe an important junction in the process of planning and execution of motor acts whether internally or externally (visually) driven. Thus, the medial-temporal lobe might serve as an integration node between the two processing streams. Our findings thus shed new light on the brain mechanisms underlying visuomotor coordination which is a crucial capacity for everyday survival, whether it is identifying and picking up food, sliding a key into a lock, driving a vehicle, or escaping a predator.

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Thomas, Nicole A., Oliver Schneider, Carl Gutwin et Lorin J. Elias. « Dorsal Stream Contributions to Perceptual Asymmetries ». Journal of the International Neuropsychological Society 18, n^o 2 (2 décembre 2011) : 251–59. http://dx.doi.org/10.1017/s1355617711001585.

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AbstractNeurologically normal individuals show a bias toward the left side of space, referred to as pseudoneglect due to its similarity to clinical hemispatial neglect. The left bias appears to be stronger in the lower visual field during free-viewing, which could result from preferential dorsal stream processing. The current experiments used modified greyscales tasks, incorporating motion and isoluminant color, to explore whether targeting dorsal or ventral stream processing influenced the strength of the left bias. It was expected that the left bias would be stronger on the motion task than on a task incorporating isoluminant color. In Study 1, similar left biases were observed during prolonged viewing for luminance, motion and red, but not green color. The unexpected finding of a leftward bias for red under prolonged viewing was replicated in Study 2. A leftward bias for motion was also evident during 150 ms viewing in Study 2. In Study 3, the left bias was not apparent when using a blue/yellow condition, suggesting the left bias for red under prolonged viewing was likely unique to red. Furthermore, the leftward bias for red disappeared under brief viewing conditions. It is suggested that dorsal stream processing likely underlies visual field differences in pseudoneglect. (JINS, 2012, 18, 251–259)

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Rafal, Robert D. « Seeing without a Scene : Neurological Observations on the Origin and Function of the Dorsal Visual Stream ». Journal of Intelligence 12, n^o 5 (11 mai 2024) : 50. http://dx.doi.org/10.3390/jintelligence12050050.

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In all vertebrates, visual signals from each visual field project to the opposite midbrain tectum (called the superior colliculus in mammals). The tectum/colliculus computes visual salience to select targets for context-contingent visually guided behavior: a frog will orient toward a small, moving stimulus (insect prey) but away from a large, looming stimulus (a predator). In mammals, visual signals competing for behavioral salience are also transmitted to the visual cortex, where they are integrated with collicular signals and then projected via the dorsal visual stream to the parietal and frontal cortices. To control visually guided behavior, visual signals must be encoded in body-centered (egocentric) coordinates, and so visual signals must be integrated with information encoding eye position in the orbit—where the individual is looking. Eye position information is derived from copies of eye movement signals transmitted from the colliculus to the frontal and parietal cortices. In the intraparietal cortex of the dorsal stream, eye movement signals from the colliculus are used to predict the sensory consequences of action. These eye position signals are integrated with retinotopic visual signals to generate scaffolding for a visual scene that contains goal-relevant objects that are seen to have spatial relationships with each other and with the observer. Patients with degeneration of the superior colliculus, although they can see, behave as though they are blind. Bilateral damage to the intraparietal cortex of the dorsal stream causes the visual scene to disappear, leaving awareness of only one object that is lost in space. This tutorial considers what we have learned from patients with damage to the colliculus, or to the intraparietal cortex, about how the phylogenetically older midbrain and the newer mammalian dorsal cortical visual stream jointly coordinate the experience of a spatially and temporally coherent visual scene.

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Schmidt, Thomas. « The Finger in Flight : Real-Time Motor Control by Visually Masked Color Stimuli ». Psychological Science 13, n^o 2 (mars 2002) : 112–18. http://dx.doi.org/10.1111/1467-9280.00421.

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Current theories of dual visual systems suggest that color is processed in a ventral cortical stream that eventually gives rise to visual awareness but is only indirectly involved in visuomotor control mediated by the dorsal stream. If the dorsal stream is indeed less sensitive to color than the ventral stream, color stimuli blocked from awareness by visual masking should also be blocked from guiding fast motor responses. In this study, pointing movements to one of two isoluminant color targets were preceded by consistent or inconsistent color primes. Trajectories were strongly affected by priming, with kinematics implying a continuous flow of color information into executive brain areas while the finger was already moving. Motor effects were more sensitive to color of the primes than were deliberate attempts to identify the primes in forced-choice tasks based on visual awareness. Priming was observed even when masking was complete.

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Claeys, K. G. « Color Discrimination Involves Ventral and Dorsal Stream Visual Areas ». Cerebral Cortex 14, n^o 7 (28 mars 2004) : 803–22. http://dx.doi.org/10.1093/cercor/bhh040.

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Hesse, Constanze, Keira Ball et Thomas Schenk. « Pointing in Visual Periphery : Is DF's Dorsal Stream Intact ? » PLoS ONE 9, n^o 3 (13 mars 2014) : e91420. http://dx.doi.org/10.1371/journal.pone.0091420.

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DUTTON, GORDON N. « ‘Dorsal stream dysfunction’ and ‘dorsal stream dysfunction plus’ : a potential classification for perceptual visual impairment in the context of cerebral visual impairment ? » Developmental Medicine & ; Child Neurology 51, n^o 3 (mars 2009) : 170–72. http://dx.doi.org/10.1111/j.1469-8749.2008.03257.x.

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BARRETT, ANNA M., J. BRENT CROSSON, GREGORY P. CRUCIAN et KENNETH M. HEILMAN. « Horizontal line bisections in upper and lower body space ». Journal of the International Neuropsychological Society 6, n^o 4 (mai 2000) : 455–59. http://dx.doi.org/10.1017/s135561770064403x.

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Whereas the ventral cortical visual stream is important in object recognition, the dorsal stream is specialized for spatial localization. In humans there are also right and left hemisphere asymmetries in visual processing: the left hemisphere being more important in object recognition and the right in specifying spatial locations. Based on these dorsal–ventral and right–left where–what dichotomies, one would expect that the dorsal right hemisphere systems would be most activated during spatial localization tasks, and this activation may induce a leftward spatial bias in lower space. To determine if visual stimuli in upper and lower body space evoke different hemispheric activation, we had 12 normal participants bisect horizontal lines above and below eye level. Participants erred leftward in lower body space relative to upper body space (M = 1.3345 mm and 0.4225 mm, respectively; p = .011). In upper body space, bisection errors did not differ from zero, but in lower body space, errors tended to deviate leftward (M = 1.3345 mm, differs from null hypotheses at p = .0755). Our results are consistent with dorsal stream/right hemisphere activation when performing a spatial localization task in lower versus upper body space. (JINS, 2000, 6, 455–459.)

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Cooper, Sarah Anne, et Michael O'Sullivan. « Here, there and everywhere : higher visual function and the dorsal visual stream ». Practical Neurology 16, n^o 3 (19 janvier 2016) : 176–83. http://dx.doi.org/10.1136/practneurol-2015-001168.

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McDowell, Nicola, et Gordon N. Dutton. « Hemianopia and Features of Bálint Syndrome following Occipital Lobe Hemorrhage : Identification and Patient Understanding Have Aided Functional Improvement Years after Onset ». Case Reports in Ophthalmological Medicine 2019 (25 mars 2019) : 1–7. http://dx.doi.org/10.1155/2019/3864572.

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Introduction. Cerebral visual impairment (CVI) can present around birth or any time thereafter. Homonymous hemianopia is a common feature. The concept that functional improvement is unattainable augurs against active management. Dorsal stream dysfunction (or Bálint syndrome when severe) results from bilateral posterior parietal dysfunction but may go undetected, especially in children. Case Presentation. At 16 the patient suffered spontaneous left occipital lobe brain hemorrhage from a ruptured arteriovenous malformation. This was surgically excised. Short lived right upper limb intermittent jerking, with additional left sided weakness, ensued. Anomalous EEG recordings, with right-sided bias, arose from the posterior temporoparietal area. A right homonymous hemianopia was evident. During the ensuing 17 years she experienced multiple complex difficulties, until, at a lecture describing how to identify and support children with CVI, she realized she herself had many of the difficulties described. Visual assessment identified hemianopia and dorsal stream dysfunction. Discussion. Following identification, characterization, and explanation of the impact of her visual difficulties, she both gained greater awareness of her visual difficulties and their impact and developed a range of strategies leading to functional improvement of her visual field loss and amelioration of her dorsal stream dysfunction, with great improvement in quality of life.

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Wu, Wayne. « Is Vision for Action Unconscious ? » Journal of Philosophy 117, n^o 8 (2020) : 413–33. http://dx.doi.org/10.5840/jphil2020117826.

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Empirical work and philosophical analysis have led to widespread acceptance that vision for action, served by the cortical dorsal stream, is unconscious. I argue that the empirical argument for this claim is unsound. That argument relies on subjects’ introspective reports. Yet on biological grounds, in light of the theory of primate cortical vision, introspection has no access to dorsal stream mediated visual states. It is wrongly assumed that introspective reports speak to absent phenomenology in the dorsal stream. In light of this, I consider a different conception of consciousness’s relation to agency in terms of access. While theoretical reasons suggest that the inaccessibility of the dorsal stream to conceptual report is evidence that it is unconscious, this position begs important questions about agency and consciousness. I propose a broader notion of access in respect of the guidance of intentional agency as the crucial link connecting agency to consciousness.

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Mahon, Bradford Z., Nicholas Kumar et Jorge Almeida. « Spatial Frequency Tuning Reveals Interactions between the Dorsal and Ventral Visual Systems ». Journal of Cognitive Neuroscience 25, n^o 6 (juin 2013) : 862–71. http://dx.doi.org/10.1162/jocn_a_00370.

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It is widely argued that the ability to recognize and identify manipulable objects depends on the retrieval and simulation of action-based information associated with using those objects. Evidence for that view comes from fMRI studies that have reported differential BOLD contrast in dorsal visual stream regions when participants view manipulable objects compared with a range of baseline categories. An alternative interpretation is that processes internal to the ventral visual pathway are sufficient to support the visual identification of manipulable objects and that the retrieval of object-associated use information is contingent on analysis of the visual input by the ventral stream. Here, we sought to distinguish these two perspectives by exploiting the fact that the dorsal stream is largely driven by magnocellular input, which is biased toward low spatial frequency visual information. Thus, any tool-selective responses in parietal cortex that are driven by high spatial frequencies would be indicative of inputs from the ventral visual pathway. Participants viewed images of tools and animals containing only low, or only high, spatial frequencies during fMRI. We find an internal parcellation of left parietal “tool-preferring” voxels: Inferior aspects of left parietal cortex are driven by high spatial frequency information and have privileged connectivity with ventral stream regions that show similar category preferences, whereas superior regions are driven by low spatial frequency information. Our findings suggest that the automatic activation of complex object-associated manipulation knowledge is contingent on analysis of the visual input by the ventral visual pathway.

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Goodale, Melvyn A., et Jonathan S. Cant. « Coming to grips with vision and touch ». Behavioral and Brain Sciences 30, n^o 2 (avril 2007) : 209–10. http://dx.doi.org/10.1017/s0140525x07001483.

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AbstractDijkerman & de Haan (D&dH) propose a convincing model of somatosensory organization that is inspired by earlier perception-action models of the visual system. In this commentary, we suggest that the dorsal and ventral visual streams both contribute to the control of action, but in different ways. Using the example of grip and load force calibration, we show how the ventral stream can invoke stored information about the material properties of objects originally derived from the somatosensory system.

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Minini, Loredana, Andrew J. Parker et Holly Bridge. « Neural Modulation by Binocular Disparity Greatest in Human Dorsal Visual Stream ». Journal of Neurophysiology 104, n^o 1 (juillet 2010) : 169–78. http://dx.doi.org/10.1152/jn.00790.2009.

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Although cortical activation to binocular disparity can be demonstrated throughout occipital and parietal cortices, the relative contributions to depth perception made by different human cortical areas have not been established. To investigate whether different regions are optimized for specific disparity ranges, we have measured the responses of occipital and parietal areas to different magnitudes of binocular disparity. Using stimuli consisting of sinusoidal depth modulations, we measured cortical activation when the stimuli were located at pedestal disparities of 0, 0.1, 0.35, and 0.7° from fixation. Across all areas, occipital and parietal, there was an increase in BOLD signal with increasing pedestal disparity, compared with a plane at zero disparity. However, the greatest modulation of response by the different pedestals was found in the dorsal visual areas and the parietal areas. These differences contrast with the response to the zero disparity plane, compared with fixation, which is greatest in the early visual areas, smaller in the ventral and dorsal visual areas, and absent in parietal areas. Using the simultaneously acquired psychophysical data we also measured a greater response to correct than to incorrect trials, an effect that increased with rising pedestal disparity and was greatest in dorsal visual and parietal areas. These results illustrate that the dorsal stream, along both its occipital and parietal branches, can reliably discriminate a large range of disparities.

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Duffield, Stuart, et Jesse Gomez. « Dorsal stream receptive field development entails growing visual field coverage ». Journal of Vision 21, n^o 9 (27 septembre 2021) : 2413. http://dx.doi.org/10.1167/jov.21.9.2413.

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Subramanian, Janani, et Carol L. Colby. « Shape selectivity and remapping in dorsal stream visual area LIP ». Journal of Neurophysiology 111, n^o 3 (1 février 2014) : 613–27. http://dx.doi.org/10.1152/jn.00841.2011.

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We explore the visual world by making rapid eye movements (saccades) to focus on objects and locations of interest. Despite abrupt retinal image shifts, we see the world as stable. Remapping contributes to visual stability by updating the internal image with every saccade. Neurons in macaque lateral intraparietal cortex (LIP) and other brain areas update information about salient locations around the time of a saccade. The depth of information transfer remains to be thoroughly investigated. Area LIP, as part of the dorsal visual stream, is regarded as a spatially selective area, yet there is evidence that LIP neurons also encode object features. We sought to determine whether LIP remaps shape information. This knowledge is important for understanding what information is retained from each glance. We identified 82 remapping neurons. First, we presented shapes within the receptive field and tested for shape selectivity in a fixation task. Among the remapping neurons, 28 neurons (34%) were selective for shape. Second, we presented the same shapes in the future location of the receptive field around the time of the saccade and tested for shape selectivity during remapping. Thirty-one (38%) neurons were selective for shape. Of 11 neurons that were shape selective in both tasks, 5 showed significant correlation between shape selectivity in the two tasks. Across the population, there was a weak but significant correlation between responses to shape in the two tasks. Our results provide neurophysiological evidence that remapped responses in area LIP can encode shape information as well as spatial information.

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Levy, Tamar, Vincent Walsh et Michal Lavidor. « Dorsal stream modulation of visual word recognition in skilled readers ». Vision Research 50, n^o 9 (avril 2010) : 883–88. http://dx.doi.org/10.1016/j.visres.2010.02.019.

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Galletti, Claudio, et Patrizia Fattori. « The dorsal visual stream revisited : Stable circuits or dynamic pathways ? » Cortex 98 (janvier 2018) : 203–17. http://dx.doi.org/10.1016/j.cortex.2017.01.009.

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Hebart, M. N., et G. Hesselmann. « What Visual Information Is Processed in the Human Dorsal Stream ? » Journal of Neuroscience 32, n^o 24 (13 juin 2012) : 8107–9. http://dx.doi.org/10.1523/jneurosci.1462-12.2012.

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Alfieri, Paolo, Laura Cesarini, Paola De Rose, Daniela Ricci, Angelo Selicorni, Deny Menghini, Andrea Guzzetta et al. « Visual processing in Noonan syndrome : Dorsal and ventral stream sensitivity ». American Journal of Medical Genetics Part A 155, n^o 10 (9 septembre 2011) : 2459–64. http://dx.doi.org/10.1002/ajmg.a.34229.

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Fias, Wim, Patrick Dupont, Bert Reynvoet et Guy A. Orban. « The Quantitative Nature of a Visual Task Differentiates between Ventral and Dorsal Stream ». Journal of Cognitive Neuroscience 14, n^o 4 (1 mai 2002) : 646–58. http://dx.doi.org/10.1162/08989290260045873.

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The aim of the present positron emission tomography (PET) study was to investigate how visual processing in dorsal and ventral streams depends on the quantitative nature of the task. In the same—different task, participants identified the presence of an orientation difference between two gratings, presented centrally in succession. In the quantification task, participants estimated the magnitude of the difference and compared it to a fixed standard. Detection of dimming of the fixation point was used as a control task. Visual input, motor responses, and performance were equated across tasks. Subtracting same— different from quantification yielded significant activation in the left superior parietal lobule and left ventral premotor cortex, consistent with results obtained in number-processing tasks. The reverse subtraction yielded activation in the right inferior temporal gyrus, in agreement with earlier results. These results demonstrate that a single attribute can be processed either in the ventral or dorsal stream, depending on the cognitive operations required by the tasks.

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Braddick, Oliver, Janette Atkinson, Erik Newman, Natacha Akshoomoff, Joshua M. Kuperman, Hauke Bartsch, Chi-Hua Chen, Anders M. Dale et Terry L. Jernigan. « Global Visual Motion Sensitivity : Associations with Parietal Area and Children's Mathematical Cognition ». Journal of Cognitive Neuroscience 28, n^o 12 (décembre 2016) : 1897–908. http://dx.doi.org/10.1162/jocn_a_01018.

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Sensitivity to global visual motion has been proposed as a signature of brain development, related to the dorsal rather than ventral cortical stream. Thresholds for global motion have been found to be elevated more than for global static form in many developmental disorders, leading to the idea of “dorsal stream vulnerability.” Here we explore the association of global motion thresholds with individual differences in children's brain development, in a group of typically developing 5- to 12-year-olds. Good performance was associated with a relative increase in parietal lobe surface area, most strongly around the intraparietal sulcus and decrease in occipital area. In line with the involvement of intraparietal sulcus, areas in visuospatial and numerical cognition, we also found that global motion performance was correlated with tests of visuomotor integration and numerical skills. Individual differences in global form detection showed none of these anatomical or cognitive correlations. This suggests that the correlations with motion sensitivity are unlikely to reflect general perceptual or attentional abilities required for both form and motion. We conclude that individual developmental variations in global motion processing are not linked to greater area in the extrastriate visual areas, which initially process such motion, but in the parietal systems that make decisions based on this information. The overlap with visuospatial and numerical abilities may indicate the anatomical substrate of the “dorsal stream vulnerability” proposed as characterizing neurodevelopmental disorders.

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Yousefi, Bardia, et Chu Kiong Loo. « Comparative Study on Interaction of Form and Motion Processing Streams by Applying Two Different Classifiers in Mechanism for Recognition of Biological Movement ». Scientific World Journal 2014 (2014) : 1–12. http://dx.doi.org/10.1155/2014/723213.

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Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM) as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM) has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility.

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Valyear, Kenneth F., et Jody C. Culham. « Observing Learned Object-specific Functional Grasps Preferentially Activates the Ventral Stream ». Journal of Cognitive Neuroscience 22, n^o 5 (mai 2010) : 970–84. http://dx.doi.org/10.1162/jocn.2009.21256.

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In one popular account of the human visual system, two streams are distinguished, a ventral stream specialized for perception and a dorsal stream specialized for action. The skillful use of familiar tools, however, is likely to involve the cooperation of both streams. Using functional magnetic resonance imaging, we scanned individuals while they viewed short movies of familiar tools being grasped in ways that were either consistent or inconsistent with how tools are typically grasped during use. Typical-for-use actions were predicted to preferentially activate parietal areas important for tool use. Instead, our results revealed several areas within the ventral stream, as well as the left posterior middle temporal gyrus, as preferentially active for our typical-for-use actions. We believe these findings reflect sensitivity to learned semantic associations and suggest a special role for these areas in representing object-specific actions. We hypothesize that during actual tool use a complex interplay between the two streams must take place, with ventral stream areas providing critical input as to how an object should be engaged in accordance with stored semantic knowledge.

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Elliott, Digby, Luc Tremblay et Timothy N. Welsh. « A fast ventral stream or early dorsal-ventral interactions ? » Behavioral and Brain Sciences 25, n^o 1 (février 2002) : 105. http://dx.doi.org/10.1017/s0140525x02310021.

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Several lines of evidence indicate that rapid target-aiming movements, involving both the eyes and hand, can be biased by the visual context in which the movements are performed. Some of these contextual influences carry-over from trial to trial. This research indicates that dissociation between the dorsal and ventral systems based on speed, conscious awareness, and frame of reference is far from clear.

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Hansen, Peter C., John F. Stein, Sam R. Orde, Jonathan L. Winter et Joel B. Talcott. « Are dyslexics?? ? visual deficits limited to measures of dorsal stream function ? » Neuroreport 12, n^o 7 (mai 2001) : 1527–30. http://dx.doi.org/10.1097/00001756-200105250-00045.

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Almeida, Jorge, Bradford Z. Mahon et Alfonso Caramazza. « The Role of the Dorsal Visual Processing Stream in Tool Identification ». Psychological Science 21, n^o 6 (18 mai 2010) : 772–78. http://dx.doi.org/10.1177/0956797610371343.

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Voss, Patrice, et Robert J. Zatorre. « Early visual deprivation changes cortical anatomical covariance in dorsal-stream structures ». NeuroImage 108 (mars 2015) : 194–202. http://dx.doi.org/10.1016/j.neuroimage.2014.12.063.

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Doniger, Glen M., John J. Foxe, Micah M. Murray, Beth A. Higgins et Daniel C. Javitt. « Impaired Visual Object Recognition and Dorsal/Ventral Stream Interaction in Schizophrenia ». Archives of General Psychiatry 59, n^o 11 (1 novembre 2002) : 1011. http://dx.doi.org/10.1001/archpsyc.59.11.1011.

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