Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex.
Motion area V5/MT+ shows a variety of characteristic visual responses, often linked to perception, which are heavily influenced by its rich connectivity with the primary visual cortex (V1). This human motion area also receives a number of inputs from other visual regions, including direct subcortica...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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2015
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| _version_ | 1826261635616997376 |
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| author | Ajina, S Kennard, C Rees, G Bridge, H |
| author_facet | Ajina, S Kennard, C Rees, G Bridge, H |
| author_sort | Ajina, S |
| collection | OXFORD |
| description | Motion area V5/MT+ shows a variety of characteristic visual responses, often linked to perception, which are heavily influenced by its rich connectivity with the primary visual cortex (V1). This human motion area also receives a number of inputs from other visual regions, including direct subcortical connections and callosal connections with the contralateral hemisphere. Little is currently known about such alternative inputs to V5/MT+ and how they may drive and influence its activity. Using functional magnetic resonance imaging, the response of human V5/MT+ to increasing the proportion of coherent motion was measured in seven patients with unilateral V1 damage acquired during adulthood, and a group of healthy age-matched controls. When V1 was damaged, the typical V5/MT+ response to increasing coherence was lost. Rather, V5/MT+ in patients showed a negative trend with coherence that was similar to coherence-related activity in V1 of healthy control subjects. This shift to a response-pattern more typical of early visual cortex suggests that in the absence of V1, V5/MT+ activity may be shaped by similar direct subcortical input. This is likely to reflect intact residual pathways rather than a change in connectivity, and has important implications for blindsight function. It also confirms predictions that V1 is critically involved in normal V5/MT+ global motion processing, consistent with a convergent model of V1 input to V5/MT+. Historically, most attempts to model cortical visual responses do not consider the contribution of direct subcortical inputs that may bypass striate cortex, such as input to V5/MT+. We have shown that the signal change driven by these non-striate pathways can be measured, and suggest that models of the intact visual system may benefit from considering their contribution. |
| first_indexed | 2024-03-06T19:24:30Z |
| format | Journal article |
| id | oxford-uuid:1b3d0dd2-8425-4e35-81c8-d806f4028bfb |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:24:30Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | oxford-uuid:1b3d0dd2-8425-4e35-81c8-d806f4028bfb2022-03-26T10:59:17ZMotion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:1b3d0dd2-8425-4e35-81c8-d806f4028bfbEnglishSymplectic Elements at Oxford2015Ajina, SKennard, CRees, GBridge, HMotion area V5/MT+ shows a variety of characteristic visual responses, often linked to perception, which are heavily influenced by its rich connectivity with the primary visual cortex (V1). This human motion area also receives a number of inputs from other visual regions, including direct subcortical connections and callosal connections with the contralateral hemisphere. Little is currently known about such alternative inputs to V5/MT+ and how they may drive and influence its activity. Using functional magnetic resonance imaging, the response of human V5/MT+ to increasing the proportion of coherent motion was measured in seven patients with unilateral V1 damage acquired during adulthood, and a group of healthy age-matched controls. When V1 was damaged, the typical V5/MT+ response to increasing coherence was lost. Rather, V5/MT+ in patients showed a negative trend with coherence that was similar to coherence-related activity in V1 of healthy control subjects. This shift to a response-pattern more typical of early visual cortex suggests that in the absence of V1, V5/MT+ activity may be shaped by similar direct subcortical input. This is likely to reflect intact residual pathways rather than a change in connectivity, and has important implications for blindsight function. It also confirms predictions that V1 is critically involved in normal V5/MT+ global motion processing, consistent with a convergent model of V1 input to V5/MT+. Historically, most attempts to model cortical visual responses do not consider the contribution of direct subcortical inputs that may bypass striate cortex, such as input to V5/MT+. We have shown that the signal change driven by these non-striate pathways can be measured, and suggest that models of the intact visual system may benefit from considering their contribution. |
| spellingShingle | Ajina, S Kennard, C Rees, G Bridge, H Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex. |
| title | Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex. |
| title_full | Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex. |
| title_fullStr | Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex. |
| title_full_unstemmed | Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex. |
| title_short | Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex. |
| title_sort | motion area v5 mt response to global motion in the absence of v1 resembles early visual cortex |
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