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Why is "blindsight" blind? A new perspective on primary visual cortex, recurrent activity and visual awareness
1University of Westminster, Faculty of Science and Technology, Department of Psychology, 309 Regent Street, W1B 2HW London, UK; Brain Research Unit, O.V. Lounasmaa Laboratory, School of Science, Aalto University, PO BOX 15100, 00076 Aalto, Finland.
Consciousness and Cognition
|September 30, 2014
Summary
Blindsight, a condition where individuals lack visual awareness despite detecting stimuli, may not stem from primary visual cortex (V1) damage. Instead, it could result from disrupted long-range neural synchrony necessary for global awareness.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Visual Perception
Background:
- The phenomenon of blindsight suggests primary visual cortex (V1) is crucial for visual awareness.
- It's theorized that extrastriate activation requires feedback to V1 for conscious perception.
Purpose of the Study:
- To evaluate the theoretical framework linking V1 to visual awareness.
- To re-examine the tenets of blindsight research.
- To explore alternative explanations for the loss of awareness in blindsight.
Main Methods:
- Review and evaluation of existing empirical evidence and arguments.
- Analysis of the role of V1 lesions in visual awareness.
- Exploration of the relationship between neural synchrony and visual awareness.
Main Results:
- The loss of phenomenal awareness in blindsight may not solely depend on feedback activity in V1.
- Blindsight might be explained by the disruption of long-range synchronous oscillatory activity required for global cognitive functions.
- Preserved extrastriate neuronal selectivity allows for local read-out and detection of basic visual attributes.
Conclusions:
- Visual awareness is a global function dependent on inter-areal long-range synchronous oscillatory activity.
- V1 lesions disrupt this synchrony, leading to blindsight.
- Blindsight involves local neural read-out from extrastriate areas, explaining preserved detection abilities.
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