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The Split-Brain Saga| title | The Split-Brain Saga |
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| start_date | 2026/10/12 |
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| schedule | 15h15 |
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| online | no |
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| location_info | Room B10 |
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| summary | What happens when the Corpus Callosum is cut for the alleviation of intractable epilepsy? This question goes back to early work in the 1940-ies by William van Wagenen and Andrew Akelaitis. It was Roger Sperry and Michael Gazzaniga who proposed the iconic model of two separate conscious agents in the two separated hemispheres in the 1960-ies, and this model stood unchallenged until recently.
In this presentation, I will first discuss why we started our own investigations into the split-brain phenomenon. Subsequently, I will present an overview of the extensive studies that we carried out with two split-brain patients. Overall, we replicated the standard finding that stimuli cannot be compared across visual half-fields, indicating that each hemisphere processes information independently of the other. Yet, crucially, we show that the canonical textbook findings that a split-brain patient can only respond to stimuli in the left visual half-field with the left hand, and to stimuli in the right visual half-field with the right hand and verbally, are not universally true. Across a wide variety of tasks, split-brain patients with a complete and radiologically confirmed transection of the corpus callosum showed full awareness of presence, and well above chance-level recognition of location, orientation and identity of stimuli throughout the entire visual field, irrespective of response type (left hand, right hand, or verbally).
These findings provoked an (adversarial) exchange across the Atlantic Ocean, more experiments, and finally an attempt to find common ground. Interestingly, these discussions led to a more general question about “what do white matter bundles do?”. |
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| responsibles | Allen |
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Workflow history| from state (1) | to state | comment | date |
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| submitted | published | | 2026/10/06 12:04 UTC |
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