AAMC FL Practice Exam

In the context of brain function, what occurs in the 'split brain' condition?

1. Both hemispheres function independently

2. Visual information is processed in one hemisphere only

3. Both sides of the brain equally share information

4. Only the left hemisphere controls language

The correct answer is: Visual information is processed in one hemisphere only

In the 'split brain' condition, which typically arises from a surgical procedure that severs the corpus callosum to alleviate severe epilepsy, the two hemispheres of the brain are unable to communicate effectively with one another. This leads to the unique situation where visual information presented to one hemisphere can only be processed and understood by that hemisphere. For example, if a visual stimulus is presented to the right visual field, it is processed by the left hemisphere, which is responsible for language and verbal tasks. Conversely, if the stimulus is presented to the left visual field, the right hemisphere, which specializes in spatial and non-verbal processing, receives the information but cannot verbally articulate it due to the disconnection. This phenomenon underscores the lateralization of brain function, demonstrating that each hemisphere can operate independently, but also has its limitations with regards to communication and processing information, particularly in a split brain scenario.