In a study, researchers tested split-brain patients whose corpus callosum had been severed. Each patient fixated on a central dot while the word "KEY" was flashed to the left visual field and "RING" to the right visual field. When asked to verbally report what they saw, patients said "RING," but when asked to use their left hand to select an object behind a screen, they chose a key.
Why did patients select the key with their left hand?
- Acheck_circle
The left hand is controlled by the right hemisphere, which received 'KEY'
- B
The right hemisphere transmitted 'KEY' to the left hemisphere via subcortical pathways
- C
The left hand is preferred for object recognition tasks
- D
The left hand bypasses cortical processing in split-brain patients
Explanation
Motor control is contralateral: the right hemisphere, which received the word KEY in the left visual field, controls the left hand and can select the matching object nonverbally.