Biological-Sperry Flashcards
(20 cards)
Background
Split-brain surgery is done to treat severe epilepsy by cutting the corpus callosum, which connects the two hemispheres of the brain.
Sperry wanted to see if the two halves of the brain functioned differently when disconnected.
Procedure
Visual tasks: Patients saw images briefly shown to one side of their visual field (left or right).
Left visual field: processed by right hemisphere.
Right visual field: processed by left hemisphere.
Tactile tasks: Patients were asked to touch objects with their left or right hand (without seeing them).
Left hand: controlled by right hemisphere.
Right hand: controlled by left hemisphere.
Tests were designed to test language abilities, object recognition, and memory.
Aim
Sample
11 split-brain patients who had already undergone surgery to sever the corpus callosum
Findings
Right hemisphere (controlled by the left hand/left visual field): Could recognize objects and draw but couldn’t speak about them.
Left hemisphere (controlled by the right hand/right visual field): Could speak and name objects but had trouble recognizing or drawing them if shown to the left visual field.
No communication between the two hemispheres, so patients struggled to describe objects seen only by one eye or hand.
Conclusions
The left hemisphere is dominant for language and speech.
The right hemisphere is more involved in spatial processing and visual recognition.
The two hemispheres of the brain have specialized functions and work independently when disconnected.
Split-brain Surgery
Surgery that cuts the brain’s connection (corpus callosum) between the left and right sides to stop seizures.
Left and Right Hemispheres
Left side: Controls the right side of the body and helps with talking and thinking.
Right side: Controls the left side of the body and helps with creativity and space awareness.
Corpus Callosum
The part of the brain that connects the two sides. Sperry’s study involved cutting this to see what happens.
Brain Specialization
Each side of the brain has its own job. The left side does language and logic, and the right side handles creativity and space.
Visual Fields
Right visual field: Seen by the left side of the brain.
Left visual field: Seen by the right side of the brain.
Sperry tested what happens when only one side of the brain sees something.
Sensory Input
Testing how things like touch or sight are processed by each side of the brain.
Contralateral Control
The idea that each side of the brain controls the opposite side of the body. Left brain = right hand, right brain = left hand.
Sperry’s Findings
When the two brain sides can’t talk to each other, they act independently. The left side talks, but the right side can’t speak.
Functional Specialization
Each brain side has special jobs. The left side is better at talking and thinking, while the right is better with space and creativity.
Experimental Methods
Sperry showed pictures or objects to just one side of the brain to see how the person responded.
Nature vs. Nurture
Nature: Sperry’s research shows that the brain has special functions in each hemisphere (left and right).
Nurture: But experiences and the environment also shape how these areas develop. The debate is about how much of who we are is due to biology vs. life experience.
Determinism vs. Free Will
Determinism: After split-brain surgery, the brain’s two sides act separately, suggesting that behavior might be controlled by biology, not free will.
Free Will: This makes us question how much control we really have over our actions
Reductionism vs. Holism
Reductionism: Sperry’s research looks at the brain in parts (left side vs. right side).
Holism: Others think we should see the brain as a whole, not just separate parts, because it works together.
Ethical Issues
Ethics: Is it okay to do brain surgery that changes how a person thinks and behaves? Some question whether this is too extreme, even for health reasons.
