Split Brain

Question 1

What does the corpus callosum do

Answer 1

Joins the two hands of the brain together and allows them to communicate

Question 2

Describe what happens when the brain is split

Answer 2

A commissurotomy is the division of the two hemispheres by surgery . The optic nerve is NOTTTTTsevered (visual pathways cross over at the optic chiasm.)

Question 3

Explain left and right vision stuff

Answer 3

• Left visual field is processed by the right hemisphere which is used in drawing and spatial tasks
• right visual field is processed by the left hemisphere which is used in language (speaking and writing)

Question 4

What did Sperry do

Answer 4

• recruited 11 participants for a quasi expedient in 1986
• all patients had their corpus callosum cut to treat epilepsy
• he asked his patients to gaze at a fixation point in the middle of a screen
• images or words were flashed to either side of the fixation point for 1/10th of a second

Question 5

Explain epilepsy

Answer 5

Epilepsy causes an electrical Storm in the brain and produces a seizure for the patient. Cutting the brain helps as an electrical seizure can’t bounce between the severed hemispheres

Question 6

Say what you see results (can)

Answer 6

Patient saw a picture of an orange in their right visual field, (which was processed by the left hemisphere) and they can verbally describe the picture and write down that it was an orange

Question 7

Say what you see results (can’t)

Answer 7

Patient saw a picture of a cat in their LVF (processed by RH) and they say they didn’t see anything

Question 8

Drawing task (can’t)

Answer 8

Patient shown a picture of a saw in RVF (processed by LH), can draw photo with right hand but not very well

Question 9

Drawing task (can)

Answer 9

Patient is shown a picture of a key in the LVF (processed by RH). They can draw a clear beautiful photo with the left hand (even if right handed)

Question 10

How did sperry show a lil bit of language in the right hemisphere

Answer 10

• a picture of a wall clock wold be shown to the right hemisphere and the patient was able to pick out a wrist watch with the left hand
• a write watch is physically different to a clock, so the patient was not guided by a visual image alone. We can assume that semantic processing took place as the link between the two objects is purely semantic
• shows that although language is primarily left hemisphere, the right does have some language function
  (Clock and watch are different but bro knew cause they are are words that have same meaning —using language)