hemispheric lateralisation

Question 1

what is hemispheric lateralisation?

Answer 1

the idea that two hemispheres are functionally different

certain mental processes and behaviours are mainly controlled by on hemisphere rather than the other,

e.g. language

Question 2

what is the difference between localisation and lateralisation?

Answer 2

localisation = identification of function in a specific region of the brain.

whereas lateralisation is the identification of a function in one hemisphere.

Question 3

which hemisphere processes the left visual field?

Answer 3

right hemisphere

Question 4

which hemisphere processed the right visual field?

Answer 4

left hemisphere

Question 5

where does the left visual field project to on the retina?

Answer 5

to the nasal retina of the left eye and the temporal retina of the right eye

Question 6

which part of the retina sends info to the contralateral hemisphere?

were does it occur

Answer 6

the nasal retina

it occurs at the optic chiasm

Question 7

which part of the retina does NOT send information to the contralateral hemisphere and where is it actually sent?

Answer 7

info from the temporal retina does not cross to the contralateral hemisphere, and is instead sent to the ipsilateral hemisphere.

Question 8

at which point is the visual information combined, and which structure is involved?

Answer 8

one the info reaches the cortex, it is shared across hemispheres via the corpus callous

Question 9

where does the right visual field project information to?

Answer 9

to the nasal retina of the right eye and to the temporal retina of the left eye.

Question 10

what happens to visual info if the corpus callous is severed?

Answer 10

each hemisphere will only have info from the contralateral visual field.

Question 11

which hemisphere is language largely processed in?

Answer 11

left

Question 12

which hemispheres are faces and facial emotion processed in

Answer 12

right

Question 13

who conducted experiments for split brain patients?

Answer 13

Roger sperry

Question 14

what do we mean b split brain patients?

Answer 14

Surgery for intractable epilepsy involved severing the corpus callosum to prevent the spread of electrical discharge

– this is known as a commissurotomy, preventing communication between the hemispheres.

Question 15

what was sperrys experiment?

Answer 15

He used a divided field task, in which patients would look ahead a dot located centrally on the screen, and then visual information would be presented to the left or right visual field for 0.1 seconds.

Underneath the screen was a table, in which participants could feel, but not see objects.

Question 16

why was the visual stimulus presented so briefly?

Answer 16

So that participants could not orient their head to the stimulus, which would then mean both hemispheres would receive the information.

Question 17

What happened when visual information was presented to the right visual field and why?

Answer 17

Subjects would correctly recall the information because language is processed in the contralateral left visual hemisphere.

Question 18

What would happen when visual information was presented to the left visual field, and why?

Answer 18

Patients would report not seeing any information, because the stimulus was processed by the contralateral right hemisphere, which does not have access to verbal information, without the input of the left hemisphere.

Question 19

What do we conclude from work on split-brain patients?

Answer 19

• the left hemisphere is responsible for speech and language and the right hemisphere specializes in visual-spatial processing and facial recognition.
• It not shown that the brain is organised into discrete regions with specific sections responsible for specific task.
• it suggests that the connectivity between the different regions is as important as the operation of the different parts.

Question 19

What happened when participants were asked to recognise objects presented to the left visual field by touch?

why?

Answer 19

Participants were able to identify the objects by touch with their left hand, because the right hemisphere was able to process spatial information.

Question 20

What happened when composite faces (composed of a female and a male face), and why?

Answer 20

The ppt would say ‘man’ but the left hand would select the woman.

The left hemisphere had superior verbal description and the right superior matching a face to a picture.