biopsychology- hemispheric lateralisation

Question 1

hemispheric lateralisation

Answer 1

2 hemispheres of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other i.e. language

Question 2

localisation of function

Answer 2

is the identification of function in a specific region of the brain e.g. the production of speech is localised to Broca’s area

Question 3

lateralisation of function

Answer 3

the identification of a function in one hemisphere e.g. the right hemisphere specialised in visual-spatial processing and facial recognition

Question 4

Which hemisphere processes the left visual field?

Answer 4

right hemisphere

Question 5

Which hemisphere processes the right visual field?

Answer 5

left hemipshere

Question 6

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

Answer 6

the nasal retina

Question 7

where does the information sent to the contralateral hemisphere occur?

Answer 7

at the optic chasm

Question 8

Which part of the retina does not send information to the contralateral hemisphere, and where is it sent?

Answer 8

Information from the temporal retina does not cross to the contralateral hemisphere, and instead sent to the ipsilateral hemisphere (same side)

Question 9

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

Answer 9

Once the information reaches the cortex, it is shared across hemispheres via the corpus callosum

Question 10

Where does the right visual field project information to?

Answer 10

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

Question 11

What happens to visual information if the corpus callosum is severed?

Answer 11

Each hemsiphere will only have information from the contralateral visual field (from the temporal retina)

Question 12

Which hemisphere is language largely processed in?

Answer 12

left

Question 13

Which hemisphere are faces and facial emotion processed in?

Answer 13

right

Question 14

Who conducted experiments on split-brain patients?

Answer 14

Sperry

Question 15

What do we mean by ‘split-brain’ patients?

Answer 15

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

Question 16

What was Sperry’s experiment?

Answer 16

-used a divided field task, p’s look at dot located centrally on the screen. then visual info presented to left or right visual field for 0.1 seconds
-underneath screen was a table, p’s could feel but not see objects

Question 17

Why was the visual stimulus presented so briefly?

Answer 17

so p’s couldn’t orient their head to stimulus which would cause both hemispheres to receive info

Question 18

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

Answer 18

-subjects correctly recall the info as language processed in the contralateral left visual hemisphere

Question 19

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

Answer 19

-p’s would nit report being any in of as as contralateral right hemisphere doesn’t have access to verbal info w/o input of left hemisphere

Question 20

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

Answer 20

able to identify by touch with left hand as right hemisphere could process spatial info

Question 21

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

Answer 21

-p would say ‘man’ but left hand select the woman
-left hemisphere had superior verbal description
-right superior matching a face to a picture.

Question 22

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

Answer 22

-left hemisphere responsible for speech and language
-right hemisphere specialises in visual-spatial processing and facial recognition
-connectivity between regions is as important the operation of different parts

Question 23

ao3- superior processing in some split brain patients

Answer 23

E- luck et al. (1989) split brain p’s twice as fast at identifying odd one out in array of similar objects. Kim peek could read 2 pages in around 10 seconds, had perfect recall of 12,000 books. likely developed bilateral language centres
E- Kingstone et al. (1995) suggests the LH’s superior processing abilities are ‘watered down’ by the inferior right hemisphere
L- supports Perry’s findings of ‘left brain’ and ‘right brain’ distinct in functions and abilities

Question 24

ao3 hemispheric lateralisation- methodological issues, population validity

Answer 24

-sample 11 p’s
-may not be large enough sample to generalise
-may be inappropriate to make generalisations ab non-epileptic brain patterns from these p’s
-epileptic seizures could have made changes to the brain that could have affected the findings. confounding variable.

Question 25

ao3 hemispheric lateralisation- contradictory evidence

Answer 25

-Gazzaniga (1998) suggests some early discoveries of research have been disconfirmed by more recent ones
-patient JW developed capacity to speak out of right hemisphere. so could speak ab info presented to the right brain
-indicates brains ability to adapt and shows language may not be exclusively limited to left hemisphere
-may not be as simplified as Sperry indicated and challenges validity of research