Blakemoore And Cooper Flashcards
Out;line th background to Blakemoore and Cooper
-Hirsch and Spinelli at Stanford university
-made kittens view horizontal lines in one eye and vertical lines in te other eye an found that most of the neurones in the visual cortex are monocularly driven (driven by one eye) and the preferred orientation of the neurones reflected tat patterns experienced in that eye
-suggests that neurones in the usual cortex show blain plasticity in that they developed in the environment they have experienced
Define what is meant by Visual cortex
-The primary region of the brain that recieves intergrates and processes visual information relayed from the retinas
Define what is meat by te startle response
-The reaction to an unexpected stimuli that is intense and has a rapid onset
Define what is meant by visual placing
The reflex act of animas in playing their legs to reach out for a surface that they can see
Outline the overall aim of Blakemore and Cooper
The aim of this study was to limit the visual experience of kittens to one orientation either vertical or horizontal strips and to compare the behavioural consequences of this restricted visual environment on the kitten
Describe the sample of Blakemore and Cooper
-2 kittens from birth
-The first two weeks of their life they were placed in a pitch black completely dark room
Outline what the environment was like from weeks 2 until 5 months
-visual experience was manipulated by exposing them to either vertically oriented lines or horizontal
-Cat placed in cylinder that was 2m tall 46cm in diameter and had a glass platform halfway up where the kittens lay
-kittens wore a ruff so that all they were looking at was the walls and notthemselve
-Only 5 hours of light a da the rest it was pitch black
What happened to the kittens once they were 5 months old
-The kittens he finished the experiment and had passed through the critical and sensitive stages of usual development
What visual deficits did the kittens show when first paced in a well lit room
-Normal papillary reflexes but showed no startle response when an object or hand was thrust towards it
-Showed no visual placing
-showed no startle response
-navigated around the room by touch and showed a fear response when they reached the edge of a table
What deficits were recovered from within 10 hours
-visual placing
-startle response
-The kitten was able to jump to the floor
What deficits remained after 10 hours
-visual tracking of objects was clumsy, jerky head movements and they often tried too reach out for objects moving across the room that were way out of their reach
-They often bumped into things
How did the horizontiically and vertically raised cats differ
-Both were virtually blind to contours perpendicular to the orientation that they had grew up with
1)A sheet of perspen with thick black and white lines was presented to the kittens. They showed no reaction if it was presented to them perpendicular to the orientation that they had grew up seeing. But would respond with the startle response in the correct orientation.
2)A rod was shaken in front of the kittens, a likely age to play with kittens who will tr and catch the rod. The kitten would only respond to it if it was shown at the ‘correct’ orientation
Outline the procedure of the neurophysiological test
-Both cats were anaesthetised and then paralysed and their eyes open.
-Electrodes were then inserted into the primary visual cortex to take readings from individual neurones
-The visual neuron activity was recorded to show the optimal orientation or each neurone
Outline what was found from the neurophysiological test in Blakemore and Cooper
-In a normal cat visual neurones demonstrate a preferred orientation; a cat experiencing the world normally would have a balance of vertical and horizontal neurones
-In the horizontally raised kitten There were no/little neurones for vertical orientations
0In the vertically raised kitten There were no/ little neurones for horizontal orientations
Outline the conclusions from Blakemore and Cooper
-visual experience in an animals early life has modified the brains and then there are profound perceptional consequences:
-The development of he visual cortex s affected by the environment
-Example of brain plasticity demonstrates the role of nurture in the development of vision
