What had previous research shown about early visual experience in cats?
Cats were reared experiencing one orientation in each eye - found visual cortex neurones = monocularly driven -> the orientation of neurones reflect the pattern seen by that eye. Shows VC neurones = susceptible to plasticity
1 of 10
What was the aim of the study?
To compare behavioural and neurophysiological consequences of limiting the visual experience of kittens to one orientation ( horizontal/vertical)
2 of 10
Who were the 'participants'?
Kittens reared from birth in the dark. Most = kept in experiment till 5 months old, 2 = kept to 7 1/2 months for neurophysiological examination
3 of 10
Outline the procedure
Kittens reared in dark till 2 weeks - manipulation of environment began. Spent 5 hours/day in the 'bin' w/ a collar on so they couldn't see their own body's orientations. Did not seem to cause distress to the cat
4 of 10
What was the 'bin' like?
2m x 46cm, w/ a glass platform halfway up & lid on top. Stripes ran from top to bottom & were either horizontal or vertical
5 of 10
What were the similarities in the behavioural results?
The cats appeared to have visual deficits - despite normal pupillary reactions, they had no startle reflex, visual spacing ability & navigated the room by touch. They'd show the fear response when reaching the end of the table they were walking on
6 of 10
What happened after 10 hours in the lit room?
A lot of deficits disappeared - they developed a startle response, visual spacing & jumped off tables. But -> they were still clumsy, visually tracked moving objects w/ jerky head movements & had poor depth perception
7 of 10
What were the differences in behavioural results?
Vertical cats couldn't see horizontal orientation & vice versa. When board w/ lines in 'right' orientation thrust at them -> startle response, compared to no response for 'wrong'. Same results for rod being moved in diff orientations
8 of 10
What were the neurophysiological results?
Normal cat's preferred orientation -> balance of vertical & horizontal. Horizontal cats had no neurones that fire seeing vertical orientations & vertical cats had none that fire seeing horizontal
9 of 10
What was the conclusion?
'The visual experience of these animals in early life has modified their brains, and there are profound perceptual consequences' - shows the role of nurture in visual development & evidence for brain plasticity (in cats at least)
10 of 10
Other cards in this set
Card 2
Front
What was the aim of the study?
Back
To compare behavioural and neurophysiological consequences of limiting the visual experience of kittens to one orientation ( horizontal/vertical)
Comments
No comments have yet been made