Blakemore and Cooper Flashcards
What is the function of neurons in the visual cortex of a normal cat?
They are selective for the orientation of lines and edges in the whole visual field.
How can early visual experience affect the orientation selectivity of neurons in cats?
Early visual experience can change the orientation selectivity of neurons.
What was the setup of the previous research involving kittens and visual stripes?
Kittens were reared with one eye viewing vertical stripes and the other eye viewing horizontal stripes.
In the previous research, how many neurons were studied and what was the outcome?
Out of 21 neurons, 20 had receptive fields that matched the pattern of stripes experienced by the eye.
What was the aim of the study?
To look at the influence of early visual experience on the development of the visual system in kittens.
What was the method of the study?
Laboratory experiment having and independant design.
What was the sample of the study?
2 kittens.
Where were the kittens raised from birth?
In a dark room.
At what age were the kittens introduced to a special apparatus, and for how long each day?
At 2 weeks old, for 5 hours a day.
Describe the apparatus the kittens were placed in.
The kitten stood on a glass table inside a cylinder (no corners no edges) which was covered with either vertical or horizontal black and white stripes.
What restricted the kittens’ visual field?
They wore a collar that restricted their visual field, preventing them from seeing their own body.
At what age were the kittens observed, and where?
At 5 months old, in a well-lit room with tables and chairs.
What were the kittens’ movement abilities within 10 hours of being placed in a normal environment?
They could jump with ease from a chair to the floor, but were clumsy when chasing moving objects and often bumped into furniture.
What was the result of the line recognition test?
They showed ‘behavioural blindness’ - those raised in the horizontal environment could not detect vertically aligned objects, and vice versa. Only the eyes of kittens raised with vertical stripes followed a vertically held rod.
At what age were the kittens’ neurones studied?
7.5 months old.
How were the neurones studied?
The kittens were anaesthetised, and neurones in the visual cortex were studied.
What were the findings of the neuronal study?
Horizontal plane neurones did not ‘fire off’ in kittens raised in the vertical environment, and vertical plane neurones did not ‘fire off’ in kittens raised in the horizontal environment. 125 neurones were studied from two cats, one horizontally, and one vertically exposed.
What does the research suggest about the visual cortex during maturation?
The visual cortex may adapt itself to the nature of its visual experience during maturation and illustrates neural plasticity.
What are the two evolutionary advantages discussed regarding an animal’s brain?
It is an evolutionary advantage for an animal’s brain to have hard-wired capacities at birth, such as the ability to respond to certain orientations, and it is also an advantage for the brain to be able to adapt to environmental conditions.
What change may occur in cells based on environmental stimuli?
Cells may change their preferred orientation towards that of the commonest type of environmental stimulus.
What is a note from this study?
This study raises ethical issues
