Question

In the development of the nervous system, what is a ‘critical period,’ and describe an example of a critical period in the visual system

Answer 1

Critical period is defined as a stage in lifespan of organism where nervous system is extremely sensitive to ceratin environmental stimuli like light,sound , touch etc.

David H. Hubel and Torsten Wiesel (1963) showed that cats that had one eye sewn shut from birth to three months of age (monocular deprivation) only fully developed vision in the open eye n not closed one. The kittens had abnormally small ocular dominance (less developed) connected to the closed eye, and abnormally large, wide columns connected to the open eye.

Since critical period is done, It was basically impossible for the kittens to develop vision in the closed eye. This never happens in adult cats even when one eye was sewn shut for a year because vision of adult cats were fully developed in critical period.so basically critical period of vision is from birth to around 6 months of age.