Question

In the original eye deprivation experiments Hubel and Wiesel closed one eye of a few days old kitten. A couple of month later they measured neuronal activity in the contralateral V1. What did they find?

Group of answer choices

They found mostly monocular cells.

They found mostly ocular dominance category 2 through 6 type cells.

They found mostly binocular cells.

They found that the receptive field of V1 neurons became large and nonspecific.

They found that V1 neurons no longer responded to visual stimulus.

Answer 1

B. They found mostly ocular dominance category 2 through 6 type cells.

David Hubel and Torsten Wiesel’s experiments showed that if a kitten is deprived of normal visual experience during a critical period at the start of its life, the circuitry of the neurons in its visual cortex is irreversibly altered.

In each of a number of newborn kittens, one eyelid was sutured shut. The kitten was allowed to grow up that way, and when it reached adulthood (around 6 months), its eyelid was opened again. Recordings were than made of the electrophysiological activity in each of the kitten’s eyes. These recordings showed an abnormally low number of neurons reacting in the eye that had been sutured shut, and an abnormally high number in the other eye. Macroscopic observation of the visual cortex showed that the ocular dominance columns for the eye that had been left open had grown larger, while those for the eye that had been closed had shrunk.

Remarkably, Hubel and Wiesel also found that if the eye of an adult cat was sutured shut for a year, the responses of the cells in its visual cortex remain identical in all respects to those of a normal cat. Later experiments showed that suturing a cat’s eye shut had no effect on its visual cortex unless this visual deprivation took place during the first three months of the cat’s life.