Question

how long does one eye have to be deprived of stimulation early in life in order to reduce its ability to activate visual cortex?

a few seconds
a few months
a few years
a few minutes
a few days

Explanation:

Early - life visual deprivation studies (e.g., Hubel and Wiesel's work on critical periods in vision development) show that even a relatively short - term deprivation during the critical period can have significant effects. A few days of deprivation during the early critical period for visual cortex development can lead to reduced ability of the deprived eye to activate the visual cortex. A few seconds or minutes are too short to cause such a long - lasting change at the level of cortical activation ability. A few years is much longer than the typical critical period duration for the initial establishment of these connections (although there can be some plasticity later, the question is about the early - life period). A few months may be longer than the minimal required time for such an effect during the most sensitive early phase.

Answer:

a few days