Visual Cortex

The region of cortex that receives visual input first and is believed to carry out the bulk of visual processing. It is located in the back of the brain in the occipital lobe.

Description

 * V1
 * monocular
 * binocular
 * V2

General Plasticity

 * Monocular deprivation (MD) during critical periods leads to a hebbian-type competition in binocular regions (t his is Ocular dominance plasticity [ODP]) and a 'weakening' of circuitry in monocular.
 * FS interneuron spiking strongly depressed in vivo cat after 6h(?) of MD

Sleep and Plasticity
Much is known about how experience affects plasticity in VC. This provides opportunity to investigate how experience and sleep work together to affect plasticity.

Sleep inhibits plasticity

 * There is evidence that sleep deprivation, REM sleep deprivation (RSD), or lesion of midbrains REM center can enhance effect of MD in LGN in vivo.
 * Did not record sleep
 * RSD can delay closure of critical period in in vitro analog of ODP.
 * did not record sleep

Sleep promotes plasticity

 * After 6 hrs of MD, kittens show little ODP if awake following surgery, but 2x plasticity after sleep. Sleep and extent of plasticity were correlated. Unlikely to be caused by differences in stress hormone levels (which they test and find need to be 10x higher levels to cause effects).
 * NMDAR antagonists have been shown to inhibit ODP during post-MD sleep.
 * After sleep, evoked responses to non-deprived eye become stronger in cat.
 * RSD strongly reduces ERK activation in VC and normal enhancement of ODP after sleep in cat.