A major question in neuroscience is how excitatory glutamatergic and inhibitory GABA-ergic cells differ in their response to altered sensory experience. The immediate early gene Arc is specific to excitatory cells and we have shown that it is involved in ocular dominance plasticity. We use functional two-photon calcium imaging in critical period heterozygote and homozygote Arc-GFP mice, in which GFP is under the control of the Arc promoter, to assay how genetic deletion of the Arc gene in GFP expressing putative excitatory cells influences response properties of these cells and their nearby neighbors not expressing GFP (putative inhibitory cells). In response to 5-6 days of monocular deprivation both GFP-positive and –negative cells in Arc heterozygotes show a significant shift in ocular dominance. However, a reduced shift occurs in GFP-positive cells within Arc homozygotes. Surprisingly, GFP-negative cells in Arc homozygotes show a normal shift in ocular dominance suggesting that plasticity in putative inhibitory neurons can operate independently of excitatory cell plasticity. To our knowledge, we provide the first in vivo calcium imaging data from the visual cortex of genetically identified knockout cells at single–cell resolution.

Society for Neuroscience Abstract, 2009.