Functional correlates of immediate early gene expression in visual cortex and hippocampus

The expression of immediate-early genes (IEGs) in visual cortex is necessary for certain forms of neuronal plasticity and plays a critical role in visual development. How IEG expression correlates with neural activity and how it changes with visuomotor learning is still unclear. Using transgenic mice expressing GFP under control of different IEG promoters, we chronically recorded both neural activity using a red calcium indicator and IEG expression levels in primary visual cortex (V1) during visuomotor learning. We quantify correlations between neural activity and expression of three different IEGs c-Fos, EGR1 and Arc and find that expression of all three IEGs correlates positively with neural activity. However, we find that the different IEGs are regulated differentially during visuomotor learning, and that IEG expression profile correlates with functional response type of the neuron. Neurons that exhibit strong motor-related activity express higher levels of EGR1, while neurons that exhibit visually driven activity express higher levels of Arc. These findings suggest that different IEG expression levels might correlate with plastic changes in the functional type of input a neuron in V1 layer 2/3 receives.