deletion of c-Fos in D1+ MSNs blunts the dendritic spine changes normally induced by cocaine in the NAc, indicating a role for c-Fos in mediating these synaptic plasticity changes. Finally, the group observed no change in the induction of cocaine CPP, but found that loss of c-Fos in D1+ MSNs prevented extinction of cocaine CPP. Such data illustrate a dynamic role for c-Fos induction in D1+ MSNs, however, one cannot rule out the differential effects at the behavioral level as being mediated by any of several other limbic brain regions that express the D1 receptor.
