Cellular correlates to spatial learning in the rat hippocampus.

Learning through exploration gives increased synaptic field potentials in the perforant path/dentate synapses, largely due to an activity-dependent brain temperature increase. After temperature compensation, spatial learning was associated with small, but significant, STP-like changes of the field potential lasting 20-30 min. A group of spatially trained adult rats showed faster spatial learning and about 10% higher basal dendritic spine density (LY-filled) compared to two control groups. With unchanged dendritic length and branching pattern, the results suggest the formation of new synapses.