The sensorimotor slice.

The reciprocal connections between primary motor cortex (M1) and primary somatosensory cortex (S1) are hypothesized to play a role in an animal's ability to update its motor plan in response to changes in the sensory periphery. These interactions provide the sensory cortex with anticipatory knowledge of motor plans. In the mouse neocortex there are representations of the body surface within both M1 and S1. Utilizing physiologically targeted micro injections of biotinylated dextran amine into either the whisker representation of M1 (wM1) or S1 (wS1) we characterized the axonal pathways connecting these two areas. We then used this data to determine a plane of section that contained both whisker M1 and whisker S1 and maintained the axonal pathway between these two areas. In vitro physiological studies demonstrated that excitatory synaptic connections are maintained in this novel plane of section. The sensorimotor slice is an ideal preparation to study inter-areal cortical connectivity.