FIG. 1.

Higher-order thalamocortical pathways in the somatosensory slice are intact. A and B: focal biocytin injections in the posterior medial nucleus (POm) labels fiber tracts that traverse across the ventral posterior nucleus (VP), the thalamic reticular nucleus (TRN), and the internal capsule, before traversing into layer 4 of the secondary somatosensory cortex (SII) (B; tracings of labeled axons). C–E: photostimulation with caged glutamate in POm (D) results in excitatory postsynaptic currents (EPSCs) from a layer 4 neuron in SII (C). E: response map plot showing the mean EPSC at each stimulation site.