ALTERED SENSORY PROCESSING IN THE SOMATOSENSORY CORTEX OF THE MOUSE MUTANT BARRELLESS

Mice homozygous for the barrelless (brl) mutation, mapped here to chro mosome 11, lack barrel-shaped arrays of cell clusters termed ''barrels '' in the primary somatosensory cortex. Deoxyglucose uptake demonstrat ed that the topology of the cortical whisker representation is neverth eless preserved. Anterograde tracers revealed a lack of spatial segreg ation of thalamic afferents into individual barrel territories, and si ngle-cell recordings demonstrated a lack of temporal discrimination of center from surround information. Thus, structural segregation of tha lamic inputs is not essential to generate topological order in the som atosensory cortex, but it is required for discrete spatiotemporal rela y of sensory information to the cortex.