Chapter 2 Local circuitry of the somatosensory thalamus in the processing of sensory information

Abstract

Publisher Summary Laboratory has been concerned for several years with elucidating the nature of the synaptic circuitry of the somatosensory thalamus, and much of the information has been obtained by various experimental approaches that have been conducted in the analysis of this circuitry. This chapter provides new information about the intrinsic circuitry of the primate thalamus and compares the findings with previously obtained findings in rat and cat. It is evident that thalamocortical projection neurons that transfer information from principle afferent sources to the cerebral cortex are subject to a variety of influences: excitatory projections from the principal afferent, facilitatory influences from the cortex, GABA mediated inhibition from the thalamic reticular nucleus and local circuit neurons (LCNs), and a mixture of excitatory and inhibitory effects from brainstem projections. The chapter shows that synaptic projections from two major elements of the somatosensory afferent system, the dorsal column nuclei and the spinal cord, are likely to have very different forms of information processing within the thalamus, one from the other, because of differing relationships with inhibitory LCNs.