Synaptic organization of the lateralis medialis-suprageniculate nuclear (LM-Sg) complex in the cat

The purpose of this chapter is to describe the afferent connections of the lateralis medialis-suprageniculate nuclear (LM-Sg) complex, and to point out the ultrastructural neural circuit of this complex. The anatomical patterns of connectivity and principles of organization of the LM-Sg complex have been recently established. Among the thalamic nuclei, the lateralis posterior-pulvinar the lateralis posterior-pulvinar (LP-pulvinar) complex is known to be a principal component of the “extrageniculate” thalamus. The most medial zone of the LP-pulvinar complex is the LM-Sg complex. There are certain differences in connective pattern between the LM-Sg complex and other subdivisions of the LP-pulVinar Complex. The deeper collicular layers sending axons to the LM- Sg complex contain neurons that respond to visual, somatic, and auditory, and/or multimodal stimuli. In addition, the chapter also examines the afferent connections of the LM-Sg complex using the wheat germ agglutinin - horseradish peroxidase (WGA-HRP) technique.