“…This observation was later confirmed by retrograde labeling of different classes of efferent collicular neurons (Castiglioni et al, 1978;Huerta et al, 1981;Murray and Coulter, 1982;Yamasaki et al, 1986). In parallel, there is a patchy innervation of most, if not all, of the collicular afferents (from cortex, Goldman and Nauta, 1976;Kü nzle and Akert, 1977;Leichnetz et al, 1981;Segal et al, 1983;Clemo and Stein, 1983; from subcortical sensory relays, Kudo and Niimi, 1980;Tashiro et al, 1980;Huerta et al, 1981;Kudo, 1981;Huerta and Harting, 1982;Harting and Van Lieshout, 1991; from basal ganglia, Jayaraman et al, 1977;Graybiel, 1978a;Beckstead et al, 1979;Harting and Van Lieshout, 1991;Redgrave et al, 1992; from cerebellum, Kawamura et al, 1982; from hypothalamus, Rieck et al, 1986). Patches in the intermediate layers are regularly described in the frontal plane as a series of groups of either terminals or neurons with generally increased size from medial to lateral SC.…”