Figure 7.

Three types of neurons in the IC. Large GABAergic tectothalamic cells (1) are encircled by VGLUT2⁺ endings. Small GABAergic neurons lack axosomatic glutamate inputs (2). Non-GABAergic neurons (3) that presumably use glutamate as a transmitter express VGLUT2 (Herzog et al., 2001). There are two kinds of tectothalamic cells; inhibitory and excitatory, and the vast majority of inhibitory tectothalamic neurons are large GABAergic cells with VGLUT2⁺ axosomatic endings. All cell types receive inhibitory axosomatic inputs (i.e., GABA and glycine) (Merchán et al., 2005). Note that distribution of terminals on dendrites is speculative.