Figure 3. SC activity across the dorsal–ventral axis. A, Histogram of sampled recording depths in the SC with sensory (blue, n = 79), sensorimotor (red, n = 80), or vocal premotor (green, n = 83) neurons. Asterisks indicate mean depth for each functional class of neuron, sensory (blue), sensorimotor (red), premotor (green). Across all pairwise comparisons, the mean depths were significantly different (two-tailed t test, sensory vs sensorimotor, p = 5.2e−5, df = 157; sensorimotor vs motor, p = 2.7e−3, df = 161; sensory vs motor, p = 1.7e−10, df = 160). B, Histological reconstruction of silicon probe tract. Left to right, Serial coronal sections arranged from rostral to caudal; the distance to bregma is indicated above each section. Lesions from silicon probe are indicated in red for each section, SC boundaries are shown with black lines, and the expanded portion of each coronal section on the bottom row are indicated in blue boxes on top row. Individual layers of the SC are also indicated in the expanded view of each coronal section on the bottom row. Identification of layers was performed by making comparisons with previous histological reconstructions in bats and other species (Covey et al., 1987; May, 2006; and Big Brown Bat Stereotaxis Brain Atlas, courtesy of E. Covey, University of Washington).