Figure 1.

Population vector readout of the owl's midbrain map of auditory space. A, Map of auditory space in the OT showing an overrepresentation of frontal space. Neural receptive fields are topographically arranged, where azimuthal tuning varies along the anterior–posterior axis (dashed lines) and tuning to elevation along the dorsoventral axis (solid lines), plotted in degrees (Adapted with permission from Knudsen, 1982, their Fig. 12). B, Population vector readout of the owl's midbrain space map. Each neuron in the space map is represented by a vector pointing toward its preferred direction (colored arrows). The overrepresentation of frontal space (dashed line) drives the resultant vector slightly more frontal than the actual location, matching the underestimation of sound sources observed across species. Adapted with permission from Peña et al., 2019 (their Fig. 1). C, Relative proportion of neuronal tuning to physiologically available ITDs. The Gaussian function predicted in Fischer and Peña (2011) was used to characterize the overrepresentation of frontal space, based on data in A. Approximately three times more neurons are tuned to frontal locations (ITDs near 0 µs; filled circle) than peripheral locations (ITDs > 100 µs; open circles).