Fig. 3.

Maps of BF from the left and right hemispheres of monkeys X (top) and Z (bottom). Rostral is up in all panels; medial is toward the midline of the figure. Axes are in mm, relative to the AI/R border. The BFs encountered within each penetration are averaged to assign each site to an octave bin, color coded from violet (low) to red (high). Open squares, sites of auditory responsiveness but no clear BF; dashed squares, sites from which no auditory response could be evoked. Sampling was generally in a 1 mm grid, but in the right hemisphere of animal X and the left hemisphere of animal Z (top right and bottom left), the low-frequency area was sampled at a finer 0.5 mm grain—for clarity, smaller squares mark these sites. Each site was assigned to AI, R, or the belt (see text), as delineated by the heavy black lines; dashed lines separate the fields of the belt.