Illustration of cat auditory cortex, recording microelectrode, and primary auditory cortex activity.

(A) Schematic of cat auditory cortex organization highlighting the location of primary auditory cortex (A1). (B) Schematic of recording microelectrode. Filled circles show location of recording channels illustrated in panels C and D. (C) Peri-stimulus time histogram (PSTH) recorded in A1 during exposure to a 500-ms long upward FM sweep signal. Recording position is illustrated in panel B, (site #1). Asterisks indicate PSTH peak locations (n = 5). (D) PSTH recorded in A1 to a 500-ms long upward FM sweep signal. Location of recording in microelectrode array is illustrated in panel B, (site #11). Asterisks indicate PSTH peak locations (n = 4). Cross-correlation analyses between the PSTHs illustrated in panels C and D resulted in a cross-correlation index at time-lag zero of 0.60 and a difference in number of response peaks of 1.