AFTER-DISCHARGES IN THE AUDITORY-CORTEX OF THE MOUSTACHED BAT - NO OSCILLATORY DISCHARGES FOR BINDING AUDITORY INFORMATION

Action potentials of single or multi-neurons were recorded from the DS CF, FM-FM and DF areas in the auditory cortex of the mustached bat to study stimulus-induced neural oscillation in the auditory system. Out of 125 neurons 120 recorded in these three areas showed after-discharg es to a best stimulus. Durations of after-discharges of 120 neurons ra nged between 4.8 and 217 ms. In the remaining 5 neurons, the duration of the discharges was shorter than that of the stimulus. The PST histo grams displaying responses of these 125 neurons showed no oscillatory component locked to the stimulus. 98% of the autocorrelograms of respo nses (122/125) showed no sign of oscillation, but the remaining two pe rcent showed a very weak oscillatory component that was not stimulus-l ocked. The duration of the after-discharges had no correlation with th e best delay or cortical depth of neurons. After-discharges are common in the auditory cortex of the mustached bat, but oscillatory discharg es are very rare, so that neural oscillations play no role in binding various types of biosonar information processed in the different 'spec ialized' areas in the auditory cortex.