Response characteristics of neurons in columnar organization of the primary auditory cortex of Mongolian gerbils

Abstract

Response characteristics of neurons in each column of the primary auditory cortex (Al) of Mongolian gerbils were studied by single-unit recording. Tone-burst stimuli were presented to the ear contralateral to the recording side. During a near-radial microelectrode penetration of Al in steps of 100 μm, best frequencies (BFs), best thresholds, best amplitudes (BAs), latencies, tuning curves, and Q10 dB’s, defined as BF/(frequency bandwidth 10 dB above the best threshold), were measured. Neurons in single penetrations had similar BFs, showing columnar organization of frequency, but had various values of best thresholds (19.1–81.3 dB SPL), BAs (44.9–102.1 dB SPL), latencies (5–80 ms), and Q10 dB’s (0.34–17.53). There was a tendency for high Q10 dB’s to be located around layer IV, while there was no tendency in the distribution of low Q10 dB’s, best thresholds, and BAs. These results provide a layer specificity of tuning properties within a single column of frequency.