Modulation of frequency receptive field plasticity in rat auditory cortical neurons by electrical stimulation of medial prefrontal cortex.

Using conventional electrophysiological technique, we investigated the effects of stimulating the medial prefrontal cortex (mPFC) on plasticity of frequency receptive field (RF) in auditory cortical (AC) neurons in rats. When the mPFC was electrically stimulated, the RF plasticity of 51 (27.2%) neurons was not affected and that of 137 neurons (72.8%) was either inhibited (71 neurons, 37.7%) or facilitated (66 neurons, 35.1%). The modulation of RF plasticity by the stimulation of mPFC was dependent upon the time interval between acoustic and electrical stimuli. The best interval time that produced optimal modulation (inhibition or facilitation) ranged from 5 to 30 ms. The inhibitory modulation of mPFC prolonged RF shifting time and shortened RF recovery time. Conversely, the facilitatory modulation of mPFC shortened RF shifting time and prolonged RF recovery time. Our results suggest that the mPFC may affect the plasticity of functional activity in AC neurons, and also may participate in the process of auditory learning and memory.