Experience alters the characteristic frequency of primary auditory cortical neuron in the rat

Using conventional electrophysiological technique, the plasticity of characteristic frequency (CF) of neurons in rat auditory cortex (AC) was investigated by determining CF and frequency tuning curve (FTC) shifts of neurons. In the AC, when the frequency difference between conditioned stimulus frequency(CSF) and the CF of neuron was in 1.0 kHz with conditioned stimulation for 30 min, 61 of 120 neurons (50.8%) completely shifted their CF to the CSF. According to the CF shift direction, complete CF shifts were classified into three patterns: CF shift toward lower frequency side(LFS) of neuron's FTC, CF shift to higher frequency side(HFS) and CF shift to both LFS and HFS. Among them, some neurons with higher CF, bigger Q₁₀-dB value and symmetry index > 0 of FTC, the probability of CF shift toward HFS of FTC is higher than other neurons. The results suggest that the experience can alter CF in rat auditory cortical neurons. These findings also provide evidence for further study of plasticity mechanisms in sensory function of the brain.