Cortical neural networks revealed by spatio-temporal neural observation and analysis on guinea pig auditory cortex

The neural network structure of the tonotopical organization in the guinea pig primary auditory cortex was studied by observing the evoked responses to tone bursts. A 128-channel optical recording system was used and the patterns were analyzed by time series analysis using on the multivariable autoregressive model. The results revealed the existence of synchronized oscillatory neural activities of about 30 Hz in the response regions to the tone bursts. In addition, the dominant sources (the cortical region) that generated the oscillation in every responding cortical region were identified. The existence of the mutual neural connections in the cortical field were identified along the tonotopical band from the dorsal to the ventral. On the other hand, the oscillation might be propagated from the source region to the cortical region in the caudal or the rostral direction. Thus neural networks of the tonotopicity in the cortex were estimated by spatio-temporal neural observation and analysis.