Changes in the Power Levels of Cortical EEG Rhythms in Cats during Training Using Acoustic Feedback Signals

Chronic experiments on two conscious cats were performed to study the dynamics of the ratios of spectral power levels of beta and theta rhythms and neuron activity in the dopaminergic system of the ventral tegmentum during EEG feedback sessions. Training was performed using a model in which the level of sound signals presented to the animals decreased as the spectral power ratios of the EEG beta and theta rhythms recorded in the frontal leads increased. In a control series, the changes in the sound signal level were independent of the ongoing EEG. These experiments showed that the ratio of the spectral power levels of the beta and theta rhythms changed during feedback sessions, with increases in the spectral power of the beta rhythm and decreases in the spectral power of the theta rhythm. These changes were accompanied by increases in the activity of presumptive dopaminergic neurons in the ventral tegmentum.