Characteristic frequency bands of the cortico-frontal EEG during the sexual interaction of the male rat as a result of factorial analysis.

The electrocorticogram (ECoG) from the prefrontal cortex was simultaneously recorded with the accelerometric signals of pelvic thrusting performed by male rats during sexual behavior. The changes in the prefrontal ECoG were precisely correlated in time with well defined elements of male rat copulation. Principal component analysis allowed to identify three distinct bands of frequencies in the frontal ECoG: the absolute power (AP) of the 4-16 Hz band was increased in the 500-ms periods before, during, and after the execution of pelvic thrusting in mount, intromission and ejaculation responses; the AP of the 18-24 Hz band was selectively increased during the execution of pelvic thrusting at the three copulatory responses, whereas the AP of the 26-32 Hz band was increased only during the pelvic moments of mount and intromission responses. These results show that the electroencephalographic activity of the prefrontal cortex of the male rat is related to the performance of sexual behavior, supporting the concept that this cortical area is involved in the organization of sequential behaviors, as sexual behavior.