A shift in information flow between prefrontal cortex and the ventral tegmental area in methamphetamine-sensitized rats.

We examined the effects of long-term methamphetamine (MAP) administration to rats on locomotor traces and reward-seeking behavior that was evaluated through ventral tegmental intracranial self-stimulation (ICSS). Furthermore, using the directed coherence (DCOH) EEG analysis method, correlation of prefrontal cortical and ventral tegmental EEGs was investigated in terms of the direction of information transmission. The results showed a transition from 'mixed type' behavior to 'fixed type' behavior during long-term MAP treatment, accompanied by a gradually diminished rate of ICSS and increased reward threshold.