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. Correlating to these changes, a dominant information flow from ventral tegmental area (VTA) to prefrontal cortex (PFC) was observed after long-term MAP administration. Together with our previously reported finding of reciprocal information flow between PFC and VTA in MAP-induced hyperactive and stereotyped behavior, the present results indicate that information flow and its direction may be useful in explaining the neuronal substrates mediating development of behavioral sensitization. The predominant information flow from the VTA to PFC that occurs with sensitization supports recent speculations concerning impulsivity in drug addiction.
Wang
Hui-Dong
HD
Department of Neuropsychiatry, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, 890-8520, Kagoshima, Japan.
Takigawa
Morikuni
M
Hamada
Koichi
K
Shiratani
Toshihiro
T
Takenouchi
Kaoru
K
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004056:Differential Threshold / Q000187:drug effects; D004334:Drug Administration Schedule; D004558:Electric Stimulation; D004569:Electroencephalography; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage* / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012653:Self Stimulation / Q000187:drug effects; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000502:physiology*
D000697:Central Nervous System Stimulants; D008694:Methamphetamine