Neuronal spike activity in the nucleus accumbens of behaving rats during ethanol self-administration.
Many lines of evidence support the importance of the nucleus accumbens (NAC) for ethanol-reinforced behavior. The nature of the neuronal activity that occurs in this region during ethanol self-administration is not known. We recorded from ensembles of single-units primarily located within the shell of the NAC during operant responding for oral ethanol solutions by well-trained rats. Of 90 units recorded from seven sessions from seven rats, 41 (46%) did not exhibit significant changes in relation to the experimental events. Of the 49 units (54%) that did exhibit significant phasic changes, alterations in firing rate occurred in relation to the following experimental events: operant response (63%), tone stimulus (20%), and ethanol delivery (63%). In addition, changes in spike activity during the intervals between the three experimental events were noted in 33% of the units. Most units (55% of responsive units) responded to multiple experimental events. Thus different but overlapping populations of neurons in the NAC represent each event that occurs along the temporal dimension of a single trial performed to obtain ethanol reward. The data suggest that the NAC plays a crucial role in linking together conditioned and unconditioned internal and external stimuli with motor plans to allow for ethanol-seeking behavior to occur.
Janak
P H
PH
Department of Physiology and Pharmacology, Wake Forest University, School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, USA.panak@intra.nida.nih.gov
Chang
J Y
JY
Woodward
D J
DJ
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D020318:Rats, Long-Evans; D012054:Reinforcement, Psychology; D012646:Self Administration
D000431:Ethanol