Phasic firing time locked to cocaine self-infusion and locomotion: Dissociable firing patterns of single nucleus accumbens neurons in the rat

Laura L. Peoples, Fred Gee, Racquel Bibi, Mark O. West

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

The activity of single nucleus accumbens (NAcc) neurons of rats was extracellularly recorded during intravenous cocaine self-administration sessions (0.7 mg/kg per infusion, fixed ratio 1). We reported previously that NAcc neurons showed a change, usually a decrease, in firing rate during the first I rain after the cocaine-reinforced lever press. This postpress change was followed by a progressive reversal of that change, which began within the first 2 min after the press and was not complete until the last 1 min before the next lever press (termed the change + progressive reversal firing pattern). In the present study we documented a regular pattern of locomotion that occurred in parallel with the change + progressive reversal firing pattern. This observation suggested that discharges time locked to locomotion may determine the change + progressive reversal firing pattern. However, 55% of the neurons failed to show firing time locked to locomotion that could have contributed to the change + progressive reversal firing pattern. Moreover, for all neurons, the change + progressive reversal firing pattern was apparent even if the calculation of firing rate excluded all periods of locomotion. The present data showed that the change + progressive reversal firing pattern is not solely attributable to phasic changes in firing time locked to the execution of locomotion. The change + progressive reversal firing pattern closely mirrors changes in drug level and dopamine overflow observed by previous researchers and may thus be a component of the neurophysiological mechanism by which drug level regulates drug-taking behavior during an ongoing self-administration session.

Original languageEnglish (US)
Pages (from-to)7588-7598
Number of pages11
JournalJournal of Neuroscience
Volume18
Issue number18
DOIs
StatePublished - Sep 15 1998

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Keywords

  • Addiction
  • Cocaine
  • Drug
  • Electrophysiology
  • Incentive motivation
  • Locomotion
  • Neuron
  • Nucleus accumbens
  • Psychomotor stimulant
  • Reinforcement
  • Reward
  • Self-administration
  • Stereotypy

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