Single unit activity of locus coeruleus neurons in the freely moving cat. II. Conditioning and pharmacologic studies

Kurt Rasmussen, Barry L. Jacobs

Research output: Contribution to journalArticle

113 Scopus citations

Abstract

A series of experiments were carried out in which the single unit activity of presumed noradrenergic (NE) neurons in the area of the locus coeruleus (LC) was examined in freely moving cats during two conditioning paradigms and in response to pharmacologic manipulations relevant to anxiety. LC unit activity was examined during conditioned emotional response (CER) and conditioned food reward (CFR) training. During CER training, LC units showed a large increase in activity in response to a stimulus paired with a noxious air puff, whereas no increase in unit activity was seen in response to a stimulus not paired with the air puff (both comparisons relative to their appropriate control conditions). By contrast, during CFR training, a stimulus paired with a rewarding food delivery did not elicit a significant increase in LC unit activity relative to its appropriate control condition. Therefore, NE units in the LC greatly increase their activity in response to a stimulus that predicts the occurrence of a noxious event, but not in response to a stimulus that predicts the occurrence of a rewarding event. Administration of the anxiolytic drug diazepam (0.25 and 2.0 mg/kg, i.p.) had no significant effect on the spontaneous activity of LC neurons, but significantly reduced the excitatory response of LC neurons to simple sensory stimuli. Administration of the anxiogenic drug yohimbine (2.0 mg/kg, i.p.) significantly increased the spontaneous activity of LC neurons. These results support the hypothesis that LC neurons play a role in aversive but not appetitive conditioning, and are consistent with the hypothesis that these neurons may play a role in anxiety. These data are discussed within the broader context of LC neurons mediating the organism's adaptive response to environmental or physiological challenges.

Original languageEnglish (US)
Pages (from-to)335-344
Number of pages10
JournalBrain Research
Volume371
Issue number2
DOIs
StatePublished - Apr 23 1986

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

Keywords

  • anxiety
  • appetitive conditioning
  • aversive conditioning
  • diazepam
  • freely moving cat
  • locus coeruleus
  • noradrenergic neuron
  • yohimbine

Fingerprint Dive into the research topics of 'Single unit activity of locus coeruleus neurons in the freely moving cat. II. Conditioning and pharmacologic studies'. Together they form a unique fingerprint.

  • Cite this