Neurophysiological Analysis of Circadian Rhythm Entrainment

Abstract

We review recent studies in our laboratory which have investigated the neural mechanisms underlying photic entrainment of the mammalian circadian system. The results from studies of extracellular single-unit recordings and of photic induction of Fos-like immunoreactivity (-lir) indicate that excitatory amino acid (EAA) transmission, and particularly, activation of the NMDA receptor subtype, is important for conveying photic information to suprachiasmatic nucleus (SCN) cells. We have also found that a sub-region of the SCN still shows Fos-lir after blockade of EAA receptors, and we have evidence suggesting that these cells are innervated by a distinct subdivision of the retinal projection to the SCN. In addition, we have found that photic responses of cells in the intergeniculate leaflet (which projects to the SCN) and of SCN cells are modulated by serotonin via a receptor that resembles the 5HT1A subtype.

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Document Details

Document Type
Technical Report
Publication Date
Mar 30, 1993
Accession Number
ADA264681

Entities

People

  • Benjamin Rusak

Organizations

  • Dalhousie University

Tags

DTIC Thesaurus Topics

  • Amino Acids
  • Biological Sciences
  • Brain
  • Chemistry
  • Circadian Rhythms
  • Firing Rate
  • Gene Expression
  • Genetics
  • Light Pulses
  • Nerves
  • Nervous System
  • Neurophysiology
  • Neurosciences
  • Optic Nerve
  • Physiology
  • Serotonin Agents

Fields of Study

  • Biology

Readers

  • Neuroscience