Elsevier

Brain Research

Volume 163, Issue 1, 9 March 1979, Pages 135-150
Brain Research

Raphe unit activity in freely moving cats: Correlation with level of behavioral arousal

https://doi.org/10.1016/0006-8993(79)90157-4Get rights and content

Abstract

Dorsal raphe unit activity in freely moving cats showed a slow, rhythmic discharge rate during quiet waking (¯X= 2.82 ± 0.17spikes/sec), and displayed a strong positive correlation with level of behavioral arousal. Presentation of an auditory stimulus during quiet waking resulted in significant increases in unit activity of 112% and 39% during the first sec and first 10 sec after the stimulus, respectively. This effect rapidly habituated with repeated stimulus presentations. During active waking, unit activity was significantly increased by 22% as compared to quiet waking, but there was no correlation between unit activity and gross body movements. Raphe unit activity showed a significant decrease of 17% during drowsiness (first appearance of EEG synchronization) as compared to quiet waking, and then progressive decreases during the early (−34%), middle (−52%) and late (−68%) phases of slow wave sleep. During all phases of slow wave sleep, the occurrence of sleep spindles was frequently associated with a transitory decrease in unit activity. The discharge rate would typically decrease during the few seconds immediately preceding the spindle, remain at this low level during the occurrence of the spindle, and then increase immediately after the spindle. Raphe unit activity showed decreases of 81% during pre-REM (the 60 sec immediately before REM onset) and 98% during REM, as compared to quiet waking. Unit activity reappeared 3.2 sec before the end of REM, with significant increases in unit activity of 83% and 17% during the first sec and first 10 sec of unit activity, respectively, as compared to quiet waking. The results of these studies are discussed in relation to the hypothesis that serotonin may play a modulatory, rather than mediative, role in behavioral and physiological processes.

References (38)

  • SheuY.-S. et al.

    Discharge patterns of cat raphe neurons during sleep and waking

    Brain Research

    (1974)
  • SimonR.P. et al.

    The role of raphe nuclei in the regulation of pontogeniculo-occipital wave activity

    Brain Research

    (1973)
  • UrsinR.

    The effects of 5-hydroxytryptophan andl-tryptophan on wakefulness and sleep patterns in the cat

    Brain Research

    (1976)
  • AghajanianG.K. et al.

    Histochemical fluorescence of raphe neurons: selective enhancement by tryptophan

    Science

    (1971)
  • AghajanianG.K. et al.

    Lysergic acid diethylamide: sensitive neuronal units in the midbrain raphe

    Science

    (1968)
  • BizziE. et al.

    Functional connections between pontine reticular formation and lateral geniculate nucleus during deep sleep

    Arch. ital. Biol.

    (1963)
  • BuendiaN. et al.

    Conditioned and discriminatory responses in wakeful and sleeping cats

    Electroenceph. clin. Neurophysiol.

    (1963)
  • ChaseT.N. et al.

    Serotonin and central nervous system function

    Ann. Rev. Pharmacol.

    (1973)
  • Cited by (634)

    • Neurochemistry of sleep

      2023, Encyclopedia of Sleep and Circadian Rhythms: Volume 1-6, Second Edition
    • A role for the claustrum in cognitive control

      2022, Trends in Cognitive Sciences
    • Sleep and Epilepsy: Practical Implications

      2022, Neurologic Clinics
      Citation Excerpt :

      Caudal brain serotonergic neurons play crucial roles in coordinating control of breathing, arousal, respiratory rhythm generation, blood pressure regulation, thermoregulation, upper airway reflexes, chemosensitivity, and synaptic plasticity. Neuronal activity in these serotonergic neurons in raphe nucleus is highest in wakefulness, reduced in NREM and nearly silent in REM sleep.110 Impaired serotonergic function following nocturnal seizures may predispose to SUDEP.

    View all citing articles on Scopus
    View full text