Responses of thalamic and hypothalamic neurons to scrotal warming in rats: Non-specific responses?

Kazuyuki Kanosue, Teruo Nakayama, Youzou Ishikawa, Takayoshi Hosono, Tatsuro Kaminaga, Akira Shosaku

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Activities of thalamic and hypothalamic neurons in response to scrotal temperature change were investigated in urethanized (1.2-1.5 g/kg) rats with special attention to changes in cortical electroencephalogram (EEG). Somatosensory relay neurons were identified electrophysiologically in the ventrobasal complex (VB) of the thalamus. These neurons had tactile receptive fields in areas outside the scrotum. Forty out of 44 of these neurons responded to scrotal warming by increase in firing rate. The responses occurred abruptly at threshold temperatures ranging from 31 to 40 °C (switching response) with simultaneous changes in EEG from high to low voltages (desynchronization). In both the thalamus and the hypothalamus, neurons excited or inhibited by scrotal warming were also excited or inhibited, respectively, by noxious stimulation that produced EEG desynchronization. Neurons showing no response to scrotal warming were not affected by noxious stimulation. In deeply anesthetized (2.5 g/kg urethane) rats, VB relay neurons responded to tactile stimulation of their receptive fields, but scrotal warming produced no change in either EEG or activities of thalamic and hypothalamic neurons. These facts suggest that the responses of thalamic and hypothalamic neurons to scrotal warming may be 'non-specific'. Most thalamic and hypothalamic neurons showing switching responses did not appear to mediate specific information concerning scrotal skin temperature.

Original languageEnglish
Pages (from-to)207-213
Number of pages7
JournalBrain Research
Volume328
Issue number2
DOIs
Publication statusPublished - 1985 Mar 4
Externally publishedYes

Keywords

  • electroencephalogram (EEG)
  • hypothalamus
  • noxious stimulation
  • scrotal thermal stimulation
  • somatosensory neuron
  • thalamus

ASJC Scopus subject areas

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

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