Neural processes in long-term thermal adaptation

Area of Science:

• Physiology
• Animal Behavior
• Thermoregulation

Background:

• Peripheral and central mechanisms influence thermoregulation.
• Habituation and adaptation to cold stimuli involve complex physiological responses.
• Sensory perception and thermal comfort may be differentially regulated.

Purpose of the Study:

• To investigate short-term habituation and long-term cold adaptation in cats.
• To examine the role of peripheral and central thermosensors in thermoregulation.
• To explore the neural pathways for temperature sensation and thermal comfort in humans.

Main Methods:

• Cats were exposed to varying ambient temperatures (5°C and 30°C) for up to 4 years.
• Rats underwent repeated local hypothalamic or spinal cooling.
• Human subjects experienced local hand cooling/warming and general temperature changes.

Main Results:

• Long-term cold adaptation in cats involved changes in cold fiber afferents and increased fur growth.
• Cold-adapted cats showed a shift in metabolic response to lower ambient temperatures.
• Repeated cooling in rats increased nonshivering thermogenesis but not general cold resistance.
• Human cold thresholds were independent of general thermoregulatory state, but thermal comfort varied.
• Short-term environmental exposure altered affective responses to thermal stimuli.

Conclusions:

• Peripheral cold receptor changes contribute to short-term habituation.
• Long-term cold adaptation in cats is robust but not solely dependent on peripheral afferent changes.
• Thermoregulatory adaptations in cats are primarily driven by peripheral thermal afferents.
• Temperature sensation and thermal comfort appear to be mediated by distinct neural pathways.
• Affective responses to thermal stimuli can be modulated by recent environmental exposure.