Abstract
1. The effects of warming and cooling the spinal cord and hypothalamus on operant thermoregulatory behaviour and posture have been studied in the pig at neutral and cold ambient temperatures.
2. Cooling the spinal cord increased and warming decreased the rate of obtaining thermal reinforcement. The response to cooling began with the onset of the stimulus and persisted for up to 5 min followed by a diminution in rate during the remaining 15 min of cooling. The peak of this `on' response was greater the lower the ambient temperature. The response to heating was a small reduction in rate of reinforcement.
3. The `on' response to cooling the spinal cord was related to changes in temperature of only the cervical region of the cord.
4. Cooling the hypothalamus led to an increase in the rate of obtaining heat and this increase was sustained during the 20 min of central cooling. Termination of cooling was followed by a marked depression in rate. Heating the hypothalamus had only a weak inhibitory effect on rate of reinforcement.
5. While working for external heat during periods when thermodes over the spine and in the hypothalamus were not being cooled, pigs lay in `cold defensive' prone positions 25% of the time and lay on their sides 75% of the time. During cooling of the spinal cord the time spent in the prone position was 95% at 5 and 15° C ambients and 71% at a 25° C ambient. During cooling of the hypothalamus the prone posture was adopted 50% of the time.
6. When the temperatures of the spinal cord and of the hypothalamus were changed in opposite directions, the operant response was determined by the temperature of the hypothalamus while the postural response was most frequently determined by the temperature of the spinal cord.
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Selected References
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- Baldwin B. A., Ingram D. L. Effect of heating & cooling the hypothalamus on behavioral thermoregulation in the pig. J Physiol. 1967 Jul;191(2):375–392. doi: 10.1113/jphysiol.1967.sp008256. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carlisle H. J., Ingram D. L. The influence of body core temperature and peripheral temperatures on oxygen consumption in the pig. J Physiol. 1973 Jun;231(2):341–352. doi: 10.1113/jphysiol.1973.sp010236. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ingram D. L., Legge K. F. The influence of deep body and skin temperatures on thermoregulatory responses to heating of the scrotum in pigs. J Physiol. 1972 Jul;224(2):477–487. doi: 10.1113/jphysiol.1972.sp009906. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ingram D. L., Legge K. F. The influence of deep body temperatures and skin temperatures on peripheral blood flow in the pig. J Physiol. 1971 Jul;215(3):693–707. doi: 10.1113/jphysiol.1971.sp009492. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ingram D. L., Legge K. F. The influence of deep body temperatures and skin temperatures on respiratory frequency in the pig. J Physiol. 1972 Jan;220(2):283–296. doi: 10.1113/jphysiol.1972.sp009707. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jessen C., Ludwig O. Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. II. Addition of signals. Pflugers Arch. 1971;324(3):205–216. doi: 10.1007/BF00586419. [DOI] [PubMed] [Google Scholar]
- Jessen C., Mayer E. T. Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. I. Equivalence of responses. Pflugers Arch. 1971;324(3):189–204. doi: 10.1007/BF00586418. [DOI] [PubMed] [Google Scholar]
- Jessen C., McLean J. A., Calvert D. T., Findlay J. D. Balanced and unbalanced temperature signals generated in spinal cord of the ox. Am J Physiol. 1972 Jun;222(6):1343–1347. doi: 10.1152/ajplegacy.1972.222.6.1343. [DOI] [PubMed] [Google Scholar]
- Jessen C., Simon E. Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. 3. Identity of functions. Pflugers Arch. 1971;324(3):217–226. doi: 10.1007/BF00586420. [DOI] [PubMed] [Google Scholar]
- Simon E., Iriki M. Sensory transmission of spinal heat and cold sensitivity in ascending spinal neurons. Pflugers Arch. 1971;328(2):103–120. doi: 10.1007/BF00592439. [DOI] [PubMed] [Google Scholar]
- Wünnenberg W., Brück K. Studies on the ascending pathways from the thermosensitive region of the spinal cord. Pflugers Arch. 1970;321(3):233–241. doi: 10.1007/BF00588444. [DOI] [PubMed] [Google Scholar]