THE RHYTHM OF SHIVERING: I. GENERAL SENSORY CONTRIBUTIONS

Influences descending from supraspinal levels seem to be essential for the development of a shivering tremor in response to cooling (l), but the extent to which maintenance and regulation of the oscillations is supported by segmental sensory inflow is less clear (2). Several studies have indicated that deafferentation of an extremity causes loss in regularity of the tremor, but does not abolish contractile activity (3-7). Whether the tremor remaining after local deaff erentation is dependent upon sensory inflow over remaining intact roots is not known; those sensory components which contribute most to the regularity of the tremor have not been identified, either. Sensory inflow conceivably could support the shivering tremor through general facilitation of contractions or, alternatively, the time relations over proprioceptive loops between the muscle and spinal cord might set the period of oscillation (6). Also, mechanical resonance of moving body parts may in some degree contribute to the rhythmicity (4). Diverse observations on shivering in cats and human subjects have been made which give additional insight into these problems. In this paper the contributions of general sensory inflow to shivering are presented. The role of mechanical factors and proprioceptive input are examined in following reports (8, 9).