Generator of locomotor activity as a probabilistic modulator of the afferent stream from thermoreptors of the dermal fields of flexor and extensor muscles

Abstract

The reflex excitability of flexors and extensors of the upper and lower extremities during local thermostimulation of their receptor fields was investigated in observations on healthy subjects and patients with spastic hemiparesis by means of monosynaptic testing. In the healthy subjects, cooling led to a reduction in reflex excitability, while warming led to its elevation. On the contralateral side thermostimulation induced the reverse effect. A change in the directionality of the reactions was observed in ill subjects in the form of an increase in excitability in response to cooling. The data obtained show that the state of the thermoreceptive fields may influence the reflex excitability of motoneurons in a specific manner. The character of this influence in its turn probably depends on the initial state of the generator of locomotion.