[Modulation of periaqueductal gray neuronal activity by influences of brain stem monoaminergic structures].

Studies of spontaneous firing (SF) in the midbrain periaqueductal gray (PAG) neurons before and after stimulation of nucleus raphe magnus, locus coeruleus and substantia nigra were performed on the rat anesthetized with Hexenal (200 mg/kg). Three types of neurons different in SF structure were found. Stimulation of indicated structures increased SF rate in 11-14.

[Changes in background activity of periaqueductal gray neurons through application of serotonin or inhibition of its synthesis].

Application of serotonin (ST, 1.10(-4) M to periaqueductal grey neurons influenced background activity (BA) only in the third group of cells. In 45.

[Experimental spinal cord contusion. I. An assessment of the state of the conductivity of different funiculi].

Experiments were conducted on albino rats to study the changes of the amplitude and latency of maxima tract and synaptic components of the dorsal surface potential before and after spinal cord injury at the level of Th9. Dorsal surface potentials were recorded from L4 after stimulation in C2. The amplitude of tract and synaptic component maxima of the short latency potential were found to be considerably reduced after the injury.

[Changes in the neuronal background activity of the central gray substance of the midbrain to motor cortex stimulation in rats].

Motor cortex stimulation induced inhibition of the background activity (BA) in 47% periaqueductal gray neurons, excitation--in 20% and had no influence in 32% neurons. Most of the activated neurons (67%) had the 3d type of BA. Neurons with the 1st type of activity did not respond to the cortex stimulation.

[Load dynamics on the extremities during locomotion in rats before and after deafferentation].

Stepping of an intact animal was characterized by a fast rise to maxima, maintenance on this level and fast decay of limbs' loading in the stance phase. In deafferentated rats a slow rise without maintenance in that phase was found. The role of afferent input intensity in reflex control of movements is discussed.