Conjugate inhibition in the presence of an eyelid reflex dominant in the rabbit

Conjugated inhibition was studied of the swallowing reflex during formation of dominant focus in the centre of the eye-lid reflex. In the initial period of the dominant focus formation when the dominant passed through the stage of summating reflex, the swallowing reflex was not inhibited. When the dominant turned to optimal stage, i. e. when it was reinforced by stimuli of various modalities, the swallowing reflex was conjugately inhibited. When the dominant turned to pessimal state, summation was not observed in the dominant focus, and conjugated inhibition went on. In the study of the influence of the eye-lid reflex on the swallowing one, it was found that during formation of temporary connection of the type of summating reflex a circular interaction between the centres took place.     

Evoked potentials in the reticular formation of the rabbit midbrain during formation of a dominant focus in it

During creation of a dominant focus in the midbrain reticular formation (RF) by its multiple stimulation with a high-frequency current (stimulation frequency 200 Hz, pulse duration 0.1-0.5 ms, voltage 1-3 V, duration 5 s) a statistically significant increase of the amplitude of the evoked potential (EP) in RF to light flashes was revealed in comparison with background data. Significant increase of EP amplitude was also observed in RF in response to the same stimuli applied in successive experiments without RF stimulation, which pointed to the existence of a latent dominant focus in the CNS.     

Effect of high local temperature on reflex cutaneous vasodilation

We examined the effect of high local forearm skin temperature (Tloc) on reflex cutaneous vasodilator responses to elevated whole-body skin (Tsk) and internal temperatures. One forearm was locally warmed to 42 degrees C while the other was left at ambient conditions to determine if a high Tloc could attenuate or abolish reflex vasodilation. Forearm blood flow (FBF) was monitored in both arms, increases being indicative of increases in skin blood flow (SkBF). In one protocol, Tsk was raised to 39-40 degrees C 30 min after Tloc in one arm had been raised to 42 degrees C. In a second protocol, Tsk and Tloc were elevated simultaneously. In protocol 1, the locally warmed arm showed little or no change in blood flow in response to increasing Tsk and esophageal temperature (average rise = 0.76 +/- 1.18 ml X 100 ml-1 X min-1), whereas FBF in the normothermic arm rose by an average of 8.84 +/- 3.85 ml X 100 ml-1 X min-1. In protocol 2, FBF in the normothermic arm converged with that in the warmed arm in three of four cases but did not surpass it. We conclude that local warming to 42 degrees C for 35-55 min prevents reflex forearm cutaneous vasodilator responses to whole-body heat stress. The data strongly suggest that this attenuation is via reduction or abolition of basal tone in the cutaneous arteriolar smooth muscle and that at a Tloc of 42 degrees C a maximum forearm SkBF has been achieved. Implicit in this conclusion is that local warming has been applied for a duration sufficient to achieve a plateau in FBF.     

Estimation of the interaction strength in the rabbit sensomotor cortex neurons before and after formation of the defense focus

The strength of interaction between neurons in the sensorimotor cortex of rabbits was compared before and after the formation of a hidden excitatory focus (dominant) in this cortical area. In control experiments the interactions between the neurons was significantly stronger in cases when the influence of the neurons with higher spike amplitude on the neurons generating lower-amplitude pulses was assessed. This difference disappeared in the dominant focus.     

The dominant motivation in the mechanisms of the conditioned reflex

It is substantiated that the mechanisms of dominant motivations play an essential role in conditioning. It is shown that motivations change convergent and chemical characteristics of single neurons of different brain structures and, especially, their sensitivity to corresponding reinforcing stimuli. As a result, motivation plays a role of an initial "canvas", against the background of which molecular "engrams of reinforcement" are built. The processes of interaction between the dominant motivation and reinforcement are mainly addressed to the apparatus of the action result acceptor. It is shown that dominant motivations participate not only in construction of molecular reinforcement engrams but also in their forestalling retrieval.