Cortical mechanisms of programmed brain activity in the organization of behavioral acts in cats

Abstract

A major question in studies of the cortical mechanisms of programmed brain activity is that of neuronal activity as a reflection of preparedness to carry out one or another act. In connection with this, we analyzed the spike activity of sensorimotor cortex neurons in the cat brain prior to carrying out a number of behavioral tasks.In the first series of experiments, each of five animals was tested using 3-6 tasks; recordings were made from the same neurons (n = 200) in each act, using a bundle of microelectrodes [1]. The following experimental programs were used: 1) positive differentiation, when a complex signal (light + sound) required the animal either to obtain reinforcement with the paw from a feeder on the right-hand side or to press a pedal below the feeder with the nose, and to respond to the components of the stimulus by carrying out the same movements, but with a feeder on the left-hand side; 2) inhibitory differentiation, in which the complex signal required the animals to carry out a movement and the components of the signal required suppression of the movement (inhibitory responses were not reinforced); 3) movement of the paw or nose to the feeder; 4) listening for stimuli after quenching of movement responses to them; 5) conditioned responses to different probabilities of obtaining reinforcement and differentiation; 6) during formation of a conditioned response. Signal sources were located at the center of a front panel. Stimuli lasted 5 msec and their intensities were 1.5 times the threshold for producing the movement response. Neuron activity was monitored for 500 msec immediately before each trial at carrying out a task.The results showed that when the animals carried out any action, neuron activity parameters stabilized before the start of the action, this being reflected as a reduction in the variability in the number of spikes occurring on different trials, as compared with that at rest (see Fig. 1A).Comparison of sensorimotor cortex neuron activity parameters before each of six tasks indicated that each task was characterized by its own group of values for three parameters: the mean number of spikes before the trial, the number of the most common interspike intervals during the study period, and the duration of this. most common interval (see Fig. 1B). Results are presented for groups of neurons with the following characteristics: narrow receptive fields within the organ concerned, the discharge phase pattern on movement, the assignment of the neuron to the pyramidal tract (determined by antidromal testing). The evoked activity of these cells during differentiation showed differences in their responses to conditioned signals when movements towards different feeders were required. Differences affected the intensity of discharges in response to conditioned stimuli, which were related to the different directions of movement [2]. When conditioned responses were carried out with the snout, these neurons changed their activity only after the movement started. As shown in Fig. 1B, the greatest disch...

Method and Device for Shock Wave Modeling (Literature Review)

“…Widespread use of explosive devices in military conflicts leads to an increase of blast-induced injuries of the organs, which differ in the mechanism of damage and clinical signs from classical mechanical injuries. The special attention of both clinicians and theoreticians is attracted by explosive blast brain traumatic injury, since its course is distinguished by the appearance of cognitive-behavioral disorders in an acute period and the development of neurodegeneration in the remote period [1]. The pathogenesis of bTBI is currently being actively investigated, but separate links have been established, and modeling methods differ.…”