[Evaluation by humans of signals modulating different sound movement directions and particulars of perception of such signals in patients with temporal epilepsy].

In patients with epileptic lesions in the hippocampus as well as in the temporal lobe and hippocampus simultaneously, studies were made on the perception of sound signals imitating sound source movement. It was established that hippocampal lesion results in disturbance of estimation of sound spatial characteristics which manifests in a change accuracy of localization and shortening of subjective sound image movement trajectory. Maximum disturbances of localization function are observed during lesions of hippocampus and temporal lobe.

Responses of cat primary auditory cortex neurons to moving stimuli with dynamically changing interaural delays.

The spike responses of individual neurons in the primary auditory cortex were studied in anesthetized cats during exposure to stationary and moving stimuli with static or dynamically changing interaural delays (deltaT). Static stimuli were tones and clicks. Dynamic stimuli were created using series of synphase and antiphase clicks with interaural delays which changed over time.

[Responses of neurons in the primary auditory cortex of the cat to the auditory motion stimuli with variable interaural delay].

Unit responses in the primary auditory cortex of anesthetized cats to stationary and apparently moving stimuli resulted from a static and dynamically varying interaural delay (ITD) were recorded. The static stimuli consisted of binaurally presented tones and clicks. The dynamic stimuli were produced by in-phase and out-of-phase binaurally presented click trains with time-varying ITD.

Methods for estimating structure of trace reactions of neurons in medial geniculate body.

The trace reactions of neurons in the medial geniculate body during the action of various auditory signals were investigated in anesthetized cats. Using the traditional peristimulus histogram (PSTH) method to analyze the impulse activity, trace reactions were found in some neurons that possessed a definite time structure with a varying degree of periodicity. Prolonged, diffuse changes in the level of activity were demonstrated in another group of neurons.

[Various ways of assessing the structure of trace reactions of neurons of the medial geniculate body].

Afterdischarges of the medial geniculate body units were recorded in anesthetized cats following different sound stimuli. With traditional PSTH-technique, a periodicity of afterdischarges was found in some neurons whereas others showed diffuse and prolonged changes of their activity. To estimate the diffuse afterdischarges a special method was used.

[Conditions affecting the nature of the neuronal afterdischarges in the medial geniculate body of the cat].

Sound signals induced afterdischarges in 20-40% medial geniculate body units. Dorsal neurons of the MGB had afterdischarges in the form of an augmentation of the activity level after cessation of the stimulation. The ventral MGB neurons revealed rhythmic afterdischarges more often, their pattern depending on the parameters of stimuli.

[Neuronal afterdischarges of the medial geniculate body in the cat after the action of a rhythmic sound sequence].

22% of neurons in the cat medial geniculate body under the effect of rhythmic sound stimuli developed afterdischarges the temporal structure of which and the amount of pulses in them being dependent on the stimulation rhythm, although no obvious driving phenomenon occurred. Changes of the firing rate in the afterdischarge related to changes in stimulation rhythm could be significant at the PST's epochs corresponding to the moment of the occurrence. The afterdischarges a periodic structure had mostly frequencies from 2 to 8 Hz, their low-frequency component being of the 0.

[Selectivity of trace reactions of medial geniculate neurons to the rate of simulated movement of a sound source in the cat].

33 out of 90 neurons of the cat medial geniculate body revealed the selectivity of their afterdischarges to movement of sound when velocity of the movement changed from 30 to 180 deg/s. There was a specific velocity of the movement for each neuron. 76% of the neurons preferred the movement of 45--90 deg/s.

[Response of medial geniculate body responses to the velocity of simulated sound source movement in the cat].

36 neurons (39%) of the anaesthetized cat medical geniculate body responded to simulated motion of the sound source (with angular velocity of 30 to 180 degrees/sec) selectivity with a certain speed of firing rate changing specific for each neuron during action of the signal. Selective response to a certain velocity of the sound motion occurred in 55% of neurons of the dorsal portion and in 27% of the ventral portion of the medial geniculate body. Response of these neurons reflected the whole range of experimental velocities.