Horizontal optokinetic nystagmus in the pigeon during static tilts in the frontal plane.

The influence of lateral static tilts of the body (30 degrees, 45 degrees) on horizontal optokinetic nystagmus induced by rotation of an optokinetic cylinder at a constant rate (16 degrees, 30 degrees/sec) was investigated in 16 pigeons. The experiments made it possible to identify a statistically significant tilt-dependent asymmetry of the tonic otolithic influences on the optokinetic system which consisted in a marked inhibitory effect on horizontal optokinetic nystagmus of right-sided tilts by contrast with left-sided. The separate recording of oculomotor responses of the right and left eyes showed that the temporonasal-nasotemporal (TN-NT) asymmetry of horizontal optokinetic nystagmus which exists in the norm in the pigeon is maintained under the conditions of stationary lateral tilts of the body for the eye which is in the upper position, and is replaced by a symmetrical pattern for the eye which is in the lower position. The results make it possible to hold the view that the mechanism of TN-NT asymmetry is controlled by otolithic inputs, and that its function may be substantially modified under the influence of the reorientation of the otolithic membranes in the gravitational field.

[Horizontal optokinetic nystagmus in the pigeon during static tilts in the frontal plane]. / Gorizontal'nyi optokineticheskii nistagm u golubia vo vremia staticheskikh naklonov vo frontal'noi ploskosti.

The influences of the static whole body roll tilts (30 or 45 degrees) on horizontal optokinetic nystagmus (HOKN) produced by optokinetic stimuli at a constant velocity (16 or 30 degrees/sec) were examined in the 16 pigeons. The significant tilt-dependent asymmetry of the tonic otolith effects on optokinetic system was revealed which consists in pronounced inhibitory effect of the right-hand tilts unlike the left-hand tilts on HOKN. Separate recording of the oculomotor responses from the right and left eyes showed that during static roll tilts the temporonasal-nasotemporal (TN-NT) asymmetry of HOKN normally existing in the pigeon remained for the eye disposed above and was replaced by symmetric pattern for the eye disposed below. The results suggest the mechanism of TN-NT asymmetry is controlled by the otolith inputs and its function can be essentially modified under the influence of otolith membranes reorientation in gravity.

[Horizontal optokinetic nystagmus in th pigeon during static tilts in the sagittal plane]. / Gorizontal'nyi optokineticheskii nistagm u golubia vo vremia staticheskikh naklonov v sagittal'noi ploskosti.

The mode of symmetrical position-related otolith influences modified the parameters of optokinetic nystagmus in pigeons. The symmetry of temporonasal-nasotemporal responses was due to increase in the NT-stimulation efficiency. The parameters of optokinetic nystagmus seems to depend on the direction of the otolith membrane shifts.

[Systems organization of cerebral processes in the cat during learning while undergoing electrical stimulation of the neocortex]. / Sistemnaia organizatsiia protsessov mozga koshki pri obuchenii na fone élektrostimuliatsii neokorteksa.

A delayed spatial choice (DSC) was elaborated in five cats during electrical stimulation (ES) of the frontal cortical parts with a frequency of 80 imp/s. Then the task fulfillment was tested following cessation of the electrostimulation or under the action of other current frequencies (35,3 and 120 imp/s). The number of erroneous choices increased in the absence of ES or during 3 imp/s ES of the frontal parts. The effects of frequencies of 35,80 and 120 imp/s did not differ. Three cats were trained to DSC without ES. The conditioned reflexes were tested during ES of the frontal cortical parts with current frequency of 3 and 80 imp/s. Statistically significant increase of the number of erroneous responses took place in both situations. The obtained data are discussed from the point of view of the integrative activity of the cerebral structures in DSC. Its disturbance during ES of the cortical zones and dissociation (discordance) after cancellation of stimulation during which the conditioned reflex had been elaborated, point to systemic organization of brain functioning in goal-directed forms of behaviour.