Biomedical subjects
Publications and source records attributed to T S Sotnichenko.
In this article we describe a new method for surgical immobilization of the cat eye in which 3 motor nerves are simultaneously destroyed where they converge in the orbital fissure. The method depends upon inserting a special instrument 'spoon' through the soft palate into the orbital fissure.
By means of the anterograde axoplasmic transport technique for a mixture of labelled aminoacids (3H-leucine and 3H-proline), ascending and descending systems of the reticular formation fibers in the cat mesencephalon have been studied. Projections from the mesencephalon reticular formation (MRF) ascend to the subthalamus, lateral, dorsal and periventricular hypothalamus, to the periventricular nuclei of the midline and to the intralaminar nuclei of the thalamus. The descending pathways project to the grey substance surrounding the aqueduct of cerebrum, locus coeruleus, parabrachial region and reticular formation of the pons and medulla oblongata. The projections to the reticular nucleus of the thalamus, ventral nucleus of the external geniculate body and superior colliculi arise from the dorsal half of the MRF, and projections to the striatum, lateral reticular nucleus of the medulla oblongata--from its ventral half. Most of the structures are reciprocally connected with the MRF.
Efferent connections of medial (nucleus cuneiformis) and lateral regions of the caudal part of the midbrain reticular formation (mRF) were investigated by anterograde autoradiographic method in cat. Projections from the mRF ascend to the globus pallidus, substantia innominata, hypothalamus, subthalamus and nonspecific, associative and relay nuclei of the thalamus. Descending pathways terminate in the reticular formation of the brain stem. The conclusion is made that the cuneiform nucleus is rather a nonspecific than auditory centre. The lateral reticular region has strong projections to the lateral geniculate body and together with the parabigeminal nucleus forms the midbrain visual complex.
Efferent connections of the centrum medianum and parafascicular nucleus (CM-Pf complex) were investigated by the anterograde autoradiographic method in cat. Projections from CM-Pf complex ascend to the ventral nuclear complex and non-specific thalamic nuclei, preoptic, dorsal, lateral and posterior fields of the hypothalamus and to the subthalamic region. The descending pathways arise only from the caudomedial parts of the CM-Pf complex. They are projected to the pretectum, superior colliculus, pontine reticular formation, locus coeruleus, nucleus parabrachialis and periaqueductal grey of the midbrain and pons, as well as to the raphe nuclei, magnocellular reticular field and the inferior olive of the medulla. Previous studies suggest that the caudomedial CM-Pf part is not projected directly to the cortex and striatum.
After injection of radioactive amino acids into the cat thalamic centrum medianum, its projections have been revealed in the ipsilateral hemisphere in the frontal, motor, limbic, orbital and basal temporal cortex, in the parasubiculum and striatum. The anterograde tracing of the fibers and terminals reveals the centrum medianum projections in the layers VI-V and I of the frontal and limbic cortex and in the layers VI-V, IV or III (or in both) and in I of the motor and orbital cortex.
After injections of horseradish peroxidase into the central tegmental field of the midbrain reticular formation and centrum medianum of the thalamus in the cat, labelled neurons were found in the nucleus of solitary tract, cuneate and gracile nuclei, spinal nuclei of trigeminal nerve, external nucleus and brachium nucleus of inferior colliculus, nuclei of the lemniscus lateralis in the area pretectalis, nucleus of the posterior commissure and stratum intermediale of the superior colliculus and in reticular structures of medulla and pons. It is concluded that midbrain reticular formation receives the main input from visceral and the centrum medianum from the somatic sensory nuclei.
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By the method of horseradish peroxidase (HP) retrograde transport (the injection was performed into the thalamic parafascicular complex in 7 cats) connections between the hypothalamus, the midbrain reticular formation and the parafascicular complex were followed. Other connections of the hypothalamus with some cerebral centers were also discussed.
In chronic experiments of alert cats, moderate electrical stimulation of different points on the lateral cortical surface led to activation of different cerebral areas. Both the high-threshold and the low-threshold points were revealed in the sensorimotor cortex and in the Ep field of auditory area. The latter had as low a threshold of the activation response as the points within the mesencephalic RF and the thalamic CM, VPL and GM. In the morphological aspect, projections from the auditory Ep field to the thalamic intralaminar nuclei and to the brain stem RF, were revealed. Major projections spread from the dorsal part of the Ep field to the lateral tegmentum. The data obtained seem to provide better comprehending of the mechanisms for corticofugal activation. The functional role of the low-threshold loci in the cortex can involve triggering of unspecific apparatus of activation with a graduated volley which controls its excitation in accordance with biological significance of analysed signals.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In chronic experiments with alert cats, stimulation with electrical current of moderate strength at various points on the lateral surface of the cerebral hemispheres leads to activation of various brain regions. In addition to high-threshold cortical points, low-threshold points have been discovered which are located in the sensorimotor region and in the Ep field of the auditory zone. The latter possess the same low thresholds for evoking an activation response as do points in the mesencephalic RF and the thalamic CM, VPL, and GM. Connections have been discovered (in the morphological part of the study) between the auditory Ep field and the intralaminar nuclei of the thalamus and the brain-stem part of the RF; the major projections run from the dorsal part of the Ep field into the lateral zone of the tegmentum. It is proposed that the role of the cortical low-threshold foci could involve the triggering of the nonspecific activation apparatus in accord with the biological significance of the signals being analyzed.