[The afferent and efferent connections of field 7 in the parietal cortex with field 18a of the visual cortex in the rat]. / Afferentnye i éfferentnye sviazi polia 7 parietal'noi kory s polem 18a zritel'noi kory krysy.

By means of administration of horseradish peroxidase to the field 7 in the parietal cortex of rat, studies have been made on antero- and retrograde axonal transport of the enzyme to reveal bilateral connections of this field with the field 18a of the visual cortex. It was shown that the field 18a is a source of afferent fibers which reach the field 7, more evident projections being observed at the ipsilateral side. Labeled neurones in the field 18a were found mostly in layer III, and to a lesser extent-in layer V. Single labeled neurones were also found in layers II and VI. Labeled terminals of efferent fibers originating from cells in the field 7 were located in layers I, II-III and V of the field 18a. Maximum density of the terminals was registered in layer II-III, less one in layer V, and very negligible-in layer I. It should be noted that labeled terminals were revealed in those cortical regions, which contained labeled neurones which gave origin to afferent fibers to the field 7.

[The laminar distribution of the neuronal sources of afferent fibers to the neocortex in the caudal regions of the limbic cortex in rats and cats]. / Posloinoe raspredelenie neironov--istochnikov afferentnykh volokon k neokorteksu v kaudal'nykh otdelakh limibicheskoi kory u krys i koshek.

Laminar distribution of neurones in the caudal limbic cortex, which form projections to the neocortex, has been studied by axonal transport of HRP. It was shown that the associative parietal cortex (field 7) receives the greatest part of limbic afferents from neurones of layer V. It is suggested that field 7 is included in the limbic efferent system together with subcortical structures of the brain. Projections of the limbic cortex to the field 7 originate partly from associative neurones of layer III which are more numerous in cats than in rats.

[Projections of the retrosplenial cortex and hippocampus to the structures of the thalamoparietal associative system in the rat]. / Proektsii retrosplenial'noi kory i gippokampa v struktury talamoparietal'noi assotsiativnoi sistemy u krysy.

Afferent connections of LP of the thalamus and parietal area 7 from the retrosplenial cortex of rat were investigated by means of the HRP retrograde transport. It was shown that neurons of area 29d sent afferent fibres to LP, while area 7 received axons from cells of areas 29d and 29c. Those projections were ipsilateral. It was found out that connections to the associative cortex were more massive than those to the thalamus. Projections from areas 29a and 29b were not revealed. Apart from the neocortical input area 7 received afferent fibres from the archicortex. Neurons of hippocampal area CA1 were a source of those projections.

[Morphophysiologic study of the afferent projections of the posterolateral nucleus of the thalamus in the rat]. / Morfofiziologicheskoe issledovanie afferentnykh proektsii zadnelateral'nogo iadra talamusa krysy.

Afferent connections of the posterolateral nucleus of the thalamus were studied in rat using retrograde axonal transport of horseradish peroxidase. It was shown that the posterolateral nucleus receives ascending projections from SC, GL, PT, VP, VL, zona incerta and hypothalamus as well as descending projections from cortical areas 18A, 20, 18, 7, 29c , 17 and 36 and from fascia dentata of rippocampus as well. In electrophysiological experiments 134 from 229 investigated neurons of the posterolateral nucleus responded to isolated or simultaneous visual, auditory and cutaneous stimulations. 53 neurons were monosensory units; they responded only to visual (41/53) or cutaneous (12/53) stimulation. Cells responding only to auditory stimulation were not found. Polysensory neurons (81/134) showed convergence of signals from two-three sensory systems and received preferential inputs from visual and somatosensory systems. The polysensory cells showed nonlinear interaction between responses during heterosensory stimulations.

[Morphological study of the medial and posterior hypothalamus projections to the forebrain in turtles]. / Morfologichesko issledovanie proektsii srednego i zadnego gipotalamusa k perednemu u bolotnoi cherepakhi.

Ascending connections of the middle and posterior hypothalamic structures (n. ventromedialis, n. periventricularis arcuatus pars ventralis, n. mammillaris medialis) have been studied in the Emys orbicularis by means of anterograde degeneration and electron microscopic techniques. It has been demonstrated that the hippocampal cortex (its dorsomedial and dorsal parts) is the main cortical zone of projections for the nuclear formations mentioned above. Their projections are ipsilateral and occupy the external plexiform hippocampal layer. At the ultrastructural level, it has been demonstrated that axodendritic synaptic contacts in the dendrites with a middle-sized diameter make the major mass of the degenerating synaptic formations in the hippocampal cortex. At early postoperative stages (14 days), large axonal terminals are the main degenerating formations; the degeneration is of the "light" type. Degeneration of small and middle terminals begins later. On the 62d day the "dark" type degeneration is predominant. Besides the hippocampal cortex, the nuclear hypothalamic formations in question have projections into the subcortical structures: medial and lateral septal nuclei, paleostriatum and, to less degree--into the medial and cortical nuclei of the amygdala.