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E R Sanseverino

Publications and source records attributed to E R Sanseverino.

16 recordsLinked to original sources
PubMed1998

Corticocortical connections between frontal periarcuate regions and visual areas of the superior temporal sulcus and the adjoining inferior parietal lobule in the macaque monkey.

In macaque monkeys, corticocortical connections between distinct parietotemporal visual areas (areas MST-FST, DP, and 7a) and frontal periarcuate areas are studied using tritiated aminoacids and WGA-HRP. While labeling within the banks of the principal sulcus, the dorsal part of the arcuate concavity, and the banks of the upper arcuate limb were present in both 7a and MST-FST injected animals; in the latter cases, additional projections were found towards frontal regions including the dorsomedial frontal cortex and the posterior bank of the arcuate ventral limb. Our results point to widespread frontal connections of the MST-FST complex, involving both prefrontal and premotor cortical regions.

Animals↗
PubMed1981

Bilateral cortical projections from cat visual areas 17 and 18. An autoradiographic study.

Associated and commisural connections of visual areas 17 and 18 were studied in the light of the latest knowledge about the anatomo-functional organization of the cat's visual cortices. Injections of L-[5-3H] proline were placed, in different animals, in area 17 or 18 of the right hemisphere. Serial histological sections of the whole brain were processed by autoradiographic technique, after long (8-16 days) or short (30 hours) survival times. Cortical areas labelled by axonally transported radioactive material were then correlated with electrophysiological and cytoarchitectonical maps. Areas 17 and 18 were found to send associational projections to area 19, to the anterior and posterior subdivisions of the lateral suprasylvian visual area and to two regions lying on the crown of the suprasylvian gyrus (areas 21A and 20). In addition, area 18 sends projections to ipsilateral areas 17, 7 and 5. Contralaterally, projections from areas 17 and 18 reach the homonymous areas near the margin of the other. Homotopical callosal connections of area 17 affect the band of the contralateral 17 in which part of the ipsilateral visual hemi-field is represented. Heterotopical commisural projections from the areas studied affect areas 19 and LS in regions adjoining the central vertical meridian representations. These results suggest that, on an anatomical basis, the interactions between the cortical targets of the classical geniculo-striate and the estrageniculo-striate systems are more complicated than previously believed. Furthermore, the geniculo-striate system supplies some visual input to non-visual areas through area 18.

Animals↗
PubMed1981

An autoradiographic study of bilateral cortical projections from cat area 19 and lateral suprasylvian visual area.

Associational and commissural connections of area 19 and of the lateral suprasylvian visual area (LS) of the cat were studied by means of an axonal anterograde transport technique. Multiple injections of L-[5-3H] proline were placed, in different animals, in area 19 and in two different subdivisions of LS (PMLS, PLLS). Serial histological sections of the whole brains were processed by autoradiographic technique after long (8-12 days) and short (30 hrs) survival times. Cortical areas labelled by accumulation of radioactive material were correlated with electrophysiological and cytoarchitectonic maps of cortical areas. Results showed a number of projections of areas 19 and LS not previously described. Area 19 sends ipsilateral projections to area 5 and to the medial bank of the anterior suprasylvian sulcus. The postero-medial (PMLS) and postero-lateral (PLLS) subdivisions of LS project to ipsilateral areas 5, 6, 7, 20, 21, 35, to the suprasylvian fringe (SF), to the cingulate gyrus and to the insular cortex. Contralaterally, new projections are found from area 19 to areas 20 and 5, and from LS to areas 19, 20, 21, 5, 7, SF to the cingulate gyrus and to the insular cortex. Results lead to conclude that the intra-modal and cross-modal interactions between cortical areas processing visual input are more complicated than previously assumed. The crucial role of the cat's LS in the cortico-cortical distribution of the visual message in emphasized.

Animals↗
PubMed1980

Autoradiographic evidence of visual cortical projections to the frontal cortex in the cat.

In II adult cats, areas 17, 18, 19 as well as the lateral suprasylvian area were separately injected with L-[5-3H] proline and their efferent projections to the frontal cortex were autoradiographically searched. Only area 19 and lateral suprasylvian area showed such projections; terminal sites were localized in the ventral and dorsal banks of the cruciate sulcus and in the adjacent mesial surface of the brain. The possibility that these labeled regions may correspond to the monkey's frontal eye field is discussed.

Animals↗
PubMed1979

Acid-base equilibrium during acute long-lasting experiments in artificially ventilated cats.

Experiments were carried out to study blood acid-base equilibrium in the cat during experiments with artificial ventilation. Blood acid-base equilibrium was examined in the arterial and venous blood by analyzing pH, carbon dioxide and oxygen partial pressure, and plasma bicarbonates. Artificial ventilation was regulated on the basis of this analysis; CO2 concentration in expired air was monitored throughout the experiment. An attempt was made to verify if artificial ventilation could be regulated indirectly only on the basis of CO2 concentration in expired air. The most appropriate acid-base equilibrium was maintained when CO2 concentration in expired air was kept within the range of 3.9-4.1%.

Acid-Base Equilibrium↗
PubMed1977

Maintained activity of single neurons in the cat visual cortex at different levels of retinal adaptation.

The influence of ambient illumination on the maintained electrical activity of single neurons of the cat visual cortex was studied by using the closed chamber technique for extracellular recordings. Several levels of light background within the scotopic-mesopic range were explored. Phasic and tonic changes in firing rate were observed following a background change. The former were irregular and unpredictable variations lasting up to 15-20 min. The latter, which usually followed the phasic changes, showed the constant characteristic of being in direct relation to luminance variations for neurons isolated in the striate area and in inverse relation for units recorded from the two non-striate areas of the visual cortex; in all cases, they lasted until a new luminous level was set. Changes in firing rate were not dependent upon either the neuron receptive field organization or the EEG pattern, simultaneously recorded. The background-locked firing rate variations recorded at the visual cortex seem to be the result of a particular cortical distribution of afferent fibers carrying luminance information. Applications to vision research are also suggested.

Action Potentials↗