Entorhinal cortex of the rat: cytoarchitectonic subdivisions and the origin and distribution of cortical efferents.

摘要: The origins and terminations of entorhinal cortical projections in the rat were analyzed detail with retrograde anterograde tracing techniques. Retrograde fluorescent tracers injected different portions olfactory, medial frontal (infralimbic prelimbic areas), lateral (motor area), temporal (auditory), parietal (somatosensory), occipital (visual), cingulate, retrosplenial, insular, perirhinal cortices. Anterograde tracer injections placed various parts cortex to demonstrate laminar topographical distribution cortex. experiments showed that each area explored receives from a specific set neurons, limited number distribution. By far most extensive projection was directed This projection, which arises all layers, originates throughout cortex, although its major origin is more caudal Projections olfactory structures originate largely layers II III much intermediate modest component neurons layer V Neurons an extremely laterally located strip positioned along rhinal fissure, give rise (motor), anterior cingulate part retrosplenial confirmed these findings general, terminal fields entorhinal-cortical densest I, II, III, particularly densely innervated areas, labeling also present. Comparably distributed, but weaker reach contralateral hemisphere. Our results show rat, hippocampal output can widespread neocortex through relay very restricted However, hippocampal-cortical connections will be mediated by way entorhinal-perirhinal-cortical connections. We conclude that, contrast previous notions, overall organization connectivity comparable monkey.