An autoradiographic study of the efferent connections of the entorhinal cortex in the rat
- 9 July 1981
- journal article
- research article
- Published by Wiley in Journal of Comparative Neurology
- Vol. 199 (4), 495-512
- https://doi.org/10.1002/cne.901990405
Abstract
The longer connections of the entorhinal cortex have been studied autoradiographically in a series of rats, each of which received a small injection of 3H-amino acids in one of the various cytoarchitectonic subfields of the entorhinal cortex. The major findings can be summarized as follows. Whereas the projection of the lateral entorhinal area (LEA) to the dentate gyrus is broad in its longitudinal extent, the medial entorhinal area (MEA), and especially the ventral portion of this zone, projects in a more lamellar fashion. In the transverse plane the LEA preferentially projects to the inner (dorsal) blade of the dentate gyrus, while the MEA innervates both blades equally. Within the radial dimension, the entorhinal cortex projects to the dentate gyrus according to a medial to lateral gradient, with lateral portions of the LEA projecting along the pial surface and successively more medial portions of the entorhinal projecting closer to the granule cells. The commissural entorhinal to dentate projections are similar to the ipsilateral projections in location; however, they are considerably reduced in septotemporal extent and do not arise from cells in the ventral half of either LEA or the intermediate entorhinal area (IEA). The projection of the entorhinal cortex to Ammon's horn reflects the same longitudinal characteristics as the denate projections. An alvear input which extends only to the pyramidal cells at the CA1-subicular junction was most noticeable at ventral hippocampal levels. Finally the extrahippocampal projections have been analyzed. These arise predominantly from cells in the LEA and project forward along the angular bundle to the piriform and periamygdaloid cortices, as well as the endopiriform nucleus, the lateral, basolateral, and cortical amygdaloid nuclei, the nucleus of the lateral olfactory tract, the olfactory tubercle, the anterior olfactory nucleus, the taenia tecta, and the indusium griseum. These extrinsic projections are to a large extent reciprocal to the major extrinsic inputs to the LEA.This publication has 40 references indexed in Scilit:
- Afferents to the entorhinal cortex of the rat studied by the method of retrograde transport of horseradish peroxidaseExperimental Neurology, 1977
- Efferent connections of the hippocampal formation in the ratBrain Research, 1977
- Topographic organization of the projections from the entorhinal area to the hippocampal formation of the ratJournal of Comparative Neurology, 1976
- Olfactory relationships of the telencephlaon and diencephalon in the rabbit. 1. An autoradiographic study of the efferent connections of the main and accessory olfactory bulbsJournal of Comparative Neurology, 1975
- Hippocampo-Hypothalamic Connections: Origin in Subicular Cortex, Not Ammon's HornScience, 1975
- Anatomical evidence for a projection from the entorhinal cortex to the contralateral dentate gyrus of the ratExperimental Neurology, 1975
- The differential projections of the olfactory bulb and accessory olfactory bulb in mammalsJournal of Comparative Neurology, 1975
- An autoradiographic study of the time of origin and the pattern of granule cell migration in the dentate gyrus of the ratJournal of Comparative Neurology, 1975
- ON THE TERMINATION OF SOME AFFERENTS TO THE HIPPOCAMPUS AND FASCIA DENTATACells Tissues Organs, 1958
- Structure and relations of limbic cortex and anterior thalamic nuclei in rabbit and catJournal of Comparative Neurology, 1948