Ventral part of the diencephalon extending from the region of the optic chiasm to the caudal border of the mammillary bodies and forming the inferior and lateral walls of the third ventricle.

The dorsal posterior subdivision of the diencephalon. The epithalamus is generally considered to include the habenular nuclei (HABENULA) and associated fiber bundles, the PINEAL BODY, and the epithelial roof of the third ventricle. The anterior and posterior paraventricular nuclei of the thalamus are included with the THALAMIC NUCLEI although they develop from the same pronuclear mass as the epithalamic nuclei and are sometimes considered part of the epithalamus.

A small protuberance at the dorsal, posterior corner of the wall of the third ventricle, adjacent to the dorsal thalamus and pineal body. It contains the habenular nuclei and is a major part of the epithalamus. (From Lockard, Desk Reference for Neuroscience, 2nd ed, p121)

Heavily myelinated fiber bundle of the TELENCEPHALON projecting from the hippocampal formation to the HYPOTHALAMUS. Some authorities consider the fornix part of the LIMBIC SYSTEM. The fimbria starts as a flattened band of axons arising from the subiculum and HIPPOCAMPUS, which then thickens to form the fornix.

Set of nerve fibers conducting impulses from olfactory receptors to the cerebral cortex. It includes the OLFACTORY NERVE; OLFACTORY BULB; olfactory tract, olfactory tubercle, anterior perforated substance, and olfactory cortex. The term rhinencephalon is restricted to structures in the CNS receiving fibers from the olfactory bulb.

Ovoid body resting on the cribriform plate of the ethmoid bone where the olfactory nerve terminates. The olfactory bulb contains several types of nerve cells including the mitral cells, on whose dendrites the olfactory nerve synapses, forming the olfactory glomeruli. The accessory olfactory bulb, which receives the projection from the VOMERONASAL ORGAN via the vomeronasal nerve, is also included here.

A curved elevation of gray matter extending the entire length of the floor of the temporal horn of the lateral ventricle (Dorland, 28th ed). The hippocampus, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation. Entorhinal Cortex; Perforant Pathway;

Projection neurons in the cerebral cortex and the hippocampus. Pyramidal cells have a pyramid-shaped soma with the apex and an apical dendrite pointed toward the pial surface and other dendrites and an axon emerging from the base. The axons may have local collaterals but also project outside their cortical region.

The cytoarchitecturally well-defined area of multilaminate cerebral cortex on the medial aspect of the parahippocampal gyrus, immediately caudal to the olfactory cortex of the uncus. The entorhinal cortex is the origin of the major neural fiber system afferent to the hippocampus, the so-called PERFORANT PATHWAY. (Stedman, 25th ed) Perforant Pathway;