Perirhinal Cortex (area 35)

The perirhinal cortex (area 35) is well-known locus for neurofibrillary tangles (NFT) in initial Alzheimer's disease (AD) and fully developed AD and may contain tau alterations in non-demented elderly.  

The hippocampal formation, including the subiculum and presubiculum, together with the entorhinal cortex (EC) and perirhinal cortex (area 35) contribute numerous axons to the fornix in a topographical manner. The medial fornix originates from cells in the caudal half of the subiculum, the lamina principalis interna of the caudal half of the presubiculum, and from the perirhinal cortex (area 35). The intermediate portion of the fornix (i.e., that part midway between the midline and most lateral parts of the fornix) originates from cells in the rostral half of the subiculum and prosubiculum, the anterior presubiculum (only from the lamina principalis externa), the caudal presubiculum (primarily from lamina principalis interna), the rostral half of CA3, the EC (primarily 28I and 28M), and the perirhinal cortex (area 35).  

In contrast, the neocortical area 17 and the lateral part of the perirhinal cortex (area 36) were innervated by evenly distributed fine fibers with a moderate number of small varicosities and few ramifications, whereas, the retrosplenial cortex (areas 29e, 29ab and 29cd), and the medial part of the perirhinal cortex (area 35) displayed an intermediate innervation pattern, probably reflecting the transitional nature of these areas being located between the paleo- and the neocortex.  

An efferent projection from the perirhinal cortex (area 35) in the rat was studied using the anterograde transport of tritiated amino acids as well as horseradish peroxidase (HRP).  

The posterior part of the perirhinal cortex (area 35) receives afferents from nonspecific thalamic nuclei (midline nuclei).  

In the monkey, HRP-labeled neurons were observed in the entorhinal cortices after injections of the rostral superior temporal gyrus (area TA or 22); the temporal polar cortex (area TG or 38); the inferior temporal cortex (area TE or 20); the perirhinal cortex (area 35) and the posterior parahippocampal cortices (areas TF and TH).  

[ View All ]