Variability in the Human Entorhinal Region May Confound Neuropsychiatric Diagnoses

Abstract

The human entorhinal region consists of a number of areas; however, there is no generally accepted nomenclature for these cytoarchitectonic fields, and the designation of its constituent layers or strata is a matter of controversy. Here, we consider a hitherto neglected adjacent field, the preamygdaloid claustrocortex. Its medial subfield has a small common border with the rostromedial entorhinal region (width maximal 2 mm). Both fields are cytoarchitectonically rather similar. The rostromedial oral entorhinal field lacks ascending terminal islands. Its unusually small pre-alpha cells are arranged in a thin band or small clusters consisting of pyramidal, triangular, or polymorphic cells. The conspicuous chromophilic pre-beta cell clusters are composed of a variety of cell types, including groups of ‘immature’ spindle-shaped or bipolar nerve cells. Furthermore, a rare sulcus within the entorhinal region (central sulcus of the entorhinal region: observed in 4% of the 450 brains examined) is associated with an unusual lamination of the entorhinal layers in its wall and floor. Both the specific shape and arrangement of neurones in the claustrocortical-rostral entorhinal border region and the unusual lamination within the rare central entorhinal sulcus are regarded as reflecting neurodevelopmental disturbances characteristic of schizophrenic brains. In contrast, our observations in a large sample of serially sectioned brains from controls, schizophrenics, and patients suffering from neuropsychiatric diseases other than schizophrenia do not support this assumption.

Schizophrenia genes, gene expression, and neuropathology: on the matter of their convergence

“…However, neither can they yet be accepted uncritically, as there are methodological limitations, negative studies, and the positive studies disagree as to the nature of the alterations. 57,[60][61][62][63] There are several other histological findings to note that lack the strong neurodevelopmental implication of aberrantly located neurons, but which are reasonably well replicated and together may provide clues about the nature of the disorder and may relate more directly to its genetic origins. First, the cell bodies of pyramidal neurons in the hippocampus and neocortex are smaller in many [64][65][66][67][68][69] though not all 70,71 studies.…”

Stereological approaches to dementia research using human brain tissue

“…The authors suggest that the dramatic loss at the earliest stages of cognitive decline, with no losses as a result of age, provide evidence for AD being a disease entity that is separate from an acceleration of the process of aging. When assessing findings from the entorhinal cortex, it should be noted that the cellular populations of the entorhinal cortex are highly variable across cases both with and without neurological disease (Heinsen et al, 1996). This is especially important as the number of cases used at certain levels was low, with only two CDR1 cases used in the former study.…”

Total number of neurons in the layers of the human entorhinal cortex

“…This area appears to correspond to the claustrocortex praepiriformis of Heinsen at al. (1994Heinsen at al. ( , 1996.…”