Biomedical subjects

E A Nimchinsky

Publications and source records attributed to E A Nimchinsky.

4 recordsLinked to original sources

PubMed1995

Human cingulate cortex: surface features, flat maps, and cytoarchitecture.

The surface morphology and cytoarchitecture of human cingulate cortex was evaluated in the brains of 27 neurologically intact individuals. Variations in surface features included a single cingulate sulcus (CS) with or without segmentation or double parallel sulci with or without segmentation. The single CS was deeper (9.7 +/- 0.81 mm) than in cases with double parallel sulci (7.5 +/- 0.48 mm). There were dimples parallel to the CS in anterior cingulate cortex (ACC) and anastomoses between the CS and the superior CS. Flat maps of the medial cortical surface were made in a two-stage reconstruction process and used to plot areas. The ACC is agranular and has a prominent layer V. Areas 33 and 25 have poor laminar differentiation, and there are three parts of area 24: area 24a adjacent to area 33 and partially within the callosal sulcus has homogeneous layers II and III, area 24b on the gyral surface has the most prominent layer Va of any cingulate area and distinct layers IIIa-b and IIIc, and area 24c in the ventral bank of the CS has thin layers II-III and no differentiation of layer V. There are four caudal divisions of area 24. Areas 24a' and 24b' have a thinner layer Va and layer III is thicker and less dense than in areas 24a and 24b. Area 24c' is caudal to area 24c and has densely packed, large pyramids throughout layer V. Area 24c' g is caudal to area 24c' and has the largest layer Vb pyramidal neurons in cingulate cortex. Area 32 is a cingulofrontal transition cortex with large layer IIIc pyramidal neurons and a dysgranular layer IV. Area 32' is caudal to area 32 and has an indistinct layer IV, larger layer IIIc pyramids, and fewer neurons in layer Va. Posterior cingulate cortex has medial and lateral parts of area 29, a dysgranular area 30, and three divisions of area 23: area 23a has a thin layer IIIc and moderate-sized pyramids in layer Va, area 23b has large and prominent pyramids in layers IIIc and Va, and area 23c has the thinnest layers V and VI in cingulate cortex. Area 31 is the cinguloparietal transition area in the parasplenial lobules and has very large layer IIIc pyramids. Finally, variations in architecture between cases were assessed in neuron perikarya counts in area 23a. There was an age-related decrease in neuron density in layer IV (r = -0.63; ages 45-102), but not in other layers.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain Mapping↗

PubMed1995

Spindle neurons of the human anterior cingulate cortex.

The human anterior cingulate cortex is distinguished by the presence of an unusual cell type, a large spindle neuron in layer Vb. This cell has been noted numerous times in the historical literature but has not been studied with modern neuroanatomic techniques. For instance, details regarding the neuronal class to which these cells belong and regarding their precise distribution along both ventrodorsal and anteroposterior axes of the cingulate gyrus are still lacking. In the present study, morphological features and the anatomic distribution of this cell type were studied using computer-assisted mapping and immunocytochemical techniques. Spindle neurons are restricted to the subfields of the anterior cingulate cortex (Brodmann's area 24), exhibiting a greater density in anterior portions of this area than in posterior portions, and tapering off in the transition zone between anterior and posterior cingulate cortex. Furthermore, a majority of the spindle cells at any level is located in subarea 24b on the gyral surface. Immunocytochemical analysis revealed that the neurofilament protein triple was present in a large percentage of these neurons and that they did not contain calcium-binding proteins. Injections of the carbocyanine dye DiI into the cingulum bundle revealed that these cells are projection neurons. Finally, spindle cells were consistently affected in Alzheimer's disease cases, with an overall loss of about 60%. Taken together, these observations indicate that the spindle cells of the human cingulate cortex represent a morphological subpopulation of pyramidal neurons whose restricted distribution may be associated with functionally distinct areas.

Aged↗

PubMed1994

Amyotrophic lateral sclerosis/parkinsonism-dementia complex of Guam: quantitative neuropathology, immunohistochemical analysis of neuronal vulnerability, and comparison with related neurodegenerative disorders.

Amyotrophic lateral sclerosis/parkinsonism-dementia complex (lytico-bodig) is a chronic neurodegenerative disorder with high prevalence among the native Chamorro population of Guam. Neuropathological, biochemical, and immunohistochemical analyses were performed on a relatively large series of Guamanian cases and compared to Alzheimer's disease cases. Thioflavin S and antibodies to amyloid beta A4 and tau proteins were used for analysis of pathological changes, and antibodies to the calcium-binding proteins parvalbumin and calretinin, and to a nonphosphorylated epitope on neurofilament protein to study select neuronal populations. A differential distribution of neurofibrillary tangles was observed in the neocortex of Guamanian cases compared to Alzheimer's disease cases, with much higher lesion counts in supragranular than in infragranular layers. Also, Guamanian cases with predominant parkinsonism had generally higher neurofibrillary tangle densities than cases with predominant amyotrophic lateral sclerosis. In addition, there was a certain degree of heterogeneity, qualitatively and quantitatively, in the biochemical distribution of tau proteins among Guamanian and Alzheimer's disease cases as revealed by Western blot analysis. Previous studies have suggested that the clinical symptomatology observed in patients suffering from Alzheimer's disease is related to the dramatic loss of specific corticocortically projecting neurons in the neocortex. Interestingly, a subset of neurofilament-rich pyramidal neurons known to be dramatically affected in Alzheimer's disease appears to be resistant in lytico-bodig. Finally, as in Alzheimer's disease, calcium-binding protein-containing interneurons are not affected. These data suggest that the set of projection neurons affected in Guamanian cases may not correspond to those involved in Alzheimer's disease, and that both disorders are characterized by specific patterns of neuronal vulnerability.

Adult↗

PubMedDate not supplied

Regional distribution of neurofilament and calcium-binding proteins in the cingulate cortex of the macaque monkey.

The cingulate cortex is composed of morphologically and functionally distinct areas. It is considered to be a major component of the limbic system and has been shown to subserve a wide range of autonomic and somatic motor functions. The anterior and posterior regions of the cingulate cortex can be differentiated according to their thalamic afferents as well as their patterns of corticocortical connectivity. The primate cingulate cortex is traditionally divided into a series of cytoarchitectonic zones that can be distinguished along a ventral-dorsal axis of differentiation in both the anterior (areas 25, 24a, 24b, and 24c), and posterior (areas 29, 30, 23a, 23b, and 23c) regions. However, little is known about the precise cellular organization of these subareas. In the present study, we attempt to define the neuronal morphological and biochemical composition of the different cingulate cortex subareas, using antibodies to the neurofilament triplet protein and calcium-binding proteins. Results indicate that there is a strong correlation between the structure and functions of the cingulate cortex and the immunostaining patterns. For instance, distribution of neurofilament-rich pyramidal neurons parallels that of specific corticocortical and corticosubcortical systems and is a useful marker to delineate the cingulate motor area. Calcium-binding protein-containing neurons display a high degree of regional and laminar specialization. In particular, parvalbumin-positive interneurons are codistributed with neurofilament-immunoreactive pyramidal cells along the ventrodorsal and rostrocaudal axes of the cingulate cortex. Calbindin- and calretinin-positive immunostaining show more monotonous laminar and regional patterns, although they exhibit a particular labeling in area 29 that may correspond to the termination of select thalamocortical afferents. These chemoarchitectural patterns of regional and laminar neuronal specialization may be envisioned as the reflection of the richness of cortical diversity in the cingulate gyrus, and make it an ideal place to explore the interplay of the distributions of various neuron types in cortical areas of known function.

Animals↗