Area 23 Of Cerebral Cortex


Labeled cells were found in medial parietal area 31; in cingulate area 23; in the anterior (AIP), ventral (VIP), and lateral (LIP) intraparietal areas; in the inferior parietal lobule (fields Opt and PG); and in the medial superior temporal area (MST).  

As in the macaque monkey, we found that pyramidal cells in anterior cingulate gyrus (area 24) were more branched and more spinous than those in posterior cingulate gyrus (area 23).  

We found that pyramidal cells in anterior cingulate gyrus (area 24) were more branched and more spinous than those in posterior cingulate gyrus (area 23).  

The transition between areas 24 and 23 does not involve a simple increase in the number of neurons in layer IV but includes an increase in neuron density in layer Va of p24', a dysgranular layer IV in area 23d, granular area 23, with a neuron-dense layer Va and area 31. The PCC is composed of a dysgranular area 23d, area 23c in the caudal cingulate sulcus, a dorsal cingulate gyral area 23a/b, and a ventral area 23a/b. Finally, a dysgranular transition zone includes both area 23d and retrosplenial area 30.  

The reductions in opioid receptor binding within the medial system were observed mainly in the dorsolateral (Brodman area 10) and anterior cingulate (Brodman area 24 with some extension into area 23) and insula cortices and the thalamus.  

Its anterior (aMCC) and posterior (pMCC) parts and transition to posterior area 23 were evaluated in six human cingulate gyri with Nissl staining and immunoreactions for neuron-specific nuclear binding protein and intermediate neurofilament proteins (NFP), and their pain and emotion functions evaluated in standard coordinates. The junction of pMCC with area 23 had a dysgranular area 23d with clumps of layer IV neurons and a very dense layer Va. Beyond midcingulate duality, this is the first report of a very dense layer Va for areas p24' and 23 and the features of transitional area 23d.  

We investigated the cortical afferents of the retrosplenial cortex and the adjacent posterior cingulate cortex (area 23) in the macaque monkey by using the retrograde tracers Fast blue and Diamidino yellow. Injections in area 23 also resulted in numerous labeled cells in the posterior cingulate and retrosplenial regions (approximately 67% of total labeled cells). As in the retrosplenial cortex, injections of area 23 led to many labeled neurons in the frontal cortex, although most of these cells were in areas 9 and 46.  

For four out of five subjects, it was located at the border of the caudal division of left anterior cingulate cortex (area 24/32') with left posterior cingulate cortex (area 23/31).  

Pro-p has a clear but thin layer IV, contains a small number of SMI-32+ neurons, and adjoins both area 23 and area 18 dorsally and area 18 ventrally. Compared with Pro-p, area 23 contains many more SMI-32+ neurons, whereas area 18 contains far more SMI-32+ neurons.  

During provocation rCBF was lowered in the right retrosplenial cortex (areas 26/29/30 extending into area 23).  

area 23a is isocortex with a clear layer IV and large, NFP-ir neurons in layers IIIc and Va. area 23b is similar to area 23a but with a thicker layer IV, more large neurons in layer Va, and a higher density of NFP-ir neurons in layer III. Thus, Brodmann's map understates the rostral extent of retrosplenial cortex, overstates its caudoventral extent, and abridges the caudomedial extent of area 23..  

This study compares in vivo imaging results and in situ postmortem analyses by examining the posterior cingulate (area 23) in 15 AD patients and 13 age-matched nondemented controls using quantitative cytochrome oxidase histochemistry as an intracellular measure of oxidative energy metabolic capacity.  

Area 7m also had major connections with the cingulate cortex (area 23), particularly the ventral bank of the cingulate sulcus.  

This analysis demonstrated that areas 29 and 30 of the retrosplenial cortex, as well as adjacent area 23 of the posterior cingulate cortex, extend together as an arch around the splenium of the corpus callosum and maintain their topographical relationship with one another throughout their entire course.  

There were also differences in cerebral blood flow response in areas involved in memory and visuospatial processing (and by extension response to threat), including posterior cingulate (area 23), precentral (motor) and inferior parietal cortex, and lingual gyrus.  

This study used multivariate analyses of area 23 in 72 cases of definite AD to assess relationships between laminar patterns of neurodegeneration, neurofibrillary tangle (NFT) and senile plaque (SP) densities, age of disease onset and duration, and apolipoprotein E (ApoE) genotype. In conclusion, multivariate pattern recognition shows that AD is composed of independent neuropathological subtypes and NFT in area 23 do not account for most neuron losses..  

Electrodermal activity was positively related to rCBF in the left primary motor cortex (MI, Brodmann's Area 4) and bilaterally in the anterior (Areas 24 and 32) and posterior cingulate cortex (area 23).  

Because area 23 is strategically located in a network that links the parietal associative (area 7a) and parahippocampal cortices, and because these cortical areas are involved in topographical orienting processes, we suggest that a transient functional inactivation of the network caused by epileptic discharges spreading from the damaged cingulate cortex towards the parahippocampal and parietal association cortex could account for the spatial disorder.  

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. Finally, variations in architecture between cases were assessed in neuron perikarya counts in area 23a.  

Fibers from the anterior CiG (area 24) passed through the anterior portion of the CC while those from the posterior CiG (area 23) passed through the posterior portion of the CC..  

Area 7b is reciprocally and precisely connected with area 5, the second somatic sensory area (SII), the retroinsular area, the granular insular area (Ig), area 23 of the cingulate cortex and with the cortex in the walls of the superior temporal sulcus.  

In the granular prefrontal (areas 46, 9, 10, 11, 12), parietal (areas 1, 2, 3, 5, 7), temporal (areas 21, 22), and posterior cingulate (area 23) cortices, DA afferents were less dense and showed a bilaminar pattern of distribution, predominating in the depth of layer I and in layers V-VI; density in layers II, III, and IV was only 20% of that in layer I.  

The cortical areas between the proisocortical regions on the one hand and the isocortical areas on the other, that is, the posterior cingulate region (area 23) and the posterior parahippocampal gyrus (areas TF and TH), project predominantly to the dorsal portion of the medial pulvinar nucleus, the anterior nuclear group (AV, AM), and the lateral dorsal (LD) nucleus.  

In the cingulate cortex, labeled cells were observed in area 25, area 32, and rostral levels of area 24; fewer cells were observed at caudal levels of area 24 or in area 23.  

Area 7b is reciprocally and precisely connected with area 5, the second somatic sensory area (SII), area 23 of the cingulate cortex, the retroinsular area (Ri), the granular insular area (Ig), and with the cortex in the walls of the superior temporal sulcus..  

Anterior cingulate areas 24a and 24b and posterior areas 29d and 30 projected to area 23. Finally, a rostromedial part of visual association area 19 also projected to area 23.  

area 23 also has three divisions, each of which has a distinct layer IV. area 23a is adjacent to the callosal sulcus and has the thinnest layers II-IV, which have the same cell density as layers V and VI. area 23b has the largest pyramids in layers IIIc and Va, and area 23c, in the depths of the posterior cingulate sulcus, has the broadest external and thinnest internal pyramidal layers.  

The topographic distribution of medial pulvinar neuronal populations projecting to area 7a and to posterior cingulate gyrus (area 23) was investigated with retrograde axonal transport of fluorescent dyes.  

The fibers from the anterior thalamic nucleus coursing in the cingulum bundle extended rostrally to the frontal cortex and caudally to area 23 and the retrosplenial cortex. Those fibers from area 24 of the cingulate gyrus are directed to the premotor and prefrontal regions as well as area 23 and retrosplenial cortex. The fibers from area 23 extend rostrally to the prefrontal cortex and caudoventrally to the presubiculum and parahippocampal gyrus.  

The posterior cingulate gyrus (area 23) is specifically connected with the associative temporal cortex, the medial temporal and orbitofrontal cortices, and with the medial pulvinar.  

Areas surrounding retrosplenial cortex in the posterior cingulate region were also evaluated in Nissl and Golgi preparations including the indusium griseum, subiculum (dorsal to the corpus callosum) and area 23. The transition from one cellular layer in the indusium griseum to five cellular layers in area 23 is made by the addition of layers II, III, IV and VI in retrosplenial cortex to the one ganglionic layer of the indusium griseum and subiculum. First, the structure of pyramidal cells progressively changes from those in the indusium griseum which have predominently round or oval somata and a preponderance of apical and few basal dendrites to those in layer V of retrosplenial cortex and area 23 which have pyramidal shaped somata and a great number of basal dendrites which branch frequently and spread horizontally for hundreds of microns. At the retrosplenial granular/agranular border, though, these cells gradually begin to constitute a greater proportion of the cell population and in area 23 form a major component of layer IV....  


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