Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Correlative light and electron microscopic immunocytochemical methods were used to analyze the 5-HT innervation of the primary auditory area (AI) of the cat cerebral cortex and to examine the synaptic relationships of 5-HT basket terminations on target neurons in that area. Three morphological types of 5-HT-immunoreactive fibers are present: type I, which is very thin and very finely beaded; type II, which is thin and coarsely beaded; and type III, which has a relatively thick main shaft and very few beads. Type I is the most abundant, type II is relatively less common, and type III is the least abundant type. The 3 types of fibers are present through the thickness of AI and in the subjacent white matter, but the densest plexus is found in layers I-III. One of the most characteristic features of type II fibers is that they commonly form small, dense clusters that resemble baskets apposed to the somata and primary dendrites of unstained neurons. The basket formations are more frequently found in layers I and II, and they vary in complexity. Simultaneous immunostaining for GABA and 5-HT reveals that many 5-HT baskets surround the somata and dendrites of GABA neurons. In 2-microns-thick plastic sections, each basket formation can be seen surrounding 1 or a group of 2 or 3 cells. In the latter case, one cell is much larger and at the electron microscope level is identified as a neuron, while the other cells are neuroglial cells. Reconstructions were made from serial electron micrographs of 135 5-HT-immunoreactive boutons. Of these boutons, 110 belonged to basket formations, 14 to type I axons located in the neuropil, and the remaining 11 to type II fibers located in the white matter. Only 4 of the 135 boutons made conventional synaptic contacts. These were of the asymmetrical type. Most of the boutons made very small, indistinct membrane specializations or none at all. The present results therefore suggest a strong interaction between 5-HT axon terminals and specific GABA neurons, which may be mediated by release sites that are not associated with morphologically distinct synaptic contacts.
Cereb Cortex
PMID:Synaptic relationships of serotonin-immunoreactive terminal baskets on GABA neurons in the cat auditory cortex. 182 29

The time course and rate of synaptogenesis were studied in the somatosensory cortex (Brodmann's areas 1 and 3b) of 27 rhesus monkeys ranging in age from embryonic day 41 to 20 years. Two to four vertical probes, each consisting of a series of overlapping electron micrographs and extending from the pial surface to the interface of the cortex with the white matter, were made from sections cut across the postcentral gyrus in the region of the upper limb representation. We found that the density of synapses per unit volume of cortex as well as per unit volume of neuropil increases steadily throughout the late fetal ages and early infancy. A density of 70/100 microns 3 of neuropil was reached by the second postnatal month; thereafter, between 1 and 3 years a slightly lower density of 50-60/100 microns 3 was maintained. At around puberty, the decrease in concentration of synapses appears to be accelerated. Thus, the average synaptic density of a group of 10 adult animals composed of monkeys over 4 years of age was 30-40 synapses per 100 microns 3 of neuropil. This value is significantly lower than that of the group of 11 infant and juvenile animals below 4 years of age. Since synaptic density per unit volume of neuropil is not affected by changes in other parameters of cortical growth, these numbers reflect an actual overproduction of synapses in infancy followed by their elimination during adolescence. The decline in the number of synapses is due primarily to elimination of asymmetrical junctions located on dendritic spines while symmetrical synapses on dendritic shafts and cell bodies remained relatively constant during postnatal life. The course of synapse formation recorded in the present study coincides with the course of overproduction and elimination of neurotransmitter receptors (Lidow et al., 1991) and the developmental schedule of synaptogenesis in other neocortical areas (Rakic et al., 1986). The timing of synaptogenesis and synaptic elimination in the postcentral gyrus may account for the maturation and plasticity of various aspects of somatosensory function during post-natal life.
Cereb Cortex
PMID:Synaptogenesis in monkey somatosensory cortex. 182 55

The effect of behavioral activation on cerebral and cerebellar glucose metabolism was studied in normal subjects when performing either a verbal memory task or a tactile somatosensory task. Each subject was also studied in a resting state control condition, either 1 h earlier or later than the activation task. Compared to the resting state, both tasks produced asymmetrical metabolic activation, which was opposite in direction within the cerebral and cerebellar hemispheres. In both tasks, the difference of activation of CMRglc in the right and left hemispheres in the cerebellum was negatively correlated with that in the sensory-motor region. This apparently coupled metabolic activation of one cerebellum and areas within the opposite cerebral hemisphere represents the inverse of the crossed cerebellar diaschisis phenomenon commonly observed when a vascular lesion affects one cerebral hemisphere and hypometabolism occurs in the opposite cerebellum. Because these correlations were selective and concordant with known anatomical connections, and were found in two different tasks, they suggest strong functional connections between these specific brain regions.
J Cereb Blood Flow Metab 1991 Jan
PMID:Cerebrocerebellar relationship during behavioral activation: a PET study. 198 4

Lesions of one cerebral hemisphere are associated with decreased glucose metabolism, oxygen metabolism, and blood flow in the contralateral cerebellar hemisphere. We used positron emission tomography to look for a functional relationship in cerebral metabolism between the cerebral cortex and the contralateral cerebellum in normal human subjects. Twenty-four normal subjects were scanned with [18F]fluoro-2-deoxy-D-glucose while in a resting state. Asymmetry in local CMRglu (LCMRglu) in the frontal cortex was strongly correlated with asymmetry in LCMRglu in the opposite direction in the cerebellar hemispheres (r = -0.60, p less than 0.001). Widespread subregions of the frontal cortex were found to contribute to this relationship. Considering these results together with previous studies demonstrating that frontal lesions are associated with decreased metabolism in the contralateral cerebellum, we conclude that the frontal cortex exerts a strong modulating influence on metabolism in the contralateral cerebellum in normal subjects, and that this influence may be asymmetrical.
J Cereb Blood Flow Metab 1988 Dec
PMID:A relationship between metabolism in frontal lobes and cerebellum in normal subjects studied with PET. 326 82

Regional CMRglc (rCMRglc) values were determined with positron emission tomography (PET) in 10 patients with mild to moderate clinically diagnosed Alzheimer's disease (AD) and in 26 healthy controls. rCMRglc in frontal, parietal, and temporal association cortices were significantly more laterally asymmetrical in AD patients than in controls (p less than 0.05). Furthermore, lateral asymmetry of rCMRglc in AD patients but not in the control subjects correlated significantly with asymmetry of language and visuospatial functions such that lower left than right rCMRglc was associated with relatively greater impairment of language and vice versa. The results demonstrate that discrepancies between language and visuospatial deficits in patients with early AD are related to asymmetrical reductions in cerebral cortical glucose metabolism.
J Cereb Blood Flow Metab 1985 Jun
PMID:Relations between neuropsychological and cerebral metabolic asymmetries in early Alzheimer's disease. 398 21

Computed mapping of the electroencephalogram (CME) is a newly developed method using a microcomputer system that displays the scalp topograph as the square roots of the average power spectra over each EEG frequency band on a color television screen. This new device has been employed in an examination of functional lesions in 20 patients with aphasia due to cerebral infarction. The results were compared with those of computer tomography (CT) and regional cerebral blood flow (rCBF) studies using intracarotid 133Xe. A high-voltage focus of slow components and an asymmetrical distribution of alpha activity were regarded as signs of functional lesions on CME. Twelve patients showed high-voltage foci and six showed asymmetrical alpha activity on CME, which correlated well with the lesions on CT and/or rCBF studies. Especially in patients with motor aphasia, CME demonstrated the abnormality in advance of the appearance of a low-density area on CT. Compared with conventional EEG interpretation, CME is very useful in topographic and objective diagnosis of functional lesions, although the source of the data is the same as for the conventional EEG.
J Cereb Blood Flow Metab 1982
PMID:Topographic electroencephalographic study of cerebral infarction using computed mapping of the EEG. 706 5

Origin and ontogenesis of human brain laterality are unknown. Using in vivo magnetic resonance morphometry we measured cerebral hemispheric asymmetry of the planum temporale, a structural substrate of functional laterality, in pairs of monozygotic twins concordant or discordant for handedness. In both groups, intraclass (i.e., within twin pair) correlations were low. The right-handers showed leftward asymmetry whereas the left-handers lacked asymmetry. The discordance for lateralized brain anatomy can be accounted for by ontogenetic models assuming twinning of an asymmetrical germ or differential action of nongenetic factors within twin pairs in utero. The findings confirm a coupling of lateralized structure and function of the human brain. At least in monozygotic twins, early epigenetic factors must play a role in anatomofunctional laterality development.
Cereb Cortex
PMID:Brain (A) symmetry in monozygotic twins. 758 Jan 22

Cholinergic innervation of the cerebral neocortex arises from the basal forebrain and projects to all cortical regions. Acetylcholinesterase (AChE), the enzyme responsible for deactivating acetylcholine, is found within both cholinergic axons arising from the basal forebrain and a subgroup of pyramidal cells in layers III and V of the cerebral cortex. This pattern of staining varies with cortical location and may contribute uniquely to cortical microcircuitry within functionally distinct regions. To explore this issue further, we examined the pattern of AChE staining within auditory, auditory association, and putative language regions of whole, postmortem human brains. The density and distribution of acetylcholine-containing axons and pyramidal cells vary systematically as a function of auditory processing level. Within primary auditory regions AChE-containing axons are dense and pyramidal cells are largely absent. Adjacent cortical regions show a decrease in the density of AChE-containing axons and an increase in AChE-containing pyramidal cells. The posterior auditory and language regions contain a relatively high density of AChE-containing pyramidal cells and AChE-containing axons. Although right and left posterior temporal regions are functionally asymmetrical, there is no apparent asymmetry in the general pattern of AChE staining between homologous regions of the two hemispheres. Thus, the pattern of AChE staining covaries with processing level in the hierarchy of auditory cortical regions, but does not vary between the functionally distinct right and left posterior regions. An asymmetry in the size of layer III AChE-rich pyramidal cells was present within a number of cortical regions. Large AChE-rich pyramidal cells of layer III were consistently greater in size in the left hemisphere as compared to the right. Asymmetry in layer III pyramidal cell size was not restricted to language-associated regions, and could potentially have a variety of etiologies including structural, connectional, and activational differences between the left and right hemisphere.
Cereb Cortex
PMID:Acetylcholinesterase staining in human auditory and language cortices: regional variation of structural features. 867 Jun 55

It is widely believed that inhibitory synapses are not present or present in only small numbers in the rodent cerebral cortex during the early postnatal period when the cortex is being innervated by thalamocortical fibers. Quantitative electron microscopy was carried out on the posteromedial barrel subfield of mouse somatosensory cortex from postnatal day 4 (P4) when thalamocortical innervation of the barrels is becoming established, through to sexual maturity (>P32), and in adulthood. Both asymmetrical (putatively excitatory) and symmetrical (putatively inhibitory) synapses were present in all layers from P4. The symmetrical synapses were immunoreactive for GABA at all ages. There was a progressive increase in both asymmetrical and symmetrical synapses up to P32, density in all layers increasing 16-fold, with the production of asymmetrical synapses leading and greatly outstripping that of symmetrical. From P32 to P120, the oldest age studied, synaptic numbers declined by 18% to 13 times the P4 level, but this affected predominantly layers II/III, IV and V, and mainly involved asymmetrical synapses. The relative percentage of asymmetrical to symmetrical synapses from P4 to P8 was 57%/43% but at P32 it was 89.5%/10.5% and in adulthood 85.4%/14.6%. These data indicate that inhibitory synaptogenesis in the rodent cortex begins earlier than previously thought, a basis for inhibition being present from the earliest period. Pruning of all synapses occurs well after thalamocortical innervation is established and inhibitory synapses are less affected by the pruning process.
Cereb Cortex
PMID:Inhibitory synaptogenesis in mouse somatosensory cortex. 937 18

Heat shock proteins serve as molecular chaperones in a protein "holding and folding" system. Protein sequencing, extraction and immunoblot analyses indicate that Hsc70, a constitutive form, is a major component of the rat postsynaptic density (PSD) fraction, while Hsp70, an inducible form, is present at the basal level. Immunohistochemical studies show that expression of Hsc70 is high, but that of Hsp70 is low, in the cerebral cortex and hippocampal formation. In dissociated hippocampal neurons, both Hsp70 and Hsc70 immunoreactivities are distributed throughout the soma and dendrites. In dendrites, there are many stained puncta which are mostly co-localized with PSD-95, a postsynaptic marker. Interestingly, variation in staining intensity of the puncta is significantly larger for Hsp70 than for Hsc70 in 2-week-old cultures, but becomes less significant in 5(1/2)-week-old cultures. At the electron microscopic level, both Hsp70 and Hsc70 are mainly associated with asymmetrical PSDs. However, Hsc70 is also associated with amorphous subsynaptic structures and spine apparatus-like cisternae. Our data indicate that both Hsp70 and Hsc70 are present in PSDs but are differentially distributed at subsynaptic sites, and provide a potential candidate system for a "synaptic tag".
Cereb Cortex 2001 Mar
PMID:Presence of both constitutive and inducible forms of heat shock protein 70 in the cerebral cortex and hippocampal synapses. 1123 95


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