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At least 19 recordsLinked to original sources

PubMed2026

High-frequency contralesional dorsal premotor cortex and low-frequency contralesional primary motor cortex rTMS in subacute stroke with severe upper limb impairment: comparable motor outcomes and differential regional degree centrality changes.

BACKGROUND: The contralesional dorsal premotor cortex has been proposed as a potential neuromodulatory target for patients with severe upper limb impairment due to subacute ischemic stroke. This proof-of-concept study aimed to compare behavioral outcomes and resting-state neuroimaging findings between high-frequency repetitive transcranial magnetic stimulation (rTMS) over the contralesional dorsal premotor cortex and guideline-supported low-frequency stimulation over the contralesional primary motor cortex. METHODS: In this randomized trial, 46 patients with severe upper limb impairment in the subacute stage after ischemic stroke were randomly assigned to receive either high-frequency rTMS over the contralesional dorsal premotor cortex or low-frequency rTMS over the contralesional primary motor cortex. Low-frequency stimulation over the contralesional primary motor cortex served as an evidence-supported active comparator for poststroke upper limb motor recovery. Stimulation was administered five times per week for two weeks using magnetic resonance imaging-guided neuronavigation. All participants received concurrent standard rehabilitation therapy. The primary outcome was the Fugl-Meyer Assessment for Upper Extremity. Secondary outcomes included the Arm Subscore of the Motricity Index, the Hong Kong version of the Functional Test for the Hemiplegic Upper Extremity, the Modified Barthel Index, and resting-state functional magnetic resonance imaging-derived degree centrality. RESULTS: Both groups showed significant improvements in the primary and secondary behavioral measures (p < 0.01), with no significant between-group differences in the magnitude of change (p > 0.05). In neuroimaging analyses, patients receiving high-frequency rTMS over the contralesional dorsal premotor cortex showed significantly greater degree centrality changes in the ipsilesional middle occipital gyrus, contralesional medial superior frontal gyrus, and contralesional middle frontal gyrus than those receiving low-frequency rTMS over the contralesional primary motor cortex (p < 0.05). Within the high-frequency stimulation group, degree centrality changes in the ipsilesional middle occipital gyrus were positively correlated with improvements in the Fugl-Meyer Assessment for Upper Extremity (r = 0.619, false discovery rate-corrected p = 0.018). CONCLUSIONS: High-frequency rTMS over the contralesional dorsal premotor cortex produced behavioral improvements comparable to guideline-supported low-frequency rTMS over the contralesional primary motor cortex, without establishing superiority or formal non-inferiority. Exploratory neuroimaging analyses showed greater degree centrality changes in the ipsilesional middle occipital gyrus after high-frequency premotor stimulation, and these changes correlated with upper-limb motor improvement. These findings support further investigation of contralesional dorsal premotor cortex-targeted high-frequency rTMS for severe subacute post-stroke upper limb impairment. REGISTRATION: URL: http://www.chictr.org.cn; Unique identifier: ChiCTR2000038049.

Humans↗

PubMed1992

Patterns of projections from area 2 of the sensory cortex to area 3a and to the motor cortex in cats.

Peripheral information reaches the motor cortex partly through corticocortical pathways that arise from two functional subdivisions, area 2 and area 3a, of the sensory cortex. These sensory areas are synaptically linked with one another. The patterns of connectivity and the different submodality input that each area receives suggest that they send different efferent signals to the motor cortex. The projections from area 2 to area 3a and to the motor cortex were studied with retrogradely transported fluorescent tracers. The pattern and distribution of neuronal labeling in area 2 was determined following injections of different tracers into the forelimb regions of area 3a and the motor cortex. The results showed that the projections from area 2 to the two target regions were topographically and somatotopically related. Multiple clusters of motor cortex projection neurons were found in area 2, and these clusters overlapped extensively with clusters of area 3a projection neurons. Although cells labeled with one of the dyes were often in close proximity to cells labeled with the other dye, no double-labeled cells were found. Two different laminar patterns were seen for the two populations of neurons. The projection to area 3a originated from cells located in layers II-III and layers V-VI. The projection to the motor cortex originated from cells spread throughout layers II-IV, but predominantly in layer III. Differences in laminar arrangement of the two populations of cells suggest a directional flow of information processing in the sensorimotor cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1975

Visual activation of neurons in inferotemporal cortex depends on striate cortex and forebrain commissures.

Neurons in inferotemporal cortex respond only to visual stimuli and a majority have receptive fields that extend well into both visual half-fields. After bilateral removal of striate cortex, no inferotemporal neurons responded to visual stimuli. After unilateral removal of striate cortex, inferotemporal neurons in both hemispheres responded only to stimuli in the hemifield contralateral to the intact striate cortex. After section of the corpus callosum and anterior commissure, inferotemporal neurons in both hemispheres responded only to stimuli in the hemifield contralateral to the recording site. These results indicate that inferotemporal cortex visual information from striate cortex and that the pathway from striate cortex to the contralateral inferotemporal cortex includes the forebrain commissures. This same striate-temporal pathway is also necessary for normal discrimination learning. We suggest that the converging input onto single inferotemporal neurons from widely separated retinal areas may provide a mechanism for stimulus equivalence over different parts of the visual field, and it may be the absence of such a mechanism that contributes to the visual discrimination deficit that follows inferotemporal lesions.

Animals↗

PubMed1978

Catecholamine innervation of the basal forebrain. II. Amygdala, suprarhinal cortex and entorhinal cortex.

The catecholamine (CA) innervation of the posterior basal forebrain, the amygdala, suprarhinal cortex and entorhinal cortex, was studied in the rat using biochemical assay and fluorescence histochemistry. The assay studies demonstrate a moderate norepinephrine (NE) content in the amygdala and entorhinal cortex with a lower value for the suprarhinal cortex. Following destruction of the locus coeruleus, the decrease in NE content of these basal forebrain structures indicates that their principal NE innervation is from locus coeruleus. An additional small NE input arises from the medullary NE neuron groups. Ablation of dopamine (DA) cell groups (substantia nigra-ventral tegmental area, SN-VTA) indicates that the DA input to the amygdala arises from the lateral VTA and medial half of the SN. Fluorescence histochemical studies using the glyoxylic acid-Vibratome technique demonstrate the presence of four distinct types of CA neuron terminal plexus in the posterior basal forebrain. These include two different DA fiber types arising in SN-VTA, small NE fibers with small varicosities arising in locus coeruleus and NE fibers with larger varicosities arising in other brainstem NE cell groups. The large NE fibers appear to enter the amygdala via the ansa peduncularis-ventral amygdaloid bundle to innervate the central and basolateral nucleus and the anterior amygdaloid area. The locus coeruleus NE fibers appear to enter the posterior basal forebrain via both the stria terminalis and ansa peduncularis-ventral amygdaloid bundle system to form a moderately dense innervation of the central and basolateral nuclei of the amygdala and a less dense innervation of the other areas. The DA neuron axons are concentrated in the central and basal nuclei and intercalated cell groups. Other areas receive a more diffuse DA input, with the exception of the moderately dense innervation of the suprarhinal cortex and DA "islands" in the ventral-anterrior entorhinal cortex, The DA input to the posterior basal forebrain is complex and heterogeneous and the axonal morphology differs greatly among the terminal fields within the amygdala and adjacent cortical areas.

Amygdala↗

PubMed1977

Characteristics of dopamine and beta-adrenergic sensitive adenylate cyclases in the frontal cerebral cortex of the rat. Comparative effects of neuroleptics on frontal cortex and striatal dopamine sensitive adenylate cyclases.

Homogenates of frontal cerebral cortex of the rat were prepared from microdiscs punched out in areas rich in dopaminergic terminals. Under optimal assay conditions, dopamine (10-4 M) stimulated an adenylate cyclase present in these homogenates by 80-100%. This stimulation reached 200% when microdiscs were punched out from the medial part of the frontal cerebral cortex, adjacent to the forceps minor. Dopamine interacted with an homogeneous population of receptor sites which had an apparent affinity (KD) of 3.8 +/- 0.9 x 10-6 M (N = 4). The dopamine receptor was blocked by fluphenazine and phentolamine but had no affinity for pindolol, propranolol or L-isoproterenol. The affinities of several neuroleptics having different chemical structures were simultaneously determined on striatal and on frontal cerebral cortex dopamine sensitive adenylate cyclases. Fluphenazine was more potent in blocking the striatal than the frontal cerebral cortex dopaminergic receptors. In contrast, in all experiments, haloperidol had an higher affinity for the cerebral frontal cortex than for the striatal dopaminergic receptors. Thus, haloperidol was less effective than fluphenazine in blocking the striatal dopaminergic receptors, and equally potent than fluphenazine in inhibiting the frontal cerebral cortex dopamine sensitive adenylate cyclase. Chlorpromazine, thioridazine and clozapine had the same affinity for the two dopaminergic adenylate cyclase systems. L-isoproterenol interacted with an homogeneous population of beta-adrenergic receptor sites (KD = 3 +/- 2 X 10-7 M; N = 4) coupled with an adenylate cyclase distince from the dopamine sensitive adenylate cyclase. This beta-receptor had no affinity for dopamine or fluphenazine but was blocked by propranolol or pindolol. L-Norepinephrine was shown to stimulate both the dopamine (KD = 1.8 +/- 1 X 10-5 M; N = 4) and the beta-adrenergic (KD = 8 +/- 3 X 10-7 M; N = 4) sensitive adenylate cyclases. Thus, the L-norepinephrine effect was totally blocked in the combined presence of fluphenazine and pindolol.

Adenylyl Cyclases↗

PubMed1976

Influence of association cortex on penicillin discharges in the primary visual cortex.

The influence of visual association cortex on the pattern of neuronal activity in the lateral geniculate body, during penicillin-induced discharges in visula cortex, was studied. In a majority of those geniculate cells which exhibited a pre-penicillin discharge increment in activity, that increment was abolished or significantly reduced during focal hypothermia of the visual association cortex. The frequency of penicillin discharges in visual cortex was, in most cases, reduced during cooling of association cortex. These findings are briefly discussed in terms of corticothalamic interactions.

Animals↗

PubMedDate not supplied

Oxidative and glicolytic metabolism of the frontal cortex (latero-frontal) and of the posterior cortex (latero-occipital) in relation with the sexual activity of the rat.

The authors of this paper have ascertained the glycolytic metabolism and the oxidative metabolism (intake of QO2), of the frontal and posterior cortex in female rats at different stages of the sexual cycle, as also in ovariectomized animals, by the intake of glucose and the production of lactates. The results indicate a statistically significant increase of the oxidative metabolism of the posterior cortex (latero-occipital) in the estrual and proestrual phases, in comparisons with the diestral phase. The frontal cortex (latero-frontal) did not show any significant difference; moreover, the glycolitic metabolism did not alter in any of the tissues under observation. These findings, seem to suggest possible participation of the posterior cortex (latero-occipital) on the regulation of sexual cycle of the rat. The activation of this cortex occurs through the preponderant imbricantion of the tri-carboxylic acid cycle.

Animals↗

PubMed1975

Organization of climbing fibre projections to the cerebellar cortex from trigeminal cutaneous afferents and from the SI face area of the cerebral cortex in the cat.

1. In cats anaesthetized with pentobarbitone, the projection of climbing fibres (CFs) to the cerebellar cortex from trigeminal cutaneous branches and from the face area of the sensorimotor (SI) cortex was mapped, using the technique of laminar field potential analysis. 2. The CF projections from both the trigeminal nerve and the SI face area were found to be localized to the same cerebellar folia, viz. chiefly the ipsilateral lobule HVI, with a small overlap on to the adjacent folia of lobule V and crus Ia of HVIIA. Frequently a projection from the superficial radial nerve to part or all of this area, was also found. 3. A correspondence in the distribution and amplitudes of CF potentials evoked at most points by stimulation of the trigeminal nerve and the SI cortex was found. This implies a convergence of afferents from these two sources at or before the inferior olive. 4. In more than half of the cats, a small area of the cerebellar hemisphere was found, in which contralateral as well as ipsilateral trigeminal stimulation would evoke CF potentials. Usually inputs from the superficial radial nerve and the SI cortex also converged upon this area. 5. The organization of CF projections from trigeminal and superficial radial nerve afferents to the cerebellar hemisphere was found to occur in the same 'patchy' pattern of somatotopy that has been described for spinal nerve inputs to the anterior lobe. 6. One constant factor was found in the pattern of organization of CF projections to this area from cutaneous afferent nerves. That is, only the afferents from overlapping areas of skin projected to a given recording point: no instance of CF projections from trigeminal branches innervating discontinuous skin areas was observed.

Animals↗

PubMed1979

Loss of hybridizable ribosomal DNA from human post-mitotic tissues during aging: II. Age-dependent loss in human cerebral cortex--hippocampal and somatosensory cortex comparison.

DNA was isolated from the hippocampal and from the somatosensory cortex of 13 humans (at autopsy). In both the cortex and hippocampus, the loss of ribosomal DNA (rDNA), as measured through hybridization in the liquid phase, approximates about 0.9% per year. The r value for somatosensory cortex was about -0.7 and that for the hippocampus was about -0.91. The correlation coefficient between the sets of two samples derived from the same individual (two different areas) in +0.945. These results are consistent with those reported concurrently for human myocardium and with earlier studies conducted with beagle dogs, in which only post-mitotic tissues (brain, heart and skeletal muscle) showed measurable decrements in these key genes. To the degree that the synthesis of new proteins is essential for sustained mental activity, these results are consistent with the observations that Nissl substance is more slowly replenished, following exhaustive work by motor cortical cells, and the fact that many older persons experience mental fatigue during continuous mental work at earlier times than do younger persons. The mechanism of loss is not certain, but may well be related to inadequacies in DNA repair systems, thereby allowing deletion of tandemly duplicated genes through cross-over "episome" formation, followed by degradation of the excised DNA segments. The ratio of loss of rDNA hybridizability in human and dogs in about 1 to 7, which approximates the relative ratios of their lifespans (reciprocals).

Adolescent↗

PubMedDate not supplied

Cadmium in kidney cortex, liver, and pancreas from Swedish autopsies. Estimation of biological half time in kidney cortex, considering calorie intake and smoking habits.

Cadmium and zinc have been analyzed in tissues from 292 persons autopsied in Stockholm. In kidney cortex, liver, and pancreas the individual cadmium levels are distributed in a lognormal way. In kidney cortex there is a continuous accumulation of cadmium with age up to 50 years, followed by a decrease. Smokers show a higher cadmium accumulation. For nonsmokers, the biological half time of cadmium in kidney cortex is estimated at 30 years, with an average concentration at age 50 of 11 mug/g wet weight. When smokers are included, the average cadmium concentration at age 50 is 22 mug/g wet weight. Based on the more pronounced cadmium accumulation among smokers than nonsmokers, the respiratory absorption rate of cadmium from tobacco smoke is estimated to be approximately 50%.

Adolescent↗

PubMed1975

Adrenal cortex adenylate cyclase. Specific binding sites for 5'-guanylyl-imidodiphosphate in partially purified plasma membranes from bovine adrenal cortex.

Specific binding sites for 5'-guanylyl-imidodiphosphate [Gpp(NG)p] have been identified in a partially purified plasma membrane fraction from bovine adrenal cortex. The apparent affinity of Gpp(nh)p at 30 degrees C was 12muM-1 and the concentration of binding sites was 100 pmoles per mg of protein. Binding of Gpp(NH)p is inhibited by Mn2+ greater than Mg2+ greater than Ca2+ and enhanced by low concentrations of the chelators ethylenediamino-tetraacetic acid (EDTA) and ethylene glycolbis-(beta-aminoethylether))-N,N'-tetraacetic acid (EGTA). High concentrations of EDTA are inhibitory and at 2.5 mM EDTA binding of Gpp(NH)p is only 10% of that observed in the absence of the chelator. The bound labeled GTP analogue exchanged only slowly with the unlabeled nucleotide after a steady state has been reached. EDTA also releases the bound labeled Gpp(NH)p from its binding sites. The slow dissociation of Gpp(NH)p can explain the persistent activation of adenylate cyclase observed after pretreatment of bovine adrenal cortex plasma membranes with Gpp(NH)p and subsequent washing. It is suggested that at least parts of these binding sites are identical to the sites identified earlier as regulatory sites for angiotensin high-affinity receptors (Glossmann et. al., 1974a) and for ACTH-stimulated cyclase Glossmann and Gips, 1974).

Adenylyl Cyclases↗

PubMed1978

[The development of the adrenal cortex in pig (Sus scrofa domestica). (A contribution on the development of the fetal interior zone of the adrenal cortex in pig) (author's transl)].

The adrenals of pigs have been investigated histologically and histochemically during different periods of time pre- and postnatally. The pig (Sus scrofa domestica) shows a proper fetal cortex in the prenatal development of the adrenal gland. This involves slowly during the last quarter of pregnancy. A weight reduction is not noted thereby. Just before delivery the adrenal cortex of the pig has been subdivided into a zona arcuata and zona fasciculata. The zona reticularis develops only postnatally.

Adrenal Cortex↗

PubMed1977

Mescaline-induced changes of brain-cortex ribosomes. Mescaline demethylase activity of brain-cortex soluble supernatant.

Brain-cortex slices demethylate mescaline and p-methoxyacetanilide, a reference O-demethylating substrate, though the rate of demethylation of mescaline is about one third that of the reference substrate. The demethylase activity is localized mostly in the soluble supernatant (105 000 x g). It is purified 47-fold with respect to the demethylation of mescaline by ammonium sulfate precipitation and DEAE cellulose chromatography. The partially purified demethylase, which is stable for 3-5 days at -5 degrees C in the presence of dithiothreitol and glutathione and is inhibited by p-chloromercuribenzoate, has maximal activity at pH between 7.2 and 8.0. It demethylates mescaline into 3,4-dimethoxy-5-hydroxyphenethylamine and 3,5-dimethoxy-4-hydroxyphenethylamine and some unidentified derivatives.

Acetamides↗

PubMed1976

Steroidogenesis in the zona glomerulosa of the adrenal cortex. II. Distribution of cytochrome P-450 in the zona glomerulosa of the bovine adrenal cortex.

Microsomes were obtained from the zona glomerulosa of the bovine adrenal cortex. Contamination of microsomes with other cellular organelles was examined using various marker enzymes and the electron microscope. Distribution of cytochrome P-450 in mitochondria and in microsomes was determined to be 0.73 and 0.32 nmol/mg protein, respectively. The CO difference spectrum was affected not only by the concentration of added deoxycholate but also by the incubation time after addition. Approximately 40-50% of cytochrome P-450 in the samples was converted to cytochrome P-420 within 20-30 sec of incubation with deoxycholate. The content of RNA, phospholipids, and cytochrome b5 in microsomes obtained from the zona glomerulosa is also evaluated in comparison to that in microsomes obtained from the zona fasciculoreticularis.

Adrenal Cortex↗

PubMed1976

[Relationship between food protein quality and adrenal cortex function. 6. Interrelationship between aminotransferase activity (GPT1, GOT2) and the status of adrenal cortex function].

Growing male Albino rats were adrenalectomized and then treated with corticosterone in an attempt to determine the activity of amino transferases (GPT and GOT) in the liver and in the mucosa of the small intestine over a period during which the animals received dietary proteins of varying quality. However, statistically significant differences in the enzyme activity were established for only those groups in which the animals exhibited differences in the functional state of the adrenal cortex. Differences due to changes in the quality of the dietary protein were not observed. From this was concluded that the activity of the amino transferases in the tissues is largely dependent on the action of corticosteroids.

Adrenal Cortex↗

PubMed1976

[Relationship between food protein quality and adrenal cortex function. 7. Relationship between activity of selected liver and small intestine hydrolases and adrenal cortex function].

Male Wistar rats received 10% true digestible crude protein of varying quality (maize gluten (MK) = low protein quality; maize gluten + lysine, tryptophan, threonine, isoleucine (MK + AS) = high protein quality) for a period of three weeks. The trial was carried out to investigate the activity of the two enzymes leucine-arylamidase (LNA) and aminotripeptidase (TP) in the liver and the mucosa of the small intestine and that of alpha and gamma amylases and of total amylases in the mucosa of the small intestine in animals exhibiting differences in the functional state of their adrenal cortices (adrenalectomized animals (AE), normal rats (N) and animals receiving additional treatment with cortisol (KS). It was found that mucosal LNA and gamma amylase did not respond to functional changes in the adrenal cortex. Mucosal LNA had a higher activity if the dietary protein was of low quality and a lower activity if the protein quality was high. The level of liver LNA activity was significantly lower in N and KS animals than in AE animals. The highest activity of mucosal and liver TP was found in KS animals; it was lowest in N animals. Statistically significant differences brought about by changes in the quality of dietary proteins were only found to occur in the KS group. The activity of alpha amylase and total amylases was found to be lowest in N animals; it was significantly higher in animals of the AE and KS groups. Animals of the N and KS groups receiving MK + AS exhibited a significantly higher level in their alpha and total amylase activities than animals in the same group receiving MK. Here, the "permissive action" of glucocorticosteroids on metabolically active hydrolases is clearly evident. The pattern of mucosal LNA activity in the small intestine and that of gamma amylase may be regarded as further characteristic evidence for the digestive action of these enzymes. Liver LNA and liver TP as well as mucosal TP and alpha amylase acted like metabolic enzymes.

Adrenal Cortex↗

PubMed1976

Zonation of the adrenal cortex. II. Effect of BSA on coupling efficiency of mitochondria isolated from the zona glomerulosa of the bovine adrenal cortex.

Effect of bovine serum albumin on coupling efficiency of mitochondria isolated from the zona glomerulosa of the bovine adrenal cortex in various media was examined polarographically and electron microscopically. Albumin restored the coupling efficiency of mitochondria isolated from the zona glomerulosa regardless of isolation media when succinate or malate was oxidizable substrate. Respiratory controls greater than 5 were obtained. Albumin, however, had no effect when glutamate, beta-hydroxybutylate and pyruvate were the oxidizable substrates. The conditions have been found under which mitochondria of the zona glomerulosa stay in the orthodox configuration and yet coupled.

Adrenal Cortex↗

PubMed1976

Zonation of the adrenal cortex. III. Distribution of cytochrome P-450 in the zona glomerulosa of the bovine adrenal cortex.

A microsomal fraction was obtained from the zona glomerulosa of the bovine adrenal cortex. Glucose-6-phosphate activity of the fraction was found to be much lower than that of the liver. Contents of RNA and phospholipids, besides electron microscopic findings, of the fraction also indicate that it is rich in smooth-surfaced endoplasmic reticulum. Distribution of cytochrome P-450 in the zona glomerulosa was studied using various fractions including the microsomal fraction described above. The amount of cytochrome P-450 in mitochondria and that in microsomes were determined to be 0.73 and 0.32 nmoles/mg protein, respectively. The CO-difference spectrum was affected not only by the concentration of added deoxycholate but also by the incubation time after addition. Approximately 40-50% of cytochrome P-450 in the samples were converted to cytochrome P-420 within 20-30 seconds of incubation with deoxycholate.

Adrenal Cortex↗