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At least 325 records · Page 18Linked to original sources
PubMed1964

TONIC INFLUENCE OF ROSTRAL BRAIN STRUCTURES ON PRESSURE REGULATORY MECHANISMS IN THE CAT.

Transection of vagi and carotid sinus nerves in anesthetized cats results in a rise of blood pressure and subsequent decerebration results in a fall. Decerebration alone results in a slight drop in blood pressure unchanged by subsequent nerve section. Rostral brain structures principally influence tonically brainstem mechanisms subserving baroreceptor reflex excitability rather than those maintaining normal blood pressure.

Blood Pressure↗
PubMed2001

Semantic memory and the brain: structure and processes.

Recent functional brain imaging studies suggest that object concepts may be represented, in part, by distributed networks of discrete cortical regions that parallel the organization of sensory and motor systems. In addition, different regions of the left lateral prefrontal cortex, and perhaps anterior temporal cortex, may have distinct roles in retrieving, maintaining and selecting semantic information.

Animals↗
PubMedDate not supplied

[Glutathione conjugation with diethylmaleate in various brain structures].

It was shown that GSH concentration and glutathione peroxidase activity in hypothalamus (H) and sensomotor cortex (SC) were twice more than in ME. After single or double injection of diethylmaleate (DEM) two-phase change of the GSH level was observed in all the investigated structures. In the first 1-3 h phase, the pool of free GSH decreases by more than 50% as a result of conjugative effect of DEM. In the second phase which is about 3 days long the level of GSH is gradually restored mainly due to the activation of its biosynthesis. In various brain structures conjugation and reduction processes has their own peculiarities: conjugation processes predominate in H and SC while the reduction processes predominate in ME. These processes were almost two times intensified in all the investigated structures under double injection of DEM.

Animals↗
PubMedDate not supplied

[Brain structure as a basis for its reliability].

The construction and activity of the brain are characterized by high degree of the reliability. Some structural-functional premises of the reliability have been described: 1) the superfluity of the nervous elements of many brain structures, which guarantees the brain reserve properties in norm and in different forms of pathology: 2) growth in the mammals row the factors of the superfluity and plasticity of the macro- and microlevels of new evolutionally cerebral systems organization; 3) the multifunctionality peculiar to diverse brain systems different degree. The study of neurochemical bases of reliability in norm and pathological conditions has now a special meaning (by stimulation of corresponding natural transmitter brain systems). The measure of reliability, its "reverse side", is the idea of the brain vulnerability. Some indices of the vulnerability increase in comparative animal row to the man, especially in the sensory and vegetative spheres.

Animals↗
PubMedDate not supplied

[Simulation of local cerebral hemorrhage in different brain structures of experimental animals].

A standardized experimental model of intracerebral hemorrhagic stroke in small laboratory animals is developed and advanced for chronic neurobiological studies of normal and pathological higher nervous activity as well as disorders developed after acute hemorrhages. A device is advanced which allows a researcher to destroy appropriate brain structures (tissues and local blood vessels) with necessary precision by four-six rotations of curved stereotaxically inserted mandrel-wire knife and, subsequently, to inject autoblood into the area of the lesion. The advanced model is convenient for the reproduction of lesions in different brain regions (for the purpose of experimental knockouts) in neurophysiological, neuropharmacological, and clinical investigations.

Animals↗
PubMed1990

[Glucocorticoid control of the mediator process in the brain structures during immediate adaptation].

In male rats with a high and low blood levels of corticosterone, the activity of serotonin-, dopamine-, noradrenaline-, glycine, GABA-, and cholinergic processes was shown to depend on the glycocorticoid content in the organism and receptor binding of 3H-corticosterone in different brain structures. The formation of adequate processes of neurotransmitter adaptation to a short-term vibration is only possible at a fairly high level of glycocorticoids in the organism.

Adaptation, Physiological↗
PubMed1975

[Space-time parameters of the biopotentials in rabbit brain structures during natural sleep].

Different stages of natural slow-wave sleep were studied in rabbits with the aid of spectro-correlation analysis using the direct input of data to the computer. The main findings regularly observed after sleep were as follows: the decrease of synchronization between biopotentials led from different brain structures, the absence of uniform Q-band rhythms and the reduced coherence of this band, phase discrepancy between low-frequency components. Thereupon the state of inhibition is concluded to be characterized by the spatio-temporal discrepancy in the brain electric activity.

Animals↗
PubMed1992

Permeability of brain structures and other peripheral tissues to prostaglandins D2, E2 and F2 alpha in rats.

Parenchymal tissue-uptake (TU) and permeability-surface area (PS) product of [3H]prostaglandins (PG) D2, E2 and F2 alpha [1.85 MBq, 0.5 mg/kg (270 nmol)] were examined in 98 regions of the brain and in 19 other tissues of urethane-anesthetized male rats (180-200 g) 15 sec after i.v. administration with [14C]dextran [0.185 MBq, 0.6 mg/kg (2 nmol)] used as a blood spacer. Slight and insignificant change in blood volume was observed in most of the tissues and brain regions between vehicle- and PG-administered groups. TU for the three PG was markedly high in kidney and lung (2388-3952 ng/g), exceeding the blood concentration (2021-2320 ng/ml), but low (less than 10% of the blood concentration) in epididymis, epididymal fat, testis (59-163 ng/g), brain and spinal cord (33-67 ng/g). TU in brain were detected about 0.1% of the administered PG. Based on a two-compartment model, the PS product for the three PG ranged from 0.75 to 4.16 microliters/g/sec in the latter tissues. The value of brain was 1.22 +/- 0.18 microliters/g/sec for PGD2, 1.69 +/- 0.05 for PGE2 and 1.33 +/- 0.13 for PGF2 alpha, indicating that PGE2 enters the brain more readily than PGD2 and PGF2 alpha. In various brain structures, the ranges of the PS product were large and completely overlapped among the three PG (PGD2, 0.14-1.56 microliters/g/sec; PGE2, 0.05-1.78; PGF2 alpha, 0.05-1.82). The highest PS product for the three PG was found in olfactory bulb and cerebellum (0.96-1.82 microliters/g/sec) and the lowest was in septum (0.05-0.53). However, the level of the PS product was different among the PG in each brain region as follows: PGD2 greater than PGE2, PGF2 alpha in septum and anterior part of pyriform cortex; PGE2 greater than PGD2, PGF2 alpha in olfactory bulb, frontal cortex, basal forebrain, middle part of pyriform cortex, thalamus, hippocampus and lateral neocortex; and PGF2 alpha greater than PGD2, PGE2 in posterior part of pyriform cortex, hypothalamus, amygdala and entorhinal and retrosplenial cortices. Low correlation coefficients (0.708, 0.522 and 0.562 for PGD2, PGE2 and PGF2 alpha, respectively) between the PS product and cerebrovascular volume in various regions revealed heterogeneous cerebrovascular permeabilities of PG.

Animals↗
PubMed2026

Characterizing the impact of plasma protein levels on human brain structure and disorders leveraging integrative multi-omics analysis.

With recent advances in high-throughput proteomic technologies, population-scale plasma proteomics datasets, often linked to extensive genetic and phenotypic information, have become increasingly accessible. Yet the relationships between circulating protein levels, brain imaging phenotypes, and risk for neurological and psychiatric disorders remain largely unexplored. Proteome-wide association studies offer a promising approach for elucidating biological mechanisms that connect genetic variation to complex brain-related traits and diseases. In this study, we integrated protein quantitative trait loci (pQTLs) from the two largest plasma proteomic resources (the UK Biobank Pharma Proteomics Project [UKB-PPP] and Ferkingstad et al. [deCODE]) with genome-wide association studies of brain imaging-derived phenotypes in UK Biobank using Mendelian randomization and colocalization analyses. We identified 120 cis and 20 trans associations between plasma proteins and imaging phenotypes and validated these findings using brain tissue-derived proteomic and transcriptomic datasets. Multivariable Mendelian randomization revealed eleven plasma proteins (coding genes APOE, ARL3, MICB, NSF, RHOC, RSPO3, ENPP2, BTN2A1, EIF2AK3, MRVI1, and OPLAH) with significant direct effects on the risk of Alzheimer's disease, Parkinson's disease, multiple sclerosis, bipolar disorder, and schizophrenia. Single-cell expression and pathway enrichment analyses further revealed cell-type-specific effects and distinct biological processes underlying these protein-disease associations. Together, these findings demonstrate robust links between plasma protein variation and brain structure, delineate protein-disease pathways, and highlight the cellular and molecular mechanisms that contribute to neurobiological diversity and pathology.

Journal Article↗
PubMed1990

Brain structures participating in mental simulation of motor behavior: a neuropsychological interpretation.

This paper reviews findings from cognitive and sport psychology, as well as from neurophysiology, concerning mental simulation of movement. A neuropsychological hypothesis is advanced to explain why mental practice can improve motor skill learning. Mental practice activates certain brain structures selectively as shown by measurements of regional cerebral blood flow. It appears likely that this activation improves the subsequent control of execution of movements. It is pointed out that the study of simulation of movements may not only be of value for sport training but also have importance for the rehabilitation of patients with motor disturbances following lesions of the central nervous system.

Brain↗
PubMed1990

[Changes in the level of the permanent potential of the deep brain structures in rabbits with a Brown-Pearce carcinoma].

Rabbits with the Brown-Pierce carcinoma have been studied in chronic experiments for dynamics of the permanent potential reflecting bioelectrochemical processes in different structures of the hypothalamic and limbic system: medial preoptic area, ventromedial nucleus, posterior hypothalamic area, basal and lateral amygdalas, hippocampus, nucleus coeruleus as well as in central nucleus of the suture. The space-temporal pattern of neurodynamic changes in the subcortical brain structures has been found. These changes correlated with developmental characteristics of the Brown-Pierce carcinoma.

Animals↗
PubMedDate not supplied

[Dynamics of functional interrelationships between different monkey brain structures during differentiation of time intervals].

Interactions between the prefrontal cortex, the hippocampus, caudate nucleus head and mediodorsal thalamic nucleus were studied during differentiation of temporal intervals in two rhesus monkeys by means of correlational analysis. The change in the signal significance of the experimental situation (time course of the investigated period) changed the animals activity. This was manifested in spatial-temporal dynamics of correlation coefficients. The participation of separate brain structures or their complexes in the differentiation of temporal intervals is discussed.

Animals↗
PubMed2003

Navigation expertise and the human hippocampus: a structural brain imaging analysis.

Grey matter volume in the posterior hippocampus of London taxi drivers is greater than in age-matched controls, and the size of this increase correlates positively with time spent taxi driving (E.A. Maguire et al., 2000. Proc Natl Acad Sci USA 97: 4398-4403). This change suggests that increased posterior hippocampal grey matter volume is acquired in response to increased taxi driving experience, perhaps reflecting their detailed representation of the city. However, an alternate hypothesis is that the difference in hippocampal volume is instead associated with innate navigational expertise, leading to an increased likelihood of becoming a taxi driver. To investigate this possibility, we used structural brain imaging and voxel-based morphometry (VBM) to examine a group of subjects who were not taxi drivers. Despite this group showing a wide range of navigational expertise, there was no association between expertise and posterior hippocampal grey matter volume (or, indeed, grey matter volume throughout the brain). This failure to find an association between hippocampal volume and navigational expertise thus suggests that structural differences in the human hippocampus reflect the detail and/or duration of use of the spatial representation acquired, and not innate navigational expertise per se.

Adolescent↗
PubMed2003

Structural brain MRI abnormalities in healthy siblings of patients with childhood-onset schizophrenia.

OBJECTIVE: Childhood-onset schizophrenia shows progressive brain magnetic resonance imaging (MRI) changes during adolescence, which follow a back-to-front "wave." The authors' goal was to examine whether healthy siblings of patients with childhood-onset schizophrenia show structural brain abnormalities and the age-related pattern of abnormalities seen in patients with childhood-onset schizophrenia. METHOD: Anatomic brain MRI scans were obtained from 15 psychiatrically healthy full siblings of 15 patients with childhood-onset schizophrenia and from 32 matched community volunteers. Automated measures were used to compare total and regional brain volumes of the siblings and volunteers. RESULTS: Siblings of patients with childhood-onset schizophrenia had smaller total cerebral volume and total, frontal, and parietal gray matter volumes than volunteers. When divided into younger and older groups, younger siblings had smaller parietal gray matter volumes and older siblings showed trends for smaller total and frontal gray matter volumes. CONCLUSIONS: Healthy siblings of patients with childhood-onset schizophrenia share brain MRI abnormalities with the patients that may follow a similar pattern of progression. Developmental brain abnormalities in childhood-onset schizophrenia may thus be genetic trait markers.

Adolescent↗
PubMedDate not supplied

Receptor binding of corticosterone in some rat brain structures following neonatal blockade of the hypophyseoadrenal system.

Administration of hydrocortisone to rats during the first five postnatal days leads to the blockade of the hypophyseoadrenal system and results in a decrease in the number of corticosterone receptors in the hypophysis, hypothalamus, and hippocampus. Such a decrease in the receptor binding of corticosterone in the brain structures involved in the regulation of the hypophyseoadrenal system by a feedback mechanism is due to a change in the number of true glucocorticoid receptors.

Animals↗
PubMedDate not supplied

[Conditioned reflex leg placing reaction induced by stimulation of brain structures].

The mechanogram of fore-leg movement and evoked potentials in the leg cortical motor area this as well as biceps EMG were recorded in 4 cats in chronic experiment during conditioned placing reactions, elicited by tactile stimulation of the paw tip and by electrical stimulation of several cortical and subcortical brain structures. Mean latency of the conditioned movement and its dispersion were of the same order of values during reactions caused both by tactile stimulation and by electrical stimulation of the cortical motor area. During placing reactions to the stimulation of the sensory cortex, ventral posterolateral nucleus of the thalamus and the cerebral peduncles these values were significantly higher than in the first case.

Animals↗
PubMed2001

Brain structure, genetic liability, and psychotic symptoms in subjects at high risk of developing schizophrenia.

BACKGROUND: Structural magnetic resonance imaging (MRI) of the brain in patients with schizophrenia has consistently demonstrated several abnormalities. These are thought to be neurodevelopmental in origin, as they have also been described in first episode cases, although there may be a progressive component. It is not known at which point in development these abnormalities are evident, nor to what extent they are genetically or environmentally mediated. METHODS: One hundred forty-seven high-risk subjects (with at least two affected first or second degree relatives), 34 patients in their first episode, and 36 healthy control subjects received an MRI scan covering the whole brain. After inhomogeneity correction, regions of interest were traced by three group-blind raters with good inter-rater reliability. Regional brain volumes were related to measures of genetic liability to schizophrenia and to psychotic symptoms elicited at structured psychiatric interviews. RESULTS: High-risk subjects had statistically significantly reduced mean volumes of the left and right amygdalo-hippocampus and thalamus, as compared to healthy control subjects. They also had bilaterally larger amygdalo-hippocampi and bilaterally smaller lenticular nuclei than the schizophrenics. High-risk subjects with symptoms had smaller brains than those without. The volumes of the prefrontal lobes and the thalamus were the only consistent associates of genetic liability. CONCLUSIONS: Subjects at high risk of developing schizophrenia have abnormalities of brain structure similar to but not identical to those found in schizophrenia. Our results suggest that some structural abnormalities are genetic trait or vulnerability markers, others are environmentally mediated, and that the development of symptoms is associated with a third overlapping group of structural changes. Particular risk factors for schizophrenia may interact at discrete time points of neurodevelopment with different effects on specific brain regions and may represent relatively distinct disease processes.

Amygdala↗
PubMed1994

Incorporation of trans long-chain n-3 polyunsaturated fatty acids in rat brain structures and retina.

During heat treatment, polyunsaturated fatty acids and specifically 18:3n-3 can undergo geometrical isomerization. In rat tissues, 18:3 delta 9c,12c,15t, one of the trans isomers of linolenic acid, can be desaturated and elongated to give trans isomers of eicosapentaenoic and docosahexaenoic acids. The present study was undertaken to determine whether such compounds are incorporated into brain structures that are rich in n-3 long-chain polyunsaturated fatty acids. Two fractions enriched in trans isomers of alpha-linolenic acid were prepared and fed to female adult rats during gestation and lactation. The pups were killed at weaning. Synaptosomes, brain microvessels and retina were shown to contain the highest levels (about 0.5% of total fatty acids) of the trans isomer of docosahexaenoic acid (22:6 delta 4c,7c,10c,13c,16c,19t). This compound was also observed in myelin and sciatic nerve, but to a lesser extent (0.1% of total fatty acids). However, the ratios of 22:6 trans to 22:6 cis were similar in all the tissues studied. When the diet was deficient in alpha-linolenic acid, the incorporation of trans isomers was apparently doubled. However, comparison of the ratios of trans 18:3n-3 to cis 18:3n-3 in the diet revealed that the cis n-3 fatty acids were more easily desaturated and elongated to 22:6n-3 than the corresponding trans n-3 fatty acids. An increase in 22:5n-6 was thus observed, as has previously been described in n-3 fatty acid deficiency. These results encourage further studies to determine whether or not incorporations of such trans isomers into tissues may have physiological implications.

Animals↗