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PubMedDate not supplied

[Characteristics of heterochromatin of heterophase nuclei from interphase neurons of various brain structures selected for the nervous system excitability].

Quantitative characteristics (the area and number of chromocenters) of the interphase C-heterochromatin in the nuclei of pyramidal neurons of the midbrain reticular formation, sensorimotor cortex, and hippocampus (CA3) of rat strains with different genetically determined excitability were studied in the normal state of the animals and after exposure to a short-term emotional pain stress. The results indicate a relationship between the excitability of the nervous system and structural-functional state of the neuronal interphase heterochromatin. The role of cytogenetic features of different brain structures in the CNS functioning and behavior and their relation with genetically determined excitability of the nervous system are discussed.

Animals↗
PubMed1975

Quantitative investigations of visual brain structures in wild and domestic sheep.

A cytoarchitectonic subdivision into visual structures and neocortical grey and white matter has been made from frontal serial sections of brains of mouflons (Ovis ammon musimon) and domestic sheep (Ovis ammon f. aries). The reduction rates determined for the volumes of the brain areas are calculated by means of intraspecific allometric methods. The overall decrease of visual brain structures in domestic sheep compared with wild sheep amounts to 25.9%, The greatest reduction is found in the striate area (30.2%), followed by the lateral geniculate body (25.4%), the optic tract (20.6%) and finally the superior colliculus (12.1%). The neocortex as a whole decreases in sheep under domestication by 26.4% in volume. The reduction rate of neocortical grey matter amounts to 24.9%, that of the white matter to 28.9%. The changes of brain size in domestic sheep may be functionally correlated to changes of the environmental conditions which are due to domestication.

Animals↗
PubMed1994

Reverse genetics of Drosophila brain structure and function.

A set of molecular genetic technologies are described, which will have far reaching consequences for the study of brain structure, function and development in Drosophila melanogaster. Site selected mutagenesis (a PCR-based screen for P-element insertion events) allows insertion mutants to be isolated for any cloned gene, and is being used in this laboratory to ask questions about the rolls of particular cellular components in learning and memory. Transposants have been isolated in genes encoding a regulatory (RI) and a catalytic (DCO) subunit of cAMP-dependent protein kinase, and in a gene encoding a Gi-like alpha subunit. The alternative use of I factors is described. The PKA RI homozygous mutants display a significant decrement in initial learning ability. Enhancer-trap strategies, for which the GAL-4 P-element system is particularly convenient, allow the identification of genes expressed in the developing fly brain. Strategies for the efficient detection of such events are described.

Animals↗
PubMed1985

[Functional interrelations of brain structures in the cat during the generation of rhythmic activity. III. Cluster analysis of rhythmic indices].

The functional interrelationships of the brain structures of freely moving cats in generation of rhythmic EEG activity during the states of drowsiness and light sleep were evaluated using the claster analysis of mean values indexes of rhythms in different structures as well as correlation coefficients between them in time. It was shown that according these parameters visual cortical areas and lateral geniculate body appeared in different clusters. Lateral geniculate body suggested not to be the only pacemaker of EEG rhythms in visual cortex. The wide convergence of subcortical inputs to the visual cortex and possibility of autonomic generation of EEG rhythms at the cortical level are discussed as putative mechanisms of dissociation of EEG activities in visual cortex and thalamus.

Animals↗
PubMed1983

Properties of a 125I-substance P derivative binding to synaptosomes from various brain structures and the spinal cord of the rat.

Using crude synaptosomal fractions (P2 fractions) and 125I-Bolton and Hunter substance P (125I-BHSP) as a ligand, the characteristics of specific binding sites were examined in various brain structures and in the spinal cord (dorsal and ventral parts) of the rat. Scatchard plots revealed the occurrence of a single class of binding sites in the various structures studied with comparable Kd values (from 0.46 to 1.10 nmol/l in the brain and 0.51, 0.56 nmol/l in the spinal cord dorsal and ventral parts respectively) and of marked differences in the number of binding sites (Bmax) (septum greater than striatum greater than hippocampus, hypothalamus greater than mesencephalon greater than cerebral cortex and dorsal part of the spinal cord greater than ventral part). In the brain no correlation was found between the number of 125I-BHSP binding sites and the amount of substance P levels (substance P-like immunoreactivity) in synaptosomes, particularly in the hippocampus and the substantia nigra since the former structure was characterized by its low substance P content and its high number of binding sites and the reverse was observed in the substantia nigra. The ability of several C- and N-terminal fragments of substance P and of tachykinins to compete with 125I-BHSP binding to synaptosomes from the hippocampus, the hypothalamus and the dorsal part of the spinal cord was then determined. Results obtained were closely similar from one structure to another and comparable to those previously reported using whole brain synaptosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Structural brain abnormalities in patients with schizophrenia and their healthy siblings.

OBJECTIVE: The authors sought to investigate the contribution of genotype on structural brain abnormalities in schizophrenia. METHOD: Intracranial volumes and volumes of the cerebrum, white and gray matter, lateral and third ventricles, frontal lobes, caudate nucleus, amygdala, hippocampus, parahippocampal gyrus, and the cerebellum were measured in 32 same-sex siblings discordant for schizophrenia and 32 matched comparison subjects by means of magnetic resonance imaging. RESULTS: Third ventricle volumes did not differ between the schizophrenic patients and their healthy siblings. However, both had higher third ventricle volumes than did the comparison subjects. The schizophrenic patients had lower cerebrum volumes than did the comparison subjects, whereas the cerebrum volume of the healthy siblings did not significantly differ from the patients or comparison subjects. Additionally, patients with schizophrenia displayed a volume reduction of the frontal lobe gray matter and a volume increase of the caudate nuclei and lateral ventricles compared to both their healthy siblings and comparison subjects. Intracranial volume, CSF volume, or volumes of the cerebellum, amygdala, hippocampus, or the parahippocampal gyrus did not significantly differ among the patients, siblings, and comparison subjects. CONCLUSIONS: Healthy siblings share third ventricle enlargement with their affected relatives and may partially display a reduction in cerebral volume. These findings suggest that third ventricular enlargement, and to some extent cerebral volume decrease, may be related to genetic defects that produce a susceptibility to schizophrenia.

Adult↗
PubMed2001

Structural brain abnormalities in chronic schizophrenia at the extremes of the outcome spectrum.

OBJECTIVE: This study investigated the relationship between outcome and structural brain abnormalities in schizophrenia. METHOD: Intracranial volume and volumes of the cerebrum, gray and white matter, lateral and third ventricles, frontal lobes, thalamus, and cerebellum were measured in 20 patients with a poor outcome, 25 with a favorable outcome, and 23 healthy comparison subjects with magnetic resonance imaging. RESULTS: Thalamic volume was significantly smaller both in poor-outcome patients and good-outcome patients. In contrast, only poor-outcome patients displayed significantly smaller cerebral gray matter, particularly prefrontal, and enlargement of the lateral and third ventricles. No significant differences were found for intracranial, cerebellar, or cortical CSF volumes. CONCLUSIONS: Smaller thalamic volumes in schizophrenia may reflect a greater susceptibility for the disorder and seem unrelated to outcome. In contrast, gray matter volume loss of the cerebrum, particularly in the frontal lobes, and lateral and third ventricular enlargement appear related to outcome in schizophrenia.

Age of Onset↗
PubMed1986

Intraraphedorsal kainic acid induces paroxysmal electroencephalographic changes in some brain structures of cats.

In acute experiments on cats the effect of kainic acid microinjected into the raphe dorsal nucleus on the EEG activity recorded from various brain structures was investigated. Kainic acid in doses of 0.2 to 32.0 nmol was injected by glass micropipets and an air-pressure system. The analysis of the EEG and the EEG power analysis in the usual frequency bands (delta, theta, alpha, and beta) revealed an activating to hyperexcitatory effect of kainic acid. This hyperexcitatory effect was manifested by the appearance of paroxysmal EEG patterns of different types which developed in some cases into seizure episodes or an epileptic state. Abnormal EEG changes occurred first in the thalamus and mesencephalic reticular formation. A dose-response relationship existed: the duration of the EEG with pathological patterns increased whereas the latency of their appearance decreased with increase of the dose of kainic acid. Five to seven hours after the injection there were no severe histopathologic changes in the region of the raphe dorsal nucleus. The hyperexcitatory effect of kainic acid on brain excitability might be a result of the excitatory action of kainic acid and of triggering of circuits of neuronal hyperactivity in structures connected with the raphe dorsal nucleus.

Animals↗
PubMed1992

[Biogenic amines in brain structures of rats of different zoo-social rank during immobilization stress].

The content of monoamines and their metabolites in different parts of the brain: mesencephalic reticular formation, locus coeruleus, sensomotor cortex was studied by high-performance liquid chromatography in rats with different zoo-social position. Content of dopamine and serotonin in the brain structures studied was found to be different in dominants and subdominants. Maximal changes of monoamines under immobilization stress were observed in dominants.

Animals↗
PubMedDate not supplied

[The function of the brain structures in rabbits under the action of hyperbaric helium and nitrogen-oxygen mixtures].

Behaviour of rabbits as well as excitability thresholds of certain brain areas were determined by intracranial electrostimulation under high pressure in the heliox and nitrox media. Excitability of the mesencephalic reticular formation and of the frontal cortex in particular, decreased under 11 ata in the nitrox medium. On the contrary, measurements of the thresholds and EEG data have shown an increase in excitability in all brain regions under 41 ata of the heliox medium. Excitability increased most of all in the dorsal hippocampus and nucleus caudatus. The role of different brain structures in the symptomatics of nitrogen narcosis and high-pressure nervous syndrome is discussed.

Animals↗
PubMed2006

Fast structural brain imaging using an MDEFT sequence with a FLASH-EPI hybrid readout.

A sequence for the fast acquisition of T1 weighted structural brain images with whole brain coverage and isotropic resolution of 1mm is presented. It is based on MDEFT with a FLASH-EPI hybrid readout. Several techniques for artefact suppression are implemented, like echo time shifting, asymmetric k-space sampling, and navigator echo acquisition. It is shown experimentally that the hybrid MDEFT sequence with a total duration of 8min yields approximately the same signal-to-noise and contrast-to-noise ratios as a 12min standard MDEFT sequence based on a FLASH readout. Further experiments show that echo time shifting suppresses artefacts in the vicinity of the scalp and in areas suffering from field inhomogeneities and that the concept of asymmetric k-space sampling reduces the susceptibility to head movement.

Adult↗
PubMed1995

Volumetric analysis of brain structures, especially of the visual system in wild and domestic turkeys (Meleagris gallopavo).

The total brain volume, the volumes of the main brain subdivisions and regions belonging to the visual system of wild and domestic turkeys of either sex were measured and related to body weight. Using allometric methods sex-related reductions in brain size from wild to domesticated state was examined. Male domestic turkeys have 29% and female domestic turkeys 24% less brain volume. The total reduction of the brain size results from decreases of the brain subdivisions and structures of functional systems at various degree. The general reduction of prosencephalic brain parts is greater (males: 35%, females: 30%) than that of the rhombencephalon (males: 21%, females: 14%). Visual brain structures are reduced by 25% in males and 22% in females. The tertiary areas of this system have more decreased than secondary and primary visual targets. It was also shown that differences in size are accompanied by changes in the proportions of the brain. Telencephalic brain parts are relatively smaller in domestic turkeys. Different decreases in brain size of diverse species from wild to domestic state are regarded as processes of functional adaptation that is controlled by intensive breeding.

Animals↗
PubMed1976

[Spectral-correlation analysis of the bioelectrical activity of rabbit brain structures during electrosleep].

Changes of electric activity of the rabbit cortical and subcortical structures were studied by means of spectrum-correlation analysis during sleep caused by low-frequency stimulation of the supraoptic hypothalamic nucleus. The electrosleep affected the similarity of the electric events in neocortex and subcortical structures. The disturbance of the spatial synchronization is supposed to be due to the activity of nonsynchronized autonomous bioelectric pace-makers in different brain structures.

Animals↗
PubMed1996

Reliability of brain structure morphometry in hydrocephalic children using MR images.

To assess the ability of human operators to make decisions about region boundaries in significantly malformed brains, we performed a study of the reliability of morphometric measurements of specific brain structures from MRI in children with hydrocephalus and controls. Cross-sectional area measures of the corpus callosum, internal capsules and centrum semiovale, and volumes of the lateral ventricles were made in 50 children. Independent measurements were made by two raters on T1 and T2-weighted MR images. Pearson's correlation coefficients (r) and intraclass correlation coefficients (ICC) between the two rater's sets of measures were computed for each structure across all subjects. ICCs ranged from a low of 0.7502 to a high of 0.9895. All ICCs were significant at the p < .0001 level and were generally less than or equal to the corresponding Pearson's r value in every case. Therefore, the Pearson's r may overestimate the reliability. The results of this study support the claim that the ICC should be used rather than the Pearson's r when assessing interater reliability in situations where large between-group differences are present. In addition, the results show that brains malformed by disorders, such as hydrocephalus, can be reliably assessed using morphometric measures of MR images.

Brain↗
PubMed1990

Computed tomography and lateral ventricular asymmetry: clinical and brain structural correlates.

Asymmetry of the ventricles of the brain without an obvious cause is a common and intriguing radiologic finding. To understand this phenomenon better the authors conducted a 24-month study to compare clinical and structural manifestations of two groups of patients who had undergone head computed tomography (CT): group A comprised 249 patients with asymmetry of the lateral ventricles of the brain without space-occupying lesions, intracranial bleeding, recent infarction or trauma and group B comprised 266 patients with the above exclusion criteria but without ventricular asymmetry. The degree of ventricular asymmetry was classified as mild, moderate or severe, according to the ratio of the larger frontal horn diameter to the smaller one. The incidence of lateral ventricular asymmetry was 5.3%. The following clinical manifestations were more frequently present in group A: headaches (p = 0.002), seizures (p = 0.007) and positive human immunodeficiency virus (HIV) status (p = 0.02). Transient ischemic attacks were more prevalent in group B (p = 0.009). Independent predictors of headache were: younger age (p less than 0.001) and the degree of ventricular asymmetry (p = 0.02). Predictors of seizures were: younger age (p less than 0.001), ventricular asymmetry (p = 0.004) and the absence of septal deviation (p = 0.009). In group A, predictors of a higher degree of asymmetry were septal deviation (p less than 0.001) and older age (p = 0.008). The authors conclude that asymmetry of the lateral ventricles of the brain is a relatively common CT finding that has important clinical and brain structural correlates and deserves more attention in the field of imaging.

Adult↗
PubMed2003

[Localization of proline-rich peptide (galarmin) in brain structures of rats (immunohistochemical study)].

In the present study the immunohistochemical localization of proline-rich peptide, so called galarmin, was examined in the brain structures of intact and galarmin-treated rats. Galarmin (a fragment of neurophysin II C-end glycopeptide) was isolated by A.A. Galoyan and coworkers in 1997, from the neurosecretory granules of bovine neurohypophysis, produced by the hypothalamic magnocellular nuclei. In intact rats galarmin-immunoreactive neurons and nerve fibers were widely distributed in the central nervous system. Single intramuscular injection of galarmin to the rats resulted in the increase of both galarmin-immunoreactivity and the number of galarmin-immunoreactive nerve cells, fibers and capillaries. In control experiments where the antisera against the fragment of immunophilin (a receptor of immunosuppressor macrolide FK-506) and the pancreatic neuropeptide Y were used as the primary antibodies, the significant increase of neuropeptide Y-immunoreactive nerve fibers and immunophilin-positive lymphocytes was revealed in galarmin-treated rats. Based on these results and the data on the motoneurons regeneration in the spinal cord hemisectioned rats given galarmin daily for 3 weeks, galarmin has been suggested to act as an immunomodulator, neurotransmitter and neuroregulator.

Animals↗
PubMedDate not supplied

[The effect of low-frequency vibration on GABA metabolism in brain structures].

Low-frequency vibration, irrespective of its duration (20 Hz, A = 0.4 mm), is shown to increase GABA level, glutamatedecarboxylase enzyme activity (EC 4.1.1.15) in the large hemispheres, cerebellum, brain stem of adult male rats (12 months). Meanwhile GABA aminotransferase activity (EC 2.6.1.19) remains, mainly, unchanged. The observed shifts are more clear under 30 min vibration than under 7h and 30 day effects. Glutaminic and aspartic acids content increases under 30 min and decreases under 7h and 30 day vibration in the given brain structures.

4-Aminobutyrate Transaminase↗