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PubMedDate not supplied

[Acidic protein content in the brain structures of hibernating animals].

The water-soluble protein extracts from the different brain structures of hibernating animals were separated by means of disc-electrophoresis in polyacrylamide gel. The relative content of the most acidic protein corresponding to the nerve-specific protein S-100 under the same experimental conditions was determined in various physiological states. It is shown that the quantity of this protein in the brain stem increased in awakening animals as compared to the hibernating ones whereas its content in the cortex and hippocampus was stable.

Animals↗
PubMed2005

An automated approach to connectivity-based partitioning of brain structures.

We present an automated approach to the problem of connectivity-based partitioning of brain structures using diffusion imaging. White-matter fibres connect different areas of the brain, allowing them to interact with each other. Diffusion-tensor MRI measures the orientation of white-matter fibres in vivo, allowing us to perform connectivity-based partitioning non-invasively. Our new approach leverages atlas-based segmentation to automate anatomical labeling of the cortex. White-matter connectivities are inferred using a probabilistic tractography algorithm that models crossing pathways explicitly. The method is demonstrated with the partitioning of the corpus callosum of eight healthy subjects.

Algorithms↗
PubMed1999

Vitamin B6 deficiency decreases the glucose utilization in cognitive brain structures of rats.

The effects of vitamin B(6) deficiency on metabolic activities of brain structures were studied. Male Sprague-Dawley weanling rats received one of the following diets: (1) 7 mg pyridoxine HCl/kg (control group); (2) 0 mg pyridoxine HCl/kg (vitamin B(6)-deficient group); or (3) 7 mg pyridoxine HCl/kg with food intake restricted in quantity to that consumed by the deficient group (pair-fed control group). After 8 weeks of dietary treatment, rats in all three groups received an intravenous injection of 2-deoxy-[(14)C] glucose (100 microCi/kg). Vitamin B(6) status was evaluated by plasma pyridoxal 5'-phosphate concentrations. The vitamin B(6)-deficient group had significantly lower levels of plasma pyridoxal 5'-phosphate than did the control and pair-fed groups. The local cerebral glucose utilization rates in structures of the limbic system, basal ganglia, sensory motor system, and hypothalamic system were determined. The local cerebral glucose utilization rates in each of the four brain regions in the deficient animals were approximately 50% lower (P < 0.05) than in the control group. Results of the present study suggest that serious cognitive deficit may occur in vitamin B(6)-deficient animals.

Journal Article↗
PubMed1986

Self-stimulation behavior can be elicited from various 'aversive' brain structures.

Electrical stimulation applied to various brain regions of the negative motivational system: the dorsal part of the mesencephalic central gray area (CG) the medial hypothalamus (MH), the medial lemniscus (ML), the lateral tegmentum (LT) and the reticular formation (RF), produces vigorous escape responses in mice. In spite of their highly aversive consequences, stimulation of all these regions also elicits self-stimulation behavior. This paradoxical approach response was clearly observed when the animals were placed in a Y-maze where they could successively trigger and turn off continuous electrical stimulation. In effect, mice stimulated in 'aversive' structures, similarly to animals stimulated in the lateral hypothalamus (LH), were able to discriminate between the reinforced arm and the non-reinforced arm of the Y-maze in order to self-administer the stimulation. When the mice were placed in a lever press box which delivered 0.2 s of electrical stimulation, an evident self-stimulation behavior was observed in LH and in some animals implanted in RF or MH. On the other hand, the very low response rates recorded in CG, LT, ML and in other RF or MH implanted mice do not permit a description of the motivational properties of these different stimulation sites. These results show that stimulation of brain structures of the negative reinforcement system has an approach component which, however, shows up clearly only in certain experimental situations.

Animals↗
PubMed2001

Drosophila Pax-6/eyeless is essential for normal adult brain structure and function.

A role for the Pax-6 homologue eyeless in adult Drosophila brain development and function is described. eyeless expression is detected in neurons, but not glial cells, of the mushroom bodies, the medullar cortex, the lateral horn, and the pars intercerebralis. Furthermore, severe defects in adult brain structures essential for vision, olfaction, and for the coordination of locomotion are provoked by two newly isolated mutations of Pax-6/eyeless that result in truncated proteins. Consistent with the morphological lesions, we observe defective walking behavior for these eyeless mutants. The implications of these data for understanding postembryonic brain development and function in Drosophila are discussed.

Age Factors↗
PubMedDate not supplied

[The effect of a peptide-containing extract of the right hemispheric cortex on the recovery of conditioned reflex activity and on the level of neuromediators in the brain structures of rats after a unilateral frontal lobectomy].

Experiments were conducted on 97 non-inbred [correction of unbred] male rats to study the effect of a peptide-containing extract of the cortex of the right hemisphere of donor rats, who underwent left lobectomy 9 days before the experiment, on restoration of conditioned reflexes of bilateral avoidance and level of neuromediators in the brain structures of recipient rats with a similar damage to the cerebral cortex. It is shown that the brain extract from the right hemisphere of operated on donors has a much higher effect on the restoration of reflexes. At the same time it was found that in left frontal lobectomy this extract produces a most manifest effect on monoamine metabolism in the structures of the right intact hemisphere. It is suggested that a directed effect may possibly be produced on the development of compensatory-restorative process in the central nervous system by endogenous substances of peptide origin which are isolated from brain structures actively contributing to the restoration of disturbed functions.

Animals↗
PubMed1991

A new method of the description of the information flow in the brain structures.

The paper describes the method of determining direction and frequency content of the brain activity flow. The method was formulated in the framework of the AR model. The transfer function matrix was found for multichannel EEG process. Elements of this matrix, properly normalized, appeared to be good estimators of the propagation direction and spectral properties of the investigated signals. Simulation experiments have shown that the estimator proposed by us unequivocally reveals the direction of the signal flow and is able to distinguish between direct and indirect transfer of information. The method was applied to the signals recorded in the brain structures of the experimental animals and also to the human normal and epileptic EEG. The sensitivity of the method and its usefulness in the neurological and clinical applications was demonstrated.

Animals↗
PubMed2002

An improved method with a long-shanked glass micropipette and ultrasonography for drug injection into deep brain structure of the monkey.

We describe an improved method to inject drug into deep brain structure of the macaque monkey. A Teflon-coated tungsten wire for extracellular recording was passed through a long-shanked (4-5 cm) glass micropipette, which was then attached to a microsyringe with dental impression material. The surface of the micropippete was coated with Teflon to reduce acoustic artifact in ultrasound imaging. Thereby, it was possible to identify the micropipette in the brain with B-mode ultrasonography. Extracellular recording combined with electrical stimulation in the input source of the target nucleus was also helpful to determine the location of the micropipette. Here, we demonstrate injection of a neuronal tracer, wheat germ agglutinin conjugated to horseradish peroxidase, into the medial mammillary nucleus of the Japanese monkey.

Action Potentials↗
PubMed2005

Segmentation of subcortical brain structures using fuzzy templates.

We propose a novel method to automatically segment subcortical structures of human brain in magnetic resonance images by using fuzzy templates. A set of fuzzy templates of the structures based on features such as intensity, spatial location, and relative spatial relationship among structures are first created from a set of training images by defining the fuzzy membership functions and by fusing the information of features. Segmentation is performed by registering the fuzzy templates of the structures on the test image and then by fusing them with the tissue maps of the test image. The final decision is taken in order to optimize the certainty in the intensity, location, relative position, and tissue content of the structure. Our method does not require specific expert definition of each structure or manual interactions during segmentation process. The technique is demonstrated with the segmentation of five structures: thalamus, putamen, caudate, hippocampus, and amygdala; the performance of the present method is comparable with previous techniques.

Algorithms↗
PubMed2004

[Chemically induced Drosophila melanogaster mutants with changes in brain structure].

Neurodegenerative human diseases are caused by nerve cell death and anatomical changes in some brain regions. Molecular genetic studies of Drosophila showed that this organism can serve as a valuable test-system for conserved mechanisms underlying human nervous system disorders. Analysis of brain functions is possible when the mutants with disturbed functions are available. In this study, we have developed a unique collection of Drosophila melanogaster mutants with morphological and neurodegenerative changes in brain structure, which were induced by chemical mutagens.

Animals↗
PubMed2003

Gender and age effects in structural brain asymmetry as measured by MRI texture analysis.

Effects of gender and age on structural brain asymmetry were studied by 3D texture analysis in 380 adults. Asymmetry is detected by comparing the complex 3D gray-scale image patterns in the left and right cerebral hemispheres as revealed by anatomical T1-weighted MRI datasets. The Talairach and Tournoux parcellation system was applied to study the asymmetry on five levels: the whole cerebrum, nine coronal sections, 12 axial sections, boxes resulting from both coronal and axial subdivisions, and by a sliding spherical window of 9 mm diameter. The analysis revealed that the brain asymmetry increases in the anterior-posterior direction starting from the central region onward. Male brains were found to be more asymmetric than female. This gender-related effect is noticeable in all brain areas but is most significant in the superior temporal gyrus, Heschl's gyrus, the adjacent white matter regions in the temporal stem and the knee of the optic radiation, the thalamus, and the posterior cingulate. The brain asymmetry increases significantly with age in the inferior frontal gyrus, anterior insula, anterior cingulate, parahippocampal gyrus, retrosplenial cortex, coronal radiata, and knee region of the internal capsule. Asymmetry decreases with age in the optic radiation, precentral gyrus, and angular gyrus. The texture-based method reported here is based on extended multisort cooccurrence matrices that employ intensity, gradient, and anisotropy features in a uniform way. It is sensitive, simple to reproduce, robust, and unbiased in the sense that segmentation of brain compartments and spatial transformations are not necessary. Thus, it should be considered as another tool for digital morphometry in neuroscience.

Adolescent↗
PubMed1984

[Sensory properties of neurons of a nonspecific brain structure--the caudate nucleus].

The paper deals with sensory function of single neurons in nonspecific high-level brain structures. Certain aspects of the problem are shown to be complex and disputable. The choice of the research object, nucleus caudatus, is substantiated. Results of experiments with alert cats are presented. Extracellularly recorded neuronal responses to various light stimuli are compared. Local light stimuli, especially under a definite spatial distribution of illuminated sites in the visual field, are found to be more advantageous in neuron activation than diffuse light. Difficulties in interpretation of the data obtained are discussed in connection with fluctuation of background activity and recorded responses under multiple application of the stimuli. An attempt is made to relate sensory properties of the neostriatum to the regulatory efferent function of this structure.

Animals↗
PubMed2006

Understanding structural brain changes in schizophrenia.

Schizophrenia is a chronic progressive disorder that has at its origin structural brain changes in both white and gray matter. It is likely that these changes begin prior to the onset of clinical symptoms in cortical regions, particularly those concerned with language processing. Later, they can be detected by progressive ventricular enlargement. Current magnetic resonance imaging (MRI) technology can provide a valuable tool for detecting early changes in cortical atrophy and anomalous language processing, which may be predictive of who will develop schizophrenia.

Antipsychotic Agents↗
PubMed2002

Structural brain abnormalities specific to childhood-onset schizophrenia identified by neuroimaging techniques.

This review discusses functional and structural brain abnormalities in childhood-onset schizophrenia identified by neuroimaging techniques. Published literature regarding both morphological and functional neuroimaging is discussed, regarding also the diversity of neuroimaging findings which partly reduces their reliability. The findings in early onset schizophrenia are compared with those of adult patients. The results of long-term investigations of structural abnormalities in early onset schizophrenia are given particular attention. The most consistent findings are ventricular enlargement and reduced total brain volume. Further, volumetric changes in the temporal and frontal cortex, thalamus, basal ganglia and limbic system are reported, as are hemispheric asymmetries and, conversely, reduction of normal differences. Findings regarding the corpus callosum and cerebellum are less consistent. In patients whose schizophrenia commenced in early childhood, the differences were generally more marked than in adolescence- or adult-onset schizophrenia. Atrophy of total brain volume was progressive throughout the course of the disorder. It is probable that neuroanatomical cerebral abnormalities present prior to disease onset play an etiopathogenic role in the development of schizophrenia.

Adolescent↗
PubMed1991

A study on the brain structures related to conditioned emotional response by means of [14C]2-deoxy-D-glucose method.

Brain structures activated during conditioned emotional response were studied by means of the [14C]2-deoxyglucose method. The experimental (CSE) animals were conditioned with paired 25 25-sec-long flicker sequences (CS) and 1-sec-long 150 V AC electric shocks (US), while the control (CSC) animals were given only 25 CS sequences. Average densities of a unit square (200 microns x 200 microns) of 47 nuclei or cortical areas in the left hemisphere were obtained from an autoradiogram and the optical density ratio (ODR), which is the relative optical density of each structure to that of the corpus callosum, was calculated. Comparison of ODRs of each structure from both groups revealed a significant increased uptake of [14C]2-deoxyglucose (P less than 0.05, Mann-Whitney U-test) in the caudal portion of area 10, area 2, area 18 and the hippocampal formation.

Animals↗
PubMedDate not supplied

[Interaction of brain structures participating in vocalization].

The study revealed a broad representation of the system, controlling vocalization, in the brain structures of hens. Sound-producing structures are mostly represented in the mesencephalon, less--in the diencephalon and the least of all--in the striatum. Further on it is shown that the excitability of the structures at the mesencephalic and diencephalic levels participating in vocalization, is influenced by the corticoid lamine and striate formations (Hyperstriatum, Neostriatum). Forward and backward interconnections are revealed between the paliostriatum and soundproducing formations in the midbrain. Such functional connections, providing for excitatory or inhibitory control, are found between the neostriatum and the diencephalic structures. A suggestion is made, that vocalization processes proceed simultaneously in several parallel anatomic pathways.

Animals↗
PubMed1997

The Maudsley Family Study. I: Structural brain changes on magnetic resonance imaging in familial schizophrenia.

1. The authors investigated the prevalence of qualitatively rated structural brain abnormalities in schizophrenic probands and their first-degree relatives from families multiply affected with schizophrenia. 2. Magnetic resonance imaging was used to evaluate brain morphology in 33 schizophrenic probands, 54 of their non-schizophrenic first-degree relatives (including 11 presumed obligate carriers) and 37 unrelated control subjects. Structural images were examined by a neuroradiologist who was blind to diagnostic and family status. 3. 52% of the schizophrenic subjects were rated as showing abnormalities compared with 27% of presumed obligate carriers, 16% of their non-schizophrenic relatives and 11% of unrelated controls. 4. Brain abnormalities were more frequent in schizophrenic subjects from multiplex families than in their first-degree relatives and controls. Abnormalities were also found in unaffected relatives particularly those who appear to be transmitting the disorder.

Adult↗