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Results for “cortical structure”

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At least 73 records · Page 4Linked to original sources
PubMed1990

Unimanual tapping during concurrent articulation: examining the role of cortical structures in the execution of programmed movement sequences.

Three experiments were conducted to examine effects of speech on concurrent unimanual tapping. Experiments 1 and 2 involved the manual tapping of a short burst of preprogrammed responses with or without concurrent articulation. Results of these experiments showed no effects of speech articulation on the concurrent execution of programmed manual movement sequences. In Experiment 3, subjects continuously tapped for 15 sec, again, with or without concurrent speech articulation. The results showed that articulation affected the speed of concurrent manual responses with larger interference for right hand tapping than for left hand tapping. Additional analysis of the tapping variability revealed equivalent effects of concurrent articulation on the timing of repetitive right and left hand tapping. Kinsbourne's Functional Cerebral Distance Principle was used to interpret these results. Within this framework, the present findings indicate that functionally distinct processes control speech articulation and the execution of programmed manual movement sequences.

Arousal↗
PubMedDate not supplied

Seizures can be triggered by stimulating non-cortical structures in the quaking mutant mouse.

Mutant Quaking mice (C57BL/6J) display convulsive tonic-clonic seizures that can be either spontaneous or triggered by manipulation of the animal or by auditory stimulation. Several abnormalities have been found (especially in the noradrenergic system) in the brainstem of this mutant strain. We first verified by electrophysiological recording that the cerebral cortex was not involved in the generation or in the development of these fits. Then we showed that tonic-clonic seizures similar to those obtained in the freely moving animal were triggered by low-threshold (LT, 5-50 microA) or high-threshold (HT, 55-150 microA) stimuli performed during head restraint. LT stimuli were mostly efficient in a number of ponto-bulbar and mesencephalic structures, including several reticular nuclei, the locus coeruleus, the nucleus subcoeruleus and the red nucleus, whereas HT stimuli were generally necessary to trigger fits by stimulating the nuclei pontis, the substantia nigra, the central gray area and the cerebellar nuclei. Seizures were also provoked at the diencephalic level with LT stimulation delivered in the medial thalamic area, the nucleus reticularis thalami and some subthalamic regions (zona incerta, H field of Forel). In contrast, no fits were obtained by stimulating the cerebellar cortex and the inferior colliculus, the ventral and lateral groups of thalamic nuclei or the telencephalic regions (hippocampus, amygdala, caudate nucleus, putamen and cerebral cortex), with the exception of the globus pallidus.

Acoustic Stimulation↗
PubMed2000

Functional anatomical abnormalities in limbic and prefrontal cortical structures in major depression.

Neuroimaging studies of major depression have identified neurophysiological abnormalities in multiple areas of the prefrontal cortex (PFC), the amygdala, and related parts of the striatum and thalamus. Some of these abnormalities are mood state-dependent, and appear in regions where cerebral blood flow (CBF) increases during other normal and pathological emotional states. These neurophysiological differences between depressives and non-depressed controls may thus locate areas where physiological activity changes to mediate or respond to the emotional, behavioral and cognitive manifestations of major depressive episodes (MDE). Other abnormalities persist following symptom remission, and are found in orbital and medial PFC areas where post mortem studies demonstrate reductions in cortex volume and/or histopathological changes in primary mood disorders. These orbital and medial PFC areas have been shown by other types of evidence to modulate emotional behavior and stress responses, suggesting that dysfunction involving these regions may be involved in the pathogenesis of depressive symptoms. Finally, physiological activity is decreased during MDE in dorsal PFC areas implicated in language, selective attention, visuospatial or mnemonic processing, but these abnormalities reverse with symptom remission. These areas of 'deactivation' during the depressed state may reflect neurophysiological interactions between cognitive and emotional processing, and may relate to the subtle cognitive impairments associated with MDE.

Adoption↗
PubMed1999

Dose-dependent impairment of inhibitory avoidance retention in rats by immediate post-training infusion of a mitogen-activated protein kinase kinase inhibitor into cortical structures.

Mitogen-activated protein kinase (MAPK) is a serine/threonine protein kinase abundantly expressed in postmitotic neurons of the developed nervous system. MAPK is activated in and required for both the induction of long-term potentiation (LTP) in hippocampal slices and the acquisition of fear conditioning training in rats. The present work was performed in order to test the effect of the specific inhibitor of MAPK kinase (MAPKK), PD 098059, on retention of a step-down inhibitory avoidance (IA). Adult male Wistar rats were bilaterally injected (0.5 microl/side) with PD 098059 (at 0.5, 5, or 50 microM) or vehicle into the entorhinal cortex or into the parietal cortex immediately after IA training using a 0.4 mA footshock. Retention testing was carried out 24 h after training. PD 098059 impaired retention when injected into the entorhinal cortex at the dose of 50 microM, but not at the doses of 5 or 0.5 microM. When infused into the parietal cortex, PD 098059 was amnestic at the doses of 5 and 50 microM. The drug had no effect when infused at the highest dose in either structure 6 h after training. Our results suggest that the MAPKK inhibitor impairs IA retention memory in a dose-dependent manner when injected immediately after training into entorhinal cortex or parietal cortex. The effective dose is variable according to the neocortical structure studied.

Animals↗
PubMed1998

Cortical structure and mental skills: Oskar Vogt and the legacy of Lenin's brain.

Anatomical study of the brain of Vladimir Ilyich Lenin, the intellectual leader of the Russian October revolution, was conducted in an unusual context. Lenin died in 1924, at 54 years of age, as a consequence of progressive cerebrovascular disease. The eminent German neuroscientist Oskar Vogt (1870-1959) was requested by the Soviet government to examine Lenin's brain; an Institute for Brain Research, directed by Vogt, was founded for this purpose in Moscow. Tens of thousands of sections were cut serially through Lenin's brain. In his official report in 1929, Vogt adduced that pyramidal neurons of layer III in several areas of Lenin's cerebral cortex were exceptionally large and numerous. Based on his opinion that these cells might subserve "associative thinking," Vogt apparently believed that this structural peculiarity could account for the strikingly acute and penetrating mental processes that had characterized Lenin's personality. Vogt's scientific activity, the cultural and political context of the study of Lenin's brain, and its modern implications are discussed briefly.

Cerebral Cortex↗
PubMed1996

Plasticity in the maternal circuit: effects of maternal experience on Fos-Lir in hypothalamic, limbic, and cortical structures in the postpartum rat.

To determine what brain sites are activated during the acquisition and retention of a maternal experience in postpartum rats, 3 studies examined the number of cells showing Fos-like immunoreactivity (Fos-lir) in brains following reexposure to pups and pup-associated cues in maternally experienced and inexperienced rats. Day 1 postpartum rats were given a 2- or 4-hr interactive experience with pups and then reexposed to pups in a perforated box, or to a neutral stimulus (perforated box only) 4 or 10 days later. At the end of the test phase, brains were prepared for immunohistochemical detection of Fos-lir. The brain sites showing the most consistent difference between experienced and inexperienced rats were the medical preoptic area, the basolateral amygdala, the parietal cortex, and the prefrontal cortex.

Amygdala↗
PubMed1956

An electron microscope study of cortical structures of Opalina obtrigonoidea.

The pellicular framework of Opalina obtrigonoidea consists of numerous longitudinal ribs parallel to the kineties. These ribs lie erect on the cell surface, and each is composed of striated longitudinal fibers. A membrane covers the ribs and the ectoplasm between them. Flagella, of conventional structure, emerge from the ectoplasm between the ribs. The two central fibers of each flagellum end at the cell surface; the nine peripheral fibers continue for about 400 mmicro into the cell to form an open tubular kinetosome. From the anterolateral curvature of each kinetosome arise two rows of fibrils, each fibril oriented perpendicular to the cell surface and about 150 A in diameter. The two rows converge anteriorly and probably meet the next adjacent kinetosome. Minute granules or tubules, arranged in oblique rows and at least sometimes accompanied by very fine fibers, lie at the surface of the ectoplasm but show no detectable connection with the kinetosomes. The whole flagellar apparatus of Opalina thus bears a general resemblance to the infraciliature of some holotrich ciliates, but the degree of evolutionary relationship between them remains uncertain.

Animals↗
PubMed2000

Mouse Tspan-5, a member of the tetraspanin superfamily, is highly expressed in brain cortical structures.

Using a subtractive hybridization method for the identification of genes related to the development of the murine cerebral cortex, we cloned a mouse homologue of a human tetraspanin family member, Tspan-5. We have isolated a 3.1 Kb cDNA fragment containing the entire coding region. Analysis of the cDNA nucleotide sequence revealed that mouse Tspan-5 shares 98% amino acid sequence identity with its human homologue. The predicted length of the mouse protein is 268 amino acids, with four putative hydrophobic domains with N- and C-intracellular tails, and two extracellular domains. Northern blot analysis of adult mouse tissues showed a single transcript, which is preferentially expressed in the brain. In situ hybridization showed prominent expression of Tspan-5 in the neocortex, the hippocampus, amygdala and in Purkinje cells in the cerebellum. The pattern of expression of Tspan-5 in the mouse brain suggests a role for the tetraspanins in the maintenance of adult brain function.

Animals↗
PubMed2005

Human leukocyte antigen sensitization after structural cortical allograft implantations.

UNLABELLED: The incidence and significance of a donor-specific human leukocyte antigen antibody response to massive fresh-frozen human bone allograft implantation is not established. This study was a prospective, multicenter study of a cohort of consecutive patients who self-randomized themselves into two groups based on their alloantibody response to allograft bone transplant. The study hypothesis was that donor-directed antibodies are an independent risk factor influencing incorporation of massive frozen bone allografts. Pretransplant and posttransplant human leukocyte antigen alloantibody analysis was performed and correlated to determine pre-existing and graft-induced antibodies. The surgical outcomes of the two groups of patients were compared to determine the relationship between alloantibody response and bone graft incorporation. Preliminary results revealed that donor-specific human leukocyte antigen sensitization occurred in 17 of 32 (53%) of previously nonsensitized patients. A survival analysis of time to healing based on human leukocyte antigen status showed no evidence of an association between human leukocyte antigen status and time to healing. Longer followup in additional patients will be required to determine if this sensitization is correlated with an alteration in the time to union or with the quality or type of bone graft incorporation. LEVEL OF EVIDENCE: Therapeutic study, Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗