Search results for "Cerebral cortex"

Cortical astrocytosis in juvenile rhesus monkeys infected with simian immunodeficiency virus

1993

The pattern of expression of GFAP immunoreactivity in astrocytes of the juvenile rhesus monkey cortex was examined following infection with simian immunodeficiency virus (SIV). Blocks of cerebral cortex plus subjacent white matter from saline- and formalin-perfused brain were examined by peroxidase-linked immunochemical and immunofluorescence staining of deparaffinized sections. Strong GFAP immunoreactivity was found in astrocytic cells in both uninfected and SIV-infected juvenile macaque in the subpial cerebral cortex and in subcortical white matter, where GFAP-positive cells were abundant. GFAP staining of cortical layers 2-6 on the other hand was weak or absent in three uninfected contro…

Control of cortical neuronal migration by glutamate and GABA

2015

Neuronal migration in the cortex is controlled by the paracrine action of the classical neurotransmitters glutamate and GABA. Glutamate controls radial migration of pyramidal neurons by acting primarily on NMDA receptors and regulates tangential migration of inhibitory interneurons by activating non-NMDA and NMDA receptors. GABA, acting on ionotropic GABAA-rho and GABAA receptors, has a dichotomic action on radially migrating neurons by acting as a GO signal in lower layers and as a STOP signal in upper cortical plate (CP), respectively. Metabotropic GABAB receptors promote radial migration into the CP and tangential migration of interneurons. Besides GABA, the endogenous GABAergic agonist …

Alterations of regional cerebral blood flow and oxygen saturation in a rat sinus-vein thrombosis model.

1996

Background and Purpose The pathophysiology of sinus-vein thrombosis (SVT) in patients and experimental animals is still poorly understood. This study was designed to examine and further elucidate the pathophysiological sequence of events, especially the relationship between local and regional blood flow and hemoglobin oxygen saturation (HbSO 2 ) detected at identical locations. The use of both parameters as outcome indicators should be compared. Methods SVT was induced by ligation of the superior sagittal sinus (SSS) and slow injection of kaolin-cephalin suspension into the SSS in rats. Regional cerebral blood flow (rCBF) was assessed by laser-Doppler flowmetry together with regional HbSO …

Ontogeny of somatostatin immunoreactive neurons in the medial cerebral cortex and other cortical areas of the lizardPodarcis hispanica

1996

The ontogeny of somatostatin immunoreactive interneurons in the cerebral cortex of the lizard Podarcis hispanica has been studied in histological series of embryos, perinatal specimens, and adults. Somatostatin immunoreactive interneurons appear in the early stages of lizard cerebral cortex ontogeny, their number increases during embryonary development, reaches a peak in early postnatal life, and decreases in adult lizards. The first somatostatin immunoreactive somata in the lizard forebrain appeared on E36, and they were located in non cortical areas. Then, on E39 and later, somatostatin immunoreactive neurons were seen in the lizard cortex in a rostral-to-caudal spatial gradient, which pa…

2016

This commentary describes important findings of the article published by Sheroziya and Timofeev in The Journal of Neuroscience in 2015. The authors use moderate cortical temperature change, local cooling or heating of somatosensory cortex, to modulate excitable states of the brain. These changes, under physiological conditions, result from neuromodulation, as well as other network effects. They report that cooling disrupts thalamocortical slow oscillations and induces an activated cortical state, while mild heating has the opposite effect and increases slow-wave rhythmicity. We evaluate these findings regarding their utility for inducing and investigating cortical state fluctuations, compar…

Satb2 Regulates Callosal Projection Neuron Identity in the Developing Cerebral Cortex

2008

SummarySatb2 is a DNA-binding protein that regulates chromatin organization and gene expression. In the developing brain, Satb2 is expressed in cortical neurons that extend axons across the corpus callosum. To assess the role of Satb2 in neurons, we analyzed mice in which the Satb2 locus was disrupted by insertion of a LacZ gene. In mutant mice, β-galactosidase-labeled axons are absent from the corpus callosum and instead descend along the corticospinal tract. Satb2 mutant neurons acquire expression of Ctip2, a transcription factor that is necessary and sufficient for the extension of subcortical projections by cortical neurons. Conversely, ectopic expression of Satb2 in neural stem cells m…

Age at First Episode Modulates Diagnosis-Related Structural Brain Abnormalities in Psychosis.

2016

Brain volume and thickness abnormalities have been reported in first-episode psychosis (FEP). However, it is unclear if and how they are modulated by brain developmental stage (and, therefore, by age at FEP as a proxy). This is a multicenter cross-sectional case-control brain magnetic resonance imaging (MRI) study. Patients with FEP (n = 196), 65.3% males, with a wide age at FEP span (12-35 y), and healthy controls (HC) (n = 157), matched for age, sex, and handedness, were scanned at 6 sites. Gray matter volume and thickness measurements were generated for several brain regions using FreeSurfer software. The nonlinear relationship between age at scan (a proxy for age at FEP in patients) and…

Bilaterally recorded multiple-unit activity of the cingulate cortex during head turning conditioning with unilateral medial forebrain bundle stimulat…

1993

Cats were conditioned to turn their heads using a tone conditioned stimulus (CS) and medial forebrain bundle stimulation (MFB) unconditioned stimulus (US). The CS+ was delivered to one ear at a time, in random order, followed by the US. A tone of a different frequency was used as a CS-. The cats learned to respond differentially to the CSs showing head movements of greater acceleration to the CS+ than CS- over sessions. Bilateral recordings of cingulate cortex multiple-unit activity showed increased response amplitudes over sessions and larger responses in the hemisphere ipsilateral to the US. Since ipsilateral multiple-unit responses did not differ for the CSs, the asymmetry was probably d…

LRRK2 is expressed in areas affected by Parkinson's disease in the adult mouse brain.

2006

The leucine-rich repeat kinase 2 (LRRK2) gene was recently found to have multiple mutations that are causative for autosomal dominant inherited Parkinson's disease (PD). Previously, we used Northern blot analysis to show that this gene was expressed in the cerebellum, cerebral cortex, medulla, spinal cord, occipital pole, frontal lobe, temporal lobe and caudate putamen. However, a more comprehensive map of LRRK2 mRNA localization in the central nervous system is still lacking. In this study we have mapped the distribution of the mRNA encoding for LRRK2 using nonradioactive in situ hybridization. We detected a moderate expression of this PD-related gene throughout the adult B2B6 mouse brain.…

Asymmetries in classically conditioned head movements and cingulate cortex slow potentials in cats.

1991

Presuming that conditioned head movements in the cat indicate a preference for a specific direction, asymmetries were also expected to be found in bilaterally recorded cingulate cortex slow potentials to a symmetrical tone stimulus during discriminative conditioning. Conditioned stimuli (CS, 1000 and 2500 Hz tones) were delivered through two miniature loudspeakers fitted to the head in front of both ears. The unconditioned stimulus (US) was an electrical stimulation of either the left or right lateral hypothalamus yielding, in addition to its rewarding effects, an unconditioned head turning response (UR) either to the left, right, forwards or upwards. Discrimination learning appeared as mor…