Search results for "Occipital lobe"
showing 10 items of 23 documents
A Mutually Stimulating Loop Involving Emx2 and Canonical Wnt Signalling Specifically Promotes Expansion of Occipital Cortex and Hippocampus
2005
The correct size of the different areas composing the mature cerebral cortex depends on the proper early allocation of cortical progenitors to their distinctive areal fates, as well as on appropriate subsequent tuning of their area-specific proliferation--differentiation profiles. Whereas much is known about the genetics of the former process, the molecular mechanisms regulating proliferation and differentiation rates within distinctive cortical proto-areas are still largely obscure. Here we show that a mutual stimulating loop, involving Emx2 and canonical Wnt signalling, specifically promotes expansion of the occipito-hippocampal anlage. Collapse of this loop occurring in Emx2 2/2 mutants …
Epidural hematoma after cochlear implantation in a 2.5-year-old boy.
2005
OBJECTIVE Report a case of an epidural hematoma after cochlear implantation in a 2.5-year-old boy, the diagnostic and therapeutical emergency management, as well as the postinterventional course and rehabilitation of the child. STUDY DESIGN Retrospective case review. PATIENT Two and a half-year-old boy, suffering from early onset, profound sensorineural hearing loss had been diagnosed at an age of 1.5 years, which had been more severe on the right side initially, but had progressed to bilateral deafness. INTERVENTION AND COMPLICATION: Cochlear implantation on the left side, followed up by an extensive epidural hematoma, causing intracranial compression with a midline shift of 15 mm to the r…
An electrophysiological study of print processing in kindergarten: the contribution of the visual n1 as a predictor of reading outcome.
2013
Sensitivity to print is characterized by a left occipito-temporal negativity to words in the event-related potential N1. This sensitivity is modulated by reading skills and may thus represent a neural marker of reading competence. Here we studied the development of the N1 in regular and poor readers from preschool age to school age to test whether the amplitude of the N1 predicts children's reading outcomes. Our results suggest a predictive value of the print-sensitive negativity over the right hemisphere. Whether this N1 may serve as a biomarker to improve prognosis in preliterate children should be clarified in future studies.
Functional relevance of cross-modal plasticity in blind humans
1997
Functional imaging studies of people who were blind from an early age have revealed that their primary visual cortex can be activated by Braille reading and other tactile discrimination tasks1. Other studies have also shown that visual cortical areas can be activated by somatosensory input in blind subjects but not those with sight2,3,4,5,6,7. The significance of this cross-modal plasticity is unclear, however, as it is not known whether the visual cortex can process somatosensory information in a functionally relevant way. To address this issue, we used transcranial magnetic stimulation to disrupt the function of different cortical areas in people who were blind from an early age as they i…
Brain density in depression: methodological and psychopathological aspects
1988
The relationship between brain density, measured by computerized tomography (CT), and severity of depression was investigated in 44 patients with a major depressive episode according to DSM-III. In order to limit methodological problems, correlations between both the Brief Psychiatric Rating Scale (BPRS) and the Bech-Rafaelsen Melancholia Scale (BRMS) with density values were controlled for age, different ventricle measurements, brain size, and density and size of the skull. The BRMS score correlated inversely with density of the right thalamus, the right head of the caudate, and with parietal grey matter and occipital regions of both hemispheres. Similar, but nonsignificant results, were o…
Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge
2005
Summary Objective To verify findings of an independently regulated anterior limbic alpha band source. Methods In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t -statistical parametric mapping [SPM{ t }]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. Results Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18,…
Location of Gliomas in Relation to Mobile Telephone Use: A Case-Case and Case-Specular Analysis
2011
The energy absorbed from the radio-frequency fields of mobile telephones depends strongly on distance from the source. The authors' objective in this study was to evaluate whether gliomas occur preferentially in the areas of the brain having the highest radio-frequency exposure. The authors used 2 approaches: In a case-case analysis, tumor locations were compared with varying exposure levels; in a case-specular analysis, a hypothetical reference location was assigned for each glioma, and the distances from the actual and specular locations to the handset were compared. The study included 888 gliomas from 7 European countries (2000-2004), with tumor midpoints defined on a 3-dimensional grid …
Attentional processes in typically developing children as revealed using brain event-related potentials and their source localization in Attention Ne…
2019
AbstractAttention-related processes include three functional sub-components: alerting, orienting, and inhibition. We investigated these components using EEG-based, brain event-related potentials and their neuronal source activations during the Attention Network Test in typically developing school-aged children. Participants were asked to detect the swimming direction of the centre fish in a group of five fish. The target stimulus was either preceded by a cue (centre, double, or spatial) or no cue. An EEG using 128 electrodes was recorded for 83 children aged 12–13 years. RTs showed significant effects across all three sub-components of attention. Alerting and orienting (responses to double …
The thalamus as the generator and modulator of EEG alpha rhythm: a combined PET/EEG study with lorazepam challenge in humans
2003
Background: Purpose of this study was to investigate the functional relationship between electroencephalographic (EEG) alpha power and cerebral glucose metabolism before and after pharmacological alpha suppression by lorazepam. Methods: Ten healthy male volunteers were examined undergoing two F18-fluorodeoxyglucose (18-FDG) positron emission tomography (PET) scans with simultaneous EEG recording: 1× placebo, 1× lorazepam. EEG power spectra were computed by means of Fourier analysis. The PET data were analyzed using SPM99, and the correlations between metabolism and alpha power were calculated for both conditions. Results: The comparison lorazepam versus placebo revealed reduced glucose meta…
Development and validation of a reliable method for studying the distribution pattern for opiates metabolites in brain
2012
Abstract Brain distribution pattern of “street” heroin metabolites (morphine and codeine) was investigated in two fatalities due to “acute narcotism”. A suitable sample pretreatment prior to solid-phase-extraction was developed to achieve a good recovery of the analytes and to eliminate the interfering species. After derivatization with MSTFA, samples were analyzed by GC/MS. Specificity, accuracy, precision and linearity of the method were evaluated; LOD and LOQ were, respectively, 10 ng/25 ng for morphine and 5 ng/10 ng for codeine. This method was applied to the analysis of six brain areas (hippocampus, frontal lobe, occipital lobe, nuclei, bulb and pons) coming from two cases of heroin-r…