Search results for "Gyrus"
showing 10 items of 277 documents
Cutaneous Painful Laser Stimuli Evoke Responses Recorded Directly From Primary Somatosensory Cortex in Awake Humans
2004
Negative and positive laser evoked potential (LEP) peaks (N2*, P2**) were simultaneously recorded from the primary somatosensory (SI), parasylvian, and medial frontal (MF: anterior cingulate and supplementary motor area) cortical surfaces through subdural electrodes implanted for the surgical treatment of intractable epilepsy. Distribution of the LEP N2*and P2**peaks was estimated to be in cortical areas (SI, parasylvian, and MF) identified by anatomic criteria, by their response to innocuous vibratory stimulation of a finger (v-SEP), and to electrical stimulation of the median nerve (e-SEP). The maximum of the LEP N2*peak was located on the CS, medial (dorsal) to the finger motor area, as …
Straight gyrus morphology in first-episode schizophrenia-spectrum patients
2010
et al.
Increased amygdala and parahippocampal gyrus activation in schizophrenic patients with auditory hallucinations: An fMRI study using independent compo…
2010
Objective: Hallucinations in patients with schizophrenia have strong emotional connotations. Functional neuroimaging techniques have been widely used to study brain activity in patients with schizophrenia with hallucinations or emotional impairments. However, few of these Studies have investigated the association between hallucinations and emotional dysfunctions using an emotional auditory paradigm. Independent component analysis (ICA) is an analysis method that is especially useful for decomposing activation during complex cognitive tasks in which multiple operations occur simultaneously. Our aim in this Study is to analyze brain activation after the presentation of emotional auditory stim…
Emotional words induce enhanced brain activity in schizophrenic patients with auditory hallucinations.
2005
Neuroimaging studies of emotional response in schizophrenia have mainly used visual (faces) paradigms and shown globally reduced brain activity. None of these studies have used an auditory paradigm. Our principal aim is to evaluate the emotional response of patients with schizophrenia to neutral and emotional words. An auditory emotional paradigm based on the most frequent words heard by psychotic patients with auditory hallucinations was designed. This paradigm was applied to evaluate cerebral activation with functional magnetic resonance imaging (fMRI) in 11 patients with schizophrenia with persistent hallucinations and 10 healthy subjects. We found a clear enhanced activity of the fronta…
Left orbitofrontal and superior temporal gyrus structural changes associated to suicidal behavior in patients with schizophrenia.
2008
Suicidal attempts are relatively frequent and clinically relevant in patients with schizophrenia. Recent studies have found gray matter differences in suicidal and non-suicidal depressive patients. However, no previous neuroimaging study has investigated possible structural abnormalities associated to suicidal behaviors in patients with schizophrenia. A whole-brain magnetic resonance voxel-based morphometric examination was performed on 37 male patients meeting the DSM-IV criteria for schizophrenia. Thirteen (35.14%) patients had attempted suicide. A non-parametric permutation test was computed to perform the comparability between groups. An analysis of covariance (AnCova) model was constru…
Functional imaging of sympathetic activation during mental stress
2010
Activation of the sympathetic nervous system (SNS) is essential in adapting to environmental stressors and in maintaining homeostasis. This reaction can also turn into maladaptation, associated with a wide spectrum of stress-related diseases. Up to now, the cortical mechanisms of sympathetic activation in acute mental stress have not been sufficiently characterized. We therefore investigated cerebral activation applying functional magnetic resonance imaging (fMRI) during performance of a mental stress task with graded levels of difficulty, i.e. four versions of a Stroop task (Colour Word Interference Test, CWT) in healthy subjects. To analyze stress-associated sympathetic activation, skin c…
The unpleasantness of tonic pain is encoded by the insular cortex
2005
Objective: Muscle pain differs from skin pain with respect to quality, accuracy of localization, and unpleasantness. This study was conducted to identify the brain regions associated with the affective-motivational component of tonic skin and muscle pain. Methods: Forty healthy volunteers were investigated in three groups with different F-18 fluorodeoxyglucose PET activation scans. A verbal rating scale (VRS) was used to quantify pain intensity and unpleasantness. One group was investigated during painful infusion of an acidified phosphate buffer (pH 5.2) into either muscle or skin for 30 minutes. Muscle and skin infusions were adjusted to achieve pain intensity rating of VRS = 40. The seco…
Neural Architecture of Selective Stopping Strategies: Distinct Brain Activity Patterns Are Associated with Attentional Capture But Not with Outright …
2017
In stimulus-selective stop-signal tasks, the salient stop signal needs attentional processing before genuine response inhibition is completed. Differential prefrontal involvement in attentional capture and response inhibition has been linked to the right inferior frontal junction (IFJ) and ventrolateral prefrontal cortex (VLPFC), respectively. Recently, it has been suggested that stimulus-selective stopping may be accomplished by the following different strategies: individuals may selectively inhibit their response only upon detecting a stop signal (independent discriminate then stop strategy) or unselectively whenever detecting a stop or attentional capture signal (stop then discriminate s…
Parieto-frontal interactions in visual-object and visual-spatial working memory: Evidence from transcranial magnetic stimulation
2001
This study aimed to investigate whether transcranial magnetic stimulation (TMS) can induce selective working memory (WM) deficits of visual-object versus visual-spatial information in normal humans. Thirty-five healthy subjects performed two computerized visual n-back tasks, in which they were required to memorize spatial locations or abstract patterns. In a first series of experiments, unilateral or bilateral TMS was delivered on posterior parietal and middle temporal regions of both hemispheres after various delays during the WM task. Bilateral temporal TMS increased reaction times (RTs) in the visual-object, whereas bilateral parietal TMS selectively increased RTs in the visual-spatial W…
fMRI signal increases and decreases in cortical areas during small-field optokinetic stimulation and central fixation
2001
Small-field optokinetic nystagmus (OKN) was performed in seven healthy volunteers in order to analyze the activation and deactivation patterns of visual motion, ocular motor, and multisensory vestibular cortex areas by means of fMRI during coherent visual motion stimulation. BOLD signal decreases (deactivations) were found in the first and second long insular gyri and retroinsular areas (the human homologue of the parietoinsular vestibular cortex and the visual posterior sylvian area in the monkey) of both hemispheres, extending into the transverse temporal gyrus and inferior-anterior parts of the superior temporal gyrus (BA 22), and the precentral gyri at two separate sites (BA 4 and 6). F…