Search results for "Cingulate cortex"
showing 10 items of 69 documents
Net influx of plasma 6-[18F]fluoro-L-DOPA (FDOPA) to the ventral striatum correlates with prefrontal processing of affective stimuli.
2006
Dopaminergic neurotransmission in the ventral and dorsal striatum interact with central processing of rewarding and reward-indicating stimuli, and may affect frontocortical-striatal-thalamic circuits regulating goal-directed behaviour. Thirteen healthy male volunteers were investigated with multimodal imaging, using the radioligand 6-[ 18 F]fluoro-L-DOPA (FDOPA) for positron emission tomography (PET) measurements of dopamine synthesis capacity, and also functional magnetic resonance imaging (fMRI) in a cognitive activation paradigm. We calculated the correlation between FDOPA net blood-brain influx (K app in ; ml/g/min) in the ventral and associative dorsal striatum and BOLD signal changes …
The val158met polymorphism of human catechol-O-methyltransferase (COMT) affects anterior cingulate cortex activation in response to painful laser sti…
2010
Background: Pain is a complex experience with sensory, emotional and cognitive aspects. Genetic and environmental factors contribute to pain-related phenotypes such as chronic pain states. Genetic variations in the gene coding for catechol-O-methyltransferase ( COMT) have been suggested to affect clinical and experimental pain-related phenotypes including regional μ-opioid system responses to painful stimulation as measured by ligand-PET (positron emission tomography). The functional val158met single nucleotide polymorphism has been most widely studied. However, apart from its impact on pain-induced opioid release the effect of this genetic variation on cerebral pain processing has not been…
Functional changes in brain activity after hypnosis in patients with dental phobia.
2015
Visiting the dentist is often accompanied by apprehension or anxiety. People, who suffer from specific dental phobia (a disproportional fear of dental) procedures show psychological and physiological symptoms which make dental treatments difficult or impossible. For such purposes, hypnosis is often used in dental practice as an alternative for a number of treatments adjuvant or instead of sedation or general anaesthetics, as medication is often associated with risks and side effects. This is the first study to address the effects of a brief dental hypnosis on the fear processing structures of the brain in dental phobics using functional magnetic resonance imaging (fMRI). 12 dental phobics (…
Amplitudes of laser evoked potential recorded from primary somatosensory, parasylvian and medial frontal cortex are graded with stimulus intensity
2003
Intensity encoding of painful stimuli in many brain regions has been suggested by imaging studies which cannot measure electrical activity of the brain directly. We have now examined the effect of laser stimulus intensity (three energy levels) on laser evoked potentials (LEPs) recorded directly from the human primary somatosensory (SI), parasylvian, and medial frontal cortical surfaces through subdural electrodes implanted for surgical treatment of medically intractable epilepsy. LEP N2* (early exogenous/stimulus-related potential) and LEP P2** (later endogenous potential) amplitudes were significantly related to the laser energy levels in all regions, although differences between regions w…
Nicotine effects on anterior cingulate cortex in schizophrenia and healthy smokers as revealed by EEG-informed fMRI
2012
Abstract Nicotine can have beneficial effects on attention performance and corresponding brain function in both schizophrenia patients and healthy controls, but it remains controversial whether nicotine affects brain function differentially in patients vs. controls. The effects of nicotine on brain activity elicited by attention-requiring oddball-type tasks have not been studied in schizophrenia patients. In this study we sought to investigate the impact of nicotine on the p300 evoked potential component and corresponding fMRI (functional magnetic resonance imaging) activation measures in schizophrenia patients and controls. Applying a double-blind, placebo-controlled cross-over design, the…
Illusion of Pain: Pre-existing Knowledge Determines Brain Activation of ‘Imagined Allodynia’
2007
Abstract Allodynia means that innocuous tactile stimulation is felt as pain. Accordingly, cerebral activations during allodynia or touch should markedly differ. The aim of this study was to investigate whether the imagination of allodynia affects brain processing of touch in healthy subjects. Seventeen healthy subjects divided into 2 subgroups were investigated: The first group (n = 7) was familiar with allodynia, based on previous pain studies, whereas the second group (n = 10) had never knowingly experienced allodynia. Using functional magnetic resonance imaging, 2 experimental conditions were investigated. In one condition the subjects were simply touched at their left hand, whereas duri…
Repetitive transcranial magnetic stimulation over the left parietal cortex facilitates visual search for a letter among its mirror images
2015
Interference by task irrelevant information is seen in visual search paradigms using letters. Thus, it is harder to find the letter 'N' among its mirror reversals 'Icyrillic' than vice versa. This observation, termed the reversed letter effect, involves both a linguistic association and an interference of task irrelevant information - the shape of 'N' or 'Icyrillic' is irrelevant, the search requires merely distinguishing the tilts of oblique bars. We adapted the repetitive transcranial magnetic stimulation (rTMS) methods that we previously used, and conducted three rTMS experiments using healthy subjects. The first experiment investigated the effects of rTMS on the left and right posterior…
Effect of mental fatigue on speed–accuracy trade-off
2015
International audience; The aim of this study was to investigate the effects of mental fatigue on the duration of actual and imagined goal-directed arm movements involving speed-accuracy trade-off. Ten participants performed actual and imagined point-to-point arm movements as accurately and as fast as possible, before and after a 90-min sustained cognitive task inducing mental fatigue, and before and after viewing a neutral control task (documentary movie) that did not induce mental fatigue. Target width and center-to-center target distance were varied, resulting in five different indexes of difficulty. Prior to mental fatigue, actual and imagined movement duration increased with the diffic…
Increased functional connectivity in gambling disorder correlates with behavioural and emotional dysregulation: Evidence of a role for the cerebellum
2020
Gambling disorder (GD) is a psychiatric disease that has been recently classified as a behavioural addiction. So far, a very few studies have investigated the alteration of functional connectivity in GD patients, thus the concrete interplay between relevant function-dependent circuitries in such disease has not been comprehensively assessed. The aim of this research was to investigate resting-state functional connectivity in GD patients, searching for a correlation with GD symptoms severity. GD patients were assessed for gambling behaviour, impulsivity, cognitive distortions, anxiety and depression, in comparison with healthy controls (HC). Afterwards, they were assessed for resting-state f…
The Functional Role of Large-scale Brain Network Coordination in Placebo-induced Anxiolysis
2018
Abstract Anxiety reduction through mere expectation of anxiolytic treatment effects (placebo anxiolysis) has enormous clinical importance. Recent behavioral and electrophysiological data suggest that placebo anxiolysis involves reduced vigilance and enhanced internalization of attention; however, the underlying neurobiological mechanisms are not yet clear. Given the fundamental function of intrinsic connectivity networks (ICNs) in basic cognitive processes, we investigated ICN activity patterns associated with externally and internally directed mental states under the influence of an anxiolytic placebo medication. Based on recent findings, we specifically analyzed the functional role of the…