Search results for " Magnetic resonance imaging"
showing 10 items of 452 documents
Emotional reactivity in chronic schizophrenia: structural and functional brain correlates and the influence of adverse childhood experiences
2011
Background. Despite behavioural signs of flattened affect, patients affected by schizophrenia show enhanced sensitivity to negative stimuli. The current literature concerning neural circuitry for emotions supports dysregulations of cortico-limbic networks, but gives contrasting results. Adverse childhood experiences (ACEs) could persistently influence emotional regulation and neural correlates of response to emotional stimuli in healthy humans. This study evaluated the effect of ACEs and chronic undifferentiated schizophrenia on neural responses to emotional stimuli (negative facial expression). Method. Brain blood-oxygen-level-dependent functional magnetic resonance imaging neural response…
Neuronal and Behavioral Correlates of Health Anxiety: Results of an Illness-Related Emotional Stroop Task
2011
<b><i>Background:</i></b> Health anxiety (HA) is defined as the objectively unfounded fear or conviction of suffering from a severe illness. Predominant attention allocation to illness-related information is regarded as a central process in the development and maintenance of HA, yet little is known about the neuronal correlates of this attentional bias. <b><i>Methods:</i></b> An emotional Stroop task with body symptom, illness, and neutral words was employed to elicit emotional interference in healthy participants with high (HA+, n = 12) and low (HA–, n = 12) HA during functional magnetic resonance imaging. <b><i>Results:</i>…
Dopamine in amygdala gates limbic processing of aversive stimuli in humans
2008
Dopamine is known to contribute to the amygdala-mediated aversive response, where increased dopamine release can augment amygdala function. Combining fMRI and PET imaging techniques, Kienast et al. present findings that suggest a functional link between anxiety temperament, dopamine storage capacity and emotional processing in the amygdala. Dopamine is released under stress and modulates processing of aversive stimuli. We found that dopamine storage capacity in human amygdala, measured with 6-[18F]fluoro-L-DOPA positron emission tomography, was positively correlated with functional magnetic resonance imaging blood oxygen level–dependent signal changes in amygdala and dorsal anterior cingula…
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 …
Automatic fuzzy classification of the washout curves from magnetic resonance first-pass perfusion imaging after myocardial infarction.
2005
International audience; Abstract: Objectives: We sought to investigate the diagnostic ability of cardiac magnetic resonance imaging (MRI) perfusion in acute reper-fused myocardial infarction. The study used fuzzy logic to automatically classify signal intensity-time curves from myocardial segments into 3 categories: normal, hypointense, and Hyperintense. Materials and Methods: Thirty-eight patients with myocardial infarction underwent short-axis cine-MRI and contrast-enhanced MRI to provide data on wall thickening and the transmural extent of infarction. Of these, 17 had a second cardiac MRI to ascertain the functional recovery in each segment. Results: The fuzzy logic based classification …
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 (…
The facilitative effect of gestures on the neural processing of semantic complexity in a continuous narrative
2019
© 2019 Elsevier Inc. Gestures are elemental components of social communication and aid comprehension of verbal messages; however, little is known about the potential role of gestures in facilitating processing of semantic complexity in an ecologically valid setting. The goal of this study was to investigate whether cognitive load, as indexed by semantic complexity, is modulated by the presentation of gestures accompanying speech. Twenty healthy participants watched 16 video clips of a short narrative while instructed to carefully listen to and watch the narrator while functional magnetic resonance imaging (fMRI) data were acquired. The videos contained passages with and without various co-s…
Surprise: Unexpected Action Execution and Unexpected Inhibition Recruit the Same Fronto-Basal-Ganglia Network.
2020
Unexpected and thus surprising events are omnipresent and oftentimes require adaptive behavior such as unexpected inhibition or unexpected action. The current theory of unexpected events suggests that such unexpected events just like global stopping recruit a fronto-basal-ganglia network. A global suppressive effect impacting ongoing motor responses and cognition is specifically attributed to the subthalamic nucleus (STN). Previous studies either used separate tasks or presented unexpected, task-unrelated stimuli during response inhibition tasks to relate the neural signature of unexpected events to that of stopping. Here, we aimed to test these predictions using a within task design with i…
Beyond the amygdala: Linguistic threat modulates peri-sylvian semantic access cortices
2015
In this study, healthy volunteers were scanned using functional magnetic resonance imaging (fMRI) to investigate the neural systems involved in processing the threatening content conveyed via visually presented “threat words.” The neural responses elicited by these words were compared to those elicited by matched neutral control words. The results demonstrate that linguistic threat, when presented in written form, can selectively engage areas of lateral temporal and inferior frontal cortex, distinct from the core language areas implicated in aphasia. Additionally, linguistic threat modulates neural activity in visceral/emotional systems (amygdala, parahippocampal gyrus and periaqueductal gr…