Search results for "Functional Neuroimaging"
showing 10 items of 32 documents
Neural mechanisms of training an auditory event‐related potential task in a brain–computer interface context
2019
Effective use of brain-computer interfaces (BCIs) typically requires training. Improved understanding of the neural mechanisms underlying BCI training will facilitate optimisation of BCIs. The current study examined the neural mechanisms related to training for electroencephalography (EEG)-based communication with an auditory event-related potential (ERP) BCI. Neural mechanisms of training in 10 healthy volunteers were assessed with functional magnetic resonance imaging (fMRI) during an auditory ERP-based BCI task before (t1) and after (t5) three ERP-BCI training sessions outside the fMRI scanner (t2, t3, and t4). Attended stimuli were contrasted with ignored stimuli in the first-level fMRI…
Motivational factors modulate left frontoparietal network during cognitive control in cocaine addiction
2020
Cocaine addiction is characterized by alterations in motivational and cognitive processes involved in goal-directed behavior. Recent studies have shown that addictive behaviors can be attributed to alterations in the activity of large functional networks. The aim of this study was to investigate how cocaine addiction affected the left frontoparietal network during goal-directed behavior in a stop-signal task (SST) with reward contingencies by correct task performance. Twenty-eight healthy controls (HC) and 30 abstinent cocaine-dependent patients (ACD) performed SST with monetary reward contingencies while undergoing a functional magnetic resonance imaging scan. The results showed that the l…
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…
Brain Function and Upper Limb Outcome in Stroke: A Cross-Sectional fMRI Study
2015
Objective The nature of changes in brain activation related to good recovery of arm function after stroke is still unclear. While the notion that this is a reflection of neuronal plasticity has gained much support, confounding by compensatory strategies cannot be ruled out. We address this issue by comparing brain activity in recovered patients 6 months after stroke with healthy controls. Methods We included 20 patients with upper limb paresis due to ischemic stroke and 15 controls. We measured brain activation during a finger flexion-extension task with functional MRI, and the relationship between brain activation and hand function. Patients exhibited various levels of recovery, but all we…
Disturbed structural connectivity is related to inattention and impulsivity in adult attention deficit hyperactivity disorder
2010
Inattention and impulsivity are the most prominent clinical features of attention deficit hyperactivity disorder (ADHD) in adulthood. Structural and functional neuroimaging studies of subjects with ADHD have demonstrated abnormalities in several brain areas, including fronto-striatal and fronto-cerebellar networks. Mostly, these studies were based on volumetric measurements and have been conducted in children. We investigated white matter (WM) integrity and correlation with measures of attention and impulsivity in adult patients with ADHD adopting diffusion tensor imaging (DTI). N = 37 (21 males) never-medicated adult patients with ADHD combined subtype and N = 34 (16 males) healthy control…
Prefrontal and temporo-parietal involvement in taking others' perspective: TMS evidence.
2008
INTRODUCTION: Understanding the mental states of others entails a number of cognitive processes known as Theory of Mind (ToM). Behavioural and functional neuroimaging evidence suggests that prefrontal and temporo-parietal cortices are involved in these abilities. The present study was aimed at investigating the role of the dorsolateral prefrontal cortex and temporo-parietal junction in ToM by using a repetitive transcranial magnetic stimulation (rTMS) paradigm. MATERIAL AND METHODS: Eleven healthy subjects participated in the study. The experimental ToM procedure was constituted by false belief and faux-pas written stories. Subjects were evaluated in baseline condition (Sham) and after 1Hz …
Opiate-induced dopamine release is modulated by severity of alcohol dependence: an [(18)F]fallypride positron emission tomography study.
2011
Background Preclinical data implicate the reinforcing effects of alcohol to be mediated by interaction between the opioid and dopamine systems of the brain. Specifically, alcohol-induced release of β-endorphins stimulates μ-opioid receptors (MORs), which is believed to cause dopamine release in the brain reward system. Individual differences in opioid or dopamine neurotransmission have been suggested to be responsible for enhanced liability to abuse alcohol. In the present study, a single dose of the MOR agonist remifentanil was administered in detoxified alcohol-dependent patients and healthy control subjects to mimic the β-endorphin-releasing properties of ethanol and to assess the effect…
Theragnostic Use of Radiolabelled Dota-Peptides in Meningioma: From Clinical Demand to Future Applications.
2019
Meningiomas account for approximately 30% of all new diagnoses of intracranial masses. The 2016 World Health Organization’s (WHO) classification currently represents the clinical standard for meningioma’s grading and prognostic stratification. However, watchful waiting is frequently the chosen treatment option, although this means the absence of a certain histological diagnosis. Consequently, MRI (or less frequently CT) brain imaging currently represents the unique available tool to define diagnosis, grading, and treatment planning in many cases. Nonetheless, these neuroimaging modalities show some limitations, particularly in the evaluation of skull base lesions. The emerging evidence supp…
Frontocingular Dysfunction in Bulimia Nervosa when Confronted with Disease-specific Stimuli
2011
Objective Bulimia nervosa (BN) is characterized by dysregulation of impulse control, in other words, uncontrolled eating. Functional neuroimaging studies have been sparse and have used variable methodologies. Method Thirteen medication-free female BN patients and 13 female healthy controls were investigated by functional magnetic resonance imaging using a disease-specific food paradigm. Stimuli were rated after the scanning procedure. Results Bulimia nervosa patients showed increased fear ratings and a trend for increased disgust. Magnetic resonance imaging data of 10 BN patients could be analysed. Three BN patients had to be excluded from the analysis because of minimal blood oxygen level …
Functional Changes in Brain Activity After Hypnosis: Neurobiological Mechanisms and Application to Patients with a Specific Phobia—Limitations and Fu…
2019
Studies of brain-plasticity changes in hypnosis using functional magnetic resonance imaging (fMRI), positron-emission-tomography (PET) and electroencephalography (EEG) were reviewed. The authors found evidence in those studies that hypnosis is a powerful and successful method for inhibiting the reaction of the fear circuitry structures. Limitations of the studies were critically discussed, and implications for future research were made. The authors are currently using a portable fNIRS apparatus to integrate the scanning device into real life situations in medical practice. Their aim is to disentangle the neuronal mechanisms and physiological correlates in patients with severe fear of medica…