Publications by authors named "Peter Erhard"

Background: Impulsivity resulting in unrestrained eating has been implicated as a contributing factor for obesity. Delay discounting (DD) tasks where individuals choose between a smaller immediate reward and a larger delayed reward provide useful data to describe impulsive decision-making and to determine the extent to which delayed rewards are discounted.

Objective: To study the association between body mass index(BMI) and delay discounting for food and money in adult women.

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Childhood obesity is a rising problem caused in part by unhealthy food choices. Food choices are based on a neural value signal encoded in the ventromedial prefrontal cortex, and self-control involves modulation of this signal by the dorsolateral prefrontal cortex (dlPFC). We determined the effects of development, body mass (BMI Cole score) and body mass history on the neural correlates of healthy food choice in children.

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The sensitivity to subject motion is one of the major challenges in functional MRI (fMRI) studies in which a precise alignment of images from different time points is required to allow reliable quantification of brain activation throughout the scan. Especially the long measurement times and laborious fMRI tasks add to the amount of subject motion found in typical fMRI measurements, even when head restraints are used. In case of moving subjects, prospective motion correction can maintain the relationship between spatial image information and subject anatomy by constantly adapting the image slice positioning to follow the subject in real time.

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Objectives: Neuroimaging data suggest that pediatric overweight and obesity are associated with morphological alterations in gray matter (GM) brain structures, but previous studies using mainly voxel-based morphometry (VBM) showed inconsistent results. Here, we aimed to examine the relationship between youth obesity and the volume of predefined reward system structures using magnetic resonance (MR) volumetry. We also aimed to complement volumetry with VBM-style analysis.

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Background: Memory performance of an individual (within the age range: 50-55 years old) showing superior memory abilities (protagonist PR) was compared to an age- and education-matched reference group in a historical facts ("famous events") retrieval task.

Results: Contrasting task versus baseline performance both PR and the reference group showed fMRI activation patterns in parietal and occipital brain regions. The reference group additionally demonstrated activation patterns in cingulate gyrus, whereas PR showed additional widespread activation patterns comprising frontal and cerebellar brain regions.

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Learning new motor skills is important for everyday life and independent living in older age. While studies on motor sequence learning and motor adaptation revealed age differences that are mostly related to frontal decline with increasing age, data for fine finger force modulation are missing. Twelve young (YA, 18-28 years) and twelve middle-aged older (OA, 55-65 years) adults practiced a force modulation task in precision grip while lying in a 3T MR scanner.

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When two tasks are performed simultaneously, performance often declines in one or both tasks. These so-called dual-task costs are more pronounced in old than in young adults. One proposed neurological mechanism of the dual-task costs is that old compared with young adults tend to execute single-tasks with higher brain activation.

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Objective: Neurobiological models of depression posit limbic hyperactivity that should normalize after successful treatment. For psychotherapy, though, brain changes in patients with depression show substantial variability. Two critical issues in relevant studies concern the use of unspecific stimulation experiments and relatively short treatment protocols.

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The combination of the principles of two fast spectroscopic imaging (SI) methods, spectroscopic missing pulse steady-state free precession and echo planar SI (EPSI) is described as an approach toward fast 3D SI. This method, termed missing pulse steady-state free precession echo planar SI, exhibits a considerably reduced minimum total measurement time T(min), allowing a higher temporal resolution, a larger spatial matrix size, and the use of k-space weighted averaging and phase cycling, while maintaining all advantages of the original spectroscopic missing pulse steady-state free precession sequence. The minor signal-to-noise ratio loss caused by using oscillating read gradients can be compensated by applying k-space weighted averaging.

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Savants and prodigies are individuals with exceptional skills in particular mental domains. In the present study we used functional magnetic resonance imaging to examine neural correlates of calendar calculation in two individuals, a savant with Asperger's disorder and a self-taught mathematical prodigy. If there is a modular neural organization of exceptional performance in a specific mental domain, calendar calculation should be reflected in a considerable overlap in the recruitment of brain circuits across expert individuals.

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Objectives: In the search for neurobiological correlates of depression, a major finding is hyperactivity in limbic-paralimbic regions. However, results so far have been inconsistent, and the stimuli used are often unspecific to depression. This study explored hemodynamic responses of the brain in patients with depression while processing individualized and clinically derived stimuli.

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Visualizing emotionally loaded pictures intensifies peripheral reflexes toward sudden auditory stimuli, suggesting that the emotional context may potentiate responses elicited by novel events in the acoustic environment. However, psychophysiological results have reported that attentional resources available to sounds become depleted, as attention allocation to emotional pictures increases. These findings have raised the challenging question of whether an emotional context actually enhances or attenuates auditory novelty processing at a central level in the brain.

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There is accumulating evidence suggesting that the visual representation of facial affect is closely linked to its motor representation. To examine whether perception of pleasant facial affect involves neural circuitries associated with its production, we performed an fMRI experiment with 'compressed image acquisition' where subjects smiled and observed movies depicting other people smiling within scan-free time intervals between the acquisition of each image volume. Overlaps between the brain activation during observation and execution of smile expressions were located in the right premotor cortex and pars opercularis of the inferior frontal gyrus, right parietal operculum (SII) and left anterior insula.

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The inability to imitate gestures is an essential feature of apraxia. However, discrepancies exist between clinical studies in apraxic patients and neuroimaging findings on imitation. We therefore aimed to investigate: (1) which areas are recruited during imitation under conditions similar to clinical tests for apraxic deficits; (2) whether there are common lateralized areas subserving imitation irrespective of the acting limb side; and also (3) whether there are differences between hand and finger gestures.

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Surprise is one of six emotions having a specific and universally recognized facial expression. Functional imaging and neuropsychologic studies have uncovered partly separable neural substrates for perceiving different facial expressions; however, the functional neuroanatomy of perceiving surprised faces has not yet been investigated. Using functional magnetic resonance imaging (fMRI), we aimed to identify the neural substrate of surprise perception from facial expressions.

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To investigate the cerebral organization for language production across the particular channels supporting linguistic behavior, a functional magnetic resonance (fMRI) study was conducted in deaf native users of American Sign Language (ASL) and age-matched hearing controls. Seven native ASL speakers and 15 vocal English speaking subjects covertly performed an object naming task inside the 4 T scanner using their native languages ASL or English, respectively. In subjects of both groups, classical language areas were found to be activated, including posterior Broca's area, the anterior insula, premotor cortex, and the posterior parts of the superior temporal cortex.

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Bimanual motor coordination is essential for piano playing. The functional neuronal substrate for high-level bimanual performance achieved by professional pianists is unclear. We compared professional pianists to musically naïve controls while carrying out in-phase (mirror) and anti-phase (parallel) bimanual sequential finger movements during functional magnetic resonance imaging (fMRI).

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Neuroimaging studies with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) have delineated a human pain network in vivo. Despite the recognition of cerebral structures engaged in pain transmission, the cerebral mechanisms involved in pain modulation are still not well understood. Here, we investigated healthy volunteers using fMRI during experimental heat pain and distraction induced by a visual incongruent color-word Stroop task.

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Functional characterisation of higher order motor systems can be obtained by modulating the processing demands imposed onto relevant motor circuitries. Here we performed whole-brain functional magnetic resonance imaging (fMRI) and parametric statistical analyses in eight healthy volunteers to study task-related recruitment of motor circuits associated with unilateral finger movement sequences of increasing length and complexity, but with equal basic motor parameters. Statistical parametric mapping software was applied for analysis.

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