Publications by authors named "Kai Lutz"

Background: Learning and learning-related neuroplasticity in motor cortex are potential mechanisms mediating recovery of movement abilities after stroke. These mechanisms depend on dopaminergic projections from midbrain that may encode reward information. Likewise, therapist experience confirms the role of feedback/reward for training efficacy after stroke.

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Aging is associated with a decline in physical functions, cognition and brain structure. Considering that human life is based on an inseparable physical-cognitive interplay, combined physical-cognitive training through exergames is a promising approach to counteract age-related impairments. The aim of this study was to assess the effects of an in-home multicomponent exergame training on [i] physical and cognitive functions and [ii] brain volume of older adults compared to a usual care control group.

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Background: Imaging studies point to a posture (finger vs. hand) and domain-specific neural basis of gestures. Furthermore, modulation of gestures by theta burst stimulation (TBS) may depend on interhemispheric disinhibition.

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Introduction: Motor skill learning can help stroke survivors to cope with motor function deficits but requires many repetitions. One factor that keeps patients motivated is obtaining reward upon successfully completing a motor task. It has been suggested that stroke survivors have deficits in reward processing which may negatively impact skill learning.

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Knowledge about possible brain mechanisms involved in the regulation of exercise intensity has vastly grown over the last decade. The current review attempts to condense this knowledge currently published with a focus on brain imaging studies. A number of psychological manipulations known to influence exercise intensity are discussed with respect to their possibly underlying brain structures.

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Purpose: Methylphenidate (MPH) and other stimulants have been shown to enhance physical performance. However, stimulant research has almost exclusively been conducted in young, active persons with a normal BMI, and may not generalize to other groups. The purpose of this study was to determine whether the ergogenic response to MPH could be predicted by individual level characteristics.

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Background: Fifty percent of all stroke survivors remain with functional impairments of their upper limb. While there is a need to improve the effectiveness of rehabilitative training, so far no new training approach has proven to be clearly superior to conventional therapy. As training with rewarding feedback has been shown to improve motor learning in humans, it is hypothesized that rehabilitative arm training could be enhanced by rewarding feedback.

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Feedback on motor performance activates the striatum and boosting ventral striatum activation with rewarding feedback during motor training supports the consolidation of the learned skill. Aging is associated with changes of the reward system, including striatal and extrastriatal loss of dopamine receptors. How these changes interact with the blood oxygenation level dependent (BOLD) response is, however, not yet fully understood.

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Introduction: A central fatigue theory proposes that force output during fatiguing exercise is limited to maintain homeostasis. The self-awareness of the body's homeostatic state is known as interoception. Brain regions thought to play a role in interoception, such as the insular and orbital frontal cortex, have been proposed as sites for the upstream regulation of fatiguing exercise.

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Background: There is no doubt that good bimanual performance is very important for skilled handball playing. The control of the non-dominant hand is especially demanding since efficient catching and throwing needs both hands.

Methodology/hypotheses: We investigated training-induced structural neuroplasticity in professional handball players using several structural neuroimaging techniques and analytic approaches and also provide a review of the literature about sport-induced structural neuroplastic alterations.

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Experimental fear conditioning in humans is widely used as a model to investigate the neural basis of fear learning and to unravel the pathogenesis of anxiety disorders. It has been observed that fear conditioning depends on stimulus salience and subject vulnerability to fear. It is further known that the prevalence of dental-related fear and phobia is exceedingly high in the population.

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The brain's reactions to error are manifested in several event related potentials (ERP) components, derived from electroencephalographic (EEG) signals. Although these components have been known for decades, their interpretation is still controversial. A current hypothesis (first indicator hypothesis) claims that the first indication of an action being erroneous leads to a negative deflection of the EEG signal over frontal midline areas.

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Objectives: The insular cortex has an important role within the cerebral pain circuitry. The aim of this study was to measure metabolic alterations by MR spectroscopy due to experimentally induced trigeminal pain in the anterior/posterior and right/left insular subdivisions.

Methods: Sixteen male volunteers were investigated using magnetic resonance (MR) spectroscopy before, during and after experimentally induced dental pain.

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Whether an agent receives positive task feedback or a monetary reward, neural activity in their striatum increases. In the latter case striatal activity reflects extrinsic reward processing, while in the former, striatal activity reflects the intrinsically rewarding effects of performing well. There can be a "hidden cost of reward", which is a detrimental effect of extrinsic on intrinsic reward value.

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Aim: Dentine hypersensitivity (DH) is characterized by a short, sharp pain arising from exposed dentin. Most published literature reports on peripheral neural aspects of this pain condition. The current investigation focused on differential cerebral activity elicited by stimulation of sensitive and insensitive teeth by means of natural air stimuli.

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In the present study, intracortical communication between mid/anterior insular and motor cortex was investigated during a fatiguing cycling exercise. From 16 healthy male subjects performing a constant-load test at 60% peak oxygen consumption (VO(2peak)) until volitional exhaustion, electroencephalography data were analysed during repetitive, artefact-free periods of 1-min duration. To quantify fatigue-induced intracortical communication, mean intra-hemispheric lagged phase synchronization between mid/anterior insular and motor cortex was calculated: (i) at the beginning of cycling; (ii) at the end of cycling; and (iii) during recovery cycling.

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Sparse and clustered-sparse temporal sampling fMRI protocols have been devised to reduce the influence of auditory scanner noise in the context of auditory fMRI studies. Here, we report an improvement of the previously established clustered-sparse acquisition scheme. The standard procedure currently used by many researchers in the field is a scanning protocol that includes relatively long silent pauses between image acquisitions (and therefore, a relatively long repetition time or cluster-onset asynchrony); it is during these pauses that stimuli are presented.

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The current fMRI study investigated cortical processing of electrically induced painful tooth stimulation of both maxillary canines and central incisors in 21 healthy, right-handed volunteers. A constant current, 150% above tooth specific pain perception thresholds was applied and corresponding online ratings of perceived pain intensity were recorded with a computerized visual analog scale during fMRI measurements. Lateralization of cortical activations was investigated by a region of interest analysis.

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We investigated the influence of spinal opioid receptor-sensitive muscle afferents on cortical changes following fatiguing unilateral knee-extensor exercise. On separate days, seven subjects performed an identical five sets of intermittent isometric right-quadriceps contractions, each consisting of eight submaximal contractions [63 ± 7% maximal voluntary contraction (MVC)] and one MVC. The exercise was performed following either lumbar interspinous saline injection or lumbar intrathecal fentanyl injection blocking the central projection of spinal opioid receptor-sensitive lower limb muscle afferents.

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In this study, we investigated central/supraspinal processes mediating cessation of a muscle fatiguing exercise. Fifteen male subjects performed 39 intermittent, isometric handgrip contractions (13 s on, 5-6 s off) with the dominant right hand while brain activation was assessed by means of functional magnetic resonance imaging (fMRI). An adaptive, partly stochastic protocol was designed such that in approximately 50% of the contraction trials the required force could not be held until the end of the trial (task failure trial).

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Promises are one of the oldest human-specific psychological mechanisms fostering cooperation and trust. Here, we study the neural underpinnings of promise keeping and promise breaking. Subjects first make a promise decision (promise stage), then they anticipate whether the promise affects the interaction partner's decision (anticipation stage) and are subsequently free to keep or break the promise (decision stage).

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It has been shown that frontal cortical areas increase their activity during error perception and error processing. However, it is not yet clear whether perception of motor errors is processed in the same frontal areas as perception of errors in cognitive tasks. It is also unclear whether brain activity level is influenced by the magnitude of error.

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The purpose of the present study was to examine the impact of the congenital absence of one hand on cortical organization of the sensorimotor cortex (S1/M1). We investigated the tongue representation in S1/M1 in nine participants with normally developed limbs, comprising the control group, and in eight persons with a congenitally completely missing hand (i.e.

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We present the design, construction, and performance of a novel multi-injector gas jet delivery capable of operating in a magnetic resonance imaging environment. This apparatus is computer controlled and built with two separate pneumatic circuits enabling gas jet applications at variable sites through four independently activated injectors. Gas jet delivery is fully controllable in terms of pressure, flow rate, gas temperature, application time, and duration of interstimulus interval.

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