Publications by authors named "Schmalbrock P"

In the literature on human action control, the binding and retrieval of responses are assumed to shape the coordination of more complex actions. Specifically, the consecutive execution of two responses is assumed to result in their integration into cognitive representations (so-called event files) and can be retrieved from that upon later response repetition, thereby influencing behavior. Against the background of ideomotor theory and more recent theorizing in the binding and retrieval in action control framework (Frings et al.

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The literature on action control is rife with differences in terminology. This consensus statement contributes shared definitions for perception-action integration concepts as informed by the framework of event coding.

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In the literature on human action control, it is assumed that features of stimuli (S) and responses (R) are integrated into internal representations (so-called event files) that are involved in the execution of an action. Experimentally, the impact of this integration on action control is typically analyzed via S-R binding effects. Recent theorizing in the BRAC framework (Frings et al.

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The ability to inhibit an already initiated response is crucial for navigating the environment. However, it is unclear which characteristics make stop-signals more likely to be processed efficiently. In three consecutive studies, we demonstrate that stop-signal modality and location are key factors that influence reactive response inhibition.

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Article Synopsis
  • Target localization is influenced by the presence of landmarks, leading to systematic shifts toward these landmarks in both visual and tactile modalities.
  • Research indicates that rather than averaging inputs from different senses, perceptual accuracy improves through optimal integration of multisensory information.
  • Experiments showed that landmark distortions were reduced when targets were presented in a different modality, with tactile targets exhibiting more pronounced changes than visual targets, suggesting multisensory integration plays a key role in how we perceive stimuli.
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In action-control research, typically, stimulus sparse displays are used. This might be one reason why previous theorizing focuses on the (top-down) demands of response selection (e.g.

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There is growing consensus that stimulus-response bindings (event files) play a central role in human action control. Here, we investigated how the integration and the retrieval of event files are affected by the predictability of stimulus components of event files. We used the distractor-response binding paradigm, in which nominally task-irrelevant distractors are repeated or alternated from a prime to a probe display.

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Nowadays there is consensus that stimulus and response features are partially represented in the same coding format furthering the binding of these features into event files. If some or all features comprised in an event file repeat later, the whole file can be retrieved thereby modulating ongoing performance (leading to so-called stimulus-response binding effects). Stimulus-response binding effects are usually investigated in sequential priming paradigms where it is assumed that binding occurs in the prime and retrieval in the probe.

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Stimulus and response features are linked together into an event file when a response is made towards a stimulus. If some or all linked features repeat, the whole event file (including the previous response) is retrieved, thereby affecting current performance (as measured in so-called binding effects). Applying the figure-ground segmentation principle to such action control experiments, previous research showed that only stimulus features that have a figure-like character led to binding effects, while features in the background did not.

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Experience-dependent white matter plasticity offers new potential for rehabilitation-induced recovery after neurotrauma. This first-in-human translational experiment combined myelin water imaging in humans and genetic fate-mapping of oligodendrocyte lineage cells in mice to investigate whether downhill locomotor rehabilitation that emphasizes eccentric muscle actions promotes white matter plasticity and recovery in chronic, incomplete spinal cord injury (SCI). In humans, of 20 individuals with SCI that enrolled, four passed the imaging screen and had myelin water imaging before and after a 12-week (3 times/week) downhill locomotor treadmill training program (SCI + DH).

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We can use information derived from passing time to anticipate an upcoming event. If time before an event varies, responses towards this event become faster with increasing waiting time. This variable-foreperiod effect has been often observed in response-speed studies.

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Purpose: To develop a non-invasive MRI-based methodology to visually and quantitatively assess the impact of head and chest rotations on the airway caliber.

Methods: An MRI table set-up was developed for independent rotations of the head and chest along B field and tested for feasibility using phantom scans. The accuracy of the head and chest rotations was validated with ten volunteer scans.

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Frontoparietal white matter supports information transfer between brain areas involved in complex haptic tasks such as somatosensory discrimination. The purpose of this study was to gain an understanding of the relationship between microstructural integrity of frontoparietal network white matter and haptic performance in persons with chronic stroke and to compare frontoparietal network integrity in participants with stroke and age matched control participants. Nineteen individuals with stroke and 16 controls participated.

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Background And Purpose: T2 hypointensity in the basal ganglia of patients with MS has been associated with clinical progression and cognitive decline. Our objectives were the following: 1) to compare signal in T2WI, R2 (ie, 1/T2), and R2* (ie, 1/T2*) relaxation rates and quantitative susceptibility mapping; and 2) to investigate the associations among MR imaging, clinical scores, and cognitive measures of inhibitory control linked to basal ganglia functioning.

Materials And Methods: Twenty-nine patients with MS underwent a battery of neuropsychological tests including the Flanker and Stroop tasks.

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MRI phase imaging in multiple sclerosis (MS) patients and in autopsy tissue have demonstrated the presence of iron depositions in white matter lesions. The accumulation of iron in some but not all lesions suggests a specific, potentially disease-relevant process, however; its pathophysiological significance remains unknown. Here, we explore the role of lesional iron in multiple sclerosis using multiple approaches: immunohistochemical examination of autoptic MS tissue, an in vitro model of iron-uptake in human cultured macrophages and ultra-highfield phase imaging of highly active and of secondary progressive MS patients.

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Article Synopsis
  • The study aimed to evaluate a new 2-week upper extremity sensorimotor training program to improve hand function and quality of life for stroke survivors.
  • Two participants, one with severe sensory impairment and another with mild deficits, underwent 4 hours of training per day, focusing on sensory tasks involving their affected hands.
  • Results showed improved motor function for both, though only the second participant experienced notable sensory improvements, and both displayed indications of neural reorganization through imaging techniques.*
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Purpose: To calculate age-related and per diopter (D) accommodative changes in crystalline lens and ciliary muscle dimensions in vivo in a single cohort of emmetropic human adults ages 30 to 50 years.

Methods: The right eyes of 26 emmetropic adults were examined using ultrasonography, phakometry, anterior segment optical coherence tomography, and high resolution magnetic resonance imaging. Accommodation was measured both subjectively and objectively.

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Purpose: Time-of-flight (ToF) and phase contrast (PC) magnetic resonance angiographies (MRAs) are noninvasive applications to depict the cerebral arteries. Both approaches can image the cerebral vasculature without the administration of intravenous contrast. Therefore, it is used in routine clinical evaluation of cerebrovascular diseases, e.

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Article Synopsis
  • The study aimed to evaluate the effectiveness of a specialized eye coil at 7 Tesla (7 T) for imaging the back of the eye and its vascular structures.
  • Eight subjects were imaged using advanced techniques that optimized parameters for capturing detailed eye structures at high resolution.
  • The results showed that the eye coil successfully visualized important eye features and blood vessels clearly, even with some imaging challenges, and highlighted that gadolinium contrast did not significantly enhance image quality.
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Background: Nearly half of stroke patients have impaired sensory discrimination, however, the neural structures that support post-stroke sensory function have not been described.

Objectives: 1) To evaluate the role of the primary somatosensory (S1) cortex in post-stroke sensory discrimination and 2) To determine the relationship between post-stroke sensory discrimination and structural integrity of the sensory component of the superior thalamic radiation (sSTR).

Methods: 10 healthy adults and 10 individuals with left hemisphere stroke participated.

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Cortical lesions have recently been a focus of multiple sclerosis (MS) MR research. In this study, we present a white matter signal attenuating sequence optimized for cortical lesion detection at 7 T. The feasibility of white matter attenuation (WHAT) for cortical lesion detection was determined by scanning eight patients (four relapsing/remitting MS, four secondary progressive MS) at 7 T.

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Recent research revealed decreased access to semantic and associative networks in acute cocaine withdrawal. In autism, such behavioral outcomes are associated with decreased functional connectivity using functional magnetic resonance imaging. Therefore, we wished to determine whether connectivity is also decreased in acute cocaine withdrawal.

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Magnetic resonance imaging of cortical lesions due to multiple sclerosis (MS) has been hampered by the lesions' small size and low contrast to adjacent, normal-appearing tissue. Knowing cortical lesion T1 and proton density (PD) would be highly beneficial for the process of developing and optimizing dedicated magnetic resonance (MR) sequences through computer modeling of MR tissue responses. Eight patients and seven healthy control subjects were scanned at 7 T using a series of inversion recovery turbo field echo scans with varying inversion times.

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Respiratory motion and capnometry monitoring were performed during blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) of the brain while a series of paced hyperventilation tasks were performed that caused significant hypocapnia. Respiration volume per time (RVT) and end-tidal carbon dioxide (ETCO(2)) were determined and compared for their ability to explain BOLD contrast changes in the data. A 35% decrease in ETCO(2) was observed along with corresponding changes in RVT.

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This study quantified the impact of the well-known physiologic noise correction algorithm RETROICOR applied to a pain functional magnetic resonance imaging (FMRI) experiment at two field strengths: 1.5 and 3.0 T.

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