We recorded frontal, central and parietal somatosensory evoked potentials (SEPs) to median nerve stimulation in 20 patients with Huntington's disease (HD) and in a group of normal controls. Two stimulus repetition rates, 1 Hz and 5 Hz, were employed. In HD patients the early cortical potentials (latency range 20-30 ms) at all 3 recording locations were replaced by a widespread, broadly configured N20-25 deflection, while later potentials at 40-80 ms did not significantly differ from those of normals. In contrast to the early P22, P27 and N30 potentials in normals, the N20-25 potential in the patients was not significantly modified by changing the stimulus repetition rate. At 40-80 ms the stimulus rate effects were similar in the patients and normals. The results show that early pre- and postcentral SEPs are both pathological in HD, while later frontal and parietal components can be totally preserved. The early N20-25 in HD is possibly a subcortical potential, seen due to unmasking in the absence of early cortical deflections.
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http://dx.doi.org/10.1016/0022-510x(93)90315-p | DOI Listing |
J Cogn Neurosci
January 2025
Universidade de Lisboa, Lisbon, Portugal.
Behavioral research has shown that inconsistency in spelling-to-sound mappings slows visual word recognition and word naming. However, the time course of this effect remains underexplored. To address this, we asked skilled adult readers to perform a 1-back repetition detection task that did not explicitly involve phonological coding, in which we manipulated lexicality (high-frequency words vs.
View Article and Find Full Text PDFMem Cognit
January 2025
Department of Neurology, University of California Davis, Sacramento, CA, 95816, USA.
In cognitive psychology, research on attention is shifting from focusing primarily on how people orient toward stimuli in the environment toward instead examining how people orient internally toward memory representations. With this new shift the question arises: What factors in the environment send attention inward? A recent proposal is that one factor is cue familiarity-detection (Cleary, Irving & Mills, Cognitive Science, 47, e13274, 2023). Within this theoretical framework, we reinterpret a decades-old empirical pattern-a primacy effect in memory for repetitions-in a novel way.
View Article and Find Full Text PDFSci Rep
January 2025
School of Biological Sciences, Georgia Institute of Technology, 315 Ferst Dr NW, Atlanta, 30332-0535, GA, USA.
iScience
December 2024
Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Neural representations for visual stimuli typically emerge with a bilateral distribution across occipitotemporal cortex (OTC)? Pediatric patients undergoing unilateral OTC resection offer an opportunity to evaluate whether representations for visual stimulus individuation can sufficiently develop in a single OTC. Here, we assessed the non-resected hemisphere of patients with pediatric resection within ( = 9) and outside ( = 12) OTC, as well as healthy controls' two hemispheres ( = 21). Using functional magnetic resonance imaging, we mapped category selectivity (CS), and representations for visual stimulus individuation (for faces, objects, and words) with repetition suppression (RS).
View Article and Find Full Text PDFAm J Physiol Cell Physiol
December 2024
Muscle Health Research Centre, School of Kinesiology & Health Science, Faculty of Health, York University, Toronto, ON, Canada.
High-load resistance exercise (>60% of 1-repetition maximum) is a well-known stimulus to enhance skeletal muscle hypertrophy with chronic training. However, studies have intriguingly shown that low-load resistance exercise training (RET) (≤60% of 1-repetition maximum) can lead to similar increases in skeletal muscle hypertrophy as compared to high-load RET. This has raised questions about the underlying mechanisms for eliciting the hypertrophic response with low-load RET.
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