{"title":"Frontal midline theta power accounts for inter-individual differences in motor learning ability.","authors":"Yuya Fukuda, Kazumasa Uehara","doi":"10.1007/s00221-025-07096-7","DOIUrl":"10.1007/s00221-025-07096-7","url":null,"abstract":"<p><p>Recent neurophysiological studies have demonstrated that frontal midline theta (FMT) activity plays a significant role in motor learning. One of the key challenges in motor learning is to understand the interindividual variability in learning proficiency rates, yet the underlying neural mechanisms remain unclear. To address this open question, this study recorded electroencephalogram activity from twenty-one healthy participants during a visuomotor tracking task to investigate whether modulation of FMT power and the theta phase synchronization across trials (theta phase consistency) during motor preparation could explain individual differences in learning proficiency. We found a significant positive correlation between increased FMT power during motor preparation and learning proficiency rates. Specifically, individuals with greater FMT power exhibited faster learning rates. In contrast, no significant correlation was observed between the consistency of the theta phase during motor preparation and learning proficiency. Together, these findings highlight that the FMT power, rather than phase synchrony, is closely associated with motor learning efficiency. This study provides a novel perspective for understanding the causes of individual differences in motor learning and further corroborates the previous evidence showing FMT power contributes to motor learning processes.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"147"},"PeriodicalIF":1.7,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12081585/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144077046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Can Wang, Zhijun Zhang, Yejin Chen, Mengzhu Huang, Rixin Tang
{"title":"Institutional position words influence the power grasp of East Asians.","authors":"Can Wang, Zhijun Zhang, Yejin Chen, Mengzhu Huang, Rixin Tang","doi":"10.1007/s00221-025-07103-x","DOIUrl":"10.1007/s00221-025-07103-x","url":null,"abstract":"<p><p>Power perceptions reflect citizens' attitudes toward social hierarchies and power inequality, whereas power metaphors reflect the cognitive process of a personal sense of power. This study examines the influence of power representations on grasp aperture in East Asian participants. In experiment 1 (n = 34), we investigated whether powerful institutional position words trigger larger grasp apertures compared to less powerful words, indicating a correlation between power and spatial dimensions. Our results demonstrate that powerful words indeed led to larger grasp apertures, suggesting a direct association between power and size representation. In experiment 2 (n = 20), the results indicate that this effect persisted even when institutional positions were not described by size-related language. These findings suggest the existence of power representations within a generalized magnitude system, influenced by relative rather than absolute size. This research sheds light on how abstract concepts, such as power, are integrated into cognitive processes related to spatial perception.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"146"},"PeriodicalIF":1.7,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144077048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Catho Schoenmaekers, Dario De Smet, Stefaan Peeters, Andrzej Zarowski, Choi Deblieck, Floris L Wuyts
{"title":"Galvanic vestibular stimulation for Mal de Debarquement syndrome: a pilot study on therapeutic potential.","authors":"Catho Schoenmaekers, Dario De Smet, Stefaan Peeters, Andrzej Zarowski, Choi Deblieck, Floris L Wuyts","doi":"10.1007/s00221-025-07102-y","DOIUrl":"10.1007/s00221-025-07102-y","url":null,"abstract":"<p><p>Mal de Debarquement Syndrome (MdDS) is a debilitating neuro-otological disorder causing a persistent sensation of self-motion, often triggered by passive motion like being on a boat (MT-MdDS) or non-motion triggered (non-MT MdDS). Due to the unknown pathophysiological mechanism, available treatment options for managing symptoms are limited. Within the framework of a pilot study, our objective was to investigate the effect, safety, and feasibility of galvanic vestibular stimulation (GVS) as a potential alternative treatment option for MdDS. The trial included 12 MdDS patients and 12 controls. In Part 1, the perceptual threshold for movement perception was determined using both sine and noisy (white noise) GVS for both patients and controls. In Part 2, patients received up to eight four-minute GVS at varying intensities, determined by their individual threshold, during both sine and noisy GVS (i.e., at their threshold, 120%, 70%, and 20%). The effectiveness was evaluated using visual analogue scale (VAS) scores and static posturography. Five patients reported improvement with noisy GVS at 70%, two at noisy threshold, one at noise 20%, one at 120%, one at sine 20%, and one at sine 120%. Our findings show statistically significant positive trends in both subjective and objective outcome measures following specific GVS sessions. Particularly, notable improvements were observed with noisy GVS at intensities 70% and 20% below perceptual threshold levels. All patients found GVS to be safe and manageable, with no worsening of their symptoms. GVS demonstrated positive trends in posturographic stability, particularly with 70% currents and noisy GVS. While further research is necessary, the potential benefits, safety, and feasibility of GVS for MdDS patients have been demonstrated as promising.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"145"},"PeriodicalIF":1.7,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12078377/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144077047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amy Siobhan Millard, Irene Sperandio, Philippe A Chouinard
{"title":"The size-distance scaling of real objects and afterimages is equivalent in typical but not reduced visual environments.","authors":"Amy Siobhan Millard, Irene Sperandio, Philippe A Chouinard","doi":"10.1007/s00221-025-07064-1","DOIUrl":"10.1007/s00221-025-07064-1","url":null,"abstract":"<p><p>Size constancy refers to the human ability to perceive an object as having the same size, despite changes in its retinal image caused by variations in viewing distance. The relationship between perceived size and perceived distance is predicted by Emmert's law. This study investigated whether the principles of size constancy apply in the same way to afterimages and real objects, hypothesising that perceptual equivalency would result in consistent size-distance scaling constancy for both types of stimuli. Twenty participants completed a size judgment task involving real objects and afterimages presented under binocular, monocular, and complete darkness conditions. Results showed that both types of stimuli adhered to Emmert's law under binocular conditions; however, afterimages exhibited greater deviations in monocular and dark environments, indicating a breakdown in size constancy. While real objects maintained perceptual scaling even in reduced environments, afterimages displayed diminished accuracy in size and distance perception, especially in darkness. The findings support the signal ambiguity theory, suggesting that afterimages rely more heavily on contextual information due to the lack of stable external references. This study highlights the utility of afterimages as a tool for exploring the limits of visual perception, offering insights into how the visual system handles ambiguous signals.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"144"},"PeriodicalIF":1.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12066382/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143993257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Eye-hand coordination during sequential reaching to uncertain targets: the effect of task difficulty, target width, movement amplitude, and task scaling.","authors":"Adrien Coudiere, Frederic R Danion","doi":"10.1007/s00221-025-07083-y","DOIUrl":"10.1007/s00221-025-07083-y","url":null,"abstract":"<p><p>When making reciprocal hand movements between two fixed/known targets, Fitts' law states that movement time (MT) is a linear function of the index of difficulty (ID) set by the ratio between movement amplitude (A) and target width (W). Crucially ID also impacts eye-hand coordination. However, because known/fixed targets limit the usefulness of eye movements, and because hand dynamics changes drastically with ID (either continuous or discrete), we reexamined this issue using a variant of the Fitts task in which the next target position was assigned randomly and unveiled only when the ongoing target was reached. Practically, hand and eye movements were recorded in participants (N = 25) who had to successively reach 12 circular targets of width W (0.3, 0.6, or 1.2 cm) separated by an amplitude A (5, 10, or 20 cm), allowing to examine IDs ranging from 2.36 to 6.08 bits. Introducing target uncertainty did not alleviate the linear relationship between MT and ID (R<sup>2</sup> = 0.99), neither the impact of ID on hand kinematics. Importantly, the influence of ID on eye-hand coordination persisted. Notably, by cross-correlating eye and hand signals, we show a trade-off between its temporal and spatial aspects. Finally, we found that eye-hand coordination was influenced to a larger extent by A than W, making it prone to task scaling effects (differences in AW combinations resulting in similar ID). Altogether these results reinforce the critical role of task difficulty on eye-hand coordination and the need to simultaneously consider its temporal and spatial aspects.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"143"},"PeriodicalIF":1.7,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143994215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of transcranial direct current stimulation (tDCS) on isometric endurance performance and electromyographic activity of the vastus lateralis in healthy male.","authors":"Geanny Zanirate, Rui Pilon, Antony Araujo Ramos, Humberto Miranda, Gonzalo Marquez, Walace Monteiro, Eduardo Lattari","doi":"10.1007/s00221-025-07062-3","DOIUrl":"10.1007/s00221-025-07062-3","url":null,"abstract":"<p><p>To investigate the effects of anodal tDCS on isometric endurance peformance and sEMG activity of the vastus lateralis in healthy male with experience in resistance training. Fifteen healthy, resistance-trained males aged 18 to 35 participated in three sessions, each separated by one week. The initial session included an maximal isometric voluntary contraction (MIVC) test and familiarization with the fatigue task. In the second and third sessions, conducted randomly, participants underwent either anodal tDCS or placebo tDCS (sham). Immediately after the conditions, the subjects performed the fatigue task for right knee in the horizontal leg-press exercise, consisting of eight, lasting five seconds and having a five-second interval between contractions. The results showed no interaction between conditions and contractions in isometric endurance performance across contractions (p = 0.78) or in the sEMG activity of the vastus lateralis muscle (p = 0.94). The specific anodal tDCS protocol used in this study does not enhance isometric strength endurance or surface electromyographic activity of the vastus lateralis muscle in strength-trained men.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"141"},"PeriodicalIF":1.7,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143981024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuya Matsuda, Mayu Akaiwa, Hidekazu Saito, Satoshi Kudoh, Yasushi Sugawara, Ryo Kurokawa, Rin Kosuge, Eriko Shibata, Takeshi Sasaki, Kazuhiro Sugawara
{"title":"Effects of Go/NoGo stimulus ratio on reaction time, prestimulus preparatory activity, and poststimulus cognitive processing.","authors":"Yuya Matsuda, Mayu Akaiwa, Hidekazu Saito, Satoshi Kudoh, Yasushi Sugawara, Ryo Kurokawa, Rin Kosuge, Eriko Shibata, Takeshi Sasaki, Kazuhiro Sugawara","doi":"10.1007/s00221-025-07063-2","DOIUrl":"10.1007/s00221-025-07063-2","url":null,"abstract":"<p><p>Reaction time (RT) tasks are used extensively to evaluate sensory-motor function for basic research and various clinical applications, so it is critical to identify methodological and environmental factors influencing RT. Further, changes in RT under different conditions may reveal novel aspects of sensory-motor processing. Previous studies have reported that RTs on Go/NoGo tasks can be modulated by changes in Go/NoGo stimulus ratio, potentially by influencing prestimulus preparatory activity and (or) poststimulus cognitive processing. To assess the underlying mechanisms, we measured RT in an S1-S2 version of the Go/NoGo task in which a warning stimulus (S1) preceded Go and NoGo stimuli (S2) delivered at two ratios (Go and NoGo frequencies), NoGo-Rare (25% NoGo/75% Go) and NoGo-Frequent (75% NoGo/25% Go). Simultaneous electroencephalographic recordings were acquired of the contingent negative variation (CNV) as a preparatory activity marker and both NoGoN2 and NoGoP3 as cognitive processing markers. Mean RT was shorter during the NoGo-Rare condition compared to the NoGo-Frequent condition, but there were no significant differences in CNV amplitudes between conditions. Alternatively, significant differences were observed in NoGoN2 amplitude, NoGoN2 latency, and NoGoP3 amplitude between conditions, suggesting that Go/NoGo stimulus ratio alters RT primarily by influencing poststimulus cognitive processing.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"142"},"PeriodicalIF":1.7,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143992714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei-Yeh Liao, Brodie J Hand, Giuseppe Rinaldi, John G Semmler, George M Opie
{"title":"Neuromodulation by repetitive paired-pulse TMS at late I-wave intervals in older adults.","authors":"Wei-Yeh Liao, Brodie J Hand, Giuseppe Rinaldi, John G Semmler, George M Opie","doi":"10.1007/s00221-025-07060-5","DOIUrl":"10.1007/s00221-025-07060-5","url":null,"abstract":"<p><p>The efficacy of indirect (I) wave periodicity repetitive transcranial magnetic stimulation (iTMS) on the excitability of primary motor cortex (M1) in young adults can be modified by changing the late I-wave interval. Given that late I-wave activity is altered in older adults, this could contribute to age-related changes in M1 plasticity. To assess this possibility, the present study investigated the effects of iTMS using three late I-wave intervals (4.0, 4.5, and 5.0 ms) on M1 excitability in 17 older adults (69.6 ± 5.7 years; 10 females), which was compared to findings obtained previously in 17 young adults (27.2 ± 6.4 years, 12 females). Changes in M1 excitability were assessed using motor evoked potentials (MEPs) recorded from the right first dorsal interosseus to index single-pulse MEP<sub>1.0mV</sub> and paired-pulse short-interval intracortical facilitation (SICF). To increase sensitivity to different intracortical circuits, both measures were also recorded using posterior-anterior (PA) and anterior-posterior (AP) TMS currents. Within older adults, PA MEP<sub>1.0mV</sub> and SICF were facilitated following iTMS (both P < 0.0001) and these were not different between iTMS ISIs (both P > 0.077). In contrast, AP MEP<sub>1.0mV</sub> and SICF were potentiated by iTMS<sub>4.0</sub> and iTMS<sub>5.0</sub> (both P < 0.023). iTMS<sub>5.0</sub> potentiation of AP circuits was also increased in older adults compared to young adults (both P < 0.004). These results suggest complex, timing-dependent effects of advancing age on the plasticity of the late I-wave circuits.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"140"},"PeriodicalIF":1.7,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12055644/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Supriyo Choudhury, Anna Baines, Swagata Sarkar, Asit Baran Bayen, Subhajit Sarkar, Mark R Baker, Hrishikesh Kumar, Stuart N Baker
{"title":"Association of a kinematic measure of upper limb reaching and StartReact in chronic hemiparetic stroke.","authors":"Supriyo Choudhury, Anna Baines, Swagata Sarkar, Asit Baran Bayen, Subhajit Sarkar, Mark R Baker, Hrishikesh Kumar, Stuart N Baker","doi":"10.1007/s00221-025-07047-2","DOIUrl":"10.1007/s00221-025-07047-2","url":null,"abstract":"<p><strong>Background: </strong>After stroke, recovery of upper limb reaching movements may partly depend on the level of activation of the reticulospinal tract (RST), but few clinical studies have explored this. Here we examined the association between the strength of reticulospinal connections and extent of reaching in post-stroke patients.</p><p><strong>Methods: </strong>Fifteen patients (all male) with right hemiparesis who had suffered a stroke at least six months prior to the assessment were selected based on predefined selection criteria. Video recordings of the reaching task from the Action Research Arm Test (ARAT) were processed for two-dimensional kinematic analysis using the markerless motion tracking software DeepLabCut. We defined a novel Index of Elbow Extension (IoEE), and validated it by comparison between simultaneously obtained two- and three-dimensional datasets in healthy people. Strength of reticulospinal outputs was estimated using the 'StartReact' paradigm, which measures the speeding up of reaction time by a loud sound cue.</p><p><strong>Results: </strong>We observed a significant negative correlation between the IoEE and StartReact (rho = 0.9, p < 0.05). There was no correlation in this cohort between ARAT and StartReact.</p><p><strong>Conclusion: </strong>We speculate that the negative correlation between reaching performance and StartReact is a consequence of the variable compensatory activation of the reticulospinal tract (RST) in response to different levels of initial damage. This study reinforces the application of freely available computer vision technology for assessment of two- dimensional kinematics in a clinical scenario.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"139"},"PeriodicalIF":1.7,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12055613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143988037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Predictable transcranial magnetic stimulation suppresses corticospinal excitability: a TMS experiment.","authors":"Napat Sriutaisuk, Elizabeth A Franz","doi":"10.1007/s00221-025-07091-y","DOIUrl":"10.1007/s00221-025-07091-y","url":null,"abstract":"<p><p>Motor skill learning plays a crucial role in human functioning and is often studied using transcranial magnetic stimulation (TMS) to assess corticospinal excitability (CSE). CSE, which reflects the motor system's responsiveness, is compared across experimental conditions to determine whether a factor facilitates or inhibits motor skill learning. However, variability in stimulation predictability may confound interpretation of CSE measures. In this study, we examined the impact of TMS predictability on CSE by comparing motor-evoked potential (MEP) responses under predictable and unpredictable conditions. Twenty right-handed participants underwent TMS-EMG recordings while observing either a predictable visual cue (a moving white bar) or an unpredictable visual cue (a static white bar). MEP amplitudes were recorded from the first dorsal interosseous (FDI) muscle and normalized across participants. Results showed that unpredictable TMS produced significantly larger MEP amplitudes compared to predictable stimulation. The findings suggest that the predictability of TMS substantially modulates CSE, potentially confounding the results in previous TMS studies on action observation and motor facilitation. Ensuring consistent stimulation predictability across experimental conditions is therefore essential for accurately interpreting TMS-induced CSE changes.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"243 6","pages":"134"},"PeriodicalIF":1.7,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12050229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143981847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}