Experimental Brain Research最新文献

{"title":"Haptic illusion during finger-held disk rotation: revisiting a deceptively simple illusion.","authors":"Akira Imai, Patrice Revol, Yves Rossetti","doi":"10.1007/s00221-026-07363-1","DOIUrl":"10.1007/s00221-026-07363-1","url":null,"abstract":"<p><p>The \"disk-rotating\" haptic illusion reported by Cormack (1973), in which a disk or coin held in one hand and turned end over end between thumb and forefinger of the other hand is perceived as longer by the turning hand. This illusion may occur because of the interplay of the rotating and holding hands. To separate the contributions of each hand, two custom-made devices were used to allow independent rotation and holding of the disk. Twenty participants handled disks (30 and 39 mm in diameter), and rotated them for one minute under the following conditions: (a) ordinary use of both hands, (b) using both hands but turning and holding the disk using the two custom-made devices simultaneously, and (c) using only one hand for turning or holding. The magnitude of illusion increased to a level comparable to that reported by Cormack (1973) under conditions (a) and (b). However, under condition (c), the illusion for the rotating hand grew about 25% of those obtained under (a) and (b), with almost no illusion for the holding hand. Nevertheless, reconstruction of the estimated illusion using each magnitude of illusion obtained for the \"one-hand\" conditions of (c), this estimation showed a moderate illusion growing gradually. Rotation by the turning hand may mainly contribute to the illusion, while holding hand is involved with this illusion interactively. The results are discussed along with adaptation, aftereffect, and contrast effect, which may be involved in processing of bimanual signals underlying this illusion.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13401564/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148591059","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":"Baseline mathematical aptitude attenuates group differences in posterior P300 during arithmetic verification in high school athletes.","authors":"Chia-Chi Hsu, Hui-Yu Hsu, Tsu-Jen Ding, Chen-Yu Yao, Zai-Fu Yao","doi":"10.1007/s00221-026-07366-y","DOIUrl":"10.1007/s00221-026-07366-y","url":null,"abstract":"<p><p>Whether the cognitive benefits of athletic training transfer to specific academic domains, such as arithmetic, remains poorly understood. This study investigated the behavioral and electrophysiological (ERP) correlates of multiplication verification in 19 high school cycling athletes and 19 matched controls. Behaviorally, athletes exhibited significantly lower baseline mathematical proficiency (SATM scores), lower accuracy, slower reaction times and poorer processing efficiency. Electrophysiologically, athletes initially demonstrated significantly larger posterior P300 amplitudes than controls. Crucially, these group differences were substantially attenuated after statistically controlling for baseline mathematical proficiency using analysis of covariance (ANCOVA). The findings suggest that arithmetic-related neural processing differences in athletes may be associated with variability in mathematical proficiency rather than reflecting a generalized neurocognitive disadvantage. More broadly, the results support the view that cognitive adaptations associated with athletic expertise may be relatively domain-specific and may not automatically generalize to highly practiced academic skills such as arithmetic verification.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13400475/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148577783","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":"Two distinct modes of ocular drift observed during figure-ground perception.","authors":"August Romeo, Maria Solé Puig, Hans Supèr","doi":"10.1007/s00221-026-07320-y","DOIUrl":"10.1007/s00221-026-07320-y","url":null,"abstract":"<p><p>Precise coordination between neurons and cortical areas is crucial for sensory perception, yet in vision, continuous fixational eye movements constantly shift retinal input. Traditionally considered random, these drifts modulate neural activity and may challenge the temporal precision needed for perceptual integration, particularly given their partial interocular independence. Recent evidence suggests that ocular drifts are not purely stochastic and play an active role in visual processing. Here, we investigated the impact of fixational eye movements on visual perception using a figure-ground segmentation task. Participants maintained central fixation while viewing textures composed of oriented line segments and reported the presence or absence of a centrally embedded figure. We simultaneously recorded binocular drift and microsaccades, analyzing interocular coordination through 2D cross-correlograms of angular velocities. We found that figure-presents trials exhibited narrow peaks in interocular correlation, while figure-absent trials showed broader, less synchronized drift patterns. Microsaccades were observed to facilitate drift alignment across the eyes. The decrease in microsaccade rate in figure-present trials may contribute to the change in drift synchrony, but it is not required for it. Changes in eye synchrony are also observed under monocular viewing conditions, whereas variations in accommodation and pupil size appear to be unrelated. These results identify two distinct ocular drift modes associated with different perceptual outcomes. Our findings suggest that ocular drift operates under closed-loop control and contributes to effective visual processing.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13396028/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148561271","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":"Stability of movement by a multi-element system: drifts and random walk within and orthogonal to the uncontrolled manifold during multi-finger force production.","authors":"Sayan Deep De, Mark L Latash","doi":"10.1007/s00221-026-07362-2","DOIUrl":"10.1007/s00221-026-07362-2","url":null,"abstract":"<p><p>We tested one of the central assumptions of the uncontrolled manifold (UCM) hypothesis, that stability within and orthogonal to the UCM differs in a task-specific way. This was done by exploring the effects of visual feedback on the fast random walk (RW) and slow drifts during multi-finger force production. Healthy participants used the index and middle fingers of both hands to produce an accurate total force magnitude with different initial sharing of the force between the hands. After 5 s, visual feedback was manipulated-kept for both force and sharing, for only one of those variables, or turned off. The subjects tried to keep their performance unchanged for 55 s. Trajectories both along and orthogonal to the UCM for total force showed fast RW and slow drifts. The diffusion plots confirmed persistent RW within the first 0.2 s and anti-persistent RW after 0.5 s. Persistent RW was similar across visual feedback conditions and larger orthogonal to the UCM. Its Hurst index correlated between the UCM and orthogonal to the UCM direction across participants. Anti-persistent RW depended strongly on visual feedback. Drift magnitude and characteristic time depended strongly on visual feedback, being similar along and orthogonal to the UCM. We conclude that RW destabilizes the state of the system, thus encouraging exploration of nearby states over short time intervals, and contributes to its stability over larger time intervals. Visual feedback plays a more important role in structuring the stability of performance compared to the explicit task formulation. RW and drift exploration promise new insights into the organization of stability in abundant systems and a potential biomarker for clinical studies.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13391454/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148561234","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":"Baby face enlarges perceived reachable space.","authors":"Naoki Kuroda, Shinya Harada, Rena Morii, Wataru Teramoto","doi":"10.1007/s00221-026-07353-3","DOIUrl":"10.1007/s00221-026-07353-3","url":null,"abstract":"<p><p>Humans perceive reachable space (RS), the space within which they judge themselves to be able to touch or grasp an object or another person when extending their arms. Previous studies have reported that perceived RS toward another person expands when the person displays an angry facial expression, suggesting that humans adjust their interaction range based on others' facial characteristics. However, how babies' faces which have cuteness as a characteristic influences perceived RS remains unclear. This study investigated the effect of baby faces and the cuteness of others' faces on perceived RS. Two experiments were conducted using facial stimuli of babies and younger adults in a virtual reality environment. Experiment 1 measured perceived RS by focusing on facial cuteness, whereas Experiment 2 examined whether the results of Experiment 1 could be explained by the size constancy of the face stimuli. Experiment 2 also measured the perceived distance of the face stimuli. Participants judged whether they could reach the face stimuli at various distances while being instructed not to move their actual hands. The results of Experiment 1 demonstrated that perceived RS was not modulated by facial cuteness but was significantly larger for baby faces than for younger adult faces. Experiment 2 replicated the results of Experiment 1 and showed that size constancy did not account for perceived RS differences between face age conditions because perceived distances did not differ significantly between face age conditions. These findings suggest that baby faces, rather than facial cuteness, contribute to the expansion of perceived RS.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148548355","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":"Distance-dependent modulation of sensory attenuation during motor imagery and overt action.","authors":"Kyung-Bok Lee, Hee-Tae Cho, Dong-Chan Huh, Ji-Hang Lee","doi":"10.1007/s00221-026-07357-z","DOIUrl":"10.1007/s00221-026-07357-z","url":null,"abstract":"<p><p>Motor imagery is thought to engage forward models that predict the sensory consequences of action, but it remains unclear whether these predictions exhibit the same spatial tuning as those during overt movement. The present study examined how sensory attenuation varies as a function of spatial separation during executed and imagined actions. Twelve participants performed a force-matching task under baseline, pressing, and imagery conditions while the distance between the acting and receiving fingers was manipulated (0, 12.5, 25 cm). Sensory attenuation was quantified as force reproduction error relative to baseline. Results revealed a significant Distance × Condition interaction. Polynomial trend analyses indicated that force reproduction error increased linearly with distance in all conditions, but at different rates: attenuation during overt pressing declined more steeply with distance and was largely absent at 25 cm, whereas attenuation during motor imagery decreased more gradually and was maintained across larger separations. These findings suggest that motor imagery and overt action engage predictive mechanisms with somewhat different spatial characteristics, consistent with the view that forward model precision is influenced by the availability of movement-related sensory feedback.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520006","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":"Limb-specific modulation of muscle synergies and segmental coordination during curved running.","authors":"Raphael M Mesquita, Thibaut D Toussaint, Patrick A Willems, Arthur H Dewolf","doi":"10.1007/s00221-026-07361-3","DOIUrl":"10.1007/s00221-026-07361-3","url":null,"abstract":"<p><p>Curved running imposes asymmetrical mechanical demands on the lower-limbs and thus provides a model to test the adaptability of the locomotor system. This study examined how curved running alters neuromuscular modularity and lower-limb intersegmental coordination relative to straight-line running. Surface EMG recordings from 14 bilateral lower-limb muscles were analysed using non-negative matrix factorisation to extract muscle synergies separately from the inner and outer limb, while segmental kinematics were used to quantify intersegmental coordination. Four synergies were identified in each limb. Although the overall modular organisation remained largely preserved, curved running induced systematic changes in both temporal and spatial activation patterns. Synergy activation timing occurred earlier in the gait cycle, particularly for modules associated with push-off and late swing, while spatial recruitment patterns diverged between the inner and outer limbs. Adaptations were limb-specific: the inner limb displayed greater reweighting and reduced complexity, while the outer limb showed earlier temporal shifts. Higuchi's fractal dimension indicated reduced complexity in touchdown and late swing synergies but increased complexity in push-off. Kinematic analyses showed that curved running modified intersegmental coordination, with divergence of the covariation plane between inner and outer limbs, reflecting their distinct functional roles in redirecting versus propelling the body. Together, these findings demonstrate that curved running preserves the fundamental organisation of locomotor modules while eliciting flexible, limb-specific adaptations in neuromuscular and kinematic coordination. The results support the view that human locomotion combines robust rhythmic structure with context-dependent modulation to accommodate asymmetric mechanical demands.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469844","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":"Transcutaneous auricular vagus nerve stimulation during a 3-back task: a high-density functional near-infrared spectroscopy study.","authors":"Michal Holowacz, Caitlin Illingworth, Jasmine Swalwell, Daniel Blackburn, Ali Ali, Arshad Majid, Li Su, Sheharyar S Baig","doi":"10.1007/s00221-026-07354-2","DOIUrl":"10.1007/s00221-026-07354-2","url":null,"abstract":"<p><p>Working memory issues are an often life-impairing deficit seen in several neurological disorders. Transcutaneous vagus nerve stimulation (tVNS) is a promising neuromodulatory adjunct to cognitive training and may improve working memory. High-density functional near-infrared spectroscopy (HD-fNIRS) is a modern neuroimaging modality that can assess cerebral blood flow in cortical areas. In the current study, we used HD-fNIRS to determine the effects of tVNS during a working memory task. Twenty-two healthy adult participants (12 female, 10 male) performed a 3-back task in a block design whilst high-density fNIRS was recorded across the bilateral prefrontal cortex using 36 sources and 48 detectors (1728 channels). Sham (earlobe) tVNS was delivered during the first task trial and active (tragus) tVNS was delivered during the second task trial. Statistical analysis was performed at a group level within trial (task - baseline) and between trials (active tVNS vs. sham tVNS) using node-level and regional approaches. Task-related increases in HbO were seen in the right dorsolateral middle frontal gyri, left inferior frontal gyrus and right lateral orbitofrontal cortex under both active and sham tVNS. Decreases were observed in the bilateral superior medial frontal gyri and medial orbital frontal cortices. No significant differences were seen between sham and active tVNS. Simultaneous recording of HD-fNIRS during a 3-back task and concurrent tVNS was feasible and well-tolerated. Robust task-related activation was seen in lateral frontal areas. No significant active-versus-sham differences in cortical activity or behavioural performance were observed under the stimulation parameters used here; however, this finding should be interpreted cautiously because the fixed-order design may have introduced fatigue or habituation effects. HD-fNIRS could be used in future studies of working memory and neuromodulation in clinical cohorts.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13357519/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148430393","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":"Exploring unintentional drifts in finger force production and muscle activity: a study of finger independence.","authors":"Paul M Tilley, Daanish M Mulla, Peter J Keir","doi":"10.1007/s00221-026-07351-5","DOIUrl":"10.1007/s00221-026-07351-5","url":null,"abstract":"<p><p>Unintentional changes in finger force during sustained exertions, known as force drifts, are thought to reflect limits in neural control of independent finger movements. Prior work has examined drifts at the level of finger force, but less is known about how these changes are reflected in muscle activity. Our study sought to quantify the phenomenon of unintentional finger force drifts in digits 2-5, performing both single-finger flexion and extension. Twenty right-handed participants (10 females, 10 males; ages 18-29) performed 30 s isometric flexion and extension exertions with digits 2-5 at 15% and 30% of their maximum voluntary contraction (MVC). Visual feedback was either continuous or removed after 10 s. Finger forces and surface EMG from flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC) were recorded. Removing visual feedback produced consistent downward drifts of instructed finger force in 15% MVC and 30% MVC flexion (0.6-8.4% MVC) and 30% MVC extension (1.4-5.2% MVC). With continuous feedback, the uninstructed fingers showed small upward force drifts (0.5-3.9% MVC), which were largely abolished when feedback was removed. Changes in instructed finger force were accompanied by modest decreases in EMG, whereas upward uninstructed drifts were associated with small increases in EMG; however, these changes were distributed across compartments and not specific to individual fingers. Extension tasks revealed similar patterns to flexion tasks but only at higher force levels, suggesting that both force magnitude and direction shape the conditions under which force drifts emerge. These findings provide evidence that finger force drifts reflect real-time changes to neural constraints on finger independence.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148430373","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":"Characteristic differences in somatosensory ERP components in Go/No-go paradigm between adolescents and adults.","authors":"Aoi Mase, Masako Nakagawa, Manabu Shibasaki, Hiroki Nakata","doi":"10.1007/s00221-026-07358-y","DOIUrl":"10.1007/s00221-026-07358-y","url":null,"abstract":"<p><p>This study investigated developmental differences in motor execution and inhibition by comparing somatosensory event-related potentials (ERPs) between adolescents and young adults. Thirty-seven adolescents (14.7 ± 0.2 years) and thirty-seven adults (21.1 ± 1.4 years) performed a somatosensory Go/No-go task while ERPs were recorded at Fz, Cz, and Pz electrodes. We analyzed the latency and amplitude of N2, additional negativity (AN), and P3 components together with behavioral indices including reaction time (RT), RT variability, omission errors, and commission errors, and also examined the scalp distribution of the P3 amplitude. Adolescents showed significantly higher commission error rates than adults, whereas other behavioral indices were comparable. ERP analyses revealed enhanced AN amplitude at Fz and shorter N2 latency at Fz, Cz, and Pz only in adolescents compared with adults. Moreover, No-go-P3 in adolescents was more parietally distributed, whereas adults exhibited a more anterior distribution, suggesting greater prefrontal involvement in adults. These findings suggest that although the speed of sensory-cognitive processing reaches an adult-like level by adolescence, inhibitory control and its underlying neural mechanisms continue to mature during this period. While adolescents exhibit ERP-behavior relationships comparable with those of adults, they may rely on broader and less specialized neural networks, particularly for frontal inhibitory control. Overall, the present results highlight adolescence as a key transitional stage in the development of cognitive control, with important implications for understanding age-related changes in sensorimotor processing and inhibitory functions.</p>","PeriodicalId":12268,"journal":{"name":"Experimental Brain Research","volume":"244 8","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148419699","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}