02582nas a2200145   4500008004100000245010600041210006900147520197600216100002702192700002302219700002402242700002302266700002202289856012502311       2025                        eng d00aBrain-computer interface (BCI)-based identification of congenital red-green color vision deficiencies0 aBraincomputer interface BCIbased identification of congenital re3 aWe demonstrate brain-computer interface (BCI)- based color vision (CV) assessment for the identification of congenital red-green CV deficiencies. Experiments were based on the identification of metamers—light sources with different spectral distributions perceived to be the same color. Metamers elicit steady-state visual evoked potentials (SSVEPs) of minimal size and are different for people with versus without CV deficiencies. Methods: Thirty-one participants (20 control (CTR), 11 color vision deficient (CVdef)) completed behaviorand BCI-based CV assessments. Experiments used a visual stimulus that alternated between a monochromatic light source (yellow; fixed luminance) and a dichromatic light source (red and green; varying luminances) at a fixed frequency. During behavior-based CV assessment, participants identified metamers by manually adjusting the dichromatic source’s settings until its color matched that of the monochromatic source. During BCI-based CV assessment, participants attended a sequence of stimuli (each with a different dichromatic source setting) while electroencephalography was recorded; metamers were defined as the dichromatic source settings that minimized SSVEP size. Results: The behavior- and BCI-identified metamers were identical within each group, but different across groups (i.e., CTR and CVdef and for people with protan- versus deutan-type CV deficiencies). Automatic identification of CVdef individuals (and type of deficiency) was demonstrated using a classification analysis (93% accuracy). Conclusion: Experiments validated BCI-based CV assessment for the identification of congenital red-green CV deficiencies. Significance: BCI-based CV assessment does not require behavioral responses and can be automated, making it suitable for people with cognitive/motor deficits. With further development, BCI-based CV assessment may enable automatic identification of many types of congenital and acquired CV deficiencies.1 aRueda-Parra, Sebastian1 aCaruso, Heather, A1 aNorton, Penelope, L1 aGemoets, Darren, E1 aNorton, James, JS  uhttps://www.neurotechcenter.org/publications/2025/brain-computer-interface-bci-based-identification-congenital-red-green02019nas a2200145   4500008004100000245008500041210006900126300001400195520145800209100002201667700002701689700002101716700002101737856011501758       2025                        eng d00aCharacterization of cutaneous reflexes elicited from saphenous nerve stimulation0 aCharacterization of cutaneous reflexes elicited from saphenous n  a2025–103 aPhantom limb pain (PLP) is a chronic neuropathic condition that affects amputees. Cutaneous reflexes (CRs), mediated by spinal interneuronal circuits, represent a potential pathway linking non-nociceptive input to nociceptive modulation that could be targeted with neuromodulatory techniques such as operant conditioning. The objective of this study was to develop and validate a novel method for eliciting CRs from proximal muscles via saphenous nerve stimulation to enable future applications in individuals with PLP. We recruited 14 healthy adults and elicited CRs in the rectus femoris muscle via transcutaneous stimulation of the saphenous nerve at multiple stimulation intensities below their pain thresholds. We evaluated the consistency and reliability of CR response latencies and magnitudes, comparing the symmetry between the bilaterally (e.g. right and left legs). We found that CRs could be reliably elicited 50-100ms post-stimulus using saphenous stimulation and that responses were reliable at stimulation intensities below pain thresholds. Furthermore, we found the CR responses were relatively symmetrical in our healthy adult population. This study is the first of its kind to show that proximal (vs distal) CRs could be consistently elicited through the saphenous nerve stimulation. These findings imply that proximal CRs may be a feasible target for neuromodulatory interventions such as operant conditioning paradigms in the future.1 aHardesty, Russell1 aRueda-Parra, Sebastian1 aWolpaw, Jonathan1 aBrangaccio, Jodi  uhttps://www.neurotechcenter.org/publications/2025/characterization-cutaneous-reflexes-elicited-saphenous-nerve02783nas a2200157   4500008004100000245011100041210006900152490000700221520216800228100002702396700002202423700002302445700001702468700001702485856012302502       2025                        eng d00aTest-retest reliability of kinematic and EEG low-beta spectral features in a robot-based arm movement task0 aTestretest reliability of kinematic and EEG lowbeta spectral fea0 v113 aObjective.Low-beta (Lβ, 13-20 Hz) power plays a key role in upper-limb motor control and afferent processing, making it a strong candidate for a neurophysiological biomarker. We investigate the test-retest reliability of Lβpower and kinematic features from a robotic task over extended intervals between sessions to assess its potential for tracking longitudinal changes in sensorimotor function.Approach.We designed and optimized a testing protocol to evaluate Lβpower and kinematic features (maximal and mean speed, reaction time, and movement duration) in ten right-handed healthy individuals that performed a planar center-out task using a robotic device and EEG for data collection. The task was performed with both hands, and the experiment was repeated approximately 40 days later under similar conditions, to resemble real-life intervention periods. We first characterized the selected features within the task context for each session, then assessed intersession agreement, the test-retest reliability (Intraclass Correlation Coefficient, ICC), and established threshold values for meaningful changes in Lβpower using Bland-Altman plots and repeatability coefficients.Main Results.Lβpower showed the expected contralateral reduction during movement preparation and onset. Both Lβpower and kinematic features exhibited good to excellent test-retest reliability (ICC > 0.8), displaying no significant intersession differences. Kinematic results align with prior literature, reinforcing the robustness of these measures in tracking motor performance over time. Changes in Lβpower between sessions exceeding 11.4% for right-arm and 16.5% for left-arm movements reflect meaningful intersession differences.Significance.This study provides evidence that Lβpower remains stable over extended intersession intervals comparable to rehabilitation timelines. The strong reliability of both Lβpower and kinematic features supports their use in monitoring upper-extremity sensorimotor function longitudinally, with Lβpower emerging as a promising biomarker for tracking therapeutic outcomes, postulating it as a reliable feature for long-term applications. 1 aRueda-Parra, Sebastian1 aHardesty, Russell1 aGemoets, Darren, E1 aHill, Jeremy1 aGupta, Disha  uhttps://www.neurotechcenter.org/publications/2025/test-retest-reliability-kinematic-and-eeg-low-beta-spectral-features02169nas a2200301   4500008004100000022001400041245015400055210006900209260001300278300000800291490000900299520119500308653000901503653002101512653001101533653001101544653000901555653001601564653001301580653001101593653002601604100002701630700001901657700002301676700002801699700001701727856012301744       2024                        eng d  a2694-060400aMultidimensional feature analysis shows stratification in robotic-motor-training gains based on the level of pre-training motor impairment in stroke.0 aMultidimensional feature analysis shows stratification in roboti  c2024 Jul  a1-50 v20243 a<p>Stroke involves heterogeneity in injury and ongoing endogenous recovery, which are seldom stratified before testing post-stroke robot assisted motor training (RAMT). Pretraining variations, especially sensory-motor differences may also affect the gains achieved from the RAMT. Moreover, one assessment test may not effectively characterize the baseline sensory-motor status or the RAMT gains. Pre-therapy stratification may help personalize therapy and increase therapy gains. Towards this goal, we propose a data-driven approach to assess multiple functional scores with t-distributed stochastic neighbor embedding and affinity propagation clustering, both for pre-therapy and RAMT gains. Data included behavioral scores from 27 people with chronic stroke who underwent RAMT for finger movement. Three clusters were observed at start-of-therapy (SoT), concurrent with the overall impairment level. Four clusters were observed for the RAMT gains, indicating specific improvements. The SoT clusters showed agreement with the RAMT gain clusters, suggesting that the pre-therapy state, assessed across multiple domains, could be useful in guiding RAMT interventions to improve outcomes.</p>10aAged10aCluster Analysis10aFemale10aHumans10aMale10aMiddle Aged10aRobotics10aStroke10aStroke Rehabilitation1 aRueda-Parra, Sebastian1 aPerry, Joel, C1 aWolbrecht, Eric, T1 aReinkensmeyer, David, J1 aGupta, Disha  uhttps://www.neurotechcenter.org/publications/2024/multidimensional-feature-analysis-shows-stratification-robotic-motor02872nas a2200169   4500008004100000245007900041210006900120260000700189300000900196490000700205520235300212100002702565700002002592700002402612700001702636856004902653       2024                        eng d00aNeural correlates of bilateral proprioception and adaptation with training0 aNeural correlates of bilateral proprioception and adaptation wit  c03  a1-210 v193 aBilateral proprioception includes the ability to sense the position and motion of one hand relative to the other, without looking. This sensory ability allows us to perform daily activities seamlessly, and its impairment is observed in various neurological disorders such as cerebral palsy and stroke. It can undergo experience-dependent plasticity, as seen in trained piano players. If its neural correlates were better understood, it would provide a useful assay and target for neurorehabilitation for people with impaired proprioception. We designed a non-invasive electroencephalography-based paradigm to assess the neural features relevant to proprioception, especially focusing on bilateral proprioception, i.e., assessing the limb distance from the body with the other limb. We compared it with a movement-only task, with and without the visibility of the target hand. Additionally, we explored proprioceptive accuracy during the tasks. We tested eleven Controls and nine Skilled musicians to assess whether sensorimotor event-related spectral perturbations in μ (8-12Hz) and low-β (12-18Hz) rhythms differ in people with musical instrument training, which intrinsically involves a bilateral proprioceptive component, or when new sensor modalities are added to the task. The Skilled group showed significantly reduced μ and low-β suppression in bilateral tasks compared to movement-only, a significative difference relative to Controls. This may be explained by reduced top-down control due to intensive training, despite this, proprioceptive errors were not smaller for this group. Target visibility significantly reduced proprioceptive error in Controls, while no change was observed in the Skilled group. During visual tasks, Controls exhibited significant μ and low-β power reversals, with significant differences relative to proprioceptive-only tasks compared to the Skilled group—possibly due to reduced uncertainty and top-down control. These results provide support for sensorimotor μ and low-β suppression as potential neuromarkers for assessing proprioceptive ability. The identification of these features is significant as they could be used to quantify altered proprioceptive neural processing in skill and movement disorders. This in turn can be useful as an assay for pre and post sensory-motor intervention research.1 aRueda-Parra, Sebastian1 aPerry, Joel, C.1 aWolbrecht, Eric, T.1 aGupta, Disha  uhttps://doi.org/10.1371/journal.pone.0299873