<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gupta, Disha</style></author><author><style face="normal" font="default" size="100%">Brangaccio, Jodi</style></author><author><style face="normal" font="default" size="100%">Mojtabavi, Helia</style></author><author><style face="normal" font="default" size="100%">Hill, NJ</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A portable cortical evoked potential operant conditioning system (C-EPOCS): System development</style></title><secondary-title><style face="normal" font="default" size="100%">bioRxiv</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2026</style></year></dates><pages><style face="normal" font="default" size="100%">2026–01</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">This study presents customizations and evaluations aimed at adapting the Cortical-Evoked Potential Operant Conditioning System (C-EPOCS) into a portable, user-friendly platform for real-time neurofeedback applications. A primary goal was to simplify the component-heavy setup by integrating electroencephalography (EEG) and electromyography (EMG) data acquisition into a single system-while still supporting cortical and muscle response assessment and real-time feedback. One key limitation of portable biosignal acquisition systems is their typically lower sampling rates (e.g., 300-600 Hz) compared to high-resolution systems (e.g., 3200 Hz), which are commonly used for detecting transient responses such as the H-reflex and M-wave. In a CEPOCS setup, these responses are useful for determining the target stimulation intensity and minimizing inter-session variability in effective afferent excitation. We evaluated whether lower-resolution EMG signals could still support the generation of H-reflex and M-wave recruitment curves for determining target stimulation intensity. Results showed that while EMG sampled at ~600 Hz and ~300 Hz produced greater dispersion in recruitment curve data, particularly at 300 Hz, they still yielded comparable estimates for stimulation intensities that elicit Hmax and Mthreshold, the key parameters for C-EPOCS. Additionally, we demonstrate the feasibility of using an automated response delineation algorithm under these conditions. Despite reduced signal clarity, the algorithm reliably identifies M-wave and H-reflex responses in real time. Overall, this study demonstrates the feasibility of a portable C-EPOCS system capable of providing immediate feedback based on both EMG and EEG signals. It also offers practical recommendations for selecting acquisition hardware to support reliable signal quality, real-time processing, and portability.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Hardesty, Russell L</style></author><author><style face="normal" font="default" size="100%">Mojtabavi, Helia</style></author><author><style face="normal" font="default" size="100%">Gemoets, Darren E</style></author><author><style face="normal" font="default" size="100%">Wolpaw, Jonathan R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Bidirectional locomotion induces asymmetric limb adaptations</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of neurophysiology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2025</style></year></dates><volume><style face="normal" font="default" size="100%">134</style></volume><pages><style face="normal" font="default" size="100%">1774–1784</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Humans can acquire and maintain motor skills throughout their lives through motor learning. Motor learning and skill acquisition are essential for rehabilitation after neurological disease or injury. Adaptation, the initial stage of motor learning, involves short-term changes in motor performance in response to a new demand in the person’s environment. Repeated adaptation can improve skill performance and result in long-term skill retention. Locomotor adaptation has been extensively studied with split-belt treadmill paradigms. In this study we explored whether bidirectional walking (BDW) on a split-belt treadmill can induce short-term gait adaptations. Twelve healthy volunteers participated in our single session, starting with 2 min of forward walking (FW), followed by four 5-min blocks of BDW with a 1-min passive rest in between blocks, and ending with another 2-min block of FW. We recorded body kinematics and ground reaction forces throughout the experiment. Participants modified both temporal (interlimb phasing, double stance duration) and spatial (step length) aspects of gait to meet the mechanical demands of backward dual walking (BDW). Adaptation occurred rapidly, with bilateral reductions in step length, adjustments in stance and swing phase timing, alterations in interlimb phasing, and decreased double stance duration in the limb walking backward. Notably, only the backward-walking limb (right) exhibited persistent aftereffects upon return to FW. These results demonstrate that BDW elicits adaptations in both spatial and temporal gait parameters, with transient aftereffects consistent with short-term motor learning. To our knowledge, this is the first report characterizing such spatiotemporal adaptations during BDW.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gupta, Disha</style></author><author><style face="normal" font="default" size="100%">Brangaccio, Jodi</style></author><author><style face="normal" font="default" size="100%">Mojtabavi, Helia</style></author><author><style face="normal" font="default" size="100%">Wolpaw, Jonathan</style></author><author><style face="normal" font="default" size="100%">Hill, NJ</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extracting robust single-trial somatosensory evoked potentials for non-invasive brain computer interfaces</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Neural Engineering</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2025</style></year></dates><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">056004</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Objective: Reliable extraction of single-trial somatosensory evoked potentials (SEPs) is essential for developing brain-computer interface (BCI) applications to support rehabilitation after brain injury. For real-time feedback, these responses must be extracted prospectively on every trial, with minimal post-processing and artifact correction. However, noninvasive SEPs elicited by electrical stimulation at recommended parameter settings (0.1–0.2 msec pulse width, stimulation at or below motor threshold, 2–5 Hz frequency) are typically small and variable, often requiring averaging across multiple trials or extensive processing. Here, we describe and evaluate ways to optimize the stimulation setup to enhance the signal-to-noise ratio (SNR) of noninvasive single-trial SEPs, enabling more reliable extraction. Approach: SEPs were recorded with scalp electroencephalography in tibial nerve stimulation in thirteen healthy people, and two people with CNS injuries. Three stimulation frequencies (lower than recommended: 0.2 Hz, 1 Hz, 2 Hz) with a pulse width longer than recommended (1 msec), at a stimulation intensity based on H-reflex and M-wave at Soleus muscle were evaluated. Detectability of single-trial SEPs relative to background noise was tested offline and in a pseudo-online analysis, followed by a real-time demonstration. Main results. SEP N70 was observed predominantly at the central scalp regions. Online decoding performance was significantly higher with Laplacian filter. Generalization performance showed an expected degradation, at all frequencies, with an average decrease of 5.9% (multivariate) and 6.5% (univariate), with an AUC score ranging from 0.78–0.90. The difference across stimulation frequencies was not significant. In individuals with injuries, AUC of 0.86 (incomplete spinal cord injury) and 0.81 (stroke) was feasible. Real-time demonstration showed SEP detection with AUC of 0.89. Significance This study describes and evaluates a system for extracting single-trial SEPs in real-time, suitable for a BCI-based operant conditioning. It enhances SNR of individual SEPs by alternate electrical stimulation parameters, dry headset, and optimized signal processing.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gupta, Disha</style></author><author><style face="normal" font="default" size="100%">Brangaccio, Jodi</style></author><author><style face="normal" font="default" size="100%">Mojtabavi, Helia</style></author><author><style face="normal" font="default" size="100%">Carp, Jonathan S</style></author><author><style face="normal" font="default" size="100%">Wolpaw, Jonathan R</style></author><author><style face="normal" font="default" size="100%">Hill, N Jeremy</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Frequency dependence of cortical somatosensory evoked response to peripheral nerve stimulation with controlled afferent excitation</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Neural Engineering</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2025</style></year></dates><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">026035</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Objective: H-reflex targeted neuroplasticity (HrTNP) protocols comprise a promising rehabilitation approach to improve motor function after brain or spinal injury. In this operant conditioning protocol, concurrent measurement of cortical responses, such as somatosensory evoked potentials (SEPs), would be useful for examining supraspinal involvement and neuroplasticity mechanisms. To date, this potential has not been exploited. However, the stimulation parameters used in the HrTNP protocol deviate from the classically recommended settings for SEP measurements. Most notably, it demands a much longer pulse width, higher stimulation intensity, and lower frequency than traditional SEP settings. In this paper, we report SEP measurements performed within the HrTNP stimulation parameter constraints, specifically characterizing the effect of stimulation frequency.
Approach: SEPs were acquired for tibial nerve stimulation at three stimulation frequencies (0.2, 1, and 2 Hz) in 13 subjects while maintaining the afferent volley by controlling the direct soleus muscle response via the Evoked Potential Operant Conditioning System. The amplitude and latency of the short-latency P40 and mid-latency N70 SEP components were measured at the central scalp region using non-invasive electroencephalography.
Main results: As frequency rose from 0.2 Hz, P40 amplitude and latency did not change. In contrast, N70 amplitude decreased significantly (39% decrease at 1 Hz, and 57% decrease at 2 Hz), presumably due to gating effects. N70 latency was not affected. Across all three frequencies, N70 amplitude increased significantly with stimulation intensity and correlated with M-wave amplitude.
Significance: We assess SEPs within an HrTNP protocol, focusing on P40 and N70, elicited with controlled afferent excitation at three stimulation frequencies. HrTNP conditioning protocols show promise for enhancing motor function after brain and spinal injuries. While SEPs offer valuable insights into supraspinal involvement, the stimulation parameters in HrTNP often differ from standard SEP measurement protocols. We address these deviations and provide recommendations for effectively integrating SEP assessments into HrTNP studies.


</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Brangaccio, Jodi A</style></author><author><style face="normal" font="default" size="100%">Gupta, Disha</style></author><author><style face="normal" font="default" size="100%">Mojtabavi, Helia</style></author><author><style face="normal" font="default" size="100%">Hardesty, Russell L</style></author><author><style face="normal" font="default" size="100%">Hill, NJ</style></author><author><style face="normal" font="default" size="100%">Carp, Jonathan S</style></author><author><style face="normal" font="default" size="100%">Gemoets, Darren E</style></author><author><style face="normal" font="default" size="100%">Vaughan, Theresa M</style></author><author><style face="normal" font="default" size="100%">Norton, James JS</style></author><author><style face="normal" font="default" size="100%">Perez, Monica A</style></author><author><style face="normal" font="default" size="100%">others</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Soleus H-reflex size versus stimulation rate in the presence of background muscle activity: a methodological study</style></title><secondary-title><style face="normal" font="default" size="100%">Experimental brain research</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2025</style></year></dates><volume><style face="normal" font="default" size="100%">243</style></volume><pages><style face="normal" font="default" size="100%">215</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Hoffmann reflex (HR) operant conditioning (HROC) is an important intervention for neurorehabilitation. Current HROC paradigms elicit HRs at low rates (~ 0.2 Hz), minimizing rate-dependent depression (RDD). We investigated the impact of higher stimulation rates on HR size. Fifteen healthy participants maintained low background soleus electromyographic activity (EMG) while standing. Soleus HR and M-wave recruitment curves were obtained at rates of 0.2, 1, and 2 Hz twice, from which Mmax and Hmax were calculated. Seventy-five HRs were collected for each rate at a target M-wave size (~ 10 to 20% of Mmax). HR depression was minimal at higher stimulation rates. The mean HR amplitude was reliable across the two repetitions and three rates, with high intraclass correlation coefficient (ICC) values. HROC could be performed consistently at rates up to 2 Hz with minimal HR depression. Faster rates enable more conditioning trials per session, reducing session duration and/or number, thereby potentially accelerating conditioning and reducing participant burden.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Hardesty, Russell L</style></author><author><style face="normal" font="default" size="100%">Mojtabavi, Helia</style></author><author><style face="normal" font="default" size="100%">Wolpaw, Jonathan R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Spinal reflexes: a potential target for treating hemiparetic gait.</style></title><secondary-title><style face="normal" font="default" size="100%">J Neurophysiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J Neurophysiol</style></alt-title></titles><dates><year><style  face="normal" font="default" size="100%">2025</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2025 Jul 01</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">134</style></volume><pages><style face="normal" font="default" size="100%">290-291</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">1</style></issue></record></records></xml>