Biology subjects

Kranczioch, C.

Publications and source records attributed to Kranczioch, C..

3 recordsLinked to original sources

bioRxiv2026

No Evidence of an Effect of a Single Mirror Visual Feedback Session on Subsequent Motor Imagery

Motor imagery (MI) and mirror therapy, based on mirror visual feedback (MVF), are recommended as adjuncts to conventional therapies for upper limb rehabilitation after stroke. Both approaches activate sensorimotor cortical networks despite the absence of overt movement, and their concurrent application has been associated with enhanced neural activation. The present study investigated whether a single session of MVF modulates subsequent kinesthetic Motor Imagery (kMI)-related neural activity. EEG data from 38 healthy participants (MVF: n = 18; sham: n = 20) were analyzed in a mixed pre-post design. Participants performed kMI before and after either an MVF or sham intervention. Analyses focused on mu-band (8-12 Hz) event-related desynchronization (ERD) and its hemispheric lateralization. Although kMI reliably elicited stronger contralateral than ipsilateral mu ERD, MVF did not significantly affect subsequent kMI-related mu ERD or its hemispheric lateralization. These findings suggest that previously reported facilitatory effects of MVF on MI may be more closely related to concurrent application than to immediate aftereffects, while potential effects of repeated MVF exposure on subsequent MI remain to be investigated. These findings provide a foundation for future studies investigating how MVF and MI can be combined to optimize upper-limb stroke rehabilitation.

neuroscience↗

bioRxiv2022

Performance comparison of systemic activity correction in fNIRS for methods with and without short distance channels

SignificanceFunctional near-infrared spectroscopy (fNIRS) is a promising tool for neurofeedback (NFB) or brain-computer interfaces (BCIs). However, fNIRS signals are typically highly contaminated by systemic activity (SA) artifacts, and, if not properly corrected, NFB or BCIs run the risk of being based on noise instead of brain activity. This risk can likely be reduced by correcting for SA, in particular when short-distance channels (SDCs) are available. Literature comparing correction methods with and without SDCs is still sparse, specifically comparisons considering single trials are lacking. AimThis study aimed at comparing the performance of SA correction methods with and without SDCs. ApproachSemisimulated and real motor task data of healthy older adults were used. Correction methods without SDCs included a simple and a more advanced spatial filter. Correction methods with SDCs included a regression approach considering only the closest SDC and two GLM-based methods, one including all eight SDCs and one using only two a priori selected SDCs as regressors. All methods were compared with data uncorrected for SA and correction performance was assessed with quality measures quantifying signal improvement and spatial specificity at single trial level. ResultsAll correction methods were found to improve signal quality and enhance spatial specificity as compared with the uncorrected data. Methods with SDCs usually outperformed methods without SDCs. Correction methods without SDCs tended to overcorrect the data. However, the exact pattern of results and the degree of differences observable between correction methods varied between semisimulated and real data, and also between quality measures. ConclusionsOverall, results confirmed that both {Delta}[HbO] and {Delta}[HbR] are affected by SA and that correction methods with SDCs outperform methods without SDCs. Nonetheless, improvements in signal quality can also be achieved without SDCs and should therefore be given priority over not correcting for SA.

neuroscience↗

bioRxiv2020

Motor Imagery EEG Neurofeedback Skill Acquisition in the Context of Declarative Interference and Sleep

Motor imagery (MI) practice in combination with neurofeedback (NF) is a promising supplement to facilitate the acquisition of motor abilities and the recovery of impaired motor abilities following brain injuries. However, the ability to control MI NF is subject to a wide range of inter-individual variability. A substantial number of users experience difficulties in achieving good results, which compromises their chances to benefit from MI NF in a learning or rehabilitation context. It has been suggested that context factors, that is, factors outside the actual motor task, can explain individual differences in motor skill acquisition. Retrospective declarative interference and sleep have already been identified as critical factors for motor execution (ME) and MI based practice. Here, we investigate whether these findings generalize to MI NF practice. Three groups underwent three blocks of MI NF practice each on two subsequent days. In two of the groups, MI NF blocks were followed by either immediate or delayed declarative memory tasks. The control group performed only MI NF and no specific interference tasks. Two of the MI NF blocks were run on the first day of the experiment, the third in the morning of the second day. Significant within-block NF gains in mu and beta frequency event-related desynchronization (ERD) where evident for all groups. However, effects of sleep on MI NF ERD were not found. Data did also not indicate an impact of immediate or delayed declarative interference on MI NF ERD. Our results indicate that effects of sleep and declarative interference context on ME or MI practice cannot unconditionally be generalized to MI NF skill acquisition. The findings are discussed in the context of variable experimental task designs, inter-individual differences, and performance measures.

neuroscience↗