Abstract:Human behavior requires interregional crosstalk to employ the sensorimotor processes in the brain. Although external neuromodulation techniques have been used to manipulate interhemispheric sensorimotor activity, a central controversy concerns whether this activity can be volitionally controlled. Experimental tools lack the power to up- or down-regulate the state of the targeted hemisphere over a large dynamic range and, therefore, cannot evaluate the possible volitional control of the activity. We addressed t… Show more
“…Transcranial magnetic stimulation (TMS) Problems with the motor cortex have been extensively studied by using TMS, with 18 articles dedicated to the issue: those by Ros et al ( 2010 ), Niazi et al ( 2012 ), Sitaram et al ( 2012 ), Mokienko et al ( 2013 ), Takemi et al ( 2013 , 2018 ), Hänselmann et al ( 2015 ), Kaplan et al ( 2016 ), Royter and Gharabaghi ( 2016 ), Schildt et al ( 2016 ), Hasegawa et al ( 2017 ), Mashat et al ( 2017 ), Daly et al ( 2018 ), Jochumsen et al ( 2018 ), Syrov et al ( 2020 ), Ding et al ( 2021 ), Grigorev et al ( 2021 ), and Mihelj et al ( 2021 ) for neugodegenerative disease. The second most commonly studied disease by using TMS was stroke, with five articles devoted to it: those by Gharabaghi et al ( 2014 ), Syrov et al ( 2019 ), Cantillo-Negrete et al ( 2021 ), Hayashi et al ( 2022 ), and Liang et al ( 2020 ). Four articles examine the sensorimotor cortex: those by Pichiorri et al ( 2011 ), Niazi et al ( 2014 ), Kraus et al ( 2016 ), and Naros et al ( 2020 ).…”
Emerging brain technologies have significantly transformed human life in recent decades. For instance, the closed-loop brain-computer interface (BCI) is an advanced software-hardware system that interprets electrical signals from neurons, allowing communication with and control of the environment. The system then transmits these signals as controlled commands and provides feedback to the brain to execute specific tasks. This paper analyzes and presents the latest research on closed-loop BCI that utilizes electric/magnetic stimulation, optogenetic, and sonogenetic techniques. These techniques have demonstrated great potential in improving the quality of life for patients suffering from neurodegenerative or psychiatric diseases. We provide a comprehensive and systematic review of research on the modalities of closed-loop BCI in recent decades. To achieve this, the authors used a set of defined criteria to shortlist studies from well-known research databases into categories of brain stimulation techniques. These categories include deep brain stimulation, transcranial magnetic stimulation, transcranial direct-current stimulation, transcranial alternating-current stimulation, and optogenetics. These techniques have been useful in treating a wide range of disorders, such as Alzheimer's and Parkinson's disease, dementia, and depression. In total, 76 studies were shortlisted and analyzed to illustrate how closed-loop BCI can considerably improve, enhance, and restore specific brain functions. The analysis revealed that literature in the area has not adequately covered closed-loop BCI in the context of cognitive neural prosthetics and implanted neural devices. However, the authors demonstrate that the applications of closed-loop BCI are highly beneficial, and the technology is continually evolving to improve the lives of individuals with various ailments, including those with sensory-motor issues or cognitive deficiencies. By utilizing emerging techniques of stimulation, closed-loop BCI can safely improve patients' cognitive and affective skills, resulting in better healthcare outcomes.
“…Transcranial magnetic stimulation (TMS) Problems with the motor cortex have been extensively studied by using TMS, with 18 articles dedicated to the issue: those by Ros et al ( 2010 ), Niazi et al ( 2012 ), Sitaram et al ( 2012 ), Mokienko et al ( 2013 ), Takemi et al ( 2013 , 2018 ), Hänselmann et al ( 2015 ), Kaplan et al ( 2016 ), Royter and Gharabaghi ( 2016 ), Schildt et al ( 2016 ), Hasegawa et al ( 2017 ), Mashat et al ( 2017 ), Daly et al ( 2018 ), Jochumsen et al ( 2018 ), Syrov et al ( 2020 ), Ding et al ( 2021 ), Grigorev et al ( 2021 ), and Mihelj et al ( 2021 ) for neugodegenerative disease. The second most commonly studied disease by using TMS was stroke, with five articles devoted to it: those by Gharabaghi et al ( 2014 ), Syrov et al ( 2019 ), Cantillo-Negrete et al ( 2021 ), Hayashi et al ( 2022 ), and Liang et al ( 2020 ). Four articles examine the sensorimotor cortex: those by Pichiorri et al ( 2011 ), Niazi et al ( 2014 ), Kraus et al ( 2016 ), and Naros et al ( 2020 ).…”
Emerging brain technologies have significantly transformed human life in recent decades. For instance, the closed-loop brain-computer interface (BCI) is an advanced software-hardware system that interprets electrical signals from neurons, allowing communication with and control of the environment. The system then transmits these signals as controlled commands and provides feedback to the brain to execute specific tasks. This paper analyzes and presents the latest research on closed-loop BCI that utilizes electric/magnetic stimulation, optogenetic, and sonogenetic techniques. These techniques have demonstrated great potential in improving the quality of life for patients suffering from neurodegenerative or psychiatric diseases. We provide a comprehensive and systematic review of research on the modalities of closed-loop BCI in recent decades. To achieve this, the authors used a set of defined criteria to shortlist studies from well-known research databases into categories of brain stimulation techniques. These categories include deep brain stimulation, transcranial magnetic stimulation, transcranial direct-current stimulation, transcranial alternating-current stimulation, and optogenetics. These techniques have been useful in treating a wide range of disorders, such as Alzheimer's and Parkinson's disease, dementia, and depression. In total, 76 studies were shortlisted and analyzed to illustrate how closed-loop BCI can considerably improve, enhance, and restore specific brain functions. The analysis revealed that literature in the area has not adequately covered closed-loop BCI in the context of cognitive neural prosthetics and implanted neural devices. However, the authors demonstrate that the applications of closed-loop BCI are highly beneficial, and the technology is continually evolving to improve the lives of individuals with various ailments, including those with sensory-motor issues or cognitive deficiencies. By utilizing emerging techniques of stimulation, closed-loop BCI can safely improve patients' cognitive and affective skills, resulting in better healthcare outcomes.
“…Here, we explore the interhemispheric functional connectivity of a region that responds to our stimuli, assessing its potential as a target for neuromodulation at different TRs. This has been successfully applied before in other neurofeedback paradigms (Pereira et al, 2019;Wang et al, 2020;Hayashi et al, 2022). Speci cally, we simulated the feedback of the perceptual switches based on the hMT + interhemispheric correlation value.…”
Functional magnetic resonance imaging (fMRI) allows to observe neural activity in real-time but tracking the neural correlates of perceptual decision as a function of interhemispheric connectivity has remained difficult. Recent advances in image acquisition, namely with the surfacing of multiband sequences, have led us to investigate this mechanism using higher temporal resolution approaches. We were able to better capture the hemodynamic responses to rapid changes in neural activity concomitantly with a task requiring either perceptual interhemispheric segregation or integration, shortening the gap to other neuroimaging techniques, which is particularly significant when considering the study of dynamic connectivity patterns. Here, we tested the hypothesis whether interhemispheric connectivity in the visual cortex relates to interhemispheric integration, when presented with bistable moving stimuli at four distinct temporal resolutions. Based on this connectivity metric, we could discern perceptual state transitions related to connectivity. First, we found that activation response metrics to visual motion in our target region of interest, the human visual motion complex hMT+, are stable across temporal resolutions. Then, we investigated interhemispheric connectivity between homologous hMT + in response to bistable moving stimuli, for all resolutions, which was critical for replication of perception related interhemispheric synchrony. The established relation between perceptual coherence and increased synchrony across the hemispheres suggests the feasibility of a real-time fMRI neurofeedback based on interhemispheric connectivity. Accordingly, we could infer perceptual states based on this connectivity metric while designing a rule that could even be used to generate feedback. We further showed that higher resolution sequences are beneficial when implementing feedback interfaces based on interhemispheric functional connectivity, both regarding the delay and the accuracy of the feedback itself. Regarding the use of real time fMRI and neurofeedback strategies, higher resolution sequences are likely needed, when relying on connectivity metrics.
“…It has also been suggested that functional connectivity at rest implies the structured pattern of brain networks associated with task-induced functional connectivity [39]. Therefore, we assessed functional connectivity during the 'Rest' epoch by computing the network intensity [11,40] based on the corrected imaginary part of coherence (ciCOH) measure [11,[40][41][42]. Specifically, ciCOH was initially estimated from preprocessed EEG data that were segmented every 1 s in the 'Rest' epoch with 50% overlap and multiplied by the Hanning window [11,41].…”
“…Specifically, ciCOH was initially estimated from preprocessed EEG data that were segmented every 1 s in the 'Rest' epoch with 50% overlap and multiplied by the Hanning window [11,41]. Subsequently, the ciCOH value was computed from the complex coherency function of the segmented data [11,[40][41][42]:…”
“…where Im (C ij ) denotes the imaginary part, and Re (C ij ) denotes the real part of the complex coherency function (C ij ). Subsequent network analysis using an asymptotic statistical procedure based on one thousand surrogate datasets was implemented to discard spurious connectivity, resulting in significant ciCOH values [11,40,43]. Finally, the network intensity was computed as the summation of significant ciCOH values between the target electrode (i.e.…”
Objective: Brain-computer interface (BCI)-controlled functional electrical stimulation (FES) could excite the central nervous system to enhance upper limb motor recovery. Our current study assessed the effectiveness of motor and prefrontal cortical activity-based BCI-FES to help elucidate the underlying neuromodulation mechanisms of this neurorehabilitation approach.
Approach: The primary motor cortex (M1) and prefrontal cortex (PFC) BCI-FES interventions were performed for 25 min on separate days with twelve non-disabled participants. During the interventions, a single electrode from the contralateral M1 or PFC was used to detect event-related desynchronization (ERD) in the calibrated frequency range. If the BCI system detected ERD within 15 s of motor imagery, FES activated wrist extensor muscles. Otherwise, if the BCI system did not detect ERD within 15 s, a subsequent trial was initiated without FES. To evaluate neuromodulation effects, corticospinal excitability was assessed using single-pulse transcranial magnetic stimulation, and cortical excitability was assessed by motor imagery ERD and resting-state functional connectivity before, immediately, 30 min, and 60 min after each intervention.
Main results: M1 and PFC BCI-FES interventions had similar success rates of approximately 80%, while the M1 intervention was faster in detecting ERD activity. Consequently, only the M1 intervention effectively elicited corticospinal excitability changes for at least 60 min around the targeted cortical area in the M1, suggesting a degree of spatial localization. However, cortical excitability measures did not indicate changes after either M1 or PFC BCI-FES.
Significance: Neural mechanisms underlying the effectiveness of BCI-FES neuromodulation may be attributed to the M1 direct corticospinal projections and/or the closer timing between ERD detection and FES, which likely enhanced Hebbian-like plasticity by synchronizing cortical activation detected by the BCI system with the sensory nerve activation and movement related reafference elicited by FES.
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