α‐tACS over the somatosensory cortex enhances tactile spatial discrimination in healthy subjects with low alpha activity

Saito, Kei; Otsuru, Naofumi; Yokota, Hirotake; Inukai, Yasuto; Miyaguchi, Shota; Kojima, Sho; Onishi, Hideaki

doi:10.1002/brb3.2019

Cited by 11 publications

(6 citation statements)

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“…Full-text articles were examined in cases of insufficient information in the title or abstract. In total, 73 full-text articles were screened for eligibility and 16 articles were removed for the following reasons: (1) primary outcome not assessed (Gundlach et al, 2017;Hornburger et al, 2019;Huh et al, 2016;Maddaluno et al, 2020;Zapallow et al, 2013); (2) primary outcome measured during rather than before and after NIBS (Manzo et al, 2020;Saito et al, 2021;Yokota et al, 2021); (3) primary outcome measured more than 24 h post-NIBS (Litvak et al, 2007); (4) SEPs measured from the lower limb (Zapallow et al, 2012); (5) NIBS not applied to the S1 (Uguisu et al, 2010); (6) number of participants for a given NIBS condition (dataset) < 5 (Sehm et al, 2013); (7) SEPs evoked by electrical stimulation only on the upper limb side ipsilateral to NIBS; (8) NIBS also administrated with repetitive tactile stimulation to induce S1 plasticity (Ragert et al, 2003); (9) SEP data filtered with a bandpass of 400-800 Hz to analyse high-frequency oscillations (Restuccia et al, 2007); and (10) data previously analysed by Hilgenstock et al (2016) (Hirtz et al, 2018). One additional article was added by the full-text assessment (Gatica Tossi et al, 2013).…”

Section: Selection Of Studiesmentioning

confidence: 99%

Therapeutic benefits of noninvasive somatosensory cortex stimulation on cortical plasticity and somatosensory function: A systematic review

Sasaki

Watanabe

Onishi

2022

Eur J of Neuroscience

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Optimal limb coordination requires efficient transmission of somatosensory information to the sensorimotor cortex. The primary somatosensory cortex (S1) is frequently damaged by stroke, resulting in both somatosensory and motor impairments. Noninvasive brain stimulation (NIBS) to the primary motor cortex is thought to induce neural plasticity that facilitates neurorehabilitation. Several studies have also examined if NIBS to the S1 can enhance somatosensory processing as assessed by somatosensory-evoked potentials (SEPs) and improve behavioural task performance, but it remains uncertain if NIBS can reliably modulate S1 plasticity or even whether SEPs can reflect this plasticity. This systematic review revealed that NIBS has relatively minor effects on SEPs or somatosensory task performance, but larger early SEP changes after NIBS can still predict improved performance. Similarly, decreased paired-pulse inhibition in S1 post-NIBS is associated with improved somatosensory performance. However, several studies still debate the role of inhibitory function in somatosensory performance after NIBS in terms of the direction of the change (i.e., disinhibition or inhibition). Altogether, early SEP and paired-pulse inhibition (particularly inter-stimulus intervals of 30-100 ms) may become useful biomarkers for somatosensory deficits, but improved NIBS protocols are required for therapeutic applications.

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Section: Selection Of Studiesmentioning

confidence: 99%

Therapeutic benefits of noninvasive somatosensory cortex stimulation on cortical plasticity and somatosensory function: A systematic review

Sasaki

Watanabe

Onishi

2022

Eur J of Neuroscience

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“…The electroencephalogram data analysis was performed by using Matlab R2020a (MathWorks, Natick, MA, USA) and the EEGLAB toolbox ( Delorme and Makeig, 2004 ). Based on previous studies ( Saito et al, 2018 , 2019 , 2021 ; Sasaki et al, 2018 ), the reference electrode was changed from AFz to Fz, and the analytical electrode was CP3 (the left primary somatosensory cortex). The recorded electroencephalogram data at 2,500 Hz were downsampled to 500 Hz.…”

Section: Methodsmentioning

confidence: 99%

Changes in excitability and GABAergic neuronal activity of the primary somatosensory cortex after motor learning

et al. 2022

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IntroductionIt is widely known that motor learning changes the excitability of the primary motor cortex. More recently, it has been shown that the primary somatosensory cortex (S1) also plays an important role in motor learning, but the details have not been fully examined. Therefore, we investigated how motor skill training affects somatosensory evoked potential (SEP) in 30 neurologically healthy subjects.MethodsSEP N20/P25_component and N20/P25 SEP paired-pulse depression (SEP-PPD) were assessed before and immediately after complex or simple visuomotor tasks.ResultsMotor learning was induced more efficiently by the complex visuomotor task than by the simple visuomotor task. Both the N20/P25 SEP amplitude and N20/P25 SEP-PPD increased significantly immediately after the complex visuomotor task, but not after the simple visuomotor task. Furthermore, the altered N20/P25 SEP amplitude was associated with an increase in motor learning efficiency.ConclusionThese results suggest that motor learning modulated primary somatosensory cortex excitability.

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“…Moreover, sensory electrical stimulation is thought to induce plasticity in the central nervous system through use-dependent, long-term potentiation-like mechanisms [88][89][90]. Although the precise mechanisms of how sensory electrical stimulation enhances sensory processing remain unclear, it has been proposed that the observed increase in alpha power changes in the whole-hand stimulation group may indicate a link between electrical stimulation and improved sensory processing [91]. In our study, enhancing sensory processing through sensory electrical stimulation might have resulted in improved task performance (touch sensibility) as observed in the whole-hand stimulation group.…”

Section: Effects Of Sensory Electrical Stimulation Combined With Sens...mentioning

confidence: 99%

Enhancing Touch Sensibility with Sensory Electrical Stimulation and Sensory Retraining

Ortega,

Buetler,

Aksoz

et al. 2023

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A large proportion of stroke survivors suffer from sensory loss, negatively impacting their independence, quality of life, and neurorehabilitation prognosis. Despite the high prevalence of somatosensory impairments, somatosensory interventions such as sensory electrical stimulation (SES) are not the standard of care, probably due to their unclear influence on neurorehabilitation. We aimed to study the effectiveness of SES combined with a sensory discrimination task in a well-controlled virtual environment. We employed electroencephalography (EEG) to gain a better understanding of the underlying neural mechanisms and dynamics associated with sensory training and SES. We conducted a single-session experiment with twenty-six healthy participants who explored a set of three visually identical virtual textures—haptically rendered by a robotic device and that differed in their spatial period— while physically guided by the robot to identify the odd texture. The experiment consisted of three phases: pre-intervention, intervention, and post-intervention. Half the participants received subthreshold whole-hand SES during the intervention, while the other half received sham stimulation. We evaluated changes in task performance —assessed by the probability of correct responses— before and after intervention and between groups. We also evaluated differences in the exploration behavior, e.g., scanning speed. EEG was employed to examine the effects of the intervention on brain activity, particularly in the alpha frequency band (8-13 Hz) associated with sensory processing. We found that participants in the SES group improved their task performance after intervention and their scanning speed during and after intervention, while the sham group did not improve their task performance. However, the differences in task performance improvements between groups only approached significance. Furthermore, we found that alpha power was sensitive to the effects of SES; participants in the stimulation group exhibited enhanced brain signals associated with improved touch sensitivity likely due to the effects of SES on the central nervous system, while the increase in alpha power for the sham group was less pronounced. Our findings suggest that SES enhances texture discrimination after training and has a positive effect on sensory-related brain areas. Further research involving brain-injured patients is needed to confirm the potential benefit of our solution in neurorehabilitation.

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α‐tACS over the somatosensory cortex enhances tactile spatial discrimination in healthy subjects with low alpha activity

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 11 publications

References 44 publications

Therapeutic benefits of noninvasive somatosensory cortex stimulation on cortical plasticity and somatosensory function: A systematic review

Therapeutic benefits of noninvasive somatosensory cortex stimulation on cortical plasticity and somatosensory function: A systematic review

Changes in excitability and GABAergic neuronal activity of the primary somatosensory cortex after motor learning

Enhancing Touch Sensibility with Sensory Electrical Stimulation and Sensory Retraining

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