Modulation of somatosensory evoked magnetic fields by intensity of interfering stimuli in human somatosensory cortex: An MEG study

Lim, Mark D.; Kim, June Sic; Chung, Chun Kee

doi:10.1016/j.neuroimage.2012.04.003

Cited by 23 publications

(19 citation statements)

References 59 publications

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“…1C). 28 For each subject, we analyzed the peak-to-peak amplitudes of the N20m-P35m and peak amplitude of the each N20m and P35m component in response to the first pulse of the pairedpulse stimulation (A1). The peak-to-peak amplitudes of the N20m-P35m and the peak amplitude of N20m and P35m components to the second pulse of the paired-pulse stimulation were obtained in the source waveform of paired-pulse minus single-pulse conditions (A2s).…”

Section: Discussionmentioning

confidence: 99%

“…Also, since it has been suggested that the N20m and P35m components largely represent excitatory and inhibitory postsynaptic potentials at Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. S1, respectively, 15,16,28,55 we further examined PPS ratios separately for each of these components.…”

Section: Introductionmentioning

confidence: 99%

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Disinhibition of the primary somatosensory cortex in patients with fibromyalgia

Lim

Roosink

Kim

et al. 2015

Pain

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Fibromyalgia (FM) is a chronic widespread pain condition linked to central sensitization. Altered excitability of sensorimotor cortex has been proposed as an underlying pathology of FM. This study aimed to investigate intracortical excitability of the primary somatosensory cortex (S1) and its potential role in clinical pain in patients with FM. Somatosensory evoked magnetic fields were recorded in 17 right-handed females with FM and 21 age-, sex-, and handedness-matched healthy control subjects. Paired-pulse median nerve stimulation was delivered to the left and right wrist. We assessed the peak-to-peak amplitudes of the N20m-P35m and peak amplitude of each N20m and P35m component. Paired-pulse suppression (PPS) of the second response was quantified as the ratio of the amplitudes of the second to the first response. Patients with FM displayed significantly higher PPS ratio for the N20m-P35m in both hemispheres, indicating reduced intracortical inhibition in the S1. Notably, PPS ratio for the P35m was higher in patients with FM than in healthy controls, whereas no differences were apparent in PPS ratio for the N20m in both hemispheres. For both the N20m-P35m and the P35m in the left hemisphere, PPS ratios were positively associated with the sensory pain on the short-form McGill Pain Questionnaire. This study demonstrated that intracortical inhibition in the S1 is compromised bilaterally in patients with FM, and the extent of disinhibition can be closely associated with increased clinical pain. Our results suggest that changes of intracortical inhibition of the S1 may contribute to the pathophysiology of FM pain.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Disinhibition of the primary somatosensory cortex in patients with fibromyalgia

Lim

Roosink

Kim

et al. 2015

Pain

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“…The peaks of these SEF deflections are affected by the stimulus rate (Tiihonen et al ., ; Karhu et al ., ; Wikström et al ., ; Nagamine et al ., ), repetitive stimuli (Hamada et al ., ; Hoshiyama & Kakigi, ; Huttunen, ), conditioning stimulus (CON) prior to test stimulus (TS) of paired‐pulse stimulation paradigm (PPS; Stevenson et al ., ; Cheng & Lin, ; Nakagawa et al ., ), and interfering stimuli between TSs (Lim et al ., ). Although N20m is robust to a change of stimulus rate, P35m and P60m deflections are very sensitive to the stimulus rate (Wikström et al ., ; Nagamine et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Inhibitory effect of intensity and interstimulus interval of conditioning stimuli on somatosensory evoked magnetic fields

Onishi

Sugawara

Yamashiro

et al. 2016

Eur J of Neuroscience

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Magnetoencephalography (MEG) recordings were performed to investigate the inhibitory effects of conditioning stimuli with various types of interstimulus intervals (ISIs) or intensities on somatosensory evoked magnetic fields (SEFs) using a 306-ch whole-head MEG system. Twenty-three healthy volunteers participated in this study. Electrical stimuli were applied to the right median nerve at the wrist. Six pulse trains with ISIs of 500 ms were presented in Experiment 1. A paired-pulse paradigm with three kinds of conditioning stimulus (CON) intensities, 500 ms before the test stimulus (TS), was applied in Experiment 2. Finally, three CONs 500 or 1000 ms before TS were presented in Experiment 3. Three main SEF deflections (N20m, P35m, and P60m) were observed, and the source activities of P35m and P60m significantly decreased after the 2nd pulse of a six pulse trains. These source activities also significantly decreased with increasing intensity of CON. In addition, these attenuations of source activities were affected by CON-CON or CON-TS intervals. These results indicated that the source activities were modulated by the intensity and ISIs of CONs. Furthermore, P35m after the stimulation were very sensitive to CONs; however, the attenuation of P60m after the stimulation lasted for a longer period than that of P35m. Our findings suggest that the conditioning stimulation had inhibitory effects on subsequent evoked cortical responses for more than 500 ms. Our results also provide important clues about the nature of short-latency somatosensory responses in human studies.

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“…In macroscopic electrophysiological recordings, these types of information are often represented by event-related potentials (ERPs) or event-related de-synchronization (ERD) in S1 (Wiest and Nicolelis, 2003; Lim et al, 2012). Further, many invasive studies, such as, electrocorticography (ECoG) and microelectrode recordings, have indicated that there are dominant high-gamma (>50 Hz) power changes in the sensorimotor area during not only passive somatosensory stimulation but also active movement (Miller et al, 2007; Ray et al, 2008a; Avanzini et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Movement-Related Sensorimotor High-Gamma Activity Mainly Represents Somatosensory Feedback

et al. 2017

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Somatosensation plays pivotal roles in the everyday motor control of humans. During active movement, there exists a prominent high-gamma (HG >50 Hz) power increase in the primary somatosensory cortex (S1), and this provides an important feature in relation to the decoding of movement in a brain-machine interface (BMI). However, one concern of BMI researchers is the inflation of the decoding performance due to the activation of somatosensory feedback, which is not elicited in patients who have lost their sensorimotor function. In fact, it is unclear as to how much the HG component activated in S1 contributes to the overall sensorimotor HG power during voluntary movement. With regard to other functional roles of HG in S1, recent findings have reported that these HG power levels increase before the onset of actual movement, which implies neural activation for top-down movement preparation or sensorimotor interaction, i.e., an efference copy. These results are promising for BMI applications but remain inconclusive. Here, we found using electrocorticography (ECoG) from eight patients that HG activation in S1 is stronger and more informative than it is in the primary motor cortex (M1) regardless of the type of movement. We also demonstrate by means of electromyography (EMG) that the onset timing of the HG power in S1 is later (49 ms) than that of the actual movement. Interestingly, we show that the HG power fluctuations in S1 are closely related to subtle muscle contractions, even during the pre-movement period. These results suggest the following: (1) movement-related HG activity in S1 strongly affects the overall sensorimotor HG power, and (2) HG activity in S1 during voluntary movement mainly represents cortical neural processing for somatosensory feedback.

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Modulation of somatosensory evoked magnetic fields by intensity of interfering stimuli in human somatosensory cortex: An MEG study

Cited by 23 publications

References 59 publications

Disinhibition of the primary somatosensory cortex in patients with fibromyalgia

Disinhibition of the primary somatosensory cortex in patients with fibromyalgia

Inhibitory effect of intensity and interstimulus interval of conditioning stimuli on somatosensory evoked magnetic fields

Movement-Related Sensorimotor High-Gamma Activity Mainly Represents Somatosensory Feedback

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