Continuous theta-burst stimulation over primary somatosensory cortex modulates short-latency afferent inhibition

Tsang, Philemon; Jacobs, Mark F.; Lee, Kevin G.H.; Asmussen, Michael J.; Zapallow, Christopher M.; Nelson, Aimee J.

doi:10.1016/j.clinph.2014.02.026

Cited by 51 publications

(54 citation statements)

References 42 publications

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“…Furthermore, we have included the corresponding current intensity needed to achieve each SNAP. Although absolute values of current reflect impedance and hardware specifics, these data indicate that amperages associated with STs and MTs closely reflect those reported in the literature (Quartarone et al 2006;Tsang et al 2014Tsang et al , 2015. Revealing the relationship between the cortical representation of the somatosensory afferent volley and the magnitude of M1 output may have implications for motor control.…”

Section: Practical Implications Of the Researchmentioning

confidence: 58%

“…Increasing the excitation of SI pyramidal cells with a larger afferent volley (and greater SEP amplitude) may potentiate the GABAergic inhibitory cells and increase SAI. In further support for the role of SI in SAI generation, TMS plasticity protocols targeting SI but not M1 modulate SAI (Kojima et al 2015;Tsang et al 2014Tsang et al , 2015.…”

Section: Discussionmentioning

confidence: 99%

“…Revealing the relationship between the cortical representation of the somatosensory afferent volley and the magnitude of M1 output may have implications for motor control. Recent research has shown the importance of SAI in both allowing movement and preventing unwanted actions (Asmussen et al 2013(Asmussen et al , 2014Voller et al 2006). In individuals with Parkinson's disease, reduced SAI is associated with slower gait speed (Rochester et al 2012) but is unrelated to freezing of gait symptoms (Picillo et al 2015).…”

Section: Practical Implications Of the Researchmentioning

confidence: 99%

“…In contrast, SAI evoked by digital nerve (DN) stimulation demonstrates a somatotopic distribution such that SAI is greater (i.e., more inhibition) and occurs at an earlier latency in muscles that are in closer proximity to the stimulating electrode (Classen et al 2000). SAI is modulated during specific phases of movement (Asmussen et al 2013(Asmussen et al , 2014Voller et al 2006), indicating its use in studying motor control. SAI is reduced and/or abolished in Alzheimer's disease (Di Lazzaro 2004) and Parkinson's disease (Sailer et al 2003(Sailer et al , 2007, particularly in those presenting with mild cognitive impairment (Yarnall et al 2013) or dementia (Celebi et al 2012), although opposite effects are also observed (Di Lazzaro et al 2004;Nardone et al 2005).…”

Section: In An Influential Studymentioning

confidence: 99%

“…First, we have identified that the stimulus-response relationship of the SAI and SEP recruitment curve is intensity specific. For example, studies that aim to alter SAI magnitude (Quartarone et al 2006;Tsang et al 2014Tsang et al , 2015 would benefit from an intensity between 25% and 50% SNAP max to allow SAI to increase or decrease accordingly. We note that MT for a twitch in APB is observed at approximately the same current needed to elicit ϳ50% SNAP max .…”

Section: Practical Implications Of the Researchmentioning

confidence: 99%

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Short-latency afferent inhibition determined by the sensory afferent volley

Bailey

Asmussen

Nelson

2016

Journal of Neurophysiology

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afferent inhibition (SAI) is characterized by the suppression of the transcranial magnetic stimulation motor evoked potential (MEP) by the cortical arrival of a somatosensory afferent volley. It remains unknown whether the magnitude of SAI reflects changes in the sensory afferent volley, similar to that observed for somatosensory evoked potentials (SEPs). The present study investigated stimulus-response relationships between sensory nerve action potentials (SNAPs), SAI, and SEPs and their interrelatedness. Experiment 1 (n ϭ 23, age 23 Ϯ 1.5 yr) investigated the stimulus-response profile for SEPs and SAI in the flexor carpi radialis muscle after stimulation of the mixed median nerve at the wrist using ϳ25%, 50%, 75%, and 100% of the maximum SNAP and at 1.2ϫ and 2.4ϫ motor threshold (the latter equated to 100% of the maximum SNAP). Experiment 2 (n ϭ 20, age 23.1 Ϯ 2 yr) probed SEPs and SAI stimulus-response relationships after stimulation of the cutaneous digital nerve at ϳ25%, 50%, 75%, and 100% of the maximum SNAP recorded at the elbow. Results indicate that, for both nerve types, SAI magnitude is dependent on the volume of the sensory afferent volley and ceases to increase once all afferent fibers within the nerve are recruited. Furthermore, for both nerve types, the magnitudes of SAI and SEPs are related such that an increase in excitation within somatosensory cortex is associated with an increase in the magnitude of afferent-induced MEP inhibition.TMS; short-latency afferent inhibition; somatosensory evoked potentials; sensory nerve action potential; recruitment curve; afferent volley NEW & NOTEWORTHY This is the first investigation of the relationship between short-latency afferent inhibition (SAI) and the sensory afferent volley and the first to examine the relationship between SAI and somatosensory evoked potentials (SEPs).The data indicate that 1) SAI increases with the recruitment of sensory fibers and 2) its stimulus-response profile is correlated with SEPs. These novel data provide practical guidelines and also contribute to our understanding of SAI mechanisms.

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Section: Practical Implications Of the Researchmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Practical Implications Of the Researchmentioning

confidence: 99%

Section: In An Influential Studymentioning

confidence: 99%

Section: Practical Implications Of the Researchmentioning

confidence: 99%

See 3 more Smart Citations

Short-latency afferent inhibition determined by the sensory afferent volley

Bailey

Asmussen

Nelson

2016

Journal of Neurophysiology

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Decrease in short‐latency afferent inhibition during corticomotor postexercise depression following repetitive finger movement

et al. 2017

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IntroductionThis study aimed to clarify cortical circuit mechanisms contributing to corticomotor excitability during postexercise depression (PED) following repetitive nonfatiguing movement. We investigated changes in short‐latency afferent inhibition (SAI) and short‐interval intracortical inhibition (SICI) by paired‐pulse transcranial magnetic stimulation (TMS) during PED.MethodsA total of 16 healthy subjects performed repetitive abduction movements of the right index finger at 2.0 Hz for 6 min at 10% maximum voluntary contraction. We measured SAI evoked by pairing ulnar nerve stimulation with TMS (interstimulus interval, 22 ms) before and during PED (n = 10, experiment 1). We also measured SICI evoked by paired TMS (interstimulus interval, 2 ms) at 80% resting motor threshold (n = 10, experiment 2), and at 80% active motor threshold (n = 8, experiment 3) before and during PED.ResultsSingle motor evoked potential amplitude significantly decreased 1–2 min after the movement task in all experiments, indicating reliable PED induction. In experiment 1, SAI significantly decreased (disinhibited) 1–2 min during PED, whereas in experiments 2 and 3, SICI showed no significant change during PED.ConclusionThis study suggests that cholinergic inhibitory circuit activity decreases during PED following repetitive nonfatiguing movement, whereas GABAA circuit activity remains stable.

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Impact of different intensities of intermittent theta burst stimulation on the cortical properties during TMS‐EEG and working memory performance

Chung

Rogasch

Hoy

et al. 2017

Human Brain Mapping

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Intermittent theta burst stimulation (iTBS) is a noninvasive brain stimulation technique capable of increasing cortical excitability beyond the stimulation period. Due to the rapid induction of modulatory effects, prefrontal application of iTBS is gaining popularity as a therapeutic tool for psychiatric disorders such as depression. In an attempt to increase efficacy, higher than conventional intensities are currently being applied. The assumption that this increases neuromodulatory may be mechanistically false for iTBS. This study examined the influence of intensity on the neurophysiological and behavioural effects of iTBS in the prefrontal cortex. Sixteen healthy participants received iTBS over prefrontal cortex at either 50, 75 or 100% resting motor threshold in separate sessions. Single-pulse TMS and concurrent electroencephalography (EEG) was used to assess changes in cortical reactivity measured as TMS-evoked potentials and oscillations. The n-back task was used to assess changes in working memory performance. The data can be summarised as an inverse U-shape relationship between intensity and iTBS plastic effects, where 75% iTBS yielded the largest neurophysiological changes. Improvement in reaction time in the 3-back task was supported by the change in alpha power, however, comparison between conditions revealed no significant differences. The assumption that higher intensity results in greater neuromodulatory effects may be false, at least in healthy individuals, and should be carefully considered for clinical populations. Neurophysiological changes associated with working memory following iTBS suggest functional relevance. However, the effects of different intensities on behavioural performance remain elusive in the present healthy sample.

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Continuous theta-burst stimulation over primary somatosensory cortex modulates short-latency afferent inhibition

Cited by 51 publications

References 42 publications

Short-latency afferent inhibition determined by the sensory afferent volley

Short-latency afferent inhibition determined by the sensory afferent volley

Decrease in short‐latency afferent inhibition during corticomotor postexercise depression following repetitive finger movement

Impact of different intensities of intermittent theta burst stimulation on the cortical properties during TMS‐EEG and working memory performance

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