scholarly journals Short-interval intracortical inhibition is not affected by varying visual feedback in an isometric task in biceps brachii muscle

2013 ◽  
Vol 7 ◽  
Author(s):  
Timo Rantalainen ◽  
Ashleigh Weier ◽  
Michael Leung ◽  
Chris Brandner ◽  
Michael Spittle ◽  
...  
Keyword(s):  
Visual Feedback ◽  
Biceps Brachii ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Biceps Brachii Muscle

scholarly journals Neurophysiological correlates of aging-related muscle weakness

2013 ◽  
Vol 110 (11) ◽  
pp. 2563-2573 ◽  
Author(s):  
Ela B. Plow ◽  
David A. Cunningham ◽  
Corin Bonnett ◽  
Dina Gohar ◽  
Mehmed Bayram ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Weakness ◽  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Biceps Brachii ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Voluntary Activation ◽  
Interhemispheric Inhibition

Muscle weakness associated with aging implicates central neural degeneration. However, role of the primary motor cortex (M1) is poorly understood, despite evidence that gains in strength in younger adults are associated with its adaptations. We investigated whether weakness of biceps brachii in aging analogously relates to processes in M1. We enrolled 20 young (22.6 ± 0.87 yr) and 28 old (74.79 ± 1.37 yr) right-handed participants. Using transcranial magnetic stimulation, representation of biceps in M1 was identified. We examined the effect of age and sex on strength of left elbow flexion, voluntary activation of biceps, corticospinal excitability and output, and short-interval intracortical and interhemispheric inhibition. Interhemispheric inhibition was significantly exaggerated in the old ( P = 0.047), while strength tended to be lower ( P = 0.075). Overall, women were weaker ( P < 0.001). Processes of M1 related to strength or voluntary activation of biceps, but only in older adults. Corticospinal excitability was lower in weaker individuals ( r = 0.38), and corticospinal output, intracortical inhibition and interhemispheric inhibition were reduced too in individuals who poorly activated biceps ( r = 0.43, 0.54 and 0.38). Lower intracortical inhibition may reflect compensation for reduced corticospinal excitability, allowing weaker older adults to spread activity in M1 to recruit synergists and attempt to sustain motor output. Exaggerated interhemispheric inhibition, however, conflicts with previous evidence, potentially related to greater callosal damage in our older sample, our choice of proximal vs. distal muscle and differing influence of measurement of inhibition in rest vs. active states of muscle. Overall, age-specific relation of M1 to strength and muscle activation emphasizes that its adaptations only emerge when necessitated, as in a weakening neuromuscular system in aging.

scholarly journals Are ipsilateral motor evoked potentials subject to intracortical inhibition?

2016 ◽  
Vol 115 (3) ◽  
pp. 1735-1739
Author(s):  
Alana B. McCambridge ◽  
James W. Stinear ◽  
Winston D. Byblow
Keyword(s):  
Evoked Potentials ◽  
Primary Motor Cortex ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Short Interval ◽  
Conditioning Stimulus ◽  
Elbow Flexion ◽  
Intracortical Inhibition ◽  
Motor Tasks ◽  
Active Motor

Paired-pulse transcranial magnetic stimulation (TMS) can be used to examine intracortical inhibition in primary motor cortex (M1), termed short-interval intracortical inhibition (SICI). To our knowledge, SICI has only been demonstrated in contralateral motor evoked potentials (MEPs). Ipsilateral MEPs (iMEPs) are assumed to reflect excitability of an uncrossed oligosynaptic pathway, and can sometimes be evoked in proximal upper-limb muscles using high-intensity TMS. We examined whether iMEPs in the biceps brachii (BB) would be suppressed by subthreshold conditioning, therefore demonstrating SICI of iMEPs. TMS was delivered to the dominant M1 to evoke conditioned (C) and nonconditioned (NC) iMEPs in the nondominant BB of healthy participants during weak bilateral elbow flexion. The conditioning stimulus intensities tested were 85%, 100%, and 115% of active motor threshold (AMT), at 2 ms and 4 ms interstimulus intervals (ISI). The iMEP ratio (C/NC) was calculated for each condition to assess the amount of inhibition. Inhibition of iMEPs was present at 2 ms ISI with 100% and 115% AMT (both P < 0.03), mediated by a reduction in persistence and size (all P < 0.05). To our knowledge, this is the first demonstration of SICI of iMEPs. This technique may be useful as a tool to better understand the role of ipsilateral M1 during functional motor tasks.

Short-interval intracortical inhibition of the biceps brachii in chronic-resistance versus non-resistance-trained individuals

2019 ◽  
Vol 237 (11) ◽  
pp. 3023-3032 ◽  
Author(s):  
Behzad Lahouti ◽  
Evan J. Lockyer ◽  
Shawn Wiseman ◽  
Kevin E. Power ◽  
Duane C. Button
Keyword(s):  
Biceps Brachii ◽  
Short Interval ◽  
Intracortical Inhibition

scholarly journals Modulation of intracortical inhibition during physically performed and mentally simulated balance tasks

2021 ◽  
Vol 121 (5) ◽  
pp. 1379-1388
Author(s):  
A. Mouthon ◽  
J. Ruffieux ◽  
W. Taube
Keyword(s):  
Motor Evoked Potentials ◽  
Action Observation ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Mental Simulation ◽  
Task Execution ◽  
Postural Tasks ◽  
Execution Condition ◽  
The One ◽  
Postural Task

Abstract Purpose Action observation (AO) during motor imagery (MI), so-called AO + MI, has been proposed as a new form of non-physical training, but the neural mechanisms involved remains largely unknown. Therefore, this study aimed to explore whether there were similarities in the modulation of short-interval intracortical inhibition (SICI) during execution and mental simulation of postural tasks, and if there was a difference in modulation of SICI between AO + MI and AO alone. Method 21 young adults (mean ± SD = 24 ± 6.3 years) were asked to either passively observe (AO) or imagine while observing (AO + MI) or physically perform a stable and an unstable standing task, while motor evoked potentials and SICI were assessed in the soleus muscle. Result SICI results showed a modulation by condition (F2,40 = 6.42, p = 0.009) with less SICI in the execution condition compared to the AO + MI (p = 0.009) and AO (p = 0.002) condition. Moreover, switching from the stable to the unstable stance condition reduced significantly SICI (F1,20 = 8.34, p = 0.009) during both, physically performed (− 38.5%; p = 0.03) and mentally simulated balance (− 10%, p < 0.001, AO + MI and AO taken together). Conclusion The data demonstrate that SICI is reduced when switching from a stable to a more unstable standing task during both real task execution and mental simulation. Therefore, our results strengthen and further support the existence of similarities between executed and mentally simulated actions by showing that not only corticospinal excitability is similarly modulated but also SICI. This proposes that the activity of the inhibitory cortical network during mental simulation of balance tasks resembles the one during physical postural task execution.

scholarly journals Is it the coracobrachialis superior muscle, or is it an unidentified rare variant of coracobrachialis muscle?

2021 ◽  
Author(s):  
Łukasz Olewnik ◽  
Nicol Zielinska ◽  
Łukasz Gołek ◽  
Paloma Aragonés ◽  
Jose Ramon Sanudo
Keyword(s):  
Case Report ◽  
Rare Variant ◽  
Shoulder Joint ◽  
Biceps Brachii ◽  
Coracoid Process ◽  
Biceps Brachii Muscle ◽  
Shoulder Region

AbstractThe coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. The CBM demonstrates variability in both the proximal and distal attachment, with some extremely rare varieties, such as the coracobrachialis superior, coracobrachialis longus and coracocapsularis muscle. This case report describes an extremely rare variant of the coracobrachialis superior muscle, or a very rare variant of the CBM. Our findings highlight the importance of muscle variants in the shoulder region, especially the coracoid region, and are significant for radiologists, anatomists, physiotherapists and surgeons specializing in the shoulder joint.

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