P071 Intracortical inhibition and facilitation in discrete motor representations of hand muscles in frontal lobe

Chen, Robert, Alda Tam, Cathrin Bütefisch, Brian Corwell, Ulf Ziemann, John C. Rothwell, and Leonardo G. Cohen. Intracortical inhibition and facilitation in different representations of the human motor cortex. J. Neurophysiol. 80: 2870–2881, 1998. Intracortical inhibition (ICI) and intracortical facilitation (ICF) of the human motor cortex can be studied with paired transcranial magnetic stimulation (TMS). Plastic changes and some neurological disorders in humans are associated with changes in ICI and ICF. Although well characterized in the hand representation, it is not known if ICI and ICF vary across different body part representations. Therefore we studied ICI and ICF in different motor representations of the human motor cortex. The target muscles were rectus abdominus (RA), biceps brachii (BB), abductor pollicis brevis (APB), quadriceps femoris (QF), and abductor hallucis (AH). For each muscle, we measured the rest and active motor thresholds (MTs), the motor-evoked potential (MEP) stimulus-response curve (MEP recruitment), ICI, and ICF. The effects of different interstimulus intervals (ISIs) were studied with a conditioning stimulus (CS) intensity of 80% active MT. The effects of different CS intensities were studied at ISI of 2 ms for ICI and ISI of 15 ms for ICF. MT was lowest for APB, followed by BB, AH, and QF, and was highest for RA. Except for BB, MEP recruitment was generally steeper for muscles with lower MT. ICI and ICF were present in all the motor representations tested. The stimulus intensity necessary to elicit ICI was consistently lower than that required to elicit ICF, suggesting that they are mediated by separate mechanisms. Despite wide differences in MT and MEP recruitment, the absolute CS intensities (expressed as percentage of the stimulator's output) required to elicit ICI and ICF appear unrelated to MT and MEP recruitment in the different muscles tested. These findings suggest that the intracortical mechanisms for inhibition and facilitation in different motor representations are not related to the strength of corticospinal projections.

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Intracortical Inhibition and Facilitation after congenital stroke

Klinische Neurophysiologie ◽

10.1055/s-2006-939101 ◽

2006 ◽

Vol 37 (01) ◽

Author(s):

S Berweck ◽

V Brodbeck ◽

M Walther ◽

N Wagner ◽

M Staudt ◽

...

Keyword(s):

Intracortical Inhibition ◽

Intracortical Inhibition And Facilitation

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Intracortical Inhibition During Volitional Inhibition of Prepared Action

Journal of Neurophysiology ◽

10.1152/jn.01334.2005 ◽

2006 ◽

Vol 95 (6) ◽

pp. 3371-3383 ◽

Cited By ~ 192

Author(s):

James P. Coxon ◽

Cathy M. Stinear ◽

Winston D. Byblow

Keyword(s):

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Short Interval ◽

Intracortical Inhibition ◽

Corticomotor Excitability ◽

Hand Muscles ◽

Cortical Level ◽

A Site ◽

Intrinsic Hand Muscles ◽

Inhibitory Networks

Volitional inhibition is the voluntary prevention of a prepared movement. Here we ask whether primary motor cortex (M1) is a site of convergence of cortical activity associated with movement preparation and volitional inhibition. Volitional inhibition was studied by presenting a stop signal before execution of an anticipated response that requires a key lift to intercept a revolving dial. Motor evoked potentials (MEPs) were elicited in intrinsic hand muscles by transcranial magnetic stimulation (TMS) to assess corticomotor excitability and short interval intracortical inhibition (sICI) during task performance. The closer the stop cue was presented to the anticipated response, the harder it was for subjects to inhibit their response. Corticomotor pathway excitability was temporally modulated during volitional inhibition. Using subthreshold TMS, corticomotor excitability was reduced for Stop trials relative to Go trials from 140 ms after the cue. sICI was significantly greater for Stop trials compared with Go trials at a time that preceded the onset of muscle activity associated with the anticipated response. These results provide evidence that volitional inhibition is exerted at a cortical level and that inhibitory networks within M1 contribute to volitional inhibition of prepared action.

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Paired-Pulse TMS and Fine-Wire Recordings Reveal Short-Interval Intracortical Inhibition and Facilitation of Deep Multifidus Muscle Fascicles

PLoS ONE ◽

10.1371/journal.pone.0159391 ◽

2016 ◽

Vol 11 (8) ◽

pp. e0159391 ◽

Cited By ~ 5

Author(s):

Hugo Massé-Alarie ◽

Edith Elgueta Cancino ◽

Cyril Schneider ◽

Paul Hodges

Keyword(s):

Short Interval ◽

Intracortical Inhibition ◽

Multifidus Muscle ◽

Paired Pulse ◽

Fine Wire ◽

Muscle Fascicles ◽

Intracortical Inhibition And Facilitation

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P2-36. Short-interval intracortical inhibition and facilitation in Parkinson’s disease

Clinical Neurophysiology ◽

10.1016/j.clinph.2013.02.103 ◽

2013 ◽

Vol 124 (8) ◽

pp. e36

Author(s):

Yuichiro Shirota ◽

Yasuo Terao ◽

Shinya Ohminami ◽

Ryosuke Tsutsumi ◽

Yoshikazu Ugawa ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Short Interval ◽

Intracortical Inhibition ◽

Intracortical Inhibition And Facilitation

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Corticospinal excitability underlying digit force planning for grasping in humans

Journal of Neurophysiology ◽

10.1152/jn.00815.2013 ◽

2014 ◽

Vol 111 (12) ◽

pp. 2560-2569 ◽

Cited By ~ 13

Author(s):

Pranav Parikh ◽

Marco Davare ◽

Patrick McGurrin ◽

Marco Santello

Keyword(s):

Primary Motor Cortex ◽

Single Pulse ◽

Intracortical Inhibition ◽

Corticospinal Excitability ◽

Reach To Grasp ◽

Grasp Planning ◽

Sensorimotor Memory ◽

Force Planning ◽

Intracortical Inhibition And Facilitation

Control of digit forces for grasping relies on sensorimotor memory gained from prior experience with the same or similar objects and on online sensory feedback. However, little is known about neural mechanisms underlying digit force planning. We addressed this question by quantifying the temporal evolution of corticospinal excitability (CSE) using single-pulse transcranial magnetic stimulation (TMS) during two reach-to-grasp tasks. These tasks differed in terms of the magnitude of force exerted on the same points on the object to isolate digit force planning from reach and grasp planning. We also addressed the role of intracortical circuitry within primary motor cortex (M1) by quantifying the balance between short intracortical inhibition and facilitation using paired-pulse TMS on the same tasks. Eighteen right-handed subjects were visually cued to plan digit placement at predetermined locations on the object and subsequently to exert either negligible force (“low-force” task, LF) or 10% of their maximum pinch force (“high-force” task, HF) on the object. We found that the HF task elicited significantly smaller CSE than the LF task, but only when the TMS pulse coincided with the signal to initiate the reach. This force planning-related CSE modulation was specific to the muscles involved in the performance of both tasks. Interestingly, digit force planning did not result in modulation of M1 intracortical inhibitory and facilitatory circuitry. Our findings suggest that planning of digit forces reflected by CSE modulation starts well before object contact and appears to be driven by inputs from frontoparietal areas other than M1.

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Physiological changes underlying bilateral isometric arm voluntary contractions in healthy humans

Journal of Neurophysiology ◽

10.1152/jn.00678.2010 ◽

2011 ◽

Vol 105 (4) ◽

pp. 1594-1602 ◽

Cited By ~ 16

Author(s):

Demetris S. Soteropoulos ◽

Monica A. Perez

Keyword(s):

Tibialis Anterior ◽

Motor Evoked Potentials ◽

Short Interval ◽

Intracortical Inhibition ◽

Voluntary Contraction ◽

Triceps Brachii ◽

Hand Muscles ◽

Healthy Humans ◽

Simultaneous Activation ◽

The Right

Many bilateral motor tasks engage simultaneous activation of distal and proximal arm muscles, but little is known about their physiological interactions. Here, we used transcranial magnetic stimulation to examine motor-evoked potentials (MEPs), interhemispheric inhibition at a conditioning-test interval of 10 (IHI10) and 40 ms (IHI40), and short-interval intracortical inhibition (SICI) in the left first dorsal interosseous (FDI) muscle during isometric index finger abduction. The right side remained at rest or performed isometric voluntary contraction with the FDI, biceps or triceps brachii, or the tibialis anterior. Left FDI MEPs were suppressed to a similar extent during contraction of the right FDI and biceps and triceps brachii but remained unchanged during contraction of the right tibialis anterior. IHI10 and IHI40 were decreased during contraction of the right biceps and triceps brachii compared with contraction of the right FDI. SICI was increased during activation of the right biceps and triceps brachii and decreased during activation of the right FDI. The present results indicate that an isometric voluntary contraction with either a distal or a proximal arm muscle, but not a foot dorsiflexor, decreases corticospinal output in a contralateral active finger muscle. Transcallosal inhibitory effects were strong during bilateral activation of distal hand muscles and weak during simultaneous activation of a distal and a proximal arm muscle, whereas GABAergic intracortical activity was modulated in the opposite manner. These findings suggest that in intact humans crossed interactions at the level of the motor cortex involved different physiological mechanisms when bilateral distal hand muscles are active and when a distal and a proximal arm muscle are simultaneously active.

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