Rapid prediction of biomechanical costs during action decisions

2014 ◽  
Vol 112 (6) ◽  
pp. 1256-1266 ◽  
Author(s):  
Ignasi Cos ◽  
Julie Duque ◽  
Paul Cisek
Keyword(s):  
Time Course ◽  
Primary Motor Cortex ◽  
Motor Evoked Potential ◽  
Single Pulse ◽  
Stimulus Presentation ◽  
Biomechanical Properties ◽  
Time Interval ◽  
Decision Task ◽  
Rapid Prediction ◽  
The One

When given a choice between actions that yield the same reward, we tend to prefer the one that requires the least effort. Recent studies have shown that humans are remarkably accurate at evaluating the effort of potential reaching actions and can predict the subtle energetic demand caused by the nonisotropic biomechanical properties of the arm. In the present study, we investigated the time course over which such information is computed and comes to influence decisions. Two independent approaches were used. First, subjects performed a reach decision task in which the time interval for deciding between two candidate reaching actions was varied from 200 to 800 ms. Second, we measured motor-evoked potential (MEPs) to single-pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) to probe the evolving decision at different times after stimulus presentation. Both studies yielded a consistent conclusion: that a prediction of the effort associated with candidate movements is computed very quickly and influences decisions within 200 ms after presentation of the candidate actions. Furthermore, whereas the MEPs measured 150 ms after stimulus presentation were well correlated with the choices that subjects ultimately made, later in the trial the MEP amplitudes were primarily related to the muscular requirements of the chosen movement. This suggests that corticospinal excitability (CSE) initially reflects a competition between candidate actions and later changes to reflect the processes of preparing to implement the winning action choice.

scholarly journals Mechanisms and Dynamics of Cortical Motor Inhibition in the Stop-signal Paradigm: A TMS Study

2010 ◽  
Vol 22 (2) ◽  
pp. 225-239 ◽  
Author(s):  
Wery P. M. van den Wildenberg ◽  
Borís Burle ◽  
Franck Vidal ◽  
Maurits W. van der Molen ◽  
K. Richard Ridderinkhof ◽  
...  
Keyword(s):  
Time Course ◽  
Primary Motor Cortex ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Single Pulse ◽  
Stop Signal ◽  
Neural Basis ◽  
Manual Response ◽  
Inhibitory Circuits ◽  
Voluntary Behavior

The ability to stop ongoing motor responses in a split-second is a vital element of human cognitive control and flexibility that relies in large part on prefrontal cortex. We used the stop-signal paradigm to elucidate the engagement of primary motor cortex (M1) in inhibiting an ongoing voluntary motor response. The stop-signal paradigm taps the ability to flexibly countermand ongoing voluntary behavior upon presentation of a stop signal. We applied single-pulse TMS to M1 at several intervals following the stop signal to track the time course of excitability of the motor system related to generating and stopping a manual response. Electromyography recorded from the flexor pollicis brevis allowed quantification of the excitability of the corticospinal tract and the involvement of intracortical GABABergic circuits within M1, indexed respectively by the amplitude of the motor-evoked potential and the duration of the late part of the cortical silent period (SP). The results extend our knowledge of the neural basis of inhibitory control in three ways. First, the results revealed a dynamic interplay between response activation and stopping processes at M1 level during stop-signal inhibition of an ongoing response. Second, increased excitability of inhibitory interneurons that drives SP prolongation was evident as early as 134 msec following the instruction to stop. Third, this pattern was followed by a stop-related reduction of corticospinal excitability implemented around 180 after the stop signal. These findings point to the recruitment of GABABergic intracortical inhibitory circuits within M1 in stop-signal inhibition and support the notion of stopping as an active act of control.

scholarly journals Chronic low-frequency rTMS of primary motor cortex diminishes exercise training-induced gains in maximal voluntary force in humans

2009 ◽  
Vol 106 (2) ◽  
pp. 403-411 ◽  
Author(s):  
Tibor Hortobágyi ◽  
Sarah Pirio Richardson ◽  
Mikhael Lomarev ◽  
Ejaz Shamim ◽  
Sabine Meunier ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Motor Evoked Potential ◽  
Single Pulse ◽  
Compound Action Potential ◽  
Voluntary Contraction ◽  
Maximal Voluntary Force ◽  
Resting Motor Threshold

Although there is consensus that the central nervous system mediates the increases in maximal voluntary force (maximal voluntary contraction, MVC) produced by resistance exercise, the involvement of the primary motor cortex (M1) in these processes remains controversial. We hypothesized that 1-Hz repetitive transcranial magnetic stimulation (rTMS) of M1 during resistance training would diminish strength gains. Forty subjects were divided equally into five groups. Subjects voluntarily (Vol) abducted the first dorsal interosseus (FDI) (5 bouts × 10 repetitions, 10 sessions, 4 wk) at 70–80% MVC. Another group also exercised but in the 1-min-long interbout rest intervals they received rTMS [Vol+rTMS, 1 Hz, FDI motor area, 300 pulses/session, 120% of the resting motor threshold (rMT)]. The third group also exercised and received sham rTMS (Vol+Sham). The fourth group received only rTMS (rTMS_only). The 37.5% and 33.3% gains in MVC in Vol and Vol+Sham groups, respectively, were greater ( P = 0.001) than the 18.9% gain in Vol+rTMS, 1.9% in rTMS_only, and 2.6% in unexercised control subjects who received no stimulation. Acutely, within sessions 5 and 10, single-pulse TMS revealed that motor-evoked potential size and recruitment curve slopes were reduced in Vol+rTMS and rTMS_only groups and accumulated to chronic reductions by session 10. There were no changes in rMT, maximum compound action potential amplitude (Mmax), and peripherally evoked twitch forces in the trained FDI and the untrained abductor digiti minimi. Although contributions from spinal sources cannot be excluded, the data suggest that M1 may play a role in mediating neural adaptations to strength training.

scholarly journals Primary Motor Cortex Excitability Is Modulated During the Mental Simulation of Hand Movement

2017 ◽  
Vol 23 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Christian Hyde ◽  
Ian Fuelscher ◽  
Jarrad A.G. Lum ◽  
Jacqueline Williams ◽  
Jason He ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Hand Movement ◽  
Single Pulse ◽  
Stimulus Presentation ◽  
Mental Simulation ◽  
Right Hand ◽  
Hand Laterality ◽  
Motor Cortex Excitability

AbstractObjectives:It is unclear whether the primary motor cortex (PMC) is involved in the mental simulation of movement [i.e., motor imagery (MI)]. The present study aimed to clarify PMC involvement using a highly novel adaptation of the hand laterality task (HLT).Methods:Participants were administered single-pulse transcranial magnetic stimulation (TMS) to the hand area of the left PMC (hPMC) at either 50 ms, 400 ms, or 650 ms post stimulus presentation. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous via electromyography. To avoid the confound of gross motor response, participant response (indicating left or right hand) was recorded via eye tracking. Participants were 22 healthy adults (18 to 36 years), 16 whose behavioral profile on the HLT was consistent with the use of a MI strategy (MI users).Results:hPMC excitability increased significantly during HLT performance for MI users, evidenced by significantly larger right hand MEPs following single-pulse TMS 50 ms, 400 ms, and 650 ms post stimulus presentation relative to baseline. Subsequent analysis showed that hPMC excitability was greater for more complex simulated hand movements, where hand MEPs at 50 ms were larger for biomechanically awkward movements (i.e., hands requiring lateral rotation) compared to simpler movements (i.e., hands requiring medial rotation).Conclusions:These findings provide support for the modulation of PMC excitability during the HLT attributable to MI, and may indicate a role for the PMC during MI. (JINS, 2017,23, 185–193)

Different Brain Activities Predict Retrieval Success during Emotional and Semantic Encoding

2011 ◽  
Vol 23 (12) ◽  
pp. 4008-4021 ◽  
Author(s):  
Tullia Padovani ◽  
Thomas Koenig ◽  
Daniel Brandeis ◽  
Walter J. Perrig
Keyword(s):  
Electric Fields ◽  
Incidental Learning ◽  
Stimulus Presentation ◽  
Brain Structures ◽  
Stimulus Onset ◽  
Memory Formation ◽  
Time Interval ◽  
Decision Task ◽  
Relative Contribution ◽  
Incidental Encoding

There is an increasing line of evidence supporting the idea that the formation of lasting memories involves neural activity preceding stimulus presentation. Following this line, we presented words in an incidental learning setting and manipulated the prestimulus state by asking the participants to perform either an emotional (neutral or emotional) or a semantic (animate or inanimate) decision task. Later, we tested the retrieval of each previously presented word with a recognition memory test. For both conditions, the subsequent memory effect (SME) was defined as ERP difference between subsequently remembered and forgotten words. Comparing the prestimulus SME between and within the two conditions yielded topographic differences in the time interval from −1300 to −700 msec before stimulus onset. This indicates that the activity of brain areas involved in incidental encoding of semantic information varied in the spatial distribution of ERPs, depending on the emotional and semantic requirements of the task. These findings provide evidence that there is a difference in semantic and emotional preparatory processes, which modulates successful encoding into episodic memory. This difference suggests that there are multiple task-specific functional neural systems that support memory formation. These systems differ in location and/or relative contribution of some of the brain structures that generate the measured scalp electric fields. Consequently, the cognitive processes that enable memory formation depend on the differential semantic nature of the study task and reflect differences in the preparatory processing of the multiple semantic components of a word's meaning.

scholarly journals A new measure of cortical inhibition by mechanomyography and paired-pulse transcranial magnetic stimulation in unanesthetized rats

2012 ◽  
Vol 107 (3) ◽  
pp. 966-972 ◽  
Author(s):  
Tsung-Hsun Hsieh ◽  
Sameer C. Dhamne ◽  
Jia-Jin J. Chen ◽  
Alvaro Pascual-Leone ◽  
Frances E. Jensen ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Time Course ◽  
Cortical Excitability ◽  
Motor Evoked Potential ◽  
Single Pulse ◽  
Cortical Inhibition ◽  
Testing Time ◽  
Paired Pulse ◽  
Awake Rats

Paired-pulse transcranial magnetic stimulation (ppTMS) is a safe and noninvasive tool for measuring cortical inhibition in humans, particularly in patients with disorders of cortical inhibition such as epilepsy. However, ppTMS protocols in rodent disease models, where mechanistic insight into the ppTMS physiology and into disease processes may be obtained, have been limited due to the requirement for anesthesia and needle electromyography. To eliminate the confounding factor of anesthesia and to approximate human ppTMS protocols in awake rats, we adapted the mechanomyogram (MMG) method to investigate the ppTMS inhibitory phenomenon in awake rats and then applied differential pharmacology to test the hypothesis that long-interval cortical inhibition is mediated by the GABAA receptor. Bilateral hindlimb-evoked MMGs were elicited in awake rats by long-interval ppTMS protocols with 50-, 100-, and 200-ms interstimulus intervals. Acute changes in ppTMS-MMG were measured before and after intraperitoneal injections of saline, the GABAA agonist pentobarbital (PB), and GABAA antagonist pentylenetetrazole (PTZ). An evoked MMG was obtained in 100% of animals by single-pulse stimulation, and ppTMS resulted in predictable inhibition of the test-evoked MMG. With increasing TMS intensity, MMG amplitudes increased in proportion to machine output to produce reliable input-output curves. Simultaneous recordings of electromyography and MMG showed a predictable latency discrepancy between the motor-evoked potential and the evoked MMG (7.55 ± 0.08 and 9.16 ± 0.14 ms, respectively). With pharmacological testing, time course observations showed that ppTMS-MMG inhibition was acutely reduced following PTZ ( P < 0.05), acutely enhanced after PB ( P < 0.01) injection, and then recovered to pretreatment baseline after 1 h. Our data support the application of the ppTMS-MMG technique for measuring the cortical excitability in awake rats and provide the evidence that GABAA receptor contributes to long-interval paired-pulse cortical inhibition. Thus ppTMS-MMG appears a well-tolerated biomarker for measuring GABAA-mediated cortical inhibition in rats.

The Time Course of Motoneuronal Excitability during the Preparation of Complex Movements

2019 ◽  
Vol 31 (6) ◽  
pp. 781-790 ◽  
Author(s):  
Michael Kennefick ◽  
Joel S. Burma ◽  
Paul van Donkelaar ◽  
Chris J. McNeil
Keyword(s):  
Time Course ◽  
Cortical Excitability ◽  
Motor Evoked Potential ◽  
Corticospinal Excitability ◽  
Prime Mover ◽  
Triceps Brachii ◽  
Cortical Level ◽  
Movement Complexity ◽  
The One ◽  
Simple Rt

For a simple RT task, movement complexity increases RT and also corticospinal excitability, as measured by the motor evoked potential (MEP) elicited by TMS of the motor cortex. However, it is unknown if complexity-related increases in corticospinal excitability during the preparation of movement are mediated at the cortical or spinal level. The purposes of this study were to establish a time course of motoneuronal excitability before prime mover activation and to assess task-dependent effects of complex movements on motoneuronal and cortical excitability in a simple RT paradigm. It was hypothesized that motoneuronal and cortical excitability would increase before prime mover activation and in response to movement complexity. In a seated position, participants completed ballistic elbow extension/flexion movements with their dominant arm to one, two, or three targets. TMS and transmastoid stimulation (TS) were delivered at 0%, 70%, 80% or 90% of mean premotor RT for each complexity level. Stimulus intensities were set to elicit MEPs and cervicomedullary MEPs (CMEPs) of ∼10% of the maximal M-wave in the triceps brachii. Compared with 0% RT, motoneuronal excitability (CMEP amplitude) was already 10% greater at 70% RT. CMEP amplitude also increased with movement complexity as both the two- and three-movement conditions had greater motoneuronal excitability than the one-movement condition ( p < .038). Importantly, when normalized to the CMEP, there was no increase in MEP amplitude. This suggests that complexity-related increases in corticospinal excitability are likely to be mediated more by increased excitability at a motoneuronal than cortical level.

Action processing in the motor system: TMS evidence of shared mechanisms in the visual and linguistic modalities.

2018 ◽  
Author(s):  
Claudia Gianelli ◽  
Katharina Kühne ◽  
Silvia Mencaraglia ◽  
Riccardo Dalla Volta
Keyword(s):  
Motor System ◽  
Native Speakers ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Stimulus Presentation ◽  
Corticospinal Excitability ◽  
First Dorsal Interosseous ◽  
Action Processing ◽  
Abductor Digiti Minimi ◽  
Hand Action

In two experiments, we compared the dynamics of corticospinal excitability when processing visually or linguistically presented tool-oriented hand actions in native speakers and sequential bilinguals. In a third experiment we used the same procedure to test non-motor, low-level stimuli, i.e. scrambled images and pseudo-words. Stimuli were presented in sequence: pictures (tool + tool-oriented hand action or their scrambled counterpart) and words (tool noun + tool-action verb or pseudo-words). Experiment 1 presented German linguistic stimuli to native speakers, while Experiment 2 presented English stimuli to non-natives. Experiment 3 tested Italian native speakers. Single-pulse trascranial brain stimulation (spTMS) was applied to the left motor cortex at five different timings: baseline, 200ms after tool/noun onset, 150, 350 and 500ms after hand/verb onset with motor-evoked potentials (MEPs) recorded from the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles.We report strong similarities in the dynamics of corticospinal excitability across the visual and linguistic modalities. MEPs’ suppression started as early as 150ms and lasted for the duration of stimulus presentation (500ms). Moreover, we show that this modulation is absent for stimuli with no motor content. Overall, our study supports the notion of a core, overarching system of action semantics shared by different modalities.

scholarly journals Motor disability in patients with multiple sclerosis: transcranial magnetic stimulation study

2020 ◽  
Vol 56 (1) ◽  
Author(s):  
Anssam Bassem Mohy ◽  
Aqeel Kareem Hatem ◽  
Hussein Ghani Kadoori ◽  
Farqad Bader Hamdan
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Lower Limb ◽  
Magnetic Stimulation ◽  
Motor Evoked Potential ◽  
Invasive Procedure ◽  
Single Pulse ◽  
Lower Limbs ◽  
Control Group ◽  
Conduction Time ◽  
Motor Disability

Abstract Background Transcranial magnetic stimulation (TMS) is a non-invasive procedure used in a small targeted region of the brain via electromagnetic induction and used diagnostically to measure the connection between the central nervous system (CNS) and skeletal muscle to evaluate the damage that occurs in MS. Objectives The study aims to investigate whether single-pulse TMS measures differ between patients with MS and healthy controls and to consider if these measures are associated with clinical disability. Patients and methods Single-pulse TMS was performed in 26 patients with MS who hand an Expanded Disability Status Scale (EDSS) score between 0 and 9.5 and in 26 normal subjects. Different TMS parameters from upper and lower limbs were investigated. Results TMS disclosed no difference in all MEP parameters between the right and left side of the upper and lower limbs in patients with MS and controls. In all patients, TMS parameters were different from the control group. Upper limb central motor conduction time (CMCT) was prolonged in MS patients with pyramidal signs. Upper and lower limb CMCT and CMCT-f wave (CMCT-f) were prolonged in patients with ataxia. Moreover, CMCT and CMCT-f were prolonged in MS patients with EDSS of 5–9.5 as compared to those with a score of 0–4.5. EDSS correlated with upper and lower limb cortical latency (CL), CMCT, and CMCT-f whereas motor evoked potential (MEP) amplitude not. Conclusion TMS yields objective data to evaluate clinical disability and its parameters correlated well with EDSS.

scholarly journals Online and offline effects of transcranial alternating current stimulation of the primary motor cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan Pozdniakov ◽  
Alicia Nunez Vorobiova ◽  
Giulia Galli ◽  
Simone Rossi ◽  
Matteo Feurra
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Random Noise ◽  
Single Pulse ◽  
Alternating Current ◽  
Online Application ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

AbstractTranscranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows interaction with endogenous cortical oscillatory rhythms by means of external sinusoidal potentials. The physiological mechanisms underlying tACS effects are still under debate. Whereas online (e.g., ongoing) tACS over the motor cortex induces robust state-, phase- and frequency-dependent effects on cortical excitability, the offline effects (i.e. after-effects) of tACS are less clear. Here, we explored online and offline effects of tACS in two single-blind, sham-controlled experiments. In both experiments we used neuronavigated transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) as a probe to index changes of cortical excitability and delivered M1 tACS at 10 Hz (alpha), 20 Hz (beta) and sham (30 s of low-frequency transcranial random noise stimulation; tRNS). Corticospinal excitability was measured by single pulse TMS-induced motor evoked potentials (MEPs). tACS was delivered online in Experiment 1 and offline in Experiment 2. In Experiment 1, the increase of MEPs size was maximal with the 20 Hz stimulation, however in Experiment 2 neither the 10 Hz nor the 20 Hz stimulation induced tACS offline effects. These findings support the idea that tACS affects cortical excitability only during online application, at least when delivered on the scalp overlying M1, thereby contributing to the development of effective protocols that can be applied to clinical populations.

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