Direct Evidence for a Binding between Cognitive and Motor Functions in Humans: A TMS Study

2003 ◽  
Vol 15 (8) ◽  
pp. 1207-1216 ◽  
Author(s):  
Mireille Bonnard ◽  
Mickael Camus ◽  
Jozina de Graaf ◽  
Jean Pailhous
Keyword(s):  
Motor Performance ◽  
Muscle Activation ◽  
Direct Evidence ◽  
Motor Behavior ◽  
Motor Evoked Potentials ◽  
Cognitive Effort ◽  
Short Latency ◽  
The One ◽  
Motor Actions ◽  
Prior Intention

During voluntary motor actions, the cortico-spinal (CS) excitability is known to be modulated, on the one hand by cognitive (intention-related) processes and, on the other hand, by motor (performance-related) processes. Here, we studied the way these processes interact in the tuning of CS excitability during voluntary wrist movement. We used transcranial magnetic stimulation (TMS) both as a reliable tool for quantifying the CS excitability, through the motor-evoked potentials (MEPs), and as a central perturbation evoking a movement (because the stimulation intensity was above threshold) with subjects instructed to prepare (without changing their muscle activation) either to “let go” or to “resist” to this evoked movement. We studied the simultaneous evolution of both the motor performance and the MEPs in the wrist flexor and extensor, separately for the successful trials (on average, 66% of the trials whatever the condition) and the unsuccessful trials; this allowed us to dissociate the intentionand performance-related processes. To their great surprise, subjects were found able to cognitively prepare themselves to resist a TMS-induced central perturbation; they all reported an important cognitive effort on the evoked movement. Moreover, because TMS only evoked short-latency MEPs (and no long-latency components), the amplitude of these short-latency MEPs was found to be related in a continuous way to the actual movement whatever the prior intention. These results demonstrate that prior intention allows an anticipatory modulation of the CS excitability, which is not only selective (as already known) but also efficient, giving the intended motor behavior a real chance to be realized. This constitutes a direct evidence of the role of the CS excitability in the binding between cognitive and motor processes in humans.

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.

DISTRIBUTIONS OF LOCAL MANDELBROT-HURST EXPONENTS: MOTOR ACTIVITY IN FETAL RATS OF COCAINIZED MOTHERS AND MANIC-DEPRESSIVE PATIENTS

Fractals ◽  
1995 ◽  
Vol 03 (04) ◽  
pp. 893-904 ◽  
Author(s):  
KAREN A. SELZ ◽  
ARNOLD J. MANDELL ◽  
CARL M. ANDERSON ◽  
WILLIAM P. SMOTHERMAN ◽  
MARTIN H. TEICHER
Keyword(s):  
Time Series ◽  
Motor Activity ◽  
Motor Behavior ◽  
Pregnant Rats ◽  
Behavioral Systems ◽  
Statistical Indices ◽  
Manic Depressive ◽  
The One ◽  
Depressive Patients ◽  
Hurst Exponents

Intermittency, in which the normalized weight of large fluctuations grows for increasingly longer statistical samples, is seen as irregular bursting activity in time and is characteristic of the behavior of many brain and behavioral systems. This pattern has been related to the brain-stabilizing interplay of the general mechanisms of silence-evoked sensitization and activity-evoked desensitization, which can be found at most levels of neurobiological function and which vary more smoothly and at much longer times than the phasic observables. We use both the global Mandelbrot-Hurst exponent and the distribution of local Mandelbrot-Hurst exponents, in combination with dynamical entropies, to quantitate the property of nonuniform persistence which we treat as both deterministically expansive and statistically diffusive. For example, varying the parameter of the one-dimensional, Manneville-Pomeau intermittency map generated time series which demonstrated systematic changes in these statistical indices of persistence. Relatively small doses of cocaine administered to pregnant rats increased statistical indices of expansiveness and persistence in fetal motor behavior. These techniques also model and characterize a breakdown of statistical scaling in 72-hour time series of the amount of motor activity in some hospitalized manic-depressive patients.

The Origins of Domestic Sheep and Goats: a Reconsideration in the Light of the Fossil Evidence

1969 ◽  
Vol 34 ◽  
pp. 368-384 ◽  
Author(s):  
Sebastian Payne
Keyword(s):  
Direct Evidence ◽  
Present Situation ◽  
Wild Relatives ◽  
The Other ◽  
Domestic Sheep ◽  
Sheep And Goats ◽  
Animal Domestication ◽  
The Past ◽  
The One ◽  
And Control

In recent discussions of the origins and process of animal domestication (Reed, 1961, Zeuner, 1963), both authors rely on two kinds of evidence: on the one hand, the present distributions and characteristics of the different breeds of whatever animal is being discussed, together with its feral and wild relatives, and, on the other hand, the past record, given by literary and pictorial sources and the bones from archaeological and geological sites. Increased recognition of the limitations of the past record, whether in the accuracy of the information it appears to give (as in the case of pictorial sources), or in the certainty of the deductions we are at present capable of drawing from it (this applies especially to the osteological record), has led these authors to argue mainly from the present situation, using the past record to confirm or amplify the existing picture.Arguing from the present, many hypotheses about the origins and process of domestication are available. The only test we have, when attempting to choose between these, lies in the direct evidence of the past record. The past record, it is freely admitted, is very fragmentary: the information provided by the present situation is more exact, ranges over a much wider field, and is more open to test and control. Nevertheless, the past record, however imperfect it is, is the only direct evidence we have about the process of domestication.

scholarly journals Central excitability does not limit postfatigue voluntary activation of quadriceps femoris

2006 ◽  
Vol 100 (6) ◽  
pp. 1757-1764 ◽  
Author(s):  
J. M. Kalmar ◽  
E. Cafarelli
Keyword(s):  
Evoked Potentials ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Motor Evoked Potentials ◽  
Vastus Lateralis ◽  
Central Fatigue ◽  
Knee Extension ◽  
Voluntary Activation ◽  
Fatigue Protocol ◽  
Central Excitability

After fatigue, motor evoked potentials (MEP) elicited by transcranial magnetic stimulation and cervicomedullary evoked potentials elicited by stimulation of the corticospinal tract are depressed. These reductions in corticomotor excitability and corticospinal transmission are accompanied by voluntary activation failure, but this may not reflect a causal relationship. Our purpose was to determine whether a decline in central excitability contributes to central fatigue. We hypothesized that, if central excitability limits voluntary activation, then a caffeine-induced increase in central excitability should offset voluntary activation failure. In this repeated-measures study, eight men each attended two sessions. Baseline measures of knee extension torque, maximal voluntary activation, peripheral transmission, contractile properties, and central excitability were made before administration of caffeine (6 mg/kg) or placebo. The amplitude of vastus lateralis MEPs elicited during minimal muscle activation provided a measure of central excitability. After a 1-h rest, baseline measures were repeated before, during, and after a fatigue protocol that ended when maximal voluntary torque declined by 35% (Tlim). Increased prefatigue MEP amplitude ( P = 0.055) and cortically evoked twitch ( P < 0.05) in the caffeine trial indicate that the drug increased central excitability. In the caffeine trial, increased MEP amplitude was correlated with time to task failure ( r = 0.74, P < 0.05). Caffeine potentiated the MEP early in the fatigue protocol ( P < 0.05) and offset the 40% decline in placebo MEP ( P < 0.05) at Tlim. However, this was not associated with enhanced maximal voluntary activation during fatigue or recovery, demonstrating that voluntary activation is not limited by central excitability.

scholarly journals An internal model approach for motor behavior

2021 ◽  
Vol 15 (5) ◽  
pp. 356-371
Author(s):  
Cláudio M. F. Leite ◽  
Carlos E. Campos ◽  
Crislaine R. Couto ◽  
Herbert Ugrinowitsch
Keyword(s):  
Motor Skills ◽  
Internal Model ◽  
Motor Behavior ◽  
External World ◽  
Internal Models ◽  
Sensory Inputs ◽  
Theoretical Approaches ◽  
Internal Coherence ◽  
Motor Actions ◽  
Model Approach

Interacting with the environment requires a remarkable ability to control, learn, and adapt motor skills to ever-changing conditions. The intriguing complexity involved in the process of controlling, learning, and adapting motor skills has led to the development of many theoretical approaches to explain and investigate motor behavior. This paper will present a theoretical approach built upon the top-down mode of motor control that shows substantial internal coherence and has a large and growing body of empirical evidence: The Internal Models. The Internal Models are representations of the external world within the CNS, which learn to predict this external world, simulate behaviors based on sensory inputs, and transform these predictions into motor actions. We present the Internal Models’ background based on two main structures, Inverse and Forward models, explain how they work, and present some applicability.

The Stoic Ontology of Geometrical Limits

Phronesis ◽  
2009 ◽  
Vol 54 (4-5) ◽  
pp. 371-389 ◽  
Author(s):  
Anna Eunyoung Ju
Keyword(s):  
Direct Evidence ◽  
The Other ◽  
Specific Topic ◽  
Textual Evidence ◽  
The One ◽  
Metaphysical Status

AbstractScholars have long recognised the interest of the Stoics' thought on geometrical limits, both as a specific topic in their physics and within the context of the school's ontological taxonomy. Unfortunately, insufficient textual evidence remains for us to reconstruct their discussion fully. The sources we do have on Stoic geometrical themes are highly polemical, tending to reveal a disagreement as to whether limit is to be understood as a mere concept, as a body or as an incorporeal. In my view, this disagreement held among the historical Stoics, rather than simply reflecting a doxographical divergence in transmission. This apparently Stoic disagreement has generated extensive debate, in which there is still no consensus as to a standard Stoic doctrine of limit. The evidence is thin, and little of it refers in detail to specific texts, especially from the school's founders. But in its overall features the evidence suggests that Posidonius and Cleomedes differed from their Stoic precursors on this topic. There are also grounds for believing that some degree of disagreement obtained between the early Stoics over the metaphysical status of shape. Assuming the Stoics did so disagree, the principal question in the scholarship on Stoic ontology is whether there were actually positions that might be called "standard" within Stoicism on the topic of limit. In attempting to answer this question, my discussion initially sets out to illuminate certain features of early Stoic thinking about limit, and then takes stock of the views offered by late Stoics, notably Posidonius and Cleomedes. Attention to Stoic arguments suggests that the school's founders developed two accounts of shape: on the one hand, as a thought-construct, and, on the other, as a body. In an attempt to resolve the crux bequeathed to them, the school's successors suggested that limits are incorporeal. While the authorship of this last notion cannot be securely identified on account of the absence of direct evidence, it may be traced back to Posidonius, and it went on to have subsequent influence on Stoic thinking, namely in Cleomedes' astronomy.

Interaction Between Finger Opposition Movements and Aftereffects of 1Hz-rTMS on Ipsilateral Motor Cortex

2009 ◽  
Vol 101 (3) ◽  
pp. 1690-1694 ◽  
Author(s):  
Laura Avanzino ◽  
Marco Bove ◽  
Andrea Tacchino ◽  
Carlo Trompetto ◽  
Carla Ogliastro ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Performance ◽  
Magnetic Stimulation ◽  
Voluntary Movement ◽  
Motor Behavior ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Motor Task ◽  
The Other ◽  
Experimental Conditions ◽  
Opposition Movements

One-hertz repetitive transcranial magnetic stimulation (1Hz-rTMS) over ipsilateral motor cortex is able to modify up to 30 min the motor performance of repetitive finger opposition movements paced with a metronome at 2 Hz. We investigated whether the long-lasting rTMS effect on motor behavior can be modulated by subsequent engagement of the contralateral sensorimotor system. Motor task was performed in different experimental conditions: immediately after rTMS, 30 min after rTMS, or when real rTMS was substituted with sham rTMS. Subjects performing the motor task immediately after rTMS showed modifications in motor behavior ≤30 min after rTMS. On the other hand, when real rTMS was substituted with sham stimulation or when subjects performed the motor task 30 min after the rTMS session, the effect was no longer present. These findings suggest that the combination of ipsilateral 1Hz-rTMS and voluntary movement is crucial to endure the effect of rTMS on the movement itself, probably acting on synaptic plasticity-like mechanism. This finding might provide some useful hints for neurorehabilitation protocols.

Control Mechanisms in Oscillatory Motor Behavior

2013 ◽  
Author(s):  
Davide Piovesan ◽  
Felix C. Huang
Keyword(s):  
Muscle Activation ◽  
Motor Behavior ◽  
Rhythmic Movement ◽  
Control Mechanisms ◽  
Rhythmic Movements ◽  
Movement Trajectories ◽  
Reduced Frequency ◽  
The Central Nervous System ◽  
Human Motor ◽  
Inertial Loading

Studies on unimpaired humans have demonstrated that the central nervous system employs internal representations of limb dynamics and intended movement trajectories for planning muscle activation during pointing and reaching tasks. However, when performing rhythmic movements, it has been hypothesized that a control scheme employing an autonomous oscillator — a simple feedback circuit lacking exogenous input — can maintain stable control. Here we investigate whether such simple control architectures that can realize rhythmic movement that we observe in experimental data. We asked subjects to perform rhythmic movements of the forearm while a robotic interface simulated inertial loading. Our protocol included unexpected increases in loading (catch trials) as a probe to reveal any systematic changes in frequency and amplitude. Our primary findings were that increased inertial loading resulted in reduced frequency of oscillations, and in some cases multiple frequencies. These results exhibit some agreement with an autonomous oscillator model, though other features are more consistent with feedforward planning of force. This investigation provides a theoretical and experimental framework to reveal basic computational elements for how the human motor system achieves skilled rhythmic movement.

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