Early neural responses to strength training

Selvanayagam, Victor S; Riek, Stephan; Carroll, Timothy J.

doi:10.1152/japplphysiol.00064.2011

Cited by 73 publications

(86 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Substantial performance gains are exhibited within a single session, which simplifies the use of brain stimulation methods such as TMS to assess the neural underpinnings of adaptation (Carroll et al 2008). Moreover, the neural responses to ballistic motor training are similar to those observed after strength training (Selvanayagam et al 2011). Accordingly, the model provides a window into the mechanisms underlying an important physical attribute that often limits function in old age and in patients with neurological disorders.…”

Section: Task and Proceduresmentioning

confidence: 96%

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

Stöckel

Carroll

Summers

et al. 2016

Journal of Neurophysiology

Self Cite

View full text Add to dashboard Cite

Performance benefits conferred in the untrained limb after unilateral motor practice are termed cross-limb transfer. Although the effect is robust, the neural mechanisms remain incompletely understood. In this study we used noninvasive brain stimulation to reveal that the neural adaptations that mediate motor learning in the trained limb are distinct from those that underlie cross-limb transfer to the opposite limb. Thirty-six participants practiced a ballistic motor task with their right index finger (150 trials), followed by intermittent theta-burst stimulation (iTBS) applied to the trained (contralateral) primary motor cortex (cM1 group), the untrained (ipsilateral) M1 (iM1 group), or the vertex (sham group). After stimulation, another 150 training trials were undertaken. Motor performance and corticospinal excitability were assessed before motor training, pre-and post-iTBS, and after the second training bout. For all groups, training significantly increased performance and excitability of the trained hand, and performance, but not excitability, of the untrained hand, indicating transfer at the level of task performance. The typical facilitatory effect of iTBS on MEPs was reversed for cM1, suggesting homeostatic metaplasticity, and prior performance gains in the trained hand were degraded, suggesting that iTBS interfered with learning. In stark contrast, iM1 iTBS facilitated both performance and excitability for the untrained hand. Importantly, the effects of cM1 and iM1 iTBS on behavior were exclusive to the hand contralateral to stimulation, suggesting that adaptations within the untrained M1 contribute to crosslimb transfer. However, the neural processes that mediate learning in the trained hemisphere vs. transfer in the untrained hemisphere appear distinct. ballistic motor learning; interlimb transfer; noninvasive brain stimulation; corticospinal excitability; motor performance

show abstract

Section: Task and Proceduresmentioning

confidence: 96%

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

Stöckel

Carroll

Summers

et al. 2016

Journal of Neurophysiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Our results are consistent with previous data from our laboratory, where twitch direction shifted significantly after training was performed at a distance of 90° away from the baseline twitch direction (Selvanayagam, et al, 2011). While some previous TMS studies, which involved repetitive ballistic thumb movements, reported that twitch directions shifted toward the training direction after 30 minutes of training at 180° away from baseline (Bütefisch et al, 2000;Bütefisch, et al, 2004;Classen, et al, 1998;Giacobbe, et al, 2011;Kaelin-Lang et al, 2005), we showed early neural adaptation occurred with a session of just 40 ballistic wrist contractions at 90° distance away from baseline (Selvanayagam, et al, 2011). The shift in twitch directions is likely to reflect the reweighting of connectivity among the forearm muscles to favour net force production in the training direction (Selvanayagam, et al, 2012a).…”

Section: Post Training Twitches In the Training Posturesupporting

confidence: 93%

“…In Chapter 5, we oriented the wrist into training and testing wrist postures and examined the resting twitch directions in these postures before and after a session of ballistic training. We sought to discover if ballistic contractions induce an adaptation toward the training direction in extrinsic or muscle-based reference frames, using the paradigm described by Selvanayagam et al (2011). We chose two wrist postures in our study so that a shift of twitch direction in one direction would imply extrinsic representation of use-dependent learning, whereas a shift in the other direction would imply a muscle-based representation.…”

Section: Pg 23mentioning

confidence: 99%

Interhemispheric interactions associated with unilateral ballistic motor tasks

Chye¹

View full text Add to dashboard Cite

The aim of this research was to enhance our understanding of the spatial reference frames in which movement is represented in the primary motor cortices of both hemispheres during unilateral ballistic actions. The broader goal was to reveal how the coordinate systems of movement representation influence the interactions between the two cerebral hemispheres which presumably underlie cross limb transfer of motor skill.The issue of reference frames may be critical for cross-limb interactions because definitions of space and movement often conflict for opposite limbs in intrinsicallyreferenced coordinate systems (e.g. muscle or joint-based coordinates) due to their mirror symmetry. This thesis describes a series of experiments to investigate the reference frames in which movement representations are shared bilaterally, and whether alignment of reference frames influences the transfer of performance to the untrained limb after unilateral ballistic training.There is increasing evidence that the primary motor cortex ipsilateral to the active limb is active during unilateral movement. Yet, the extent to which such activity represents functional details of movement with the ipsilateral limb, and the coordinates of any such representation, is unclear. Hence, Chapter 2 reports work aimed at understanding the timing and coordinates of interactions between the two motor cortices when movement with one hand is being prepared. Studying the time course of changes in twitch directions evoked by transcranial magnetic stimulation (TMS) enabled us to examine whether activity in the "resting" motor cortex functionally represents the impending movement, and the reference frame of any such representation. Our results showed that twitch directions in the resting limb shifted toward the impending direction of the active hand in a musclebased reference frame. Evident changes in TMS-evoked twitch parameters right before movement onset might be associated with decreases in interhemispheric inhibition and intracortical inhibition, brought about by the release of motor commands to the active limb.Use-dependent learning was previously reported to generalise according to extrinsic coordinates when posture changes were used to dissociate reference frames within the active limb, however it is unclear whether this form of learning generalises to the untrained limb. Chapter 3 assessed whether use-dependent bias in aiming performance occurred in the opposite untrained limb under postural manipulations that varied the extent to which spatial coordinates were aligned for the two limbs according to extrinsic, musclebased and midline reference frames. The results revealed that systematic bias occurred ii only when both limbs were oriented such that training and aiming targets were aligned according to all reference frames. The data suggest that aiming biases in the untrained limb after contralateral ballistic training are represented according to a combination of coordinate systems.In order to understand the role of reference frame conflicts in...

show abstract

“…The experiment was designed based on a previous motor control study of Classen et al (6) who showed that short-term practice of directionspecific thumb movements can change the direction of stimulation-evoked thumb twitches. As in this earlier study, Selvanayagam et al (12) used suprathreshold transcranial magnetic stimulation (TMS) to induce directionally consistent movements of the forearm. After the initial test, subjects underwent three different strength training sessions involving either 1) brief contractions or 2) sustained ballistic contractions or 3) slow, sustained contractions.…”

mentioning

confidence: 99%

“…This could be done by identifying the neural mechanisms underlying the changes in twitch torque direction and, in the next step, inhibit their formation. As Selvanayagam and coworkers (12) have transferred a well-explored motor learning paradigm into the field of strength training, comparisons can be easily made. For instance, LTP was shown to play a role in the skill acquisition after repetitive thumb movements on the basis of pharmacological evidence (3).…”

mentioning

confidence: 99%

“What trains together, gains together”: strength training strengthens not only muscles but also neural networks

Taube

2011

Journal of Applied Physiology

View full text Add to dashboard Cite

"WHAT FIRES TOGETHER, WIRES TOGETHER" (8): on the cellular level, the use-dependent plasticity of neural networks has been known for over 60 years. Dependent on the timing of pre-and postsynaptic activation, transmission across synapses can either be facilitated or inhibited (2). On the level of the whole organism, these neural adaptations are thought to be the first step in a series of others to improve specific motor skills. Thus, depending on the learning stage, motor skill acquisition involves different physiological processes. In the human motor cortex, for instance, long-term potentiation (LTP) is thought to occur at existing synapses during the early phase of motor skill learning, whereas later phases involve neural processes like synaptogenesis (10).Similar to motor skill learning, strength training comprises different stages, which differ with respect to the substrate of adaptation. The early force gains after strength training are thought to rely primarily on neural adaptations, while later on, structural changes within the tendomuscular system are considered to be predominant. So far, it is unknown whether the early neural plasticity after strength training relies on similar mechanisms than the one after motor skill training. Although previous electrophysiological strength training studies could indeed demonstrate that neural adaptations take place at the spinal and supraspinal level, the findings of those reports are inconsistent (for review, see 5): some studies assumed increased spinal excitability (e.g., 1, 13) while results obtained in other experiments suggested the opposite (e.g., 4). Similarly, some authors reported enhanced corticospinal excitability following strength training (7) whereas others did not (4, 9). These discrepancies may be due to a differential contribution of the central nervous system (CNS) in different strength tasks (static vs. dynamic, tonic vs. ballistic, etc.), may depend on the duration of the training intervention, and/or may be related to methodological reasons. In this respect it could be demonstrated that adaptations assessed at rest may differ from adaptations measured during activity (e.g., 1, 9). Furthermore, when subjects were tested during a task they had previously trained, changes of the corticospinal excitability were opposed to those observed after measurements in an unfamiliar task involving the same muscles (11).The above-mentioned examples highlight that there is the need for further research and especially new methodological approaches in order to gain a better understanding of the mechanisms related to strength training. In this issue of the Journal of Applied Physiology, Selvanayagam and colleagues (12) provide such a new insight in their paper "Early neural responses to strength training" as they have chosen an experimental set-up in which the neural plasticity in response to one single session of strength training, could be directly observed in changes of the behavioral outcome. The experiment was designed based on a previous motor control study of...

show abstract

Early neural responses to strength training

Cited by 73 publications

References 48 publications

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

Interhemispheric interactions associated with unilateral ballistic motor tasks

“What trains together, gains together”: strength training strengthens not only muscles but also neural networks

Contact Info

Product

Resources

About