Neural synchrony within the motor system: what have we learned so far?

Wijk, Bernadette C. M. van; Beek, Peter J.; Daffertshofer, Andreas

doi:10.3389/fnhum.2012.00252

Cited by 215 publications

(193 citation statements)

References 240 publications

(284 reference statements)

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“…First, movement occurs at a preferential phase of baseline tremor (5 -10 Hz) [24]. Second, short latency saccades are initiated at a preferential phase of 10 Hz alpha oscillations [25] (4) the frequency limit on single-digit movements is approximately 10 Hz, as demonstrated by the upper limit on typing speed at about 10 characters per second (http://10fastfingers.com/typing-test/english/top50) (5) single-unit [26] and field potentials [27,28] reveal oscillations in various frequency bands in motor cortex during actions (6) the psychological refractory period occurs when an individual has to complete two tasks that are separated by a certain time interval. If this time interval is too short, there is a bottleneck in performance, suggesting that some portion of processing occurs in a discrete, serial, oneafter-the-other manner [29].…”

Section: Resultsmentioning

confidence: 99%

Two-phase model of the basal ganglia: implications for discontinuous control of the motor system

Lisman

2014

Phil. Trans. R. Soc. B

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In this article, I point out that simple one-phase models of the role of the basal ganglia in action selection have a problem. Furthermore, I suggest a solution with major implications for the organization of the action-selection and motor systems. In current models, the striatum evaluates multiple potential actions by adding biases based on previous conditioning. These biases may arise in both the direct (bias for) and indirect (bias against) pathways. Together, these biases influence which action is ultimately chosen. For efficient conditioning to occur, a positive outcome must selectively strengthen the striatal bias for the chosen action (via a dopaminergic mechanism). This is problematic, however, because all potential action choices have influenced firing patterns in striatal cells during the selection process; it is therefore unclear how the synapses that represent the chosen plan could be selectively strengthened. I suggest a simple solution in which the striatum has two functional phases. In the first phase, the basal ganglia provide biases for multiple potential actions (using both the direct and indirect pathways), leading to the choice of a single action in the cortex. In the second phase, an efference copy of the chosen action is sent to the striatum, where it contributes to the establishment of the eligibility trace for that action. This trace, when acted on by subsequent dopaminergic reinforcement, leads to specific strengthening of the bias only for the chosen action. Consistent with this model, recordings show post-choice imposition onto the striatum of signals corresponding to the chosen action. The existence of dual phases of basal ganglia function implies that decisions about action choice are sent to the motor system in a discontinuous manner. This would not be problematic if the motor system also operated discontinuously. I will review evidence suggesting that this is the case, notably that action is organized by approximately 10 Hz oscillations.

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Section: Resultsmentioning

confidence: 99%

Two-phase model of the basal ganglia: implications for discontinuous control of the motor system

Lisman

2014

Phil. Trans. R. Soc. B

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“…Corticomuscular beta-band coherence is most prominent during tonic muscle contractions and disappears during movement (Baker et al, 1997;Riddle and Baker, 2006;Kilner et al, 2000;Baker et al, 1999) and beta-band activity is enhanced when higher precision is required Kristeva-Feige et al, 2002;Witte et al, 2007;Gilbertson et al, 2005). These findings suggest that the beta-band activity is related to a mechanism that maintains the current sensorimotor state (Baker, 2007;Engel and Fries, 2010;Van Wijk et al, 2012).…”

Section: Introductionmentioning

confidence: 89%

The reorganization of corticomuscular coherence during a transition between sensorimotor states

2014

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Recent research suggests that neural oscillations in di↵erent frequency bands support distinct and sometimes parallel processing streams in neural circuits. Studies of the neural dynamics of human motor control have primarily focused on oscillations in the beta band (15 30 Hz). During sustained muscle contractions, corticomuscular coherence is mainly present in the beta band, while coherence in the alpha (8 12 Hz) and gamma (30 80 Hz) bands has not been consistently found. Here we test the hypothesis that the frequency of corticomuscular coherence changes during transitions between sensorimotor states. Corticomuscular coherence was investigated in twelve participants making rapid transitions in force output between two targets. Corticomuscular coherence was present in the beta band during sustained contractions but vanished before movement onset, being replaced by transient synchronization in the alpha and gamma bands during dynamic force output. Analysis of the phase spectra suggested a time delay from muscle to cortex for alpha-band coherence, by contrast to a time delay from cortex to muscle for gamma-band coherence, indicating a↵erent and e↵erent corticospinal interactions respectively. Moreover, alpha and gamma -band coherence revealed distinct spatial topologies, suggesting di↵erent generative mechanisms. Coherence in the alpha and gamma bands was almost exclusively confined to trials showing a movement overshoot, suggesting a functional role related to error correction. We interpret the dual-band synchronization in the alpha and gamma bands as parallel streams of corticospinal processing involved in parsing prediction errors and generating new motor predictions.

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“…These fine tongue movements are accurately regulated by descending motor commands from the cortex to the tongue muscles and by afferent sensory feedback from the tongue muscles to the cortex. Such bi-directional functional connections between the cortex and muscles are mainly reflected in the cortico-muscular coherence (CMC) (Mima and Hallett, 1999;van Wijk et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Cortico-muscular synchronization by proprioceptive afferents from the tongue muscles during isometric tongue protrusion

et al. 2016

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Tongue movements contribute to oral functions including swallowing, vocalizing, and breathing. Fine tongue movements are regulated through efferent and afferent connections between the cortex and tongue. It has been demonstrated that cortico-muscular coherence (CMC) is reflected at two frequency bands during isometric tongue protrusions: the beta (β) band at 15-35 Hz and the low-frequency band at 2-10 Hz. The CMC at the β band (β-CMC) reflects motor commands from the primary motor cortex (M1) to the tongue muscles through hypoglossal motoneuron pools. However, the generator mechanism of the CMC at the low-frequency band (low-CMC) remains unknown. Here, we evaluated the mechanism of low-CMC during isometric tongue protrusion using magnetoencephalography (MEG). Somatosensory evoked fields (SEFs) were also recorded following electrical tongue stimulation. Significant low-CMC and β-CMC were observed over both hemispheres for each side of the tongue.Time-domain analysis showed that the MEG signal followed the electromyography signal for low-CMC, which was contrary to the finding that the MEG signal preceded the electromyography signal for β-CMC. The mean conduction time from the tongue to the cortex was not significantly different between the low-CMC (mean, 80.9 ms) and SEFs (mean, 71.1 ms). The cortical sources of low-CMC were located significantly posterior (mean, 10.1 mm) to the sources of β-CMC in M1, but were in the same area as tongue SEFs in the primary somatosensory cortex (S1). These results reveal that the low-CMC may be driven by proprioceptive afferents from the tongue muscles to S1, and that the oscillatory interaction was derived from each side of the tongue to both hemispheres. Oscillatory proprioceptive feedback from the tongue muscles may aid in the coordination of sophisticated tongue movements in humans.

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Neural synchrony within the motor system: what have we learned so far?

Cited by 215 publications

References 240 publications

Two-phase model of the basal ganglia: implications for discontinuous control of the motor system

Two-phase model of the basal ganglia: implications for discontinuous control of the motor system

The reorganization of corticomuscular coherence during a transition between sensorimotor states

Cortico-muscular synchronization by proprioceptive afferents from the tongue muscles during isometric tongue protrusion

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