Finger-responses in RT tasks: Goal-coding and movement-preparation

Abstract Although it has long been suggested that the basal ganglia and thalamus are involved in movement planning and preparation, there was little direct evidence in humans to support this hypothesis. Deep brain stimulation (DBS) is a well-established treatment for movement disorders such as Parkinson's disease, tremor, and dystonia. In patients undergoing DBS surgery, we recorded simultaneously from scalp contacts and from electrodes surgically implanted in the subthalamic nucleus (STN) of 13 patients with Parkinson's disease and in the “cerebellar” thalamus of 5 patients with tremor. The aim of our studies was to assess the role of the cortico-basal ganglia-thalamocortical loop through the STN and the cerebello-thalamocortical circuit through the “cerebellar” thalamus in movement preparation. The patients were asked to perform self-paced wrist extension movements. All subjects showed a cortical readiness potential (RP) with onset ranging between 1.5 to 2s before the onset of movement. Subcortical RPs were recorded in 11 of 13 with electrodes in the STN and in 4 of 5 patients with electrodes in the thalamus. The onset time of the STN and thalamic RPs were not significantly different from the onset time of the scalp RP. The STN and thalamic RPs were present before both contralateral and ipsilateral hand movements. Postoperative MRI studies showed that contacts with maximum RP amplitude generally were inside the target nucleus. These findings indicate that both the basal ganglia and the cerebellar circuits participate in movement preparation in parallel with the cortex.

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Combining Movement-Related Cortical Potentials and Event-Related Desynchronization to Study Movement Preparation and Execution

Frontiers in Neurology ◽

10.3389/fneur.2018.00822 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 8

Author(s):

Hai Li ◽

Gan Huang ◽

Qiang Lin ◽

Jiang-Li Zhao ◽

Wai-Leung Ambrose Lo ◽

...

Keyword(s):

Movement Preparation ◽

Event Related Desynchronization ◽

Cortical Potentials

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Thinking Outside the Block: External Focus of Attention Improves Reaction Times and Movement Preparation Times in Collegiate Track Sprinters

Sports ◽

10.3390/sports6040120 ◽

2018 ◽

Vol 6 (4) ◽

pp. 120 ◽

Cited By ~ 2

Author(s):

Attila Kovacs ◽

Garrett Miles ◽

Harsimran Baweja

Keyword(s):

Muscle Activation ◽

Vastus Lateralis ◽

Reaction Times ◽

Focus Of Attention ◽

Track And Field ◽

Movement Preparation ◽

External Focus ◽

Internal Focus ◽

Coaching Methods ◽

Gastrocnemius Muscles

While focusing attention on external cues (EF) has been shown to enhance performance track and field coaches tend to provide instructions that promote internal focus of attention (IF) during block starts. The aims of this study were to determine: (1) whether promoting EF versus IF would improve reaction time (RT) of sprinters, and (2) if changes occur at the level of central processes during movement preparation (premotor RT) or peripheral processes during movement execution (motor RT). Twelve collegiate track sprinters (age 20.8 ± 1.7) completed three testing sessions under EF, IF, and no focus instruction (NF) conditions. RT was recorded from the left and right blocks. Muscle activation time (EMG) was recorded from the vastus lateralis and gastrocnemius muscles. Mean rear foot RT was significantly shorter (p < 0.0001) under the EF (212.11 ms) compared with the IF (234.21 ms) and NF conditions (236.87 ms). Front foot RT was significantly shorter (p < 0.05) during EF (250.24 ms), compared to IF (266.98 ms) but not shorter than the NF (268.73 ms) condition. Mean premotor RT under the EF condition (157.75 ms) was significantly shorter (p < 0.001) compared with the IF (181.90 ms) and NF (173.60 ms) conditions. No differences were found in motor RT across conditions (p > 0.05). Adopting an EF improves RT during sprint starts. This improvement likely originates from a shortening in movement preparation time, as opposed to a faster excitation contraction coupling of the muscle fibers. These findings could potentially contribute to the development of new coaching methods aimed at improving the starting technique of athletes.

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Changes in activity of fast-spiking interneurons of the monkey striatum during reaching at a visual target

Journal of Neurophysiology ◽

10.1152/jn.00566.2016 ◽

2017 ◽

Vol 117 (1) ◽

pp. 65-78 ◽

Cited By ~ 3

Author(s):

Kévin Marche ◽

Paul Apicella

Keyword(s):

Target Location ◽

Visual Target ◽

Movement Speed ◽

Gabaergic Interneurons ◽

Movement Preparation ◽

Movement Initiation ◽

Reaching Task ◽

Advance Information ◽

Fast Spiking ◽

Task Conditions

Recent works highlight the importance of local inhibitory interneurons in regulating the function of the striatum. In particular, fast-spiking interneurons (FSIs), which likely correspond to a subgroup of GABAergic interneurons, have been involved in the control of movement by exerting strong inhibition on striatal output pathways. However, little is known about the exact contribution of these presumed interneurons in movement preparation, initiation, and execution. We recorded the activity of FSIs in the striatum of monkeys as they performed reaching movements to a visual target under two task conditions: one in which the movement target was presented at unsignaled left or right locations, and another in which advance information about target location was available, thus allowing monkeys to react faster. Modulations of FSI activity around the initiation of movement (53% of 55 neurons) consisted mostly of increases reaching maximal firing immediately before or, less frequently, after movement onset. Another subset of FSIs showed decreases in activity during movement execution. Rarely did movement-related changes in FSI firing depend on response direction and movement speed. Modulations of FSI activity occurring relatively early in relation to movement initiation were more influenced by the preparation for movement, compared with those occurring later. Conversely, FSI activity remained unaffected, as monkeys were preparing a movement toward a specific location and instead moved to the opposite direction when the trigger occurred. These results provide evidence that changes in activity of presumed GABAergic interneurons of the primate striatum could make distinct contributions to processes involved in movement generation. NEW & NOTEWORTHY We explored the functional contributions of striatal fast-spiking interneurons (FSIs), presumed GABAergic interneurons, to distinct steps of movement generation in monkeys performing a reaching task. The activity of individual FSIs was modulated before and during the movement, consisting mostly of increased in firing rates. Changes in activity also occurred during movement preparation. We interpret this variety of modulation types at different moments of task performance as reflecting differential FSI control over distinct phases of movement.

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Dissociation between sustained single-neuron spiking and transient β-LFP oscillations in primate motor cortex

Journal of Neurophysiology ◽

10.1152/jn.00651.2016 ◽

2017 ◽

Vol 117 (4) ◽

pp. 1524-1543 ◽

Cited By ~ 13

Author(s):

Michael E. Rule ◽

Carlos E. Vargas-Irwin ◽

John P. Donoghue ◽

Wilson Truccolo

Keyword(s):

Steady State ◽

Motor Cortex ◽

Local Field ◽

Single Neuron ◽

Field Potential ◽

Movement Preparation ◽

Phase Coupling ◽

Firing Rates ◽

Sources Of Variation ◽

Transient Events

Determining the relationship between single-neuron spiking and transient (20 Hz) β-local field potential (β-LFP) oscillations is an important step for understanding the role of these oscillations in motor cortex. We show that whereas motor cortex firing rates and beta spiking rhythmicity remain sustained during steady-state movement preparation periods, β-LFP oscillations emerge, in contrast, as short transient events. Single-neuron mean firing rates within and outside transient β-LFP events showed no differences, and no consistent correlation was found between the beta oscillation amplitude and firing rates, as was the case for movement- and visual cue-related β-LFP suppression. Importantly, well-isolated single units featuring beta-rhythmic spiking (43%, 125/292) showed no apparent or only weak phase coupling with the transient β-LFP oscillations. Similar results were obtained for the population spiking. These findings were common in triple microelectrode array recordings from primary motor (M1), ventral (PMv), and dorsal premotor (PMd) cortices in nonhuman primates during movement preparation. Although beta spiking rhythmicity indicates strong membrane potential fluctuations in the beta band, it does not imply strong phase coupling with β-LFP oscillations. The observed dissociation points to two different sources of variation in motor cortex β-LFPs: one that impacts single-neuron spiking dynamics and another related to the generation of mesoscopic β-LFP signals. Furthermore, our findings indicate that rhythmic spiking and diverse neuronal firing rates, which encode planned actions during movement preparation, may naturally limit the ability of different neuronal populations to strongly phase-couple to a single dominant oscillation frequency, leading to the observed spiking and β-LFP dissociation. NEW & NOTEWORTHY We show that whereas motor cortex spiking rates and beta (~20 Hz) spiking rhythmicity remain sustained during steady-state movement preparation periods, β-local field potential (β-LFP) oscillations emerge, in contrast, as transient events. Furthermore, the β-LFP phase at which neurons spike drifts: phase coupling is typically weak or absent. This dissociation points to two sources of variation in the level of motor cortex beta: one that impacts single-neuron spiking and another related to the generation of measured mesoscopic β-LFPs.

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