Underlying Motor Learning Research Articles

What Does It Take to Play the Piano? Cognito-Motor Functions Underlying Motor Learning in Older Adults.

The acquisition of skills, such as learning to play a musical instrument, involves various phases that make specific demands on the learner. Knowledge of the cognitive and motor contributions during learning phases can be helpful in developing effective and targeted interventions for healthy aging. Eighty-six healthy older participants underwent an extensive cognitive, motoric, and musical test battery. Within one session, one piano-related and one music-independent movement sequence were both learned. We tested the associations between skill performance and cognito-motor abilities with Bayesian mixed models accounting for individual learning rates. Results showed that performance was positively associated with all cognito-motor abilities. Learning a piano-related task was characterized by relatively strong initial associations between performance and abilities. These associations then weakened considerably before increasing exponentially from the second trial onwards, approaching a plateau. Similar performance-ability relationships were detected in the course of learning a music-unrelated motor task. Positive performance-ability associations emphasize the potential of learning new skills to produce positive cognitive and motor transfer effects. Consistent high-performance tasks that demand maximum effort from the participants could be very effective. However, interventions should be sufficiently long so that the transfer potential can be fully exploited.

The effects of reward and punishment on the performance of ping-pong ball bouncing.

Reward and punishment modulate behavior. In real-world motor skill learning, reward and punishment have been found to have dissociable effects on optimizing motor skill learning, but the scientific basis for these effects is largely unknown. In the present study, we investigated the effects of reward and punishment on the performance of real-world motor skill learning. Specifically, three groups of participants were trained and tested on a ping-pong ball bouncing task for three consecutive days. The training and testing sessions were identical across the three days: participants were trained with their right (dominant) hand each day under conditions of either reward, punishment, or a neutral control condition (neither). Before and after the training session, all participants were tested with their right and left hands without any feedback. We found that punishment promoted early learning, while reward promoted late learning. Reward facilitated short-term memory, while punishment impaired long-term memory. Both reward and punishment interfered with long-term memory gains. Interestingly, the effects of reward and punishment transferred to the left hand. The results show that reward and punishment have different effects on real-world motor skill learning. The effects change with training and transfer readily to novel contexts. The results suggest that reward and punishment may act on different learning processes and engage different neural mechanisms during real-world motor skill learning. In addition, high-level metacognitive processes may be enabled by the additional reinforcement feedback during real-world motor skill learning. Our findings provide new insights into the mechanisms underlying motor learning, and may have important implications for practical applications such as sports training and motor rehabilitation.

Cx3cr1 deficiency interferes with learning- and direct current stimulation-mediated neuroplasticity of the motor cortex.

Microglia are essential contributors to synaptic transmission and stability and communicate with neurons via the fractalkine pathway. Transcranial direct current stimulation [(t)DCS], a form of non-invasive electrical brain stimulation, modulates cortical excitability and promotes neuroplasticity, which has been extensively demonstrated in the motor cortex and for motor learning. The role of microglia and their fractalkine receptor CX3CR1 in motor cortical neuroplasticity mediated by DCS or motor learning requires further elucidation. We demonstrate the effects of pharmacological microglial depletion and genetic Cx3cr1 deficiency on the induction of DCS-induced long-term potentiation (DCS-LTP) ex vivo. The relevance of microglia-neuron communication for DCS response and structural neuroplasticity underlying motor learning are assessed via 2-photon in vivo imaging. The behavioural consequences of impaired CX3CR1 signalling are investigated for both gross and fine motor learning. We show that DCS-mediated neuroplasticity in the motor cortex depends on the presence of microglia and is driven in part by CX3CR1 signalling ex vivo and provide the first evidence of microglia interacting with neurons during DCS in vivo. Furthermore, CX3CR1 signalling is required for motor learning and underlying structural neuroplasticity in concert with microglia interaction. Although we have recently demonstrated the microglial response to DCS in vivo, we now provide a link between microglial integrity and neuronal activity for the expression of DCS-dependent neuroplasticity. In addition, we extend the knowledge on the relevance of CX3CR1 signalling for motor learning and structural neuroplasticity. The underlying molecular mechanisms and the potential impact of DCS in rescuing CX3CR1 deficits remain to be addressed in the future.

Cortical activation of neuromuscular electrical stimulation synchronized mirror neuron rehabilitation strategies: an fNIRS study.

The mirror neuron system (MNS) plays a key role in the neural mechanism underlying motor learning and neural plasticity. Action observation (AO), action execution (AE), and a combination of both, known as action imitation (AI), are the most commonly used rehabilitation strategies based on MNS. It is possible to enhance the cortical activation area and amplitude by combining traditional neuromuscular electrical stimulation (NMES) with other top-down and active rehabilitation strategies based on the MNS theory. This study aimed to explore the cortical activation patterns induced by NMES synchronized with rehabilitation strategies based on MNS, namely NMES+AO, NMES+AE, and NMES+AI. In addition, the study aimed to assess the feasibility of these three novel rehabilitative treatments in order to provide insights and evidence for the design, implementation, and application of brain-computer interfaces. A total of 70 healthy adults were recruited from July 2022 to February 2023, and 66 of them were finally included in the analysis. The cortical activation patterns during NMES+AO, NMES+AE, and NMES+AI were detected using the functional Near-Infrared Spectroscopy (fNIRS) technique. The action to be observed, executed, or imitated was right wrist and hand extension, and two square-shaped NMES electrodes were placed on the right extensor digitorum communis. A block design was adopted to evaluate the activation intensity of the left MNS brain regions. General linear model results showed that compared with the control condition, the number of channels significantly activated (PFDR < 0.05) in the NMES+AO, NMES+AE, and NMES+AI conditions were 3, 9, and 9, respectively. Region of interest (ROI) analysis showed that 2 ROIs were significantly activated (PFDR < 0.05) in the NMES+AO condition, including BA6 and BA44; 5 ROIs were significantly activated in the NMES+AE condition, including BA6, BA40, BA44, BA45, and BA46; and 6 ROIs were significantly activated in the NMES+AI condition, including BA6, BA7, BA40, BA44, BA45, and BA46. The MNS was activated during neuromuscular electrical stimulation combined with an AO, AE, and AI intervention. The synchronous application of NMES and mirror neuron rehabilitation strategies is feasible in clinical rehabilitation. The fNIRS signal patterns observed in this study could be used to develop brain-computer interface and neurofeedback therapy rehabilitation devices.

Time to reconcile research findings and clinical practice on upper limb neurorehabilitation.

The problemIn the field of upper limb neurorehabilitation, the translation from research findings to clinical practice remains troublesome. Patients are not receiving treatments based on the best available evidence. There are certainly multiple reasons to account for this issue, including the power of habit over innovation, subjective beliefs over objective results. We need to take a step forward, by looking at most important results from randomized controlled trials, and then identify key active ingredients that determined the success of interventions. On the other hand, we need to recognize those specific categories of patients having the greatest benefit from each intervention, and why. The aim is to reach the ability to design a neurorehabilitation program based on motor learning principles with established clinical efficacy and tailored for specific patient's needs.Proposed solutionsThe objective of the present manuscript is to facilitate the translation of research findings to clinical practice. Starting from a literature review of selected neurorehabilitation approaches, for each intervention the following elements were highlighted: definition of active ingredients; identification of underlying motor learning principles and neural mechanisms of recovery; inferences from research findings; and recommendations for clinical practice. Furthermore, we included a dedicated chapter on the importance of a comprehensive assessment (objective impairments and patient's perspective) to design personalized and effective neurorehabilitation interventions.ConclusionsIt's time to reconcile research findings with clinical practice. Evidence from literature is consistently showing that neurological patients improve upper limb function, when core strategies based on motor learning principles are applied. To this end, practical take-home messages in the concluding section are provided, focusing on the importance of graded task practice, high number of repetitions, interventions tailored to patient's goals and expectations, solutions to increase and distribute therapy beyond the formal patient-therapist session, and how to integrate different interventions to maximize upper limb motor outcomes. We hope that this manuscript will serve as starting point to fill the gap between theory and practice in upper limb neurorehabilitation, and as a practical tool to leverage the positive impact of clinicians on patients' recovery.

Temporospatial Alterations in Upper-Limb and Mallet Control Underlie Motor Learning in Marimba Performance.

Sound-producing movements in percussion performance require a high degree of fine motor control. However, there remains a relatively limited empirical understanding of how performance level abilities develop in percussion performance in general, and marimba performance specifically. To address this issue, nine percussionists performed individualised excerpts on marimba within three testing sessions spaced 29 days apart to assess early, intermediate, and late stages of motor learning. Motor learning was quantified via analyses of both the temporal control of mallet movements, and the spatial variability of upper-limb movements. The results showed that temporal control of mallet movements was greater in the intermediate compared to the early learning session, with no significant additional improvements revealed in the late learning session. In addition, spatial variability in the left and right elbows decreased within the intermediate compared to the early learning session. The results suggest that temporal control of mallet movements may be driven by reductions in spatial variability of elbow movements specifically. As a result, this study provides novel evidence for kinematic mechanisms underlying motor learning in percussion which can be applied towards enhancing musical training.

Relationship between motor learning and gambling propensity in Parkinson’s disease

ABSTRACT Introduction The basal ganglia and related dopaminergic cortical areas are important neural systems underlying motor learning and are also implicated in impulse control disorders (ICDs). Motor learning impairments and ICDs are frequently observed in Parkinson’s disease (PD). Nevertheless, the relationship between motor learning ability and ICDs has not been elucidated. Methods We examined the relationship between motor learning ability and gambling propensity, a possible symptom for prodromal ICDs, in PD patients. Fifty-nine PD patients without clinical ICDs and 43 normal controls (NC) were administered a visuomotor rotation perturbation task and the Iowa Gambling Task (IGT) to evaluate motor learning ability and gambling propensity, respectively. Participants also performed additional cognitive assessments and underwent brain perfusion SPECT imaging. Results Better motor learning ability was significantly correlated with lower IGT scores, i.e., higher gambling propensity, in PD patients but not in NC. The higher scores on assessments reflecting prefrontal lobe function and well-preserved blood perfusion in prefrontal areas were correlated with lower IGT scores along with better motor learning ability. Conclusions Our findings suggest that better motor learning ability and higher gambling propensity are based on better prefrontal functions, which are in accordance with the theory that the prefrontal cortex is one of the common essential regions for both motor learning and ICDs.

Coordination chemogenetics for regulation of glutamate receptors in neuron

Transmembrane receptors transmit extracellular information into cells. In many cases, protein families are composed of highly homologous subtypes, each of which has unique cellular functions. Therefore, it is highly desired for understanding the physiological roles of the receptor in tissues or animals. However, it is difficult to control the activity of receptors in a cell-type- and subtype-specific manner with high temporal resolution using traditional pharmacological or genetic engineering methods. Recently, chemogenetics has been focused on controlling the cellular signaling in a cell-type-specific manner, which allows for elucidating the function of specific cell types with high temporal resolution. However, conventional chemogenetics are not suitable for understanding the roles of each receptor. Therefore, we have developed a chemogenetic method, termed coordination chemogenetics, in which coordination chemistry and genetic engineering are combined. The coordination chemogenetics enabled artificial activation of ionotropic glutamate receptor (GluA2) and metabotropic glutamate receptor (mGlu1). A palladium (Pd) complex successfully activated mGlu1 in mGlu1(N264H) knock-in mice, demonstrating that endogenous mGlu1 activation is sufficient to evoke a key cellular mechanism of synaptic plasticity that underlies motor learning in the cerebellum. We also expanded the coordination chemogenetics for orthogonal activation of mGlu1 activity using Cu2+, Zn2+, and Pd complexes for analyzing the individual roles of mGlu1 simultaneously. Notably, coordination chemogenetics can be expanded to apply selective inhibition of transmembrane receptors, and the dissociation is much slower than that of conventional inhibitors. Thus, coordination chemogenetics would be a unique method for controlling mGlu1 in a cell-type-specific manner.

Neurons in Primary Motor Cortex Encode External Perturbations during an Orientation Reaching Task

When confronting an abrupt external perturbation force during movement, subjects continuously adjust their behaviors to adapt to changes. Such adaptation is of great importance for realizing flexible motor control in varied environments, but the potential cortical neuronal mechanisms behind it have not yet been elucidated. Aiming to reveal potential neural control system compensation for external disturbances, we applied an external orientation perturbation while monkeys performed an orientation reaching task and simultaneously recorded the neural activity in the primary motor cortex (M1). We found that a subpopulation of neurons in the primary motor cortex specially created a time-locked activity in response to a “go” signal in the adaptation phase of the impending orientation perturbation and did not react to a “go” signal under the normal task condition without perturbation. Such neuronal activity was amplified as the alteration was processed and retained in the extinction phase; then, the activity gradually faded out. The increases in activity during the adaptation to the orientation perturbation may prepare the system for the impending response. Our work provides important evidence for understanding how the motor cortex responds to external perturbations and should advance research about the neurophysiological mechanisms underlying motor learning and adaptation.

Psychophysiological Markers of Performance and Learning during Simulated Marksmanship in Immersive Virtual Reality.

The fusion of immersive virtual reality, kinematic movement tracking, and EEG offers a powerful test bed for naturalistic neuroscience research. Here, we combined these elements to investigate the neuro-behavioral mechanisms underlying precision visual-motor control as 20 participants completed a three-visit, visual-motor, coincidence-anticipation task, modeled after Olympic Trap Shooting and performed in immersive and interactive virtual reality. Analyses of the kinematic metrics demonstrated learning of more efficient movements with significantly faster hand RTs, earlier trigger response times, and higher spatial precision, leading to an average of 13% improvement in shot scores across the visits. As revealed through spectral and time-locked analyses of the EEG beta band (13-30 Hz), power measured prior to target launch and visual-evoked potential amplitudes measured immediately after the target launch correlated with subsequent reactive kinematic performance in the shooting task. Moreover, both launch-locked and shot/feedback-locked visual-evoked potentials became earlier and more negative with practice, pointing to neural mechanisms that may contribute to the development of visual-motor proficiency. Collectively, these findings illustrate EEG and kinematic biomarkers of precision motor control and changes in the neurophysiological substrates that may underlie motor learning.

Age-dependent modulation of motor network connectivity for skill acquisition, consolidation and interlimb transfer after motor practice

ObjectiveAge-related differences in neural strategies for motor learning are not fully understood. We determined the effects of age on the relationship between motor network connectivity and motor skill acquisition, consolidation, and interlimb transfer using dynamic imaging of coherent sources. MethodsHealthy younger (n = 24, 18–24 y) and older (n = 24, 65–87 y) adults unilaterally practiced a visuomotor task and resting-state electroencephalographic data was acquired before and after practice as well as at retention. ResultsThe results showed that right-hand skill acquisition and consolidation did not differ between age groups. However, age affected the ability to transfer the newly acquired motor skill to the non-practiced limb. Moreover, strengthened left- and right-primary motor cortex-related beta connectivity was negatively and positively associated with right-hand skill acquisition and left-hand skill consolidation in older adults, respectively. ConclusionAge-dependent modulations of bilateral resting-state motor network connectivity indicate age-specific strategies for the acquisition, consolidation, and interlimb transfer of novel motor tasks. SignificanceThe present results provide insights into the mechanisms underlying motor learning that are important for the development of interventions for patients with unilateral injuries.

Sequence Structure Has a Differential Effect on Underlying Motor Learning Processes

Current methods to understand implicit motor sequence learning inadequately assess motor skill acquisition in daily life. Using fixed sequences in the serial reaction time task is not ideal as participants may become aware of the sequence, thereby changing the learning from implicit to explicit. Probabilistic sequences, in which stimuli are linked by statistical, rather than deterministic, associations can ensure that learning remains implicit. Additionally, the processes underlying the learning of motor sequences may differ based on sequence structure. Here, the authors compared the learning of fixed and probabilistic sequences to randomly ordered stimuli using a modified serial reaction time task. Both the fixed and probabilistic sequence groups exhibited learning as indicated by decreased response time and variability. In the initial stage of learning, fixed sequences exhibited both online and offline gains in response time; however, only the offline gain was observed during the learning of probabilistic sequences. These results indicated that probabilistic structures may be learned differently from fixed structures and have important implications for our current understanding of motor learning. Probabilistic sequences more accurately reflect motor skill acquisition in daily life, offer ecological validity to the serial reaction time framework, and advance our understanding of motor learning.

Reorganization of Muscle Coordination Underlying Motor Learning in Cycling Tasks.

The hypothesis of modular control, which stands on the existence of muscle synergies as building blocks of muscle coordination, has been investigated in a great variety of motor tasks and species. Yet, its role during learning processes is still largely unexplored. To what extent is such modular control flexible, in terms of spatial structure and temporal activation, to externally or internally induced adaptations, is a debated issue. To address this question, we designed a biofeedback experiment to induce changes in the timing of muscle activations during leg cycling movements. The protocol consisted in delaying the peak of activation of one target muscle and using its electromyography (EMG) envelope as visual biofeedback. For each of the 10 healthy participants, the protocol was repeated for three different target muscles: Tibialis Anterioris (TA), Gastrocnemius Medialis (GM), and Vastus Lateralis (VL). To explore the effects of the conditioning protocol, we analyzed changes in the activity of eight lower limb muscles by applying different models of modular motor control [i.e., fixed spatial components (FSC) and fixed temporal components (FTC)]. Our results confirm the hypothesis that visual EMG biofeedback is able to induce changes in muscle coordination. Subjects were able to shift the peak of activation of the target muscle, with a delay of (49 ± 27°) across subjects and conditions. This time shift generated a reorganization of all the other muscles in terms of timing and amplitude. By using different models of modular motor control, we demonstrated that neither spatially invariant nor temporally invariant muscle synergies alone were able to account for these changes in muscle coordination after learning, while temporally invariant muscle synergies with adjustments in timing could capture most of muscle activity adaptations observed after the conditioning protocol. These results suggest that short-term learning in rhythmic tasks is built upon synergistic temporal commands that are robust to changes in the task demands.

Learning New Feedforward Motor Commands Based on Feedback Responses.

Learning a new motor task modifies feedforward (i.e., voluntary) motor commands and such learning also changes the sensitivity of feedback responses (i.e., reflexes) to mechanical perturbations [1-9]. For example, after people learn to generate straight reaching movements in the presence of an external force field or learn to reduce shoulder muscle activity when generating pure elbow movements with shoulder fixation, evoked stretch reflex responses to mechanical perturbations reflect the learning expressed during self-initiated reaching. Such a transfer from feedforward motor commands to feedback responses is thought to take place because of shared neural circuits at the level of the spinal cord, brainstem, and cerebral cortex [10-13]. The presence of shared neural resources also predicts the transfer from feedback responses to feedforward motor commands. Little is known about such a transfer presumably because it is relatively hard to elicit learning in reflexes without engaging associated voluntary responses following mechanical perturbations. Here, we demonstrate such transfer by leveraging two approaches to elicit stretch reflexes while minimizing engagement of voluntary motor responses in the learning process: applying very short mechanical perturbations [14-19] and instructing participants to not respond to them [20-26]. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

An acute session of motor imagery training induces use-dependent plasticity

Motor imagery, defined as the mental representation of an action without movement-related sensory inputs, is a well-known intervention to improve motor performance. In the current study, we tested whether use-dependent plasticity, a mechanism underlying motor learning, could be induced by an acute session of motor imagery. By means of transcranial magnetic stimulation (TMS) over the left primary motor cortex, we evoked isolated thumb movements in the right hand and assessed corticospinal excitability in the flexor and extensor pollicis brevis muscles. We measured the mean TMS-induced movement direction before and after an acute session of motor imagery practice. In a first experiment, participants of the imagery group were instructed to repeatedly imagine their thumb moving in a direction deviated by 90° from the pre-test movement. This group, but not the control group, deviated the post-training TMS-induced movements toward the training target direction (+44° ± 62° and −1° ± 23°, respectively). Interestingly, the deviation magnitude was driven by the corticospinal excitability increase in the agonist muscle. In a second experiment, we found that post-training TMS-induced movements were proportionally deviated toward the trained direction and returned to baseline 30 minutes after the motor imagery training. These findings suggest that motor imagery induces use-dependent plasticity and, this neural process is accompanied by corticospinal excitability increase in the agonist muscle.

Complex Motor Learning and Police Training: Applied, Cognitive, and Clinical Perspectives.

The practices surrounding police training of complex motor skills, including the use of force, varies greatly around the world, and even over the course of an officer’s career. As the nature of policing changes with society and the advancement of science and technology, so should the training practices that officers undertake at both central (i.e., police academy basic recruit training) and local (i.e., individual agency or precinct) levels. The following review is intended to bridge the gap between scientific knowledge and applied practice to inform best practices for training complex motor skills that are unique and critical to law enforcement, including the use of lethal force. We begin by providing a basic understanding of the fundamental cognitive processes underlying motor learning, from novel skill acquisition to complex behaviors including situational awareness, and decision-making that precede and inform action. Motor learning, memory, and perception are then discussed within the context of occupationally relevant stress, with a review of evidence-based training practices that promote officer performance and physiological responses to stress during high-stakes encounters. A lack of applied research identifying the neurophysiological mechanisms underlying motor learning in police is inferred from a review of evidence from various clinical populations suffering from disorders of cognitive and motor systems, including Alzheimer’s and Parkinson’s disease and stroke. We conclude this review by identifying practical, organizational, and systemic challenges to implementing evidence-based practices in policing and provide recommendations for best practices that will promote training effectiveness and occupational safety of end-users (i.e., police trainers and officers).

Potentiation of cerebellar Purkinje cells facilitates whisker reflex adaptation through increased simple spike activity.

Cerebellar plasticity underlies motor learning. However, how the cerebellum operates to enable learned changes in motor output is largely unknown. We developed a sensory-driven adaptation protocol for reflexive whisker protraction and recorded Purkinje cell activity from crus 1 and 2 of awake mice. Before training, simple spikes of individual Purkinje cells correlated during reflexive protraction with the whisker position without lead or lag. After training, simple spikes and whisker protractions were both enhanced with the spiking activity now leading behavioral responses. Neuronal and behavioral changes did not occur in two cell-specific mouse models with impaired long-term potentiation at their parallel fiber to Purkinje cell synapses. Consistent with cerebellar plasticity rules, increased simple spike activity was prominent in cells with low complex spike response probability. Thus, potentiation at parallel fiber to Purkinje cell synapses may contribute to reflex adaptation and enable expression of cerebellar learning through increases in simple spike activity.

Age-related changes in brain deactivation but not in activation after motor learning

It is poorly understood how healthy aging affects neural mechanisms underlying motor learning. We used blood-oxygen-level dependent (BOLD) contrasts to examine age-related changes in brain activation after acquisition and consolidation (24 h) of a visuomotor tracking skill. Additionally, structural magnetic resonance imaging and diffusion tensor imaging were used to examine age-related structural changes in the brain. Older adults had reduced gray matter volume (628 ± 57 ml) and mean white matter anisotropy (0.18 ± 0.03) compared with young adults (741 ± 59 ml and 0.22 ± 0.02, respectively). Although motor performance was 53% lower in older (n = 15, mean age 63.1 years) compared with young adults (n = 15, mean age 25.5 years), motor practice improved motor performance similarly in both age groups. While executing the task, older adults showed in general greater brain activation compared with young adults. BOLD activation decreased in parietal and occipital areas after skill acquisition but activation increased in these areas after consolidation in both age groups, indicating more efficient visuospatial processing immediately after skill acquisition. Changes in deactivation in specific areas were age-dependent after consolidating the motor skill into motor memory. Young adults showed greater deactivations from post-test to retention in parietal, occipital and temporal cortices, whereas older adults showed smaller deactivation in the frontal cortex. Since learning rate was similar between age groups, age-related changes in activation patterns may be interpreted as a compensatory mechanism for age-related structural decline.

Molecular Mechanisms for Learning and Memory: What Happens at the Synapses?

The synapse is a structure connecting neurons in the brain, which is crucial for learning and memory. Accumulating evidence suggests that synapses continuously change in function and structure in response to learning and memory. Especially, in the cerebellum, which underlies motor learning and memory, synapses are highly dynamic throughout life. Recently, various types of molecules involving synapse integrity, learning and memory, such as δ-type glutamate receptors (GluD receptors) and C1q-family proteins, have been identified.

Neural Population Dynamics Underlying Motor Learning Transfer

Covert motor learning can sometimes transfer to overt behavior. We investigated the neural mechanism underlying transfer by constructing a two-context paradigm. Subjects performed cursor movements either overtly using arm movements, or covertly via a brain-machine interface that moves the cursor based on motor cortical activity (in lieu of arm movement). These tasks helped evaluate whether and how cortical changes resulting from "covert rehearsal" affect overt performance. We found that covert learning indeed transfers to overt performance and is accompanied by systematic population-level changes in motor preparatory activity. Current models of motor cortical function ascribe motor preparation to achieving initial conditions favorable for subsequent movement-period neural dynamics. We found that covert and overt contexts share these initial conditions, and covert rehearsal manipulates them in a manner that persists across context changes, thus facilitating overt motor learning. This transfer learning mechanism might provide new insights into other covert processes like mental rehearsal.