Reward timing matters in motor learning

IntroductionThere is growing evidence that sleep is disrupted after stroke, with worse sleep relating to poorer motor outcomes. It is also widely acknowledged that consolidation of motor learning, a critical...

Interference with Existing Memories Alters Offline Intrinsic Functional Brain Connectivity

Background and aim Children with autism spectrum disorder (ASD) may experience coordination disorders, but the effects of different training conditions on motor learning in these children remain unclear. This study examined how constant versus variable practice impacts motor performance and learning in children with ASD and motor impairments. Methods Thirty-four children attending child development and daycare centers participated. Assessments included fine motor skills (Purdue Pegboard), gross motor skills (target-target task), visuospatial working memory (Corsi block tapping task), and the developmental disability questionnaire (Strengths and Difficulties Questionnaire). The primary outcome was the change in target-task performance before, during, and after practice, analyzed using repeated measures two-way ANOVA and Pearson's correlation. Results No significant differences were observed for practice conditions or time effects alone, but significant interactions were found (F = 6.641, p = 0.015). Variable practice resulted in reduced pre- to post-test scores (p = 0.047), while constant practice showed stronger correlations between practice improvements and overall performance changes (p = 0.004, r = 0.666). Prosocial behavior was positively associated with performance improvements in the constant practice group (p = 0.018, r = 0.564). No significant correlations were found in the variable practice group. Conclusions Constant practice yielded greater motor learning improvements than variable practice. Additionally, prosocial behavior positively influenced motor learning in structured settings, highlighting the potential benefits of integrating motor and social skill interventions for children with ASD.

Behavior is shaped by actions, and actions necessitate motor skills such as strength, coordination, and learning. None of the behaviors essential for sustaining life would be possible without the ability to transition from one position to another. Unfortunately, motor skills can be compromised in a wide array of diseases. Therefore, investigating the mechanisms of motor functions at the cellular, molecular, and circuit levels, as well as understanding the symptoms, causes, and progression of motor disorders, is crucial for developing effective treatments. Mouse models are frequently employed for this purpose. This article describes a protocol that allows the monitoring of various aspects of motor performance and learning in mice using an automated tool called the Erasmus Ladder. The assay involves two phases: an initial phase where mice are trained to navigate a horizontal ladder built of irregular rungs ("fine motor learning"), and a second phase where an obstacle is presented in the path of the moving animal. The perturbation can be unexpected ("challenged motor learning") or preceded by an auditory tone ("associative motor learning"). The task is easy to conduct and is fully supported by automated software. This report shows how different readouts from the test, when analyzed with sensitive statistical methods, allow fine monitoring of mouse motor skills using a small cohort of mice. We propose that the method will be highly sensitive to evaluate motor adaptations driven by environmental modifications as well as early-stage subtle motor deficits in mutant mice with compromised motor functions.

The synaptic pathways in the striatum are central to basal ganglia functions including motor control, learning and organization, action selection, acquisition of motor skills, cognitive function, and emotion. Here, we review the role of the striatum and its connections in motor learning and performance. The development of new techniques to record neuronal activity and animal models of motor disorders using neurotoxin, pharmacological, and genetic manipulations are revealing pathways that underlie motor performance and motor learning, as well as how they are altered by pathophysiological mechanisms. We discuss approaches that can be used to analyze complex motor skills, particularly in rodents, and identify specific questions central to understanding how striatal circuits mediate motor learning.

Key pointsThe ability to learn new motor skills is supported by plasticity in the structural and functional organisation of the primary motor cortex in the human brain.Changes inhibitory to signalling by GABA are thought to be crucial in inducing motor cortex plasticity.This study used magnetic resonance spectroscopy (MRS) to quantify the concentration of GABA in human motor cortex during a period of motor learning, as well as during a period of movement and a period at rest.We report evidence for a reduction in the MRS‐measured concentration of GABA specific to learning. Further, the GABA concentration early in the learning task was strongly correlated with the magnitude of subsequent learning: higher GABA concentrations were associated with poorer learning.The results provide initial insight into the neurochemical correlates of cortical plasticity associated with motor learning, specifically relevant in therapeutic efforts to induce cortical plasticity during recovery from stroke.The ability to learn novel motor skills is a central part of our daily lives and can provide a model for rehabilitation after a stroke. However, there are still fundamental gaps in our understanding of the physiological mechanisms that underpin human motor plasticity. The acquisition of new motor skills is dependent on changes in local circuitry within the primary motor cortex (M1). This reorganisation has been hypothesised to be facilitated by a decrease in local inhibition via modulation of the neurotransmitter GABA, but this link has not been conclusively demonstrated in humans. Here, we used 7 T magnetic resonance spectroscopy to investigate the dynamics of GABA concentrations in human M1 during the learning of an explicit, serial reaction time task. We observed a significant reduction in GABA concentration during motor learning that was not seen in an equivalent motor task lacking a learnable sequence, nor during a passive resting task of the same duration. No change in glutamate was observed in any group. Furthermore, M1 GABA measured early in task performance was strongly correlated with the degree of subsequent learning, such that greater inhibition was associated with poorer subsequent learning. This result suggests that higher levels of cortical inhibition may present a barrier that must be surmounted in order to achieve an increase in M1 excitability, and hence encoding of a new motor skill. These results provide strong support for the mechanistic role of GABAergic inhibition in motor plasticity, raising questions regarding the link between population variability in motor learning and GABA metabolism in the brain.

Background:Jump-landing is a fundamental movement critical for enhancing athletic performance and preventing injuries, making the facilitation of rapid motor learning essential. Motor learning and performance are commonly evaluated using biomechanical measures. Although neurophysiological processes such as predictive control and self-reflection are thought to contribute to motor learning, studies from this perspective remain limited. In this study, we focused on three neural markers: Bereitschaftspotential (BP), which reflects predictive control before movement initiation; posterior parietal cortex (PPC) activity, which is involved in sensory information processing during motor learning; and error-related negativity (ERN), which reflects self-reflection following movement. We aimed to clarify the relationships between these neural markers and motor learning during jump-landing tasks. Methods:A cross-sectional study was conducted with eight healthy male participants, each performing twenty single-leg drop jumps. Participants were instructed to land on a designated target point, and the error distance between the big toe and the target was measured. Reduction in error distance across trials was quantified as a learning curve, and its slope was used as an index of motor learning ability. Bereitschaftspotential (BP) was measured at the Cz electrode, and activity in the posterior parietal cortex (PPC) was analyzed at the Pz electrode; integral values over the three seconds prior to jump takeoff were calculated. ERN was extracted from the Fz electrode as the maximum negative amplitude occurring 50-150 ms after landing. Statistical analyses were conducted to examine the correlations between electroencephalography indices and the learning curve slope. In addition, classification using a support vector machine (SVM) was performed to assess whether ERN amplitude could predict high or low motor learning ability. Results: BP and PPC activity were significantly negatively correlated with the learning curve slope, indicating faster motor learning. In contrast, ERN amplitude showed no significant correlation with the slope. However, the SVM classification model demonstrated that ERN amplitude could accurately predict high and low motor learning ability. Conclusion:BP and PPC activity contributed to faster motor learning, while ERN enabled classification of learning ability. These findings suggest that predictive control, sensory integration, and self-reflection are key components of motor learning. This study is among the first to integratively examine the roles of BP, PPC, and ERN in a dynamic jump-landing. The findings demonstrate that predictive control, sensory integration, and self-reflection are key contributors to motor learning efficiency. These insights offer novel perspectives for assessment and training design in sports science and rehabilitation, with implications for performance enhancement and injury prevention.

Aim:Define the subtype-specific contributions of nigrostriatal dopaminergic neurons (DANs) to motor and non-motor behaviors by comparing Calbindin 1-positive (Calb1+) and Aldehyde dehydrogenase 1a1-positive (Aldh1a1+) DANs.Methods:Intersectional genetic strategy and chemogenetic inhibition were applied to selectively silence Calb1+ or Aldh1a1+ DANs in mice. An adeno-associated viral vector (AAV-CreOn-FlpOn-hM4Di-P2A-mCherry) was stereotactically delivered into the substantia nigra pars compacta of double knock-in lines ThFlp; Calb1IRESCre or ThFlp; Aldh1a1CreERT2. Following expression, subtype-specific neuronal inhibition was induced with a designer receptor exclusively activated by designer drugs (DREADD) ligand, and the mice were assessed in assays of voluntary movement, motor skill learning, and early associative learning behavior.Results:Chemogenetic inhibition of either Calb1+ or Aldh1a1+ DANs produced a marked reduction in voluntary movement and impaired acquisition of motor skills, indicating that both subtypes are necessary for normal motor function and learning. In contrast, only inhibition of Calb1+ DANs altered early associative-learning performance, revealing a dissociable, subtype-specific role for Calb1+ neurons in reinforcement-related behavior that was not observed with Aldh1a1+ neuron inhibition.Conclusion:Both Calb1+ and Aldh1a1+ nigrostriatal DANs are key regulators of movement and motor learning, with Calb1+ neurons additionally modulating reward-based associative learning. These findings highlight the functional heterogeneity of nigrostriatal DAN subtypes and identify potential therapeutic targets for addressing motor and non-motor deficits in Parkinson’s disease.

Repeated pairing of electrical stimulation of a peripheral nerve with transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) representation for a target muscle can induce neuroplastic adaptations in the human brain related to motor learning. The extent to which the motor state during this form of paired associative stimulation (PAS) influences the degree and mechanisms of neuroplasticity or motor learning is unclear. Here, we investigated the effect of volitional muscle contraction during PAS on: (1) measures of general corticomotor excitability and intracortical circuit excitability; and (2) motor performance and learning. We assessed measures of corticomotor excitability using TMS and motor skill performance during a serial reaction time task (SRTT) at baseline and at 0, 30, 60 min post-PAS. Participants completed a SRTT retention test 1 week following the first two PAS sessions. Following the PAS intervention where the hand muscle maintained an active muscle contraction (PASACTIVE), there was lower short interval intracortical inhibition compared to PAS during a resting motor state (PASREST) and a sham PAS condition (PASCONTROL). SRTT performance improved within the session regardless of PAS condition. SRTT retention was greater following both PASACTIVE and PASREST after 1 week compared to PASCONTROL. These findings suggest that PAS may enhance motor learning retention and that motor state may be used to target different neural mechanisms of intracortical excitation and inhibition during PAS. This observation may be important to consider for the use of therapeutic noninvasive brain stimulation in neurologic patient populations.

Variable training does not lead to better motor learning compared to repetitive training in children with and without DCD when exposed to active video games

Evidence for motor learning in Parkinson's disease: Acquisition, automaticity and retention of cued gait performance after training with external rhythmical cues

The study's objective was to develop a comprehensive definition for operational excellence (OE) while identifying its attributes, most suitable theoretical lens and dimensions. Attributes of OE were collected by evaluating 32 existing definitions of OE and interviewing 30 OE experts. A focus group interview with 15 OE experts was employed to consensus on the critical attributes and tentative dimensions of OE. Content analysis was employed for data analysis. Continuous improvement of sustainable operational performance, deriving sustainable competitive advantages and implementing the operation strategy consistently and reliably were determined as the critical attributes. Based on the identified critical attributes of OE, the Resource-Based Theory (RBT) was recognized as the most applicable theory for explaining OE. Based on the identified theoretical lens and identified critical attributes, the new definition of OE involves, ‘utilization of valuable, rare, costly to imitate and non-substitutable resources & capabilities to execute the operations strategy consistently and reliably as the organization can achieve: a continuous improvement of the sustainable operational performance and sustainable competitive advantages while upholding the satisfaction of employees, customers, suppliers and other important stakeholders.' Continuous improvement of sustainable operational performance and sustainable competitive advantages were determined as the possible dimensions of OE. 
 Keywords: Operational Excellence; Resource-Based Theory; Construct Definition, Operational Performance, Competitive Advantages

The cholinergic basal forebrain projects throughout the neocortex, exerting a critical role in modulating plasticity associated with normal learning. Cholinergic modulation of cortical plasticity could arise from 3 distinct mechanisms by 1) "direct" modulation via cholinergic inputs to regions undergoing plasticity, 2) "indirect" modulation via cholinergic projections to anterior, prefrontal attentional systems, or 3) modulating more global aspects of processing via distributed inputs throughout the cortex. To segregate these potential mechanisms, we investigated cholinergic-dependent reorganization of cortical motor representations in rats undergoing skilled motor learning. Behavioral and electrophysiological consequences of depleting cholinergic inputs to either motor cortex, prefrontal cortex, or globally, were compared. We find that local depletion of cholinergic afferents to motor cortex significantly disrupts map plasticity and skilled motor behavior, whereas prefrontal cholinergic depletion has no effect on these measures. Global cholinergic depletion perturbs map plasticity comparable with motor cortex depletions but results in significantly greater impairments in skilled motor acquisition. These findings indicate that local cholinergic activation within motor cortex, as opposed to indirect regulation of prefrontal systems, modulate cortical map plasticity and motor learning. More globally acting cholinergic mechanisms provide additional support for the acquisition of skilled motor behaviors, beyond those associated with cortical map reorganization.

P195. Impaired motor learning in older adults-concepts of underlying mechanisms and strategies for supporting impaired functions

Stone toolmaking is a human motor skill which provides the earliest archeological evidence motor skill and social learning. Intentionally shaping a stone into a functional tool relies on the interaction of action observation and practice to support motor skill acquisition. The emergence of adaptive and efficient visuomotor processes during motor learning of such a novel motor skill requiring complex semantic understanding, like stone toolmaking, is not understood. Through the examination of eye movements and motor skill, the current study sought to evaluate the changes and relationship in perceptuomotor processes during motor learning and performance over 90 h of training. Participants’ gaze and motor performance were assessed before, during and following training. Gaze patterns reveal a transition from initially high gaze variability during initial observation to lower gaze variability after training. Perceptual changes were strongly associated with motor performance improvements suggesting a coupling of perceptual and motor processes during motor learning.