David L Wright

• Doctor of Philosophy
• Omar Smith Endowed Chair and Professor at Texas A&M University

Many motor skills require precise coordination between the arms to accomplish. The use of transcranial direct current stimulation (tDCS) has helped to reveal hemispheric contributions to bimanual skills. In this study, three bilateral montages were used to explore hemispheric contributions to a rhythmic bimanual skill: anode left M1/cathode right M...

The primary motor cortex (M1) is crucial for motor skill learning. We examined its role in interleaved practice, which enhances retention (vs. repetitive practice) through M1-dependent consolidation. We hypothesized that cathodal transcranial direct current stimulation (ctDCS) to M1 would disrupt retention. We found that ctDCS reduced retention due...

In recent years, dual-coil paired-pulse transcranial magnetic stimulation (ppTMS) has garnered interest for its potential in elucidating neural circuit dynamics. In this study, the dual-coil ppTMS was utilized to assess the effective connectivity between the supplementary motor complex (SMC) and the primary motor cortex (M1) in humans. A robust fac...

Caffeine is consumed in various beverages, such as coffee, energy drinks, soda, and tea. The effects of caffeine have been shown to manifest in various ways across different studies. Some studies suggest that caffeine can enhance motor performance. Despite this, numerous motor learning studies do not control for participants' caffeine intake or do...

The ability to coordinate movements between the hands is crucial for many daily tasks. However, the precise mechanisms governing the storage and utilization of bimanual movement and the distinct contributions of each limb in this process are currently not fully understood. Two key questions persist: 1) How is the neural representation of bimanual c...

Administering anodal transcranial direct current stimulation (tDCS) at the primary motor cortex (M1) at various temporal loci relative to motor training is reported to affect subsequent performance gains. Stimulation administered in conjunction with motor training appears to offer the most robust benefit that emerges during offline epochs. This con...

Motor learning involves acquiring new movement sequences and adapting motor commands to novel conditions. Labile motor memories, acquired through sequence learning and dynamic adaptation, undergo a consolidation process during wakefulness after initial training. This process stabilizes the new memories, leading to long-term memory formation. Howeve...

The primary motor cortex (M1) is broadly acknowledged for its crucial role in executing voluntary movements. Yet, its contributions to cognitive and sensory functions remain largely unexplored. Transcranial direct current stimulation (tDCS) is a noninvasive neurostimulation method that can modify brain activity, thereby enabling the establishment o...

Primary motor cortex (M1) plays a major role in motor memory acquisition and retention in humans, but its role in interleaved practice (as opposed to repetitive practice) remains unknown. We anticipated that the improved retention typically associated with interleaved practice depends on M1, and thus cathodal transcranial direct current (ctDCS) sti...

The C3 region in the international 10-20 system for electroencephalography (EEG) recording is assumed to represent the right motor hand area. Therefore, in the absence of transcranial magnetic stimulation (TMS) or a neuronavigational system, neuromodulation methods, such as transcranial direct current stimulation, target C3 or C4, based on the inte...

Posttraining meditation has been shown to promote wakeful memory stabilization of explicit motor sequence information in learners who are experienced meditators. We investigated the effect of single-session mindfulness meditation on wakeful and sleep-dependent forms of implicit motor memory consolidation in meditation naïve adults. Immediately afte...

Administering anodal tDCS at the primary motor cortex (M1) at various temporal loci relative to motor training is reported to affect subsequent performance gains. Stimulation administered in conjunction with motor training appears to offer the most robust benefit that emerges during offline epochs. This conclusion is made, however, based on between...

Different motor tasks may recruit different neural circuits during the process of motor memory consolidation. The present investigation has revealed some evidence indicating M1-dependent and S1-dependent mechanism involved in the memory consolidation process following the training of SRT and force adaptation task respectively.

Consolidation is recognized as a post-practice process critical for stabilizing labile motor memories. Implementation of this process relies on the learner having sufficient uninterrupted time between training and test or exposure to sleep. It has been demonstrated that consolidation of a motor skill is improved when acquisition is coupled with ano...

Introduction: Distinct cortical activities contribute to unilateral and bilateral motor control. However, it remains largely unknown whether the behavior of motor neurons differs between unilateral and bilateral isometric force generation. Here, we first investigated motor units (MUs) recruitment patterns during unilateral and bilateral force gene...

Learning a motor adaptation task produces intrinsically unstable or transient motor memories. Despite the presence of effector-independent motor memories following the learning of novel environmental dynamics, it remains largely unknown how those memory traces decay in different contexts and whether an “offline” consolidation period protects memori...

ROIG, M., J. CRISTINI, Z. PARWANTA, B. AYOTTE, L. RODRIGUES, B. DE LAS HERAS, J-F. NEPVEU, R. HUBER, J. CARRIER, S. STEIB, S.D. YOUNGSTEDT, and D.L. WRIGHT. Exercising the sleepy-ing brain: exercise, sleep, and sleep loss on memory. Exerc. Sport Sci. Rev., Vol. 50, No. 1, pp. 38–48, 2022. We examine the novel hypothesis that physical exercise and s...

Afferent inputs to the primary somatosensory cortex (S1) are differentially processed during precision and power grip in humans. However, it remains unclear how S1 interacts with the primary motor cortex (M1) during these two grasping behaviors. To address this question, we measured short-latency afferent inhibition (SAI), reflecting S1-M1 interact...

Administering anodal transcranial direct current stimulation at the left dorsal premotor cortex (PMd) but not right PMd throughout the repetitive practice of three novel motor sequences resulted in improved offline performance usually only observed after interleaved practice. This gain only emerged following overnight sleep. These data are consiste...

Post-training meditation has been shown to promote wakeful motor memory stabilization in experienced meditators. We investigated the effect of single-session mindfulness meditation on wakeful and sleep-dependent forms of implicit motor memory consolidation in mediation naïve adults. Immediately after implicit sequence training, participants (N = 20...

We examine the novel hypothesis that physical exercise and sleep have synergistic effects on memory. Exercise can trigger mechanisms that can create an optimal brain state during sleep to facilitate memory processing. The possibility that exercise could counteract the deleterious effects of sleep deprivation on memory by protecting neuroplasticity...

When discussing procedural learning, it is now routine to consider both online and offline influences for skill acquisition. This is because it is commonly assumed that the evolution of a novel skill memory continues well after practice is over. Indeed, factors impacting offline contributions to skill memory development such as sleep and exercise h...

Introduction: Distinct cortical activities contribute to unilateral and bilateral motor control. However, it remains largely unknown whether the behavior of motor neurons differs between unilateral and bilateral isometric force generation. Here, we first investigated motor units (MUs) recruitment patterns during unilateral and bilateral force gener...

The present study investigated the long-term benefit of Random-Practice (RP) over Blocked-Practice (BP) within the contextual interference (CI) effect for motor learning. We addressed the extent to which motor sequence length and practice amount factors moderate the CI effect given that previous reports, often in applied research, have reported no...

Following training, novel motor memory is initially fragile before consolidation processes render the memory stabilized into long-term memory. Of the two types of time-dependent consolidation processes that occur following training, those associated with sleep have attracted the most attention at the cost of consideration for processes that occur i...

There is increasing interest in mindfulness meditation for memory augmentation. For example, post-training meditation has been shown to promote wakeful motor memory stabilization in experienced meditators (Immink, 2016). We investigated the effect of single-session mindfulness meditation on wakeful and sleep-dependent forms of motor memory consolid...

Research has supported two distinct forms of motor skill consolidation that can occur between practice sessions: (1) off-line learning, and (2) memory stabilization. Off-line learning describes performance improvement between practice sessions that is above the gain observed at the end of practice, while memory stabilization describes a gain in per...

Training under high interference conditions through interleaved practice (IP) results in performance suppression during training but enhances long-term performance relative to repetitive practice (RP) involving low interference. Previous neuroimaging work addressing this contextual interference effect of motor learning has relied heavily on the blo...

Learning a motor adaptation task produces intrinsically unstable or transient motor memories. Despite the presence of effector-independent motor memories following the learning of novel environmental dynamics, it remains largely unknown how those memory traces decay in different contexts and whether an “offline” consolidation period protects memori...

Reactive balance training (RBT) is an emerging fall prevention exercise intervention for older adults. To better understand factors that influence improvements after RBT, the goal of this study was to identify key factors that strongly associate with training-induced improvements in reactive balance. This study is a secondary analysis of data from...

Engagement of primary motor cortex (M1) is important for successful consolidation of motor skills. Recruitment of M1 has been reported to be more extensive during interleaved compared to repetitive practice and this differential recruitment has been proposed to contribute to the long-term retention benefit associated with interleaved practice. The...

The neural systems that govern declarative and procedural memory processing do not always operate independently. Direct evidence of competition between these two memory systems in humans is supported by studies showing that performing a declarative learning task immediately after motor skill learning can disrupt procedural memory and abolish the of...

The purpose of the study was twofold: (1) determine if different time delays (30 min or 6 h) between training and a post-training test with a rhythmic bimanual pattern (90° relative phase) would be associated with different levels of consolidation for the motor and spatial representations of the pattern; and (2) determine if training with the rhyth...

Two experiments examined whether practicing discrete key pressing sequences eventually leads to a disregard of the key-specific stimuli, as suggested by sequence learning models, or whether these stimuli continue to be relied upon because the associated luminance increase attracts visuospatial attention. Participants practiced two sequences by reac...

Interleaved rather than repetitive practice is associated with superior retention of motor skills. It has been argued that this results from improved post-practice consolidation reflected in greater offline gains following interleaved practice. The magnitude of this offline benefit has been associated with greater recruitment of supplementary motor...

Skill acquisition represents a progression from high to low reliance on the conscious control of the action. The ability to produce action without drawing upon limited attentional resources has traditionally been the defining characteristic of skill automaticity. As such, learning represents a progression from low to high efficiency in the cognitiv...

Tecchio et al. (J Neurophysiology 104: 1134–1140, 2010) reported that the application of anodal tDCS at primary motor cortex (M1) immediately after practice of a procedural motor skill enhanced consolidation, which in turn improved offline gain. Tecchio et al. noted, however, that this study did not account for known after-effects associated with t...

Numerous studies have reported a positive impact of acute exercise for procedural skill memory. Previous work has revealed this effect, but these findings are confounded by a potential contribution of a night of sleep to the reported exercise-mediated reduction in interference. Thus, it remains unclear if exposure to a brief bout of exercise can pr...

The influence of monitoring-pressure and verbal feedback on the performance of the intrinsically stable bimanual coordination patterns of in-phase and anti-phase was examined. The two bimanual patterns were produced under three conditions: 1) no-monitoring, 2) monitoring-pressure (viewed by experts), and 3) monitoring-pressure (viewed by experts) c...

The influence of monitoring-pressure and verbal feedback on the performance of the intrinsically stable bimanual coordination patterns of in-phase and anti-phase was examined. The two bimanual patterns were produced under three conditions: 1) no-monitoring, 2) monitoring-pressure (viewed by experts), and 3) monitoring-pressure (viewed by experts) c...

The primary objective of the present experiment was to examine the influence of recent practice in a random and blocked format for future motor learning. First, individuals practiced three unique discrete sequence production tasks in either a blocked or random schedule. One day later, all individuals practiced a new motor sequence not previously pr...

The contextual interference (CI) effect, where high CI conditions suppress practice performance but then enhance delayed test performance, appears to extend beyond motor planning to also involve executive processes. As this implies a role for prefrontal cortex (PFC) activation in the CI effect, the present experiment utilized two-channel near-infra...

Explanations for the contextual interference (CI) effect focus on motor planning or memory development although the role of CI might also extend to early motor processes associated with response selection. The present experiment adopted the Simon effect heuristic to compare sequence learning under high and low CI conditions with and without stimulu...

The influence of monitoring-pressure on the performance of anti-phase and in-phase bimanual coordination was examined. The two bimanual patterns were produced under no-monitoring and monitoring-pressure conditions at self-paced frequencies. Anti-phase coordination was always less stable than in-phase coordination, with or without monitoring. When p...

Sleep enhances motor sequence learning (MSL) in young adults by concatenating subsequences (" chunks ") formed during skill acquisition. To examine whether this process is reduced in aging, we assessed performance changes on the MSL task following overnight sleep or daytime wake in healthy young and older adults. Young adult performance enhancement...

In healthy young adults motor learning is typically improved by practice under conditions of high contextual interference such as that created when a series of skills are practiced in a random sequence. The authors examined whether individuals with Parkinson's disease and age-matched older adults might also benefit from such a learning environment....

In order to determine how participants represent practiced, discrete keying sequences in the discrete sequence production task, we had 24 participants practice two six-key sequences on the basis of two pre-learned six-digit numbers. These sequences were carried out by fingers of the left (L) and right (R) hand with between-hand transitions always o...

Two experiments were conducted to examine the efficacy of random (RP) and blocked practice (BP) for enhancing later motor learning. Each experiment involved practicing three unique seven key serial reaction time (SRT) tasks in either a blocked or random format followed by practice of a novel SRT task either 2-min (Experiment 1) or 24-h (Experiment...

We performed two experiments to determine whether amplified motor output variability and compromised processing of visual information in older adults impair short-term adaptations when learning novel fine motor tasks. In Experiment 1, 12 young and 12 older adults underwent training to learn how to accurately trace a sinusoidal position target with...

The present study examined the efficacy of a short bout of moderately intensive exercise to protect knowledge of a newly acquired motor sequence. Previous work revealed that sleep-dependent offline gains in motor sequence performance are reduced by practicing an alternative motor sequence in close temporal proximity to the original practice with th...

Motor sequence learning under high levels of contextual interference (CI) disrupts initial performance but supports delayed test and transfer performance when compared to learning under low CI. Integrating findings from early behavioral work and more recent experimental efforts that incorporated neurophysiologic measures led to a novel account of t...

Robust offline gains occur during explicit motor sequence learning. However practice of a motor sequence, other than the target sequence, within 4-6 hr after initial practice interferes with these gains. This work assessed if experiencing supplemental practice of spatially or motorically similar sequences influenced the extent of offline gain. A co...

Behavioral research produced many task-specific cognitive models that do not say much about the underlying information processing architecture. Such an architecture is badly needed to understand better how cognitive neuroscience can benefit from existing cognitive models. This problem is especially pertinent in the domain of sequential behavior whe...

A substantial amount of research has addressed how people learn and control movement sequences. Recent results suggested that practice with discrete key pressing sequences results in two types of sequence learning: associative learning and motor chunk development (Verwey & Abrahamse, 2012). In the present study, we addressed whether in keying seque...

Procedural learning benefits from memory processes occurring outside practice resulting in offline learning. Offline gains have been demonstrated almost exclusively for the ordinal structure of sequential motor tasks. Many skills also demand that the correct serial order of events be appropriately timed. Evidence indicates that the temporal aspect...

The present study investigated the role of temperature as a contextual condition for motor skill learning. Precision grip task training occurred while forearm cutaneous temperature was either heated (40-45 °C) or cooled (10-15 °C). At test, temperature was either reinstated or changed. Performance was comparable between training conditions while at...

Both observational and physical practices support the acquisition of motor skill knowledge in the form of spatiotemporal coordination patterns. The current experiment examined the extent that observation and physical practice can support the transfer of spatiotemporal knowledge and amplitude knowledge associated with motor skills. Evidence from a m...

Robust offline performance gains, beyond those that would be anticipated by being exposed to additional physical practice, have been reported during procedural learning and have been attributed to enhancement consolidation, a process by which memory is transformed in such a way that it is not only more resistant to forgetting but may also involve a...

Purpose The authors examined the involvement of 2 speech motor programming processes identified by S. T. Klapp (1995, 2003) during the articulation of utterances differing in syllable and sequence complexity. According to S. T. Klapp, 1 process, INT, resolves the demands of the programmed unit, whereas a second process, SEQ, oversees the serial ord...

Motor programming at the self-select paradigm was adopted in 2 experiments to examine the processing demands of independent processes. One process (INT) is responsible for organizing the internal features of the individual elements in a movement (e.g., response duration). The 2nd process (SEQ) is responsible for placing the elements into the proper...

The learning of relative and absolute motion features as a function of physical (actor group) and observational (observer group) practice was examined in a rhythmic single limb multi-joint coordination task. The task required the participants to learn a 90 degrees relative phase pattern between the elbow and wrist in combination with an absolute el...

Apraxia of Speech (AOS) is an impairment of motor programming. However, the exact nature of this deficit remains unclear. The present study examined motor programming in AOS in the context of a recent two-stage model [Klapp, S. T. (1995). Motor response programming during simple and choice reaction time: The role of practice. Journal of Experimenta...

The learning of relative and absolute motion features as a function of physical (actor group) and observational (observer group) practice was examined in a rhythmic single limb multi-joint coordination task. The task required the participants to learn a 90° relative phase pattern between the elbow and wrist in combination with an absolute elbow joi...