Influence of taping on force sense accuracy: a systematic review with between and within group meta-analysis

Taping is a common technique used to address proprioceptive deficits in both healthy and patient population groups. Although there is increasing interest in taping to address proprioceptive deficits, little is known about its effects on the kinetic aspects of proprioception as measured by force sense accuracy. To address this gap in the literature, the present systematic review and meta-analysis was conducted to evaluate the impact of taping on force sense accuracy. A search for relevant literature was conducted following PRISMA guidelines across seven databases and one register. Eleven studies with 279 participants were included in the review out of 7362 records. In the between-group analyses, we found a significant improvement in absolute (p < 0.01) and relative (p = 0.01) force sense accuracy with taping compared to no comparator. Likewise, a significant improvement in absolute (p = 0.01) force sense accuracy was also observed with taping compared to placebo tape. In the within group analysis, this reduction in the absolute (p = 0.11) force sense accuracy was not significant. Additional exploratory subgroup analyses revealed between group improvement in force sense accuracy in both healthy individuals and individuals affected by medial epicondylitis. The findings of this meta-analysis should be interpreted with caution due to the limited number of studies and a lack of blinded randomized controlled trials, which may impact the generalizability of the results. More high-quality research is needed to confirm the overall effect of taping on force sense accuracy.

Extended training improves the accuracy and efficiency of goal-directed reaching guided by supplemental kinesthetic vibrotactile feedback

Prior studies have shown that the accuracy and efficiency of reaching can be improved using novel sensory interfaces to apply task-specific vibrotactile feedback (VTF) during movement. However, those studies have typically evaluated performance after less than 1 h of training using VTF. Here, we tested the effects of extended training using a specific form of vibrotactile cues-supplemental kinesthetic VTF-on the accuracy and temporal efficiency of goal-directed reaching. Healthy young adults performed planar reaching with VTF encoding of the moving hand's instantaneous position, applied to the non-moving arm. We compared target capture errors and movement times before, during, and after approximately 10 h (20 sessions) of training on the VTF-guided reaching task. Initial performance of VTF-guided reaching showed that people were able to use supplemental VTF to improve reaching accuracy. Performance improvements were retained from one training session to the next. After 20 sessions of training, the accuracy and temporal efficiency of VTF-guided reaching were equivalent to or better than reaches performed with only proprioception. However, hand paths during VTF-guided reaching exhibited a persistent strategy where movements were decomposed into discrete sub-movements along the cardinal axes of the VTF display. We also used a dual-task condition to assess the extent to which performance gains in VTF-guided reaching resist dual-task interference. Dual-tasking capability improved over the 20 sessions, such that the primary VTF-guided reaching and a secondary choice reaction time task were performed with increasing concurrency. Thus, VTF-guided reaching is a learnable skill in young adults, who can achieve levels of accuracy and temporal efficiency equaling or exceeding those observed during movements guided only by proprioception. Future studies are warranted to explore learnability in older adults and patients with proprioceptive deficits, who might benefit from using wearable sensory augmentation technologies to enhance control of arm movements.

Facilitative effects of use-dependent learning on interlimb transfer of visuomotor adaptation in a person with congenital mirror movements

It has been shown that use-dependent learning can facilitate interlimb transfer of motor learning in neurologically intact individuals. However, it is unknown whether it can also facilitate interlimb transfer in individuals with neurological impairment. In this case study, we examined the effect of use-dependent learning on interlimb transfer of visuomotor adaptation in a person with congenital mirror movements, DB, who showed no interlimb transfer in our previous studies (Bao, Morgan, Lei, & Wang, 2020; Javidialsaadi, & Wang, 2021). DB first performed reaching movements with the right arm repeatedly while adapting to a visuomotor rotation condition with the left arm (training session), and then adapted to the same rotation condition with the right arm (transfer session). DB's right arm performance in the transfer session was significantly better than that observed in our previous studies, indicating interlimb transfer of visuomotor adaptation. The percentage of transfer was over 90%, which is similar to that observed in healthy young adults previously. These findings suggest that interlimb transfer of visuomotor adaptation can occur by involving model-based learning, which is effector independent, and/or use-dependent (or model-free) learning, which is effector specific; and also that the relative contribution of use-dependent learning to interlimb transfer of visuomotor adaptation can be as large as that of model-based learning.

Ventromedial Thalamus-Projecting DCN Neurons Modulate Associative Sensorimotor Responses in Mice

The deep cerebellar nuclei (DCN) integrate various inputs to the cerebellum and form the final cerebellar outputs critical for associative sensorimotor learning. However, the functional relevance of distinct neuronal subpopulations within the DCN remains poorly understood. Here, we examined a subpopulation of mouse DCN neurons whose axons specifically project to the ventromedial (Vm) thalamus (DCN^Vm neurons), and found that these neurons represent a specific subset of DCN units whose activity varies with trace eyeblink conditioning (tEBC), a classical associative sensorimotor learning task. Upon conditioning, the activity of DCN^Vm neurons signaled the performance of conditioned eyeblink responses (CRs). Optogenetic activation and inhibition of the DCN^Vm neurons in well-trained mice amplified and diminished the CRs, respectively. Chemogenetic manipulation of the DCN^Vm neurons had no effects on non-associative motor coordination. Furthermore, optogenetic activation of the DCN^Vm neurons caused rapid elevated firing activity in the cingulate cortex, a brain area critical for bridging the time gap between sensory stimuli and motor execution during tEBC. Together, our data highlights DCN^Vm neurons' function and delineates their kinematic parameters that modulate the strength of associative sensorimotor responses.

Computational benefits of structural plasticity, illustrated in songbirds

The plasticity of nervous systems allows animals to quickly adapt to a changing environment. In particular, the structural plasticity of brain networks is often critical to the development of the central nervous system and the acquisition of complex behaviors. As an example, structural plasticity is central to the development of song-related brain circuits and may be critical for song acquisition in juvenile songbirds. Here, we review current evidences for structural plasticity and their significance from a computational point of view. We start by reviewing evidence for structural plasticity across species and categorizing them along the spatial axes as well as the along the time course during development. We introduce the vocal learning circuitry in zebra finches, as a useful example of structural plasticity, and use this specific case to explore the possible contributions of structural plasticity to computational models. Finally, we discuss current modeling studies incorporating structural plasticity and unexplored questions which are raised by such models.

Seasonal regulation of singing-driven gene expression associated with song plasticity in the canary, an open-ended vocal learner

Songbirds are one of the few animal taxa that possess vocal learning abilities. Different species of songbirds exhibit species-specific learning programs during song acquisition. Songbirds with open-ended vocal learning capacity, such as the canary, modify their songs during adulthood. Nevertheless, the neural molecular mechanisms underlying open-ended vocal learning are not fully understood. We investigated the singing-driven expression of neural activity-dependent genes (Arc, Egr1, c-fos, Nr4a1, Sik1, Dusp6, and Gadd45β) in the canary to examine a potential relationship between the gene expression level and the degree of seasonal vocal plasticity at different ages. The expression of these genes was differently regulated throughout the critical period of vocal learning in the zebra finch, a closed-ended song learner. In the canary, the neural activity-dependent genes were induced by singing in the song nuclei throughout the year. However, in the vocal motor nucleus, the robust nucleus of the arcopallium (RA), all genes were regulated with a higher induction rate by singing in the fall than in the spring. The singing-driven expression of these genes showed a similar induction rate in the fall between the first year juvenile and the second year adult canaries, suggesting a seasonal, not age-dependent, regulation of the neural activity-dependent genes. By measuring seasonal vocal plasticity and singing-driven gene expression, we found that in RA, the induction intensity of the neural activity-dependent genes was correlated with the state of vocal plasticity. These results demonstrate a correlation between vocal plasticity and the singing-driven expression of neural activity-dependent genes in RA through song development, regardless of whether a songbird species possesses an open- or closed-ended vocal learning capacity.

The impact of early musical training on striatal functional connectivity

Evidence from language, visual and sensorimotor learning suggests that training early in life is more effective. The present work explores the hypothesis that learning during sensitive periods involves distinct brain networks in addition to those involved when learning later in life. Expert pianists were tested who started their musical training early (<7 years of age; n = 21) or late (n = 15), but were matched for total lifetime practice. Motor timing expertise was assessed using a musical scale playing task. Brain activity at rest was measured using fMRI and compared with a control group of nonmusicians (n = 17). Functional connectivity from seeds in the striatum revealed a striatal-cortical-sensorimotor network that was observed only in the early-onset group. In this network, higher connectivity correlated with greater motor timing expertise, which resulted from early/late group differences in motor timing expertise. By contrast, networks that differentiated musicians and nonmusicians, namely a striatal-occipital-frontal-cerebellar network in which connectivity was higher in musicians, tended to not show differences between early and late musicians and not be correlated with motor timing expertise. These results parcel musical sensorimotor neuroplasticity into a set of musicianship-related networks and a distinct set of predominantly early-onset networks. The findings lend support to the possibility that we can learn skills more easily early in development because during sensitive periods we recruit distinct brain networks that are no longer implicated in learning later in life.

Differentiation among bio- and augmented- feedback in technologically assisted rehabilitation

Introduction: In rehabilitation practice, the term 'feedback' is often improperly used, with augmented feedback and biofeedback frequently confused, especially when referring to the human-machine interaction during technologically assisted training. The absence of a clear differentiation between these categories represents an unmet need for rehabilitation, emphasized by the advent of new technologies making extensive use of video feedback, exergame, and virtual reality.Area covered: In this review we tried to present scientific knowledge about feedback, biofeedback, augmented feedback and neurofeedback, and related differences in rehabilitation settings, for a more proper use of this terminology. Despite the continuous expansion of the field, few researches clarify the differences among these terms. This scoping review was conducted through the searching of current literature up to May 2020, using following databases: PUBMED, EMBASE and Web of Science. After literature search a classification system, distinguishing feedback, augmented feedback, and biofeedback, was applied.Expert opinion: There is a need for clear definitions of feedback, biofeedback, augmented feedback, and neurofeedback in rehabilitation, especially in the technologically assisted one based on human-machine interaction. In fact, the fast development of new technologies requires to be based on solid concepts and on a common terminology shared among bioengineers and clinicians.

Obesity impairs performing and learning a timing perception task regardless of the body position

Obesity has been associated with poorer sensorimotor performance. However, it remains unclear whether these obesity-related impairments can be mitigated by practice. In the present study, we sought to investigate the effects of practice on performing and learning a temporal estimation task, in women with and without obesity. The experimental task consisted of synchronizing the arrival of two rectangles at a target point. Limited to the pressing of a switch, the task was intended to minimize possible muscular fatigue, self-generated perturbations to balance and the need to accelerate/decelerate body segments. Participants were allowed to choose the displacement velocity of the rectangle they controlled and were informed that they would not be offered any choice over it during a test to come. To control for the effect of different body positions on sensorimotor performance and learning, the 19 women with obesity (BMI = 40.0 + 7.33, age = 44.2 + 6.6) and 20 without obesity (BMI = 22.3 + 1.95, age = 43 + 6.9) were assigned into 4 groups, according to their BMI and body position assumed during practice (standing upright with feet together or sitting). As no significant differences concerning body position were found, the data were reanalysed disregarding this factor. Results revealed that while both groups reduced errors during the Acquisition, participants with obesity showed poorer performance (Acquisition) and sensorimotor learning (Transfer). Given the experimental task and adopted procedures, our results tend to support the hypothesis that hindered perception and/or integration of sensory information is associated with obesity.

A condition that produces sensory recalibration and abolishes multisensory integration

We examined the influence of extended exposure to a visuomotor rotation, which induces both motor adaptation and sensory recalibration, on (partial) multisensory integration in a cursor-control task. Participants adapted to a 30° (adaptation condition) or 0° (control condition) visuomotor rotation by making center-out movements to remembered targets. In subsequent test trials of sensory integration, they made center-out movements with variable visuomotor rotations and judged the position of hand or cursor at the end of these movements. Test trials were randomly embedded among twice the number of maintenance trials with 30° or 0° rotation. The biases of perceived hand (or cursor) position toward the cursor (or hand) position were measured. We found motor adaptation together with proprioceptive and visual recalibrations in the adaptation condition. Unexpectedly, multisensory integration was absent in both the adaptation and control condition. The absence stemmed from the extensive experience of constant visuomotor rotations of 30° or 0°, which probably produced highly precise predictions of the visual consequences of hand movements. The frequently confirmed predictions then dominated the estimate of the visual movement consequences, leaving no influence of the actual visuomotor rotations in the minority of test trials. Conversely, multisensory integration was present for sensed hand positions when these were indirectly assessed from movement characteristics, indicating that the relative weighting of discrepant estimates of hand position was different for motor control. The existence of a condition that abolishes multisensory integration while keeping sensory recalibration suggests that mechanisms that reduce sensory discrepancies (partly) differ between integration and recalibration.

Guiding functional reorganization of motor redundancy using a body-machine interface

Background

Body-machine interfaces map movements onto commands to external devices. Redundant motion signals derived from inertial sensors are mapped onto lower-dimensional device commands. Then, the device users face two problems, a) the structural problem of understanding the operation of the interface and b) the performance problem of controlling the external device with high efficiency. We hypothesize that these problems, while being distinct are connected in that aligning the space of body movements with the space encoded by the interface, i.e. solving the structural problem, facilitates redundancy resolution towards increasing efficiency, i.e. solving the performance problem.

Methods

Twenty unimpaired volunteers practiced controlling the movement of a computer cursor by moving their arms. Eight signals from four inertial sensors were mapped onto the two cursor’s coordinates on a screen. The mapping matrix was initialized by asking each user to perform free-form spontaneous upper-limb motions and deriving the two main principal components of the motion signals. Participants engaged in a reaching task for 18 min, followed by a tracking task. One group of 10 participants practiced with the same mapping throughout the experiment, while the other 10 with an adaptive mapping that was iteratively updated by recalculating the principal components based on ongoing movements.

Results

Participants quickly reduced reaching time while also learning to distribute most movement variance over two dimensions. Participants with the fixed mapping distributed movement variance over a subspace that did not match the potent subspace defined by the interface map. In contrast, participant with the adaptive map reduced the difference between the two subspaces, resulting in a smaller amount of arm motions distributed over the null space of the interface map. This, in turn, enhanced movement efficiency without impairing generalization from reaching to tracking.

Conclusions

Aligning the potent subspace encoded by the interface map to the user’s movement subspace guides redundancy resolution towards increasing movement efficiency, with implications for controlling assistive devices. In contrast, in the pursuit of rehabilitative goals, results would suggest that the interface must change to drive the statistics of user’s motions away from the established pattern and toward the engagement of movements to be recovered.

Trial registration

ClinicalTrials.gov, NCT01608438, Registered 16 April 2012.

The evolving sense of agency: Context recency and quality modulate the interaction between prospective and retrospective processes

Humans acquire a sense of agency through their interactions with the world and their sensory consequences. Previous studies have highlighted stable agency-related phenomena like intentional binding, which depend on both prospective, context-dependent and retrospective, outcome-dependent processes. In the current study, we investigated the interaction between prospective and retrospective processes underlying the adaptation of an ongoing sense of agency. The results showed that prospective intentional binding developed during a temporal window of up to 20 prior events was independent of the nature of the ongoing event. By contrast, the characteristics of the ongoing event retrospectively influenced prospective intentional binding developed during a temporal window narrower than 6 prior events. These findings characterize the interaction between prospective and retrospective mechanisms as a fundamental process to continuously update the sense of agency through sensorimotor learning. High psychosis-like experience traits weakened this interaction, suggesting that reduced adaption to the context contributes to altered self-experience.

Transfer of sensorimotor learning reveals phoneme representations in preliterate children

Reading acquisition is strongly intertwined with phoneme awareness that relies on implicit phoneme representations. We asked whether phoneme representations emerge before literacy. We recruited two groups of children, 4 to 5-year-old preschoolers (N = 29) and 7 to 8-year-old schoolchildren (N = 24), whose phonological awareness was evaluated, and one adult control group (N = 17). We altered speakers' auditory feedback in real time to elicit persisting pronunciation changes, referred to as auditory-motor adaptation or learning. Assessing the transfer of learning at phoneme level enabled us to investigate the developmental time-course of phoneme representations. Significant transfer at phoneme level occurred in preschoolers, as well as schoolchildren and adults. In addition, we found a relationship between auditory-motor adaptation and phonological awareness in both groups of children. Overall, these results suggest that phoneme representations emerge before literacy acquisition, and that these sensorimotor representations may set the ground for phonological awareness.

Sensorimotor training modulates automatic imitation of visual speech

The observation-execution links underlying automatic-imitation processes are suggested to result from associative sensorimotor experience of performing and watching the same actions. Past research supporting the associative sequence learning (ASL) model has demonstrated that sensorimotor training modulates automatic imitation of perceptually transparent manual actions, but ASL has been criticized for not being able to account for opaque actions, such as orofacial movements that include visual speech. To investigate whether the observation-execution links underlying opaque actions are as flexible as has been demonstrated for transparent actions, we tested whether sensorimotor training modulated the automatic imitation of visual speech. Automatic imitation was defined as a facilitation in response times for syllable articulation (ba or da) when in the presence of a compatible visual speech distractor, relative to when in the presence of an incompatible distractor. Participants received either mirror (say /ba/ when the speaker silently says /ba/, and likewise for /da/) or countermirror (say /da/ when the speaker silently says /ba/, and vice versa) training, and automatic imitation was measured before and after training. The automatic-imitation effect was enhanced following mirror training and reduced following countermirror training, suggesting that sensorimotor learning plays a critical role in linking speech perception and production, and that the links between these two systems remain flexible in adulthood. Additionally, as compared to manual movements, automatic imitation of speech was susceptible to mirror training but was relatively resilient to countermirror training. We propose that social factors and the multimodal nature of speech might account for the resilience to countermirror training of sensorimotor associations of speech actions.

Individual differences in TMS sensitivity influence the efficacy of tDCS in facilitating sensorimotor adaptation

BACKGROUND

Transcranial direct current stimulation (tDCS) can enhance cognitive function in healthy individuals, with promising applications as a therapeutic intervention. Despite this potential, variability in the efficacy of tDCS has been a considerable concern.

OBJECTIVE

/Hypothesis: Given that tDCS is always applied at a set intensity, we examined whether individual differences in sensitivity to brain stimulation might be one variable that modulates the efficacy of tDCS in a motor learning task.

METHODS

In the first part of the experiment, single-pulse transcranial magnetic stimulation (TMS) over primary motor cortex (M1) was used to determine each participant's resting motor threshold (rMT). This measure was used as a proxy of individual sensitivity to brain stimulation. In an experimental group of 28 participants, 2 mA tDCS was then applied during a motor learning task with the anodal electrode positioned over left M1. Another 14 participants received sham stimulation.

RESULTS

M1-Anodal tDCS facilitated learning relative to participants who received sham stimulation. Of primary interest was a within-group analysis of the experimental group, showing that the rate of learning was positively correlated with rMT: Participants who were more sensitive to brain stimulation as operationalized by our TMS proxy (low rMT), showed faster adaptation.

CONCLUSIONS

Methodologically, the results indicate that TMS sensitivity can predict tDCS efficacy in a behavioral task, providing insight into one source of variability that may contribute to replication problems with tDCS. Theoretically, the results provide further evidence of a role of sensorimotor cortex in adaptation, with the boost from tDCS observed during acquisition.

Correlation between changes in functional connectivity in the dorsal attention network and the after-effects induced by prism adaptation in healthy humans: A dataset of resting-state fMRI and pointing after prism adaptation

It has been reported that it is possible to observe transient changes in resting-state functional connectivity (FC) in the attention networks of healthy adults during treatment with prism adaptation. by using functional magnetic resonance imaging (fMRI) (see “Prism adaptation changes resting-state functional connectivity in the dorsal stream of visual attention networks in healthy adults: A fMRI study” (Tsujimoto et al., 2018) [1].

Recent neuroimaging and neurophysiological studies support the idea that prism adaptation (PA) affects the visual attention and sensorimotor networks, which include the parietal cortex and cerebellum.

These data demonstrate the effect of PA on resting-state functional connectivity between the primary motor cortex and cerebellum. Additionally, it evaluates changes of resting-state FC before and after PA in healthy individuals using fMRI. Analyses focus on FC between the primary motor cortex and cerebellum, and the correlation between changes in FC and its after-effects following a single PA session. Here, we show data that demonstrate the change in resting-state FC between the primary motor cortex and cerebellum, as well as a correlation between the change ratio of FC and the amplitude of the after-effect.

A cost of musical training? Sensorimotor flexibility in musical sequence learning

We report an experiment that tested the flexibility of sensorimotor learning in sequence production. Nonpianists and pianists learned simple melodies by ear under one of two auditory feedback conditions: one with normal pitch mapping (higher pitches to the right) and one with an inverted (reversed) mapping. After learning, both groups played melodies from memory while experiencing each feedback condition. Both groups exhibited sensorimotor learning and produced fewer errors at test while hearing the feedback used during training as opposed to the alternate feedback condition. However, learning was unstable for pianists who learned melodies with an inverted feedback condition, who produced more errors at test than pianists who learned melodies with normal-pitch mapping. Acquiring musical skill may therefore constrain subsequent sensorimotor flexibility.

Eye-hand coordination during visuomotor adaptation: effects of hemispace and joint coordination

We previously examined adaptive changes of eye-hand coordination during learning of a visuomotor rotation. Gazes during reaching movements were initially directed to a feedback cursor in early practice, but were gradually shifted toward the target with more practice, indicating an emerging gaze anchoring behavior. This adaptive pattern reflected a functional change of gaze control from exploring the cursor-hand relation to guiding the hand to the task goal. The present study further examined the effects of hemispace and joint coordination associated with target directions on this behavior. Young adults performed center-out reaching movements to four targets with their right hand on a horizontal digitizer, while looking at a rotated visual feedback cursor on a computer monitor. To examine the effect of hemispace related to visual stimuli, two out of the four targets were located in the ipsilateral workspace relative to the hand used, the other two in the contralateral workspace. To examine the effect of hemispace related to manual actions, two among the four targets were related to reaches made in the ipsilateral workspace, the other two to reaches made in the contralateral workspace. Furthermore, to examine the effect of the complexity of joint coordination, two among the four targets were reaches involving a direct path from the start to the target involving elbow movements (simple), whereas the other two targets were reaches involving both shoulder and elbow movements (complex). The results showed that the gaze anchoring behavior gradually emerged during practice for reaches made in all target directions. The speed of this change was affected mainly by the hemispace related to manual actions, whereas the other two effects were minimal. The gaze anchoring occurred faster for the ipsilateral reaches than for the contralateral reaches; gazes prior to the gaze anchoring were also directed less at the cursor vicinity but more at the mid-area between the starting point and the target. These results suggest that ipsilateral reaches result in a better predictability of the cursor-hand relation under the visuomotor rotation, thereby prompting an earlier functional change of gaze control through practice from a reactive to a predictive control.

Investigating three types of continuous auditory feedback in visuo-manual tracking

The use of continuous auditory feedback for motor control and learning is still understudied and deserves more attention regarding fundamental mechanisms and applications. This paper presents the results of three experiments studying the contribution of task-, error-, and user-related sonification to visuo-manual tracking and assessing its benefits on sensorimotor learning. First results show that sonification can help decreasing the tracking error, as well as increasing the energy in participant's movement. In the second experiment, when alternating feedback presence, the user-related sonification did not show feedback dependency effects, contrary to the error and task-related feedback. In the third experiment, a reduced exposure of 50% diminished the positive effect of sonification on performance, whereas the increase of the average energy with sound was still significant. In a retention test performed on the next day without auditory feedback, movement energy was still superior for the groups previously trained with the feedback. Although performance was not affected by sound, a learning effect was measurable in both sessions and the user-related group improved its performance also in the retention test. These results confirm that a continuous auditory feedback can be beneficial for movement training and also show an interesting effect of sonification on movement energy. User-related sonification can prevent feedback dependency and increase retention. Consequently, sonification of the user's own motion appears as a promising solution to support movement learning with interactive feedback.

Improving training for sensory augmentation using the science of expertise

Sensory substitution and augmentation devices (SSADs) allow users to perceive information about their environment that is usually beyond their sensory capabilities. Despite an extensive history, SSADs are arguably not used to their fullest, both as assistive technology for people with sensory impairment or as research tools in the psychology and neuroscience of sensory perception. Studies of the non-use of other assistive technologies suggest one factor is the balance of benefits gained against the costs incurred. We argue that improving the learning experience would improve this balance, suggest three ways in which it can be improved by leveraging existing cognitive science findings on expertise and skill development, and acknowledge limitations and relevant concerns. We encourage the systematic evaluation of learning programs, and suggest that a more effective learning process for SSADs could reduce the barrier to uptake and allow users to reach higher levels of overall capacity.

Is insight a godsend? Explicit knowledge in the serial response-time task has precursors in EEG potentials already at task onset

Whether, and how, explicit knowledge about some regularity arises from implicit sensorimotor learning by practice has been a matter of long-standing debate. Previously, we had found in the number reduction task that participants who will acquire explicit knowledge differ from other participants in their event-related potentials (ERPs) already at task onset. In the present study, we investigated such ERP precursors and correlates both of explicit and of sensorimotor knowledge (response speeding) about the regular sequence in a large sample of participants (n≈100) in the serial response time task. Already when perceiving random sequences at task onset, those participants had largest P3 amplitudes who would later gain explicit knowledge but whose responses were not speeded. Later in the task, sensorimotor knowledge was reflected in increased fronto-central negativity in irregular blocks, overlapping the early part of P3, and participants with later explicit knowledge generally had increased P3 amplitudes. These results support the notion that explicit knowledge about covert regularities is acquired in two ways: on the one hand by a particular subgroup of participants possibly independently of sequence-specific response speeding, and on the other hand by transforming such sensorimotor to explicit knowledge through practice.

Diurnal oscillation of vocal development associated with clustered singing by juvenile songbirds

Spaced practice affects learning efficiency in humans and other animals. However, it is not well understood how spaced practice contributes to learning during development. Here, we show the behavioral significance of singing frequency in song development in a songbird, the zebra finch. Songbirds learn a complex song pattern by trial-and-error vocalizations as self-motivated practice, which is executed over a thousand times per day during the sensitive period of vocal learning. Notably, juveniles generate songs with a high frequency of singing in clusters with dense singing, whereas adults sing with low frequency in short clusters. This juvenile-specific clustered singing was characterized by clear separations of daily time for intense practice and rest. During the epochs of vocal practice in juveniles, the song structure approached that of song produced at the end of the day. In contrast, during the epochs of vocal rest, the structure of juvenile songs regressed toward that of songs produced at the beginning of the day, indicating a dynamic progression and regression of song development over the course of the day. When the singing frequency was manipulated to decrease it at the juvenile stage, the oscillation rate of song development was dramatically reduced. Although the juvenile-specific clustered singing occurred in non-tutored socially isolated birds or those with auditory deprivation, the diurnal oscillation of vocal development was only observed in non-tutored isolated juveniles. These results show the impact of 'self-motivated' vocal practice on diurnal song developmental plasticity, modulated by the amount of vocal output and auditory feedback.

Mental representations of magnitude and order: a dissociation by sensorimotor learning

Numbers and spatially directed actions share cognitive representations. This assertion is derived from studies that have demonstrated that the processing of small- and large-magnitude numbers facilitates motor behaviors that are directed to the left and right, respectively. However, little is known about the role of sensorimotor learning for such number-action associations. In this study, we show that sensorimotor learning in a serial reaction-time task can modify the associations between number magnitudes and spatially directed movements. Experiments 1 and 3 revealed that this effect is present only for the learned sequence and does not transfer to a novel unpracticed sequence. Experiments 2 and 4 showed that the modification of stimulus-action associations by sensorimotor learning does not occur for other sets of ordered stimuli such as letters of the alphabet. These results strongly suggest that numbers and actions share a common magnitude representation that differs from the common order representation shared by letters and spatially directed actions. Only the magnitude representation, but not the order representation, can be modified episodically by sensorimotor learning.

Biographic and behavioral factors are associated with music-related motor skills in children pianists

This study aimed to identify biographical and behavioral factors associated with children pianists' motor skills using an objective assessment of a music-relevant motor task. Motor skills at the piano were assessed in 30 children pianists by measuring temporal unevenness in standardized scale playing using musical instrument digital interface (MIDI)-based scale analysis. Questionnaires were used to collect detailed information about the amount of time playing the piano, practice characteristics, attitudes toward music and practice, and the environment of music and practice. Associations between performance values and variables from the questionnaire were investigated using multivariable linear regression. A higher number of years playing the piano, more frequent parental involvement in the child's practice, more frequent practice of technical exercises, and greater enjoyment of practice and of the visual arts were associated with better motor performance. In addition to cumulative experience and aspects of practice, extrinsic motivational factors (e.g., parental interest) and intrinsic motivational factors (e.g., an artistic disposition) were associated with better performance on a musically-relevant motor task in children pianists.

Conscious awareness of action potentiates sensorimotor learning

Many everyday skills are unconsciously learned through repetitions of the same behaviour by binding independent motor acts into unified sets of actions. However, our ability to be consciously aware of producing newly and highly trained motor skills raises the question of the role played by conscious awareness of action upon skill acquisition. In this study we strengthened conscious awareness of self-produced sequential finger movements by way of asking participants to judge their performance in terms of maximal fluency after each trial. Control conditions in which participants did not make any judgment or performance-unrelated judgments were also included. Findings indicate that conscious awareness of action, enhanced via subjective appraisal of motor efficiency, potentiates sensorimotor learning and skilful motor production in optimising the processing and sequencing of action units, as compared to the control groups. The current work lends support to the claim that the learning and skilful expression of sensorimotor behaviours might be grounded upon our ability to be consciously aware of our own motor capability and efficiency.

The putative pigeon homologue to song bird LMAN does not modulate behavioral variability

The active generation of behavioral variability is thought to be a pivotal element in reinforcement based learning. One example for this principle is song learning in oscine birds. Oscines possess a highly specialized set of brain areas that compose the song system. It is yet unclear how the song system evolved. One important hypothesis assumes a motor origin of the song system, i.e. the song system may have developed from motor pathways that were present in an early ancestor of extant birds. Indeed, in pigeons neural pathways are present that parallel the song system. We examined whether one component of these pathways, a forebrain area termed nidopallium intermedium medialis pars laterale (NIML), is functionally comparable to its putative homologue, the lateral magnocellular nucleus of the anterior nidopallium (LMAN) of the song system. LMAN conveys variability into the motor output during singing; a function crucial for song learning and maintenance. We tested if NIML is likewise associated with the generation of variability. We used a behavioral paradigm in which pigeons had to find hidden target areas on a touch screen to gain food rewards. Alterations in pecking variability would result in changes of performance levels in this search paradigm. We found that pharmacological inactivation of NIML did not reduce pecking variability contrasting increases of song stereotypy observed after LMAN inactivation.