Perceptual error based on Bayesian cue combination drives implicit motor adaptation.

The sensorimotor system can recalibrate itself without our conscious awareness, a type of procedural learning whose computational mechanism remains undefined. Recent findings on implicit motor adaptation, such as over-learning from small perturbations and fast saturation for increasing perturbation size, challenge existing theories based on sensory errors. We argue that perceptual error, arising from the optimal combination of movement-related cues, is the primary driver of implicit adaptation. Central to our theory is the increasing sensory uncertainty of visual cues with increasing perturbations, which was validated through perceptual psychophysics (Experiment 1). Our theory predicts the learning dynamics of implicit adaptation across a spectrum of perturbation sizes on a trial-by-trial basis (Experiment 2). It explains proprioception changes and their relation to visual perturbation (Experiment 3). By modulating visual uncertainty in perturbation, we induced unique adaptation responses in line with our model predictions (Experiment 4). Overall, our perceptual error framework outperforms existing models based on sensory errors, suggesting that perceptual error in locating one's effector, supported by Bayesian cue integration, underpins the sensorimotor system's implicit adaptation.

Sense of Agency and Skills Learning in Virtual-Mediated Environment: A Systematic Review.

Agency is central to remote actions, and it may enhance skills learning due to a partial overlap between brain structures and networks, the promotion of confidence towards a telemanipulator, and the feeling of congruence of the motor choice to the motor plan. We systematically reviewed studies aiming to verify the role of agency in improving learning. Fifteen studies were selected from MEDLINE and Scopus®. When a mismatch is introduced between observed and performed actions, the decrease in agency and learning is proportional to the intensity of the mismatch, which is due to greater interference with the motor programming. Thanks to multisensory integration, agency and learning benefit both from sensory and performance feedback and from the timing of feedback based on control at the goal level or the perceptual-motor level. This work constitutes a bedrock for professional teleoperation settings (e.g., robotic surgery), with particular reference to the role of agency in performing complex tasks with remote control.

Does transcranial direct current stimulation of the primary motor cortex improve implicit motor sequence learning in Parkinson's disease?

Implicit motor sequence learning (IMSL) is a cognitive function that is known to be associated with impaired motor function in Parkinson's disease (PD). We previously reported positive effects of transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) on IMSL in 11 individuals with PD with mild cognitive impairments (MCI), with the largest effects occurring during reacquisition. In the present study, we included 35 individuals with PD, with (n = 15) and without MCI (n = 20), and 35 age- and sex-matched controls without PD, with (n = 13) and without MCI (n = 22). We used mixed-effects models to analyze anodal M1 tDCS effects on acquisition (during tDCS), short-term (five minutes post-tDCS) and long-term reacquisition (one-week post-tDCS) of general and sequence-specific learning skills, as measured by the serial reaction time task. At long-term reacquisition, anodal tDCS resulted in smaller general learning effects compared to sham, only in the PD group, p = .018, possibly due to floor effects. Anodal tDCS facilitated the acquisition of sequence-specific learning (M = 54.26 ms) compared to sham (M = 38.98 ms), p = .003, regardless of group (PD/controls). Further analyses revealed that this positive effect was the largest in the PD-MCI group (anodal: M = 69.07 ms; sham: M = 24.33 ms), p < .001. Although the observed effect did not exceed the stimulation period, this single-session tDCS study confirms the potential of tDCS to enhance IMSL, with the largest effects observed in patients with lower cognitive status. These findings add to the body of evidence that anodal tDCS can beneficially modulate the abnormal basal ganglia network activity that occurs in PD.

Autistic Adults Show Intact Learning on a Visuospatial Serial Reaction Time Task.

Some theories have proposed that autistic individuals have difficulty learning predictive relationships. We tested this hypothesis using a serial reaction time task in which participants learned to predict the locations of a repeating sequence of target locations. We conducted a large-sample online study with 61 autistic and 71 neurotypical adults. The autistic group had slower overall reaction times, but demonstrated sequence-specific learning equivalent to the neurotypical group, consistent with other findings of typical procedural memory in autism. The neurotypical group, however, made significantly more prediction-related errors early in the experiment when the stimuli changed from repeated sequences to random locations, suggesting certain limited behavioural differences in the learning or utilization of predictive relationships for autistic adults.

Alternative covariance structures in mixed-effects models: Addressing intra- and inter-individual heterogeneity.

Mixed-effects models for repeated measures and longitudinal data include random coefficients that are unique to the individual, and thus permit subject-specific growth trajectories, as well as direct study of how the coefficients of a growth function vary as a function of covariates. Although applications of these models often assume homogeneity of the within-subject residual variance that characterizes within-person variation after accounting for systematic change and the variances of the random coefficients of a growth model that quantify individual differences in aspects of change, alternative covariance structures can be considered. These include allowing for serial correlations between the within-subject residuals to account for dependencies in data that remain after fitting a particular growth model or specifying the within-subject residual variance to be a function of covariates or a random subject effect to address between-subject heterogeneity due to unmeasured influences. Further, the variances of the random coefficients can be functions of covariates to relax the assumption that these variances are constant across subjects and to allow for the study of determinants of these sources of variation. In this paper, we consider combinations of these structures that permit flexibility in how mixed-effects models are specified to understand within- and between-subject variation in repeated measures and longitudinal data. Data from three learning studies are analyzed using these different specifications of mixed-effects models.

Plasticity-stability dynamics during post-training processing of learning.

Learning continues beyond the end of training. Post-training learning is supported by changes in plasticity and stability in the brain during both wakefulness and sleep. However, the lack of a unified measure for assessing plasticity and stability dynamics during training and post-training periods has limited our understanding of how these dynamics shape learning. Focusing primarily on procedural learning, we integrate work using behavioral paradigms and a recently developed measure, the excitatory-to-inhibitory (E/I) ratio, to explore the delicate balance between plasticity and stability and its relationship to post-training learning. This reveals plasticity-stability cycles during both wakefulness and sleep that enhance learning and protect it from new learning during post-training processing.

A Dyadic Cooking-Based Intervention for Improving Subjective Health and Well-Being of Older Adults with Subjective Cognitive Decline and Their Caregivers: A Randomized Controlled Trial.

OBJECTIVES: Evidence on the effectiveness of cooking activities as a well-being promotion intervention for older adults with subjective cognitive decline (SCD) and their caregivers is scarce. In view of this, a randomized controlled trial was conducted to examine whether a dyadic cooking-based intervention can improve the subjective health and well-being of older adults with SCD and their caregivers, as well as the cooking competence of the former group. DESIGN: Randomized controlled trial. SETTING: Community. PARTICIPANTS: Sixty pairs of community-dwelling older adults aged 60 years or above with SCD (mean age = 78.4 years) and their caregivers (mean age = 65.3 years) were randomly assigned to the intervention group (N = 30 pairs) and the wait-list control group (N = 30 pairs). INTERVENTION: The intervention was an innovative 5-week (two hours per week) dyadic cooking-based intervention employing procedural learning methods specifically adapted for older adults with SCD. MEASUREMENTS: The outcome measures included 1) a well-being index composed by four indicators: life satisfaction, feeling of happiness, sense of purpose and meaning in life, and perceived health, and 2) cooking competence. RESULTS: For both older adults with SCD and their caregivers, the increases in the well-being index were significantly greater in the intervention group than in the control group (ß = 0.508, 95% CI [0.036, 0.980]). For older adults with SCD, the increases in the cooking competence score were significantly greater in the intervention group than in the control group (ß = 1.629, 95% CI [0.165, 3.071]). CONCLUSION: The dyadic cooking-based intervention resulted in improvements in the cooking competence and well-being of older adults with SCD, as well as the well-being of caregivers.

Procedural auditory category learning is selectively disrupted in developmental language disorder.

Speech communication depends on accurate perception and identification of speech sounds, which vary across talkers and word or sentence contexts. The ability to map this variable input onto discrete speech sound representations relies on categorization. Recent research and theoretical models implicate the procedural learning system in the ability to learn novel speech and non-speech categories. This connection is particularly intriguing because several language disorders that demonstrate linguistic impairments are proposed to stem from procedural learning and memory dysfunction. One such disorder, Developmental Language Disorder (DLD), affects 7.5% of children and persists into adulthood. While DLD is associated with general linguistic impairments, it is not yet clear how fundamental perceptual and cognitive processes supporting language are impacted, such as the ability to learn novel auditory categories. We examined auditory category learning in children with DLD and typically developed (TD) children using two well-matched nonspeech auditory category learning challenges to draw upon presumed procedural (information-integration) versus declarative (rule-based) learning systems. We observed impaired information-integration category learning and intact rule-based category learning in the DLD group. Quantitative model-based analyses revealed reduced use of, and slower shifting to, optimal procedural-based strategies in DLD and slower shifting to but similarly efficient use of optimal hypothesis-testing strategies. The dissociation is consistent with the Procedural Deficit Hypothesis of language disorders and supports the theoretical distinction of multiple category learning systems. These findings demonstrate that highly controlled experimental tasks assessing perceptual and cognitive abilities can relate to real-world challenges facing individuals with DLD in forming stable linguistic representations.

When practice does not make a perfect - paradoxical learning curve in schizophrenia and bipolar disorder revealed by different serial reaction time task variants.

Introduction: Our previous studies identified a paradoxical implicit motor learning curve in schizophrenia (SZ) and bipolar disorder (BD) patients. This study aimed to verify whether those previously observed deficits may be captured by a new version of the ambidextrous serial reaction time task (SRTT), prepared for use in the MRI. Methods: This study involved 186 participants. A total of 97 participants (33 BD, 33 SZ, and 31 healthy controls, HCs) completed the original, unlimited time response variant of SRTT. A total of 90 individuals (30 BD, 30 SZ, and 30 HCs) underwent a newer, limited response time version of this procedure. Results: There was no significant difference in terms of implicit motor learning indices between both limited and unlimited response time SRTT. Compared to HCs, SZ, and BD patients presented decreased indices of implicit motor learning. Both clinical groups showed a paradoxical learning pattern that differed significantly from the HCs. Moreover, in the SZ group, the pattern depended on the hand performing SRTT. Discussion: The limited response time SRTT variant allowed us to replicate the findings of disrupted implicit motor learning in SZ and BD. The use of this paradigm in further neuroimaging studies may help to determine the neuronal underpinnings of this cognitive dysfunction in the abovementioned clinical groups.

Development and assessment of a vaccine administration training course for medical students.

BACKGROUND: Vaccine administration skills are very important for physicians, especially in the era of global pandemics. However, medical students have reported that practical sessions to develop these skills are insufficient. Therefore, the aim of our study was to develop a vaccination training course for medical students. We also examined its educational effectiveness. METHODS: 5th- and 6th-year medical students at the University of Tokyo were recruited to attend the vaccine administration training course in 2021. These students were our study participants. Our course consisted of an orientation part, which included a lecture on the indications, adverse events, and vaccination techniques of flu vaccines and practice on a simulator, and a main part in which the staff of the University of Tokyo Hospital were actually vaccinated. Before and after the main part of the course, study participants completed an online questionnaire that assessed their confidence in vaccine administration technique through a five-point Likert scale. We also surveyed their feedback about the course content and process. At the beginning and end of the main part, their technical competence in vaccination was assessed by two independent doctors. These doctors used a validated checklist scale (ranging from 16 to 80) and a global rating scale (ranging from 0 to 10). We used their mean scores for analysis. The quantitative data were analyzed through the Wilcoxon signed-rank test. For the qualitative data of the questionnaire, thematic analysis was conducted. RESULTS: All 48 course participants participated in our study. Participants' confidence in vaccination technique (Z = -5.244, p < 0.05) and vaccination skill significantly improved (checklist rating: Z = -5.852, p < 0.05; global rating: Z = -5.868, p < 0.05). All participants rated the course as, "overall educational." Our thematic analysis identified four emerging themes: interest in medical procedures, efficacy of supervision and feedback, efficacy of "near-peer" learning, and very instructive course. CONCLUSIONS: In our study, we developed a vaccine administration course for medical students, assessed their vaccination techniques and confidence in those techniques, and investigated their perceptions of the course. Students' vaccination skills and confidence improved significantly after the course, and they positively evaluated the course based on a variety of factors. Our course will be effective in educating medical students about vaccination techniques.

Optogenetic disruption of the prelimbic cortex alters long-term decision strategy but not valuation on a spatial delay discounting task.

Rats demonstrate a preference for smaller, immediate rewards over larger, delayed ones, a phenomenon known as delay-discounting (DD). Behavior arises from the interaction of multiple decision-making systems, and the medial prefrontal cortex (mPFC) has been identified as a central component in the mediation between these decision systems. To investigate the role of the prelimbic (PL) subregion of mPFC on decision strategy interaction, we compared two cohorts of rats (ChR2-opsin-expressing 'Active' and opsin-absent 'Control') on a spatial delay-discounting task while delivering in-vivo light stimulation into PL at the choice point of select trials. By analyzing the overall delay-adjustment along with deliberative and procedural behavioral strategy markers, our study revealed differences in the decision strategies used between the active and control animals despite both groups showing similar valuations. Control animals developed the expected shift from deliberative to procedural decision strategy on this task (indicated by reaching delay-stability, particularly during late-session laps); however, active-virus animals repeatedly over-adjusted around their preferred delay throughout the entire session, suggesting a significant deficit in procedural decision-making on this task. Active animals showed a significant decrease in proportion of vicarious trial and error events (VTE, a behavior correlated with deliberative processes) on delay adjustment laps relative to control animals. This points to a more nuanced role for VTE, not just in executing deliberation, but in shifting from deliberative to procedural processes. This opto-induced change in VTE was especially pronounced for late-session adjustment laps. We found no other session-by-session or lap-by-lap effects, leaving a particular role for PL in the long-term development of procedural strategies on this task.

Impaired and Spared Auditory Category Learning in Developmental Dyslexia.

Categorization has a deep impact on behavior, but whether category learning is served by a single system or multiple systems remains debated. Here, we designed two well-equated nonspeech auditory category learning challenges to draw on putative procedural (information-integration) versus declarative (rule-based) learning systems among adult Hebrew-speaking control participants and individuals with dyslexia, a language disorder that has been linked to a selective disruption in the procedural memory system and in which phonological deficits are ubiquitous. We observed impaired information-integration category learning and spared rule-based category learning in the dyslexia group compared with the neurotypical group. Quantitative model-based analyses revealed reduced use of, and slower shifting to, optimal procedural-based strategies in dyslexia with hypothesis-testing strategy use on par with control participants. The dissociation is consistent with multiple category learning systems and points to the possibility that procedural learning inefficiencies across categories defined by complex, multidimensional exemplars may result in difficulty in phonetic category acquisition in dyslexia.

An Assessment of Upper-Extremity Surgical Technique Videos and Their Relationship With Procedural Learning Theory.

PURPOSE: Our purpose was to ascertain how well award-winning and highly viewed upper-extremity surgical videos meet the needs of users and adhere to procedural learning theory. We hypothesized that upper-extremity videos hosted on academic society websites meet user needs better than upper-extremity videos hosted on a commercial website. METHODS: Twenty-five upper-extremity videos were evaluated by 3 reviewers. A standardized scoring sheet was used to assess each video's content, production quality, and adequacy. Video lengths were compared. The inclusion frequencies of specific content categories, the adequacy of content, and meeting certain production standards, all of which assess consistency with procedural learning theory, were reported, stratified by video host. Associations between the video host and video content, production quality, and adequacy were assessed. RESULTS: The median lengths of academically hosted and commercially hosted videos were similar. Regardless of the video host, no video contained information in all content categories. Sixty percent of the scored categories were present in less than 75% of evaluated videos. Academically hosted videos contained scored content more frequently than commercially hosted videos in 68.4% of categories. There were significant associations between academic hosts and inclusion of a case presentation, surgical indications, outcomes literature, a preoperative examination, follow-up visit intervals, and alternative surgical techniques. Overall, academically hosted videos had a higher percentage of adequate content categories compared with commercially hosted videos. CONCLUSIONS: Videos on academic websites more consistently meet users' content needs and production expectations, as informed by procedural learning theory, while having higher rates of adequate content compared with videos on commercial websites. CLINICAL RELEVANCE: While academically hosted videos appear to more consistently adhere to the tenets of procedural learning theory, opportunity exists for video creators to more consistently apply procedural learning theory, allowing for the creation of even more educationally beneficial online surgical videos.

Atypical procedural learning skills in children with Developmental Coordination Disorder.

We investigated the procedural learning deficit hypothesis in Developmental Coordination Disorder (DCD) while controlling for global performance such as slower reaction times (RTs) and variability. Procedural (sequence) learning was assessed in 31 children with DCD and 31 age-matched typically developing (TD) children through a serial reaction time task (SRTT). Sequential and random trial conditions were intermixed within five training epochs. Two repeated measures ANOVAs were conducted on a Sequence-Specific Learning Index (SSLI) and a Global Performance Index (GPI, speed/accuracy measure) with Epoch (for SSLI and GPI) and Condition (for GPI) as within-subjects factors, and Group as between-subjects factor. Controlling for RTs differences through normalized RTs, revealed a global reduction of SSLI in children with DCD compared with TD peers suggesting reduced sequence learning skills in DCD. Still, a significant Group x Condition interaction observed on GPI indicated that children from both groups were able to discriminate between sequential and random trials. DCD presented reduced procedural learning skills after controlling for global performance. This finding highlights the importance of considering the general functioning of the child while assessing learning skills in patients.

Differences in implicit motor learning between adults who do and do not stutter.

Implicit learning allows us to acquire complex motor skills through repeated exposure to sensory cues and repetition of motor behaviours, without awareness or effort. Implicit learning is also critical to the incremental fine-tuning of the perceptual-motor system. To understand how implicit learning and associated domain-general learning processes may contribute to motor learning differences in people who stutter, we investigated implicit finger-sequencing skills in adults who do (AWS) and do not stutter (ANS) on an Alternating Serial Reaction Time task. Our results demonstrated that, while all participants showed evidence of significant sequence-specific learning in their speed of performance, male AWS were slower and made fewer sequence-specific learning gains than their ANS counterparts. Although there were no learning gains evident in accuracy of performance, AWS performed the implicit learning task more accurately than ANS, overall. These findings may have implications for sex-based differences in the experience of developmental stuttering, for the successful acquisition of complex motor skills during development by individuals who stutter, and for the updating and automatization of speech motor plans during the therapeutic process.

Procedural learning and school-age language outcomes in children with and without a history of late talking.

BACKGROUND: 'Late talkers' (LTs) are toddlers with late language emergence that cannot be explained by other impairments. It is difficult to predict which of these children continue to present long-term restrictions in language abilities and will later be identified as having a developmental language disorder. Procedural memory weaknesses have been suggested to underlie developmental language disorders, but have not been investigated in LTs. AIMS: We investigated the relationships between aspects of procedural memory and school-age language abilities in children with and without a history of LT. We hypothesized that children with a history of LT exhibit (1) restrictions in procedural memory when compared with children with typical early development (TED); and (2) a positive association between procedural memory and school-age language abilities. METHODS & PROCEDURES: We recruited 79 children (7;5-10;5), 43 of whom had a history of LT. Aspects of procedural memory, procedural learning and motor planning were assessed using the serial reaction time and the end-state comfort tasks. School-age language abilities were measured using standardized tests. OUTCOMES & RESULTS: Counter to expectations, motor planning was not associated with a history of LT or school-age language abilities, and the children with TED did not show stronger procedural learning as compared with peers with a history of LT. However, weaker school-age language abilities were associated with weak procedural learning in TED group. CONCLUSIONS & IMPLICATIONS: Factors other than deficits in procedural memory are likely to underlie LT. Procedural learning shows promise as a potential predictor of language development in children that are not identified as LTs. WHAT THIS PAPER ADDS: What is already known on the subject Poor procedural learning has been associated with developmental language disorders and suggested to underlie language difficulties. However, to our knowledge, this study is the first to investigate procedural learning and its associations with language outcomes in LTs. What this paper adds to existing knowledge Consistent with prior research, we found an association between language abilities and procedural learning in school-aged children, but found no evidence for poor procedural learning in children with a history of LT. Furthermore, the school-age language outcomes were only associated with procedural learning in children with no history of LT. What are the potential or actual clinical implications of this work? Our findings suggest that factors other than limitations in procedural learning underlie LT. However, procedural learning could be a useful predictor for school-aged language outcomes in children not identified as LTs.

Memory leaks: information shared across memory systems.

The brain is highly segregated. Multiple mechanisms ensure that different types of memories are processed independently. Nonetheless, information leaks out across these memory systems. Only recently has the diversity of these leaks been revealed. Different memory types (skills vs. facts) can interact in simple ways, either allowing or preventing their further processing, or in more complex ways, allowing the sharing of abstract information between memories. Leaks occur from memories dependent upon hippocampal circuits, which have properties critical for leaks and activity patterns related to memory interactions. This hippocampal contribution is likely achieved in concert with cortical areas. Leaks between memories enable the application of knowledge in novel situations, explain learning dynamics, and solve important problems inherent to memory formation.

Striatum expresses region-specific plasticity consistent with distinct memory abilities.

The striatum mediates two learning modalities: goal-directed behavior in dorsomedial (DMS) and habits in dorsolateral (DLS) striata. The synaptic bases of these learnings are still elusive. Indeed, while ample research has described DLS plasticity, little remains known about DMS plasticity and its involvement in procedural learning. Here, we find symmetric and asymmetric anti-Hebbian spike-timing-dependent plasticity (STDP) in DMS and DLS, respectively, with opposite plasticity dominance upon increasing corticostriatal activity. During motor-skill learning, plasticity is engaged in DMS and striatonigral DLS neurons only during early learning stages, whereas striatopallidal DLS neurons are mobilized only during late phases. With a mathematical modeling approach, we find that symmetric anti-Hebbian STDP favors memory flexibility, while asymmetric anti-Hebbian STDP favors memory maintenance, consistent with memory processes at play in procedural learning.

Implicit learning in children with Childhood Apraxia of Speech.

BACKGROUND: Childhood Apraxia of Speech is a severe and persistent clinical subtype of Speech Sound Disorder. Given the difficulties in the acquisition, programming and control of the movements underlying speech and the slowdown in a wide range of non-linguistic skills, the difficulty in implicit learning of sequential information could play a role in the disorder, contributing to understand its etiopathological mechanisms and behavioral manifestations. AIMS: The present study was aimed at investigating implicit learning in children with Childhood Apraxia of Speech. METHODS AND PROCEDURES: Twenty-five children with Childhood Apraxia of Speech, aged between 4 and 12 years, were matched for IQ and age to a control group of 25 typically developing children. Implicit learning of participants was assessed by Serial Reaction Time Task. OUTCOME AND RESULTS: Children with Childhood Apraxia of Speech did not show implicit learning, as documented by the absence of differences between reaction times in the sequenced block and the random block, usually considered as a measure of implicit learning effect. CONCLUSION AND IMPLICATIONS: Our results underline an implicit learning deficit in children with Childhood Apraxia of Speech, supporting the concept of a disorder not only confined to the speech domain, but also involving non-linguistic skills, in a composite and complex picture.

Atypical Reinforcement Learning in Developmental Dyslexia.

OBJECTIVES: According to the Procedural Deficit Hypothesis, abnormalities in corticostriatal pathways could account for the language-related deficits observed in developmental dyslexia. The same neural network has also been implicated in the ability to learn contingencies based on trial and error (i.e., reinforcement learning [RL]). On this basis, the present study tested the assumption that dyslexic individuals would be impaired in RL compared with neurotypicals in two different tasks. METHODS: In a probabilistic selection task, participants were required to learn reinforcement contingencies based on probabilistic feedback. In an implicit transitive inference task, participants were also required to base their decisions on reinforcement histories, but feedback was deterministic and stimulus pairs were partially overlapping, such that participants were required to learn hierarchical relations. RESULTS: Across tasks, results revealed that although the ability to learn from positive/negative feedback did not differ between the two groups, the learning of reinforcement contingencies was poorer in the dyslexia group compared with the neurotypicals group. Furthermore, in novel test pairs where previously learned information was presented in new combinations, dyslexic individuals performed similarly to neurotypicals. CONCLUSIONS: Taken together, these results suggest that learning of reinforcement contingencies occurs less robustly in individuals with developmental dyslexia. Inferences for the neuro-cognitive mechanisms of developmental dyslexia are discussed.