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.

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.

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.

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.

Dorsolateral Striatal Task-initiation Bursts Represent Past Experiences More than Future Action Plans.

The dorsolateral striatum (DLS) is involved in learning and executing procedural actions. Cell ensembles in the DLS, but not the dorsomedial striatum (DMS), exhibit a burst of firing at the start of a well-learned action sequence ("task-bracketing"). However, it is currently unclear what information is contained in these bursts. Some theories suggest that these bursts should represent the procedural action sequence itself (that they should be about future action chains), whereas others suggest that they should contain representations of the current state of the world, taking into account primarily past information. In addition, the DLS local field potential shows transient bursts of power in the 50 Hz range (γ50) around the time a learned action sequence is initiated. However, it is currently unknown how bursts of activity in DLS cell ensembles and bursts of γ50 power in the DLS local field potential are related to each other. We found that DLS bursts at lap initiation in rats represented recently experienced reward locations more than future procedural actions, indicating that task-initiation DLS bursts contain primarily retrospective, rather than prospective, information to guide procedural actions. Furthermore, representations of past reward locations increased during periods of increased γ50 power in the DLS. There was no evidence of task-initiation bursts, increased γ50 power, or retrospective reward location information in the neighboring dorsomedial striatum. These data support a role for the DLS in model-free theories of procedural decision-making over planned action-chain theories, suggesting that procedural actions derive from representations of the current and recent past.SIGNIFICANCE STATEMENT While it is well-established that the dorsolateral striatum (DLS) plays a critical role in procedural decision-making, open questions remain about the kinds of representations contained in DLS ensemble activity that guide procedural actions. We found that DLS, but not DMS, cell ensembles contained nonlocal representations of past reward locations that appear moments before task-initiation DLS bursts. These retrospective representations were temporally linked to a rise in γ50 power that also preceded the characteristic DLS burst at task-initiation. These results support models of procedural decision-making based on associations between available actions and the current state of the world over models based on planning over action-chains.

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.

Impaired Sensorimotor Adaption in Schizophrenia in Comparison to Age-Matched and Elderly Controls.

BACKGROUND: The "cognitive dysmetria hypothesis" of schizophrenia proposes a disrupted communication between the cerebellum and cerebral cortex, resulting in sensorimotor and cognitive symptoms. Sensorimotor adaptation relies strongly on the function of the cerebellum. OBJECTIVES: This study investigated whether sensorimotor adaptation is reduced in schizophrenia compared with age-matched and elderly healthy controls. METHODS: Twenty-nine stably treated patients with schizophrenia, 30 age-matched, and 30 elderly controls were tested in three motor adaptation tasks in which visual movement feedback was unexpectedly altered. In the "rotation adaptation task" the perturbation consisted of a rotation (30° clockwise), in the "gain adaptation task" the extent of the movement feedback was reduced (by a factor of 0.7) and in the "vertical reversal task," up- and downward pen movements were reversed by 180°. RESULTS: Patients with schizophrenia adapted to the perturbations, but their movement times and errors were substantially larger than controls. Unexpectedly, the magnitude of adaptation was significantly smaller in schizophrenia than elderly participants. The impairment already occurred during the first adaptation trials, pointing to a decline in explicit strategy use. Additionally, post-adaptation aftereffects provided strong evidence for impaired implicit adaptation learning. Both negative and positive schizophrenia symptom severities were correlated with indices of the amount of adaptation and its aftereffects. CONCLUSIONS: Both explicit and implicit components of sensorimotor adaptation learning were reduced in patients with schizophrenia, adding to the evidence for a role of the cerebellum in the pathophysiology of schizophrenia. Elderly individuals outperformed schizophrenia patients in the adaptation learning tasks.

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.

Resting-state functional brain connectivity is related to subsequent procedural learning skills in school-aged children.

This magnetoencephalography (MEG) study investigates how procedural sequence learning performance is related to prior brain resting-state functional connectivity (rsFC), and to what extent sequence learning induces rapid changes in brain rsFC in school-aged children. Procedural learning was assessed in 30 typically developing children (mean age ± SD: 9.99 years ± 1.35) using a serial reaction time task (SRTT). During SRTT, participants touched as quickly and accurately as possible a stimulus sequentially or randomly appearing in one of the quadrants of a touchscreen. Band-limited power envelope correlation (brain rsFC) was applied to MEG data acquired at rest pre- and post-learning. Correlation analyses were performed between brain rsFC and sequence-specific learning or response time indices. Stronger pre-learning interhemispheric rsFC between inferior parietal and primary somatosensory/motor areas correlated with better subsequent sequence learning performance and faster visuomotor response time. Faster response time was associated with post-learning decreased rsFC within the dorsal extra-striate visual stream and increased rsFC between temporo-cerebellar regions. In school-aged children, variations in functional brain architecture at rest within the sensorimotor network account for interindividual differences in sequence learning and visuomotor performance. After learning, rapid adjustments in functional brain architecture are associated with visuomotor performance but not sequence learning skills.

Registered report: 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 directly associated with impaired motor function in Parkinson's disease (PD). Research on healthy young participants shows the potential for transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, over the primary motor cortex (M1) to enhance IMSL. tDCS has direct effects on the underlying cortex, but also induces distant (basal ganglia) network effects-hence its potential value in PD, a prime model of basal ganglia dysfunction. To date, only null effects have been reported in persons with PD. However, these studies did not determine the reacquisition effects, although previous studies in healthy young adults suggest that tDCS specifically exerts its beneficial effects on IMSL on reacquisition rather than acquisition. In the current study, we will therefore establish possible reacquisition effects, which are of a particular interest, as long-term effects are vital for the successful functional rehabilitation of persons with PD. Using a sham-controlled, counterbalanced design, we will investigate the potential of tDCS delivered over M1 to enhance IMSL, as measured by the serial reaction time task, in persons with PD and a neurologically healthy age- and sex-matched control (HC) group. Multilevel Mixed Models will be implemented to analyze the sequence-specific aspect of IMSL (primary outcome) and general learning (secondary outcome). We will determine not only the immediate effects that may occur concurrently with the application of tDCS but also the short-term (5 min post-tDCS) and long-term (1 week post-tDCS) reacquisition effects.

Whole-body procedural learning benefits from targeted memory reactivation in REM sleep and task-related dreaming.

Sleep facilitates memory consolidation through offline reactivations of memory traces. Dreaming may play a role in memory improvement and may reflect these memory reactivations. To experimentally address this question, we used targeted memory reactivation (TMR), i.e., application, during sleep, of a stimulus that was previously associated with learning, to assess whether it influences task-related dream imagery (or task-dream reactivations). Specifically, we asked if TMR or task-dream reactivations in either slow-wave (SWS) or rapid eye movement (REM) sleep benefit whole-body procedural learning. Healthy participants completed a virtual reality (VR) flying task prior to and following a morning nap or rest period during which task-associated tones were readministered in either SWS, REM sleep, wake or not at all. Findings indicate that learning benefits most from TMR when applied in REM sleep compared to a Control-sleep group. REM dreams that reactivated kinesthetic elements of the VR task (e.g., flying, accelerating) were also associated with higher improvement on the task than were dreams that reactivated visual elements (e.g., landscapes) or that had no reactivations. TMR did not itself influence dream content but its effects on performance were greater when coexisting with task-dream reactivations in REM sleep. Findings may help explain the mechanistic relationships between dream and memory reactivations and may contribute to the development of sleep-based methods to optimize complex skill learning.

Procedural Learning in Individuals with Amnestic Mild Cognitive Impairment and Alzheimer's Dementia: a Systematic Review and Meta-analysis.

The notion that procedural learning and memory is spared in Alzheimer's disease (AD) has important implications for interventions aiming to build on intact cognitive functions. However, despite these clinical implications, there are mixed findings in the literature about whether or not procedural learning remains intact. This meta-analysis examines the standard mean difference of all published studies regarding procedural learning in AD dementia or amnestic Mild Cognitive Impairment (aMCI) compared to cognitively healthy older adults. Additionally, we conducted statistical equivalence analyses. Our systematic review showed that only a limited number of studies (k = 17) have compared procedural learning between individuals with aMCI or AD dementia and healthy controls. Our meta-analysis, which synthesized these studies, demonstrated that while procedural learning performance was not statistically equivalent between individuals with aMCI or AD dementia, and healthy older adults, the difference was clinically and statistically trivial. Although larger studies are needed, the present findings suggest that procedural learning does appear to remain spared in aMCI and AD dementia.

Adaptive Plasticity Under Adverse Listening Conditions is Disrupted in Developmental Dyslexia.

OBJECTIVE: Acoustic distortions to the speech signal impair spoken language recognition, but healthy listeners exhibit adaptive plasticity consistent with rapid adjustments in how the distorted speech input maps to speech representations, perhaps through engagement of supervised error-driven learning. This puts adaptive plasticity in speech perception in an interesting position with regard to developmental dyslexia inasmuch as dyslexia impacts speech processing and may involve dysfunction in neurobiological systems hypothesized to be involved in adaptive plasticity. METHOD: Here, we examined typical young adult listeners (N = 17), and those with dyslexia (N = 16), as they reported the identity of native-language monosyllabic spoken words to which signal processing had been applied to create a systematic acoustic distortion. During training, all participants experienced incremental signal distortion increases to mildly distorted speech along with orthographic and auditory feedback indicating word identity following response across a brief, 250-trial training block. During pretest and posttest phases, no feedback was provided to participants. RESULTS: Word recognition across severely distorted speech was poor at pretest and equivalent across groups. Training led to improved word recognition for the most severely distorted speech at posttest, with evidence that adaptive plasticity generalized to support recognition of new tokens not previously experienced under distortion. However, training-related recognition gains for listeners with dyslexia were significantly less robust than for control listeners. CONCLUSIONS: Less efficient adaptive plasticity to speech distortions may impact the ability of individuals with dyslexia to deal with variability arising from sources like acoustic noise and foreign-accented speech.

Non-linguistic cognitive measures as predictors of functionally defined developmental language disorder in monolingual and bilingual children.

BACKGROUND & AIMS: Given that standardized language measures alone are inadequate for identifying functionally defined developmental language disorder (fDLD), this study investigated whether non-linguistic cognitive abilities (procedural learning, motor functions, executive attention, processing speed) can increase the prediction accuracy of fDLD in children in linguistically diverse settings. METHODS & PROCEDURES: We examined non-linguistic cognitive abilities in mono- and bilingual school-aged children (ages 8-12) with and without fDLD. Typically developing (TD) children (14 monolinguals, 12 bilinguals) and children with fDLD (28 monolinguals, 12 bilinguals) completed tasks measuring motor functions, procedural learning, executive attention and processing speed. Children were assigned as fDLD based on parental or professional concerns regarding children's daily language functioning. If no concerns were present, children were assigned as TD. Standardized English scores, non-verbal IQ scores and years of maternal education were also obtained. Likelihood ratios were used to examine how well each measure separated the fDLD versus TD groups. A binary logistic regression was used to test whether combined measures enhanced the prediction of identifying fDLD status. OUTCOMES & RESULTS: A combination of linguistic and non-linguistic measures provided the best distinction between fDLD and TD for both mono- and bilingual groups. For monolingual children, the combined measures include English language scores, functional motor abilities and processing speed, whereas for bilinguals, the combined measures include English language scores and procedural learning. CONCLUSIONS & IMPLICATIONS: A combination of non-linguistic and linguistic measures significantly improved the distinction between fDLD and TD for both mono- and bilingual groups. This study supports the possibility of using non-linguistic cognitive measures to identify fDLD in linguistically diverse settings. WHAT THIS PAPER ADDS: What is already known on the subject Given that standardized English language measures may fail to identify functional language disorder, we examined whether supplementing English language measures with non-linguistic cognitive tasks could resolve the problem. Our study is based on the hypothesis that non-linguistic cognitive abilities contribute to language processing and learning. This is further supported by previous findings that children with language disorder exhibit non-linguistic cognitive deficits. What this paper adds to existing knowledge The results indicated that a combination of linguistic and non-linguistic cognitive abilities increased the prediction of functional language disorder in both mono- and bilingual children. What are the potential or actual clinical implications of this work? This study supports the possibility of using non-linguistic cognitive measures to identify the risk of language disorder in linguistically diverse settings.

Experience Level Influences Users' Interactions With and Expectations For Online Surgical Videos: A Mixed-Methods Study.

PURPOSE: Upper-extremity surgeons and trainees widely use online surgical videos, and the use of these videos can assist with procedural learning. The purpose of this study was to characterize online video use and understand the role videos play in the learning process of orthopedic residents and practicing surgeons. We hypothesized that the use of surgical videos and video content desired among orthopedic learners differs based on their experience level. METHODS: Four focus groups were conducted to discuss online surgical videos and their role in the learning process of orthopedic learners. Participants were separated based on their experience level. Three reviewers qualitatively analyzed the transcripts of the focus groups using constant comparative methods to identify overarching themes and categories. Findings regarding the participants' desires for video content and production quality were translated into a survey. The survey results were analyzed to assess their associations with experience level. RESULTS: The focus group analysis helped identify 4 overarching themes that reflected users' interactions with videos: prewatching experience, choosing a video, video use, and video design, with the users' comments differing based on their experience level. The survey results showed that the median ideal length for a video was 10 minutes and that all users, regardless of their experience level, ranked showing the surgical procedure as the most important part of a video. Junior residents more frequently desired background information and a written outline of surgical steps, whereas more senior learners placed greater emphasis on advanced surgical decision-making and the use of particular implants/devices. CONCLUSIONS: Experience level influences users' interactions with videos, including how they are chosen and used, and their expectations in terms of content and production. CLINICAL RELEVANCE: Video creators should specify their targeted audience's experience level and adjust content to meet users' needs. Our results can provide video creators and hosts a checklist for appropriate content and production standards.

Sleep deprivation directly following eyeblink-conditioning impairs memory consolidation.

The relation between sleep and different forms of memory formation continues to be a relevant topic in our daily life. Sleep has been found to affect cerebellum-dependent procedural memory formation, but it remains to be elucidated to what extent the level of sleep deprivation directly after motor training also influences our ability to store and retrieve memories. Here, we studied the effect of disturbed sleep in mice during two different time-windows, one covering the first four hours following eyeblink conditioning (EBC) and another window following the next period of four hours. Compared to control mice with sleep ad libitum, the percentage of conditioned responses and their amplitude were impaired when mice were deprived of sleep directly after conditioning. This impairment was still significant when the learned EBC responses were extinguished and later reacquired. However, consolidation of eyeblink responses was not affected when mice were deprived later than four hours after acquisition, not even when tested during a different day-night cycle for control. Moreover, mice that slept longer directly following EBC showed a tendency for more conditioned responses. Our data indicate that consolidation of motor memories can benefit from sleep directly following memory formation.

Application of anodal tDCS at primary motor cortex immediately after practice of a motor sequence does not improve offline gain.

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 this form of non-invasive stimulation. The present study was designed to explicitly reevaluate Tecchio et al.'s claim. As in the original study, individuals experienced either anodal or sham stimulation at M1 after practice of a serial reaction time task (SRTT) followed by test trials 15-min later. Two additional novel conditions experienced the test trials after 120-min rather than 15-min thus allowing potential stimulation after-effects to dissipate. The expectation was that if anodal stimulation influences post-practice consolidation leading to offline gain, this effect would be present not only at 15-min but also after 120-min. In agreement with the working hypothesis, findings revealed offline gain at both 15-min and the longer 2-h time period. Unexpectedly, we found no interaction between real and sham conditions. The lack of difference between Real and Sham effects weakens confidence in the potential of post-practice tDCS for consolidation enhancement, while it is more consistent with other claims that decoupling practice and anodal tDCS stimulation in time can reduce the effectiveness of exogenous stimulation for procedural skill gain.

Procedural and declarative learning in dyslexia.

The procedural deficit hypothesis claims that impaired procedural learning is at least partly responsible for the deficits in learning to read seen in children with developmental dyslexia. This study used a reading ability-matched design to examine group differences in both procedural and declarative learning. Both children with dyslexia and typically developing children demonstrated procedural learning on a serial reaction time task, although learning in the typically developing group increased at a greater rate towards the end of the task compared with children with dyslexia. However, these results do not provide strong evidence for the procedural deficit hypothesis, because poorer procedural learning in the group with dyslexia may reflect impairments in motor learning, rather than sequence specific procedural learning. In addition, neither group showed a relationship between procedural learning and reading ability.