Volatile working memory representations crystallize with practice.

Working memory, the process through which information is transiently maintained and manipulated over a brief period, is essential for most cognitive functions1-4. However, the mechanisms underlying the generation and evolution of working-memory neuronal representations at the population level over long timescales remain unclear. Here, to identify these mechanisms, we trained head-fixed mice to perform an olfactory delayed-association task in which the mice made decisions depending on the sequential identity of two odours separated by a 5 s delay. Optogenetic inhibition of secondary motor neurons during the late-delay and choice epochs strongly impaired the task performance of the mice. Mesoscopic calcium imaging of large neuronal populations of the secondary motor cortex (M2), retrosplenial cortex (RSA) and primary motor cortex (M1) showed that many late-delay-epoch-selective neurons emerged in M2 as the mice learned the task. Working-memory late-delay decoding accuracy substantially improved in the M2, but not in the M1 or RSA, as the mice became experts. During the early expert phase, working-memory representations during the late-delay epoch drifted across days, while the stimulus and choice representations stabilized. In contrast to single-plane layer 2/3 (L2/3) imaging, simultaneous volumetric calcium imaging of up to 73,307 M2 neurons, which included superficial L5 neurons, also revealed stabilization of late-delay working-memory representations with continued practice. Thus, delay- and choice-related activities that are essential for working-memory performance drift during learning and stabilize only after several days of expert performance.

Effect of positive social comparative feedback on the resting state connectivity of dopaminergic neural pathways: A preliminary investigation.

Positive social comparative feedback is hypothesized to generate a dopamine response in the brain, similar to reward, by enhancing expectancies to support motor skill learning. However, no studies have utilized neuroimaging to examine this hypothesized dopaminergic mechanism. Therefore, the aim of this preliminary study was to investigate the effect of positive social comparative feedback on dopaminergic neural pathways measured by resting state connectivity. Thirty individuals practiced an implicit, motor sequence learning task and were assigned to groups that differed in feedback type. One group received feedback about their actual response time to complete the task (RT ONLY), while the other group received feedback about their response time with positive social comparison (RT + POS). Magnetic resonance imaging was acquired at the beginning and end of repetitive motor practice with feedback to measure practice-dependent changes in resting state brain connectivity. While both groups showed improvements in task performance and increases in performance expectancies, ventral tegmental area and the left nucleus accumbens (mesolimbic dopamine pathway) resting state connectivity increased in the RT + POS group but not in the RT ONLY group. Instead, the RT ONLY group showed increased connectivity between ventral tegmental area and primary motor cortex. Positive social comparative feedback during practice of a motor sequence task may induce a dopaminergic response in the brain along the mesolimbic pathway. However, given that absence of effects on expectancies and motor learning, more robust and individualized approaches may be needed to provide beneficial psychological and behavioral effects.

Explaining the influence of practice on the grooved pegboard times of older adults: role of force steadiness.

The purpose was to identify the variables that can explain the variance in the grooved pegboard times of older adults categorized as either fast or slow performers. Participants (n = 28; 60-83 years) completed two experimental sessions, before and after 6 practice sessions of the grooved pegboard test. The 2 groups were identified based on average pegboard times during the practice sessions. Average pegboard time during practice was 73 ± 11 s for the fast group and 85 ± 13 s for the slow group. Explanatory variables for the pegboard times before and after practice were the durations of 4 peg-manipulation phases and 12 measures of force steadiness (coefficient of variation [CV] for force) during isometric contractions with the index finger abductor and wrist extensor muscles. Time to complete the grooved pegboard test after practice decreased by 25 ± 11% for the fast group and by 28 ± 10% for the slow group. Multiple regression models explained more of the variance in the pegboard times for the fast group before practice (Adjusted R2 = 0.85) than after practice (R2 = 0.51), whereas the variance explained for the slow group was similar before (Adjusted R2 = 0.67) and after (Adjusted R2 = 0.64) practice. The explanatory variables differed between before and after practice for the fast group but only slightly for the slow group. These findings indicate that performance-based stratification of older adults can identify unique adjustments in motor function that are independent of chronological age.

Mental Practice: Applying Successful Strategies in Sports to the Practice of Emergency Medicine.

Emergency physicians are expected to learn and maintain a large and varied set of competencies for clinical practice. These include high acuity, low occurrence procedures that may not be encountered frequently in the clinical environment and are difficult to practice with high fidelity and frequency in a simulated environment. Mental practice is a form of a cognitive walk-through that has been shown to be an effective method for improving motor and cognitive skills, with literature in sports science and emerging evidence supporting its use in medicine. In this article, we review the literature on mental practice in sports and medicine as well as the underlying neuroscientific theories that support its use. We review best-known practices and provide a framework to design and use mental imagery scripts to augment learning and maintaining the competencies necessary for physicians at all levels of training and clinical environments in the practice of emergency medicine.

Implicit visuospatial sequence representations are accessible in both the practice and the transfer hand.

A serial reaction time task was used to test whether the representations of a probabilistic second-order sequence structure are (i) stored in an effector-dependent, effector-independent intrinsic or effector-independent visuospatial code and (ii) are inter-manually accessible. Participants were trained either with the dominant or non-dominant hand. Tests were performed with both hands in the practice sequence, a random sequence, and a mirror sequence. Learning did not differ significantly between left and right-hand practice, suggesting symmetric intermanual transfer from the dominant to the non-dominant hand and vice versa. In the posttest, RTs were shorter for the practice sequence than for the random sequence, and longest for the mirror sequence. Participants were unable to freely generate or recognize the practice sequence, indicating implicit knowledge of the probabilistic sequence structure. Because sequence-specific learning did not differ significantly between hands, we conclude that representations of the probabilistic sequence structure are stored in an effector-independent visuospatial code.

Imagery practice of motor skills without conscious awareness?: a commentary to Frank et al.

Modifications of imagined sensory consequences will not benefit overt performance when they cannot be transformed into motor outflow that produces them. With physical practice, the acquisition of internal models of motor transformations is largely based on prediction errors that are absent in imagery practice. What can imagery practice nevertheless contribute to transformation learning? Explicit, strategic adjustments to novel transformations should be possible. This appears less likely for implicit adjustments. Are there variants of imagery practice that can produce adjustments without conscious awareness of the transformation and/or the resultant movement changes?

Interaction of motor practice and memory training in expressive piano performance: expanding the possibilities of improvisation.

This paper aimed to investigate the influence of motor practice and music performance experiences on musicians' auditory memory, the effect of auditory distinctiveness on melody recognition, and the differences in the working memory of classical and jazz pianists. The study was conducted among 26 jazz and 24 classical music students at Shenyang Conservatory of Music. To achieve the goal set, a melody recognition ability was analyzed after listening, performing without sound, and simultaneous listening and performing using computer recordings and pianist-taken notes. The study was conducted following repeated measures mixed design. The within-group variable was the learning condition. As the within-participant variable, the number of melody practicing trials was chosen. The type of influence on auditory memory was chosen as a between-group variable. The dependent variables were auditory recognition score, motor imagery ability, and auditory imagery ability. Students' recognition of the heard melodies was assessed by means of a 3-point Likert scale. Pearson's correlation coefficient was calculated to investigate the relationship between working memory and other student characteristics. The study outcomes unveiled that pianists are much better at recognizing tunes they generate themselves in auditory-motor practice than auditory practice alone. It was pointed out that the ability to recognize melody in auditory-motor learning is influenced by its acoustic characteristics. Hence, melodies that are slow in tempo and regular in time and intensity are easier to recognize than more variable pieces.

Competencies for Psychology Practice in Pediatric Palliative Care.

OBJECTIVE: Pediatric psychologists have unique expertise to contribute to the care of youth with serious illnesses yet are not routinely integrated into pediatric palliative care (PPC) teams. To better define the role and unique skillset of psychologists practicing in PPC, support their systematic inclusion as part of PPC teams, and advance trainee knowledge of PPC principles and skills, the PPC Psychology Working Group sought to develop core competencies for psychologists in this subspecialty. METHODS: A Working Group of pediatric psychologists with expertise in PPC met monthly to review literature and existing competencies in pediatrics, pediatric and subspecialty psychology, adult palliative care, and PPC subspecialties. Using the modified competency cube framework, the Working Group drafted core competencies for PPC psychologists. Interdisciplinary review was conducted by a diverse group of PPC professionals and parent advocates, and competencies were revised accordingly. RESULTS: The six competency clusters include Science, Application, Education, Interpersonal, Professionalism, and Systems. Each cluster includes essential competencies (i.e., knowledge, skills, attitudes, roles) and behavioral anchors (i.e., examples of concrete application). Reviewer feedback highlighted clarity and thoroughness of competencies and suggested additional consideration of siblings and caregivers, spirituality, and psychologists' own positionality. CONCLUSIONS: Newly developed competencies for PPC psychologists highlight unique contributions to PPC patient care and research and provide a framework for highlighting psychology's value in this emerging subspecialty. Competencies help to advocate for inclusion of psychologists as routine members of PPC teams, standardize best practices among the PPC workforce, and provide optimal care for youth with serious illness and their families.

Differential effects of skilled reaching training on the temporal and spatial organization of somatosensory input to cortical and striatal motor circuits.

It has been hypothesized that to perform sensorimotor transformations efficiently, somatosensory information being fed back to a particular motor circuit is organized in accordance with the mechanical loading patterns of the skin that result from the motor activity generated by that circuit. Rearrangements of sensory information to different motor circuits could in this respect constitute a key component of sensorimotor learning. We here explored whether the organization of tactile input from the plantar forepaw of the rat to cortical and striatal circuits is affected by a period of extensive sensorimotor training in a skilled reaching and grasping task. Our data show that the representation of tactile stimuli in terms of both temporal and spatial response patterns changes as a consequence of the training and that spatial changes particularly involve the primary motor cortex. Based on the observed reorganization, we propose that reshaping of the spatiotemporal representation of the tactile afference to motor circuits is an integral component of the learning process that underlies skill acquisition in reaching and grasping.NEW & NOTEWORTHY Sensorimotor transformations are fundamental to the function of the nervous system and determine how patterns of sensory input are converted into appropriate movements. We here investigated the extent to which experience-dependent processes can reshape the organization of somatosensory input feeding into cortico-basal ganglia motor structures. Our data point to a particularly important role for the primary motor cortex in the functional adaptions associated with skilled motor learning.

Aging Modulates Prefrontal Plasticity Induced by Executive Control Training.

While declines in inhibitory control, the capacity to suppress unwanted neurocognitive processes, represent a hallmark of healthy aging, whether this function is susceptible to training-induced plasticity in older populations remains largely unresolved. We addressed this question with a randomized controlled trial investigating the changes in behavior and electrical neuroimaging activity induced by a 3-week adaptive gamified Go/NoGo inhibitory control training (ICT). Performance improvements were accompanied by the development of more impulsive response strategies, but did not generalize to impulsivity traits nor quality of life. As compared with a 2-back working-memory training, the ICT in the older adults resulted in a purely quantitative reduction in the strength of the activity in a medial and ventrolateral prefrontal network over the 400 ms P3 inhibition-related event-related potentials component. However, as compared with young adults, the ICT induced distinct configurational modifications in older adults' 200 ms N2 conflict monitoring medial-frontal functional network. Hence, while older populations show preserved capacities for training-induced plasticity in executive control, aging interacts with the underlying plastic brain mechanisms. Training improves the efficiency of the inhibition process in older adults, but its effects differ from those in young adults at the level of the coping with inhibition demands.

Relearning can eliminate the effect of retrieval-induced forgetting.

The retrieval of a subset of items can cause the forgetting of other, non-retrieved items, a phenomenon known as retrieval-induced forgetting. Initial work suggested that giving people the opportunity to restudy non-retrieved items following retrieval practice is sufficient to eliminate the effect of retrieval-induced forgetting, but more recent work has suggested otherwise. If retrieval-induced forgetting is not eliminated by restudy, then such a finding would have important implications for understanding the theoretical nature of retrieval-induced forgetting. It would suggest, for example, that retrieval-induced forgetting reflects more than the temporary reduction in the accessibility of non-retrieved items in memory. The two experiments reported here sought to clarify this issue, with the results suggesting that retrieval-induced forgetting can be eliminated by restudy. Indeed, retrieval-induced forgetting was eliminated by restudy even when the forgetting effect was produced by three rounds of retrieval practice instead of one round of retrieval practice. These findings are consistent with the idea that retrieval-induced forgetting, at least under the conditions of the current experiments, reflects a temporary reduction in the accessibility of non-retrieved items in memory.

Progressive retrieval practice leads to greater memory for image-word pairs than standard retrieval practice.

The benefits of retrieval practice on learning are robust and have transferred from laboratory findings to many real-world educational settings. We report two experiments that investigated a novel retrieval practice technique for remembering arbitrary associations (image-word pairs), with and without reward as a motivator. As well as typical retrieval practice and restudy conditions, we added a third condition of graded retrieval practice in which the image cue was partially released in a progressive process. Experiment 1 found significant benefits of retrieval practice over restudy, with an additional benefit of graded retrieval practice compared with standard retrieval practice after a 48-hour delay between study and retrieval. Experiment 2 included a reward manipulation by giving participants money based on their memory performance. The findings replicated the retrieval practice effects observed in Experiment 1, including a robust advantage for graded retrieval practice. Reward neither changed the additive advantage of graded recall nor the benefit of retrieval practice. The present study adds to the literature indicating that retrieval with progressive retrieval cues can boost the benefit of retrieval practice by generating repeated retrieval attempts. This benefit occurs most for items that are neither too easy nor too challenging to retrieve.

Reduction of contextual control of conditioned responses by extended Pavlovian training in an insect.

The effect of repetitive training on learned behavior has been an important subject in neuroscience. In instrumental conditioning in mammals, learned action early in training is often goal-driven and controlled by outcome expectancy, but as training progresses, it becomes more habitual and insensitive to outcome devaluation. Similarly, we recently showed in Pavlovian conditioning in crickets (Gryllus bimaculatus) that a conditioned response (CR) is initially sensitive to devaluation of the unconditioned stimulus but becomes insensitive to it after extended training. It is known that habitual responses after extended instrumental training are characterized by a higher context specificity than are initial goal-directed actions in mammals. In this study, we investigated whether this is applicable to Pavlovian conditioning in crickets. In crickets that received a standard amount of training to associate an odor with water reward under illumination, CR under illumination was stronger than that in the dark. In crickets that received extended training under illumination, on the other hand, the level of CR did not differ in different light conditions. Further experiments confirmed that context specificity decreases with the development of behavioral automaticity by extended training, as opposed to findings in instrumental training in mammals. We conclude that the nature of habitual behaviors after extended training differs in different learning systems of animals.

Visual object recognition is facilitated by temporal community structure.

Humans and others primates are highly attuned to temporal consistencies and regularities in their sensory environment and learn to predict such statistical structure. Moreover, in several instances, the presence of temporal structure has been found to facilitate procedural learning and to improve task performance. Here we extend these findings to visual object recognition and to presentation sequences in which mutually predictive objects form distinct clusters or "communities." Our results show that temporal community structure accelerates recognition learning and affects the order in which objects are learned ("onset of familiarity").

Better later: evening practice is advantageous for motor skill consolidation in the elderly.

How does the time of day of a practice session affect learning of a new motor sequence in the elderly? Participants practiced a given finger tapping sequence either during morning or evening hours. All participants robustly improved performance speed within the session concurrent with a reorganization of the tapping pattern of the sequence. However, evening-trained participants showed additional gains overnight and at 1 wk posttraining; moreover, evening training led to a further reorganization of the tapping pattern offline. A learning experience preceding nocturnal sleep can lead to a task-specific movement routine as an expression of novel "how to" knowledge in the elderly.

Composition and decomposition of visuomotor maps during manual tracking.

Adapting hand movements to changes in our body or the environment is essential for skilled motor behavior, as is the ability to flexibly combine experience gathered in separate contexts. However, it has been shown that when adapting hand movements to two different visuomotor perturbations in succession, interference effects can occur. Here, we investigate whether these interference effects compromise our ability to adapt to the superposition of the two perturbations. Participants tracked with a joystick, a visual target that followed a smooth but an unpredictable trajectory. Four separate groups of participants (total n = 83) completed one block of 50 trials under each of three mappings: one in which the cursor was rotated by 90° (ROTATION), one in which the cursor mimicked the behavior of a mass-spring system (SPRING), and one in which the SPRING and ROTATION mappings were superimposed (SPROT). The order of the blocks differed across groups. Although interference effects were found when switching between SPRING and ROTATION, participants who performed these blocks first performed better in SPROT than participants who had no prior experience with SPRING and ROTATION (i.e., composition). Moreover, participants who started with SPROT exhibited better performance under SPRING and ROTATION than participants who had no prior experience with each of these mappings (i.e., decomposition). Additional analyses confirmed that these effects resulted from components of learning that were specific to the rotational and spring perturbations. These results show that interference effects do not preclude the ability to compose/decompose various forms of visuomotor adaptation.NEW & NOTEWORTHY The ability to compose/decompose task representations is critical for both cognitive and behavioral flexibility. Here, we show that this ability extends to two forms of visuomotor adaptation in which humans have to perform visually guided hand movements. Despite the presence of interference effects when switching between visuomotor maps, we show that participants are able to flexibly compose or decompose knowledge acquired in previous sessions. These results further demonstrate the flexibility of sensorimotor adaptation in humans.

Motor skill training without online visual feedback enhances feedforward control.

Motor skill learning involves improvement in feedforward control, the ability to execute a motor plan more reliably, and feedback control, the ability to adjust the motor plan on the fly. The dependence between these control components and the association between training conditions and their improvement have not been directly examined. This study characterizes the contribution of feedforward and feedback control components to motor skill learning using the arc-pointing task (APT), a drawing task that requires high motor acuity. In experiment 1, the performance of three groups of subjects was tested before and after training with online visual feedback (OF group), with knowledge of performance feedback that was presented after movement completion (KP group), and with both online and KP feedback (KP + OF group). Although the improvement of the OF group was not different from the improvement of the KP + OF group, comparison of the KP and KP + OF groups revealed an advantage to the KP group in the fast test speed, suggesting that training without online feedback leads to a greater improvement in feedforward control. In experiment 2, subject's improvement was examined using test probes for estimating feedback and feedforward control. Both KP + OF and KP groups showed improvement in feedforward and feedback conditions with a trend toward a greater improvement of the KP group. Our results suggest that online visual feedback suppresses improvement in feedforward control during motor skill learning.NEW & NOTEWORTHY Becoming a skillful player requires both executing reliable movements and being able to efficiently control them online. We study here how training with and without online visual feedback affects feedforward and feedback control improvement in a drawing task that requires high precision. We show that training with online feedback suppresses improvement in feedforward control and leads to inferior performance in fast movements.

Music-selective neural populations arise without musical training.

Recent work has shown that human auditory cortex contains neural populations anterior and posterior to primary auditory cortex that respond selectively to music. However, it is unknown how this selectivity for music arises. To test whether musical training is necessary, we measured fMRI responses to 192 natural sounds in 10 people with almost no musical training. When voxel responses were decomposed into underlying components, this group exhibited a music-selective component that was very similar in response profile and anatomical distribution to that previously seen in individuals with moderate musical training. We also found that musical genres that were less familiar to our participants (e.g., Balinese gamelan) produced strong responses within the music component, as did drum clips with rhythm but little melody, suggesting that these neural populations are broadly responsive to music as a whole. Our findings demonstrate that the signature properties of neural music selectivity do not require musical training to develop, showing that the music-selective neural populations are a fundamental and widespread property of the human brain.NEW & NOTEWORTHY We show that music-selective neural populations are clearly present in people without musical training, demonstrating that they are a fundamental and widespread property of the human brain. Additionally, we show music-selective neural populations respond strongly to music from unfamiliar genres as well as music with rhythm but little pitch information, suggesting that they are broadly responsive to music as a whole.

Functional brain plasticity during L1 training on complex sentences: Changes in gamma-band oscillatory activity.

The adult human brain remains plastic even after puberty. However, whether first language (L1) training in adults can alter the language network is yet largely unknown. Thus, we conducted a longitudinal training experiment on syntactically complex German sentence comprehension. Sentence complexity was varied by the depth of the center embedded relative clauses (i.e., single or double embedded). Comprehension was tested after each sentence with a question on the thematic role assignment. Thirty adult, native German speakers were recruited for 4 days of training. Magnetoencephalography (MEG) data were recorded and subjected to spectral power analysis covering the classical frequency bands (i.e., theta, alpha, beta, low gamma, and gamma). Normalized spectral power, time-locked to the final closure of the relative clause, was subjected to a two-factor analysis ("sentence complexity" and "training days"). Results showed that for the more complex sentences, the interaction of sentence complexity and training days was observed in Brodmann area 44 (BA 44) as a decrease of gamma power with training. Moreover, in the gamma band (55-95 Hz) functional connectivity between BA 44 and other brain regions such as the inferior frontal sulcus and the inferior parietal cortex were correlated with behavioral performance increase due to training. These results show that even for native speakers, complex L1 sentence training improves language performance and alters neural activities of the left hemispheric language network. Training strengthens the use of the dorsal processing stream with working-memory-related brain regions for syntactically complex sentences, thereby demonstrating the brain's functional plasticity for L1 training.

Cortical and subcortical responsiveness to intensive adaptive working memory training: An MRI surface-based analysis.

Working memory training (WMT) has been shown to have effects on cognitive performance, the precise effects and the underlying neurobiological mechanisms are, however, still a matter of debate. In particular, the impact of WMT on gray matter morphology is still rather unclear. In the present study, 59 healthy middle-aged participants (age range 50-65 years) were pseudo-randomly single-blinded allocated to an 8-week adaptive WMT or an 8-week nonadaptive intervention. Before and after the intervention, high resolution magnetic resonance imaging (MRI) was performed and cognitive test performance was assessed in all participants. Vertex-wise cortical volume, thickness, surface area, and cortical folding was calculated. Seven subcortical volumes of interest and global mean cortical thickness were also measured. Comparisons of symmetrized percent change (SPC) between groups were conducted to identify group by time interactions. Greater increases in cortical gyrification in bilateral parietal regions, including superior parietal cortex and inferior parietal lobule as well as precuneus, greater increases in cortical volume and thickness in bilateral primary motor cortex, and changes in surface area in bilateral occipital cortex (medial and lateral occipital cortex) were detected in WMT group after training compared to active controls. Structural training-induced changes in WM-related regions, especially parietal regions, might provide a better brain processing environment for higher WM load.