Coexistence of sensory qualities and value representations in human orbitofrontal cortex.

Despite the multiple regions and neural networks associated with value-based decision-making, the orbitofrontal cortex (OFC) is possible a particularly important one. Although the role of the OFC in reinforcer devaluation tasks, which assess the ability to represent identity, sensory qualities, and subjective values of the expected outcomes, has been established, the specific aspect represented in this area remains unclear. In this study, using functional magnetic resonance imaging, wherein participants rated the palatability of 128 food items using photographs, we investigated whether the human OFC represents object identity, sensory qualities, or value. Employing many items helped us dissociate object identity from sensory qualities and values; the inferred sensory qualities of identical items were manipulated by a change in metabolic state. Moreover, value differences between items were analytically controlled by employing a technique similar to age adjustment. The palatability ratings for food items significantly decreased after a meal. Using representational similarity analysis, we confirmed that the OFC represents value. Moreover, identical items were represented similarly in the lateral OFC in a given metabolic state; however, these representations were altered post-feeding. Importantly, this change was not explained by subjective value, suggesting that the OFC represents sensory quality and value, but not object identity.

Coherence analysis of the calcium activity of putative astrocytic and neuronal cells on the L5 ventral horn and neural output in activated lumbar CPG networks.

Astrocytes are thought to play a crucial role in providing structure to the spinal cord and maintaining efficient synaptic function and metabolism because their fine processes envelop the synapses of neurons and form many neuronal networks within the central nervous system (CNS). To investigate whether putative astrocytes and putative neurons distributed on the ventral horn play a role in the modulation of lumbar locomotor central pattern generator (CPG) networks, we used extracellular recording and optical imaging techniques and recorded the neural output from the left L5 ventral root and the calcium activity of putative astrocytes and neurons in the L5 ventral horn at the same time when activating an isolated L1-L5 spinal cord preparation from rats aged 0-2 days. Optical measurements detected cells that showed a fluorescence intensity change under all experimental conditions, namely, (1) 5-HT + NMDA, (2) TTX, and (3) TTX + Low K+. These cells were semiautomatically identified using an in-house MATLAB-based program, as putative astrocytes and neurons according to the cell classification, i.e., increased or decreased fluorescence intensity change (ΔF/F0), and subjective judgment based on their soma size. Coherence and its phase were calculated according to the calcium activity of the putative astrocytes and putative neurons, and neural output was calculated during fictive locomotion with in-house MATLAB-based programs. We found that the number of putative astrocytes activated by applying low K+ tends not to differ from that activated by applying the protease-activated receptor 1 (PAR1) selective agonist TFLLR-NH2 (TFLLR). Moreover, the calcium activity of several putative astrocytes and neurons synchronized with locomotor-like activity at a frequency range below 0.5 Hz and the time lag between peaks of cellular calcium activity and locomotor-like activity ranged from -1000 to + 1000 ms. These findings presumably indicates that these putative astrocytes and neurons in the left L5 ventral horn require -1000 to + 1000 ms to communicate with lumbar CPG networks and maintain efficient synaptic function and metabolism in activated lumbar CPG networks. This finding suggests the possibility that putative astrocytic and neuronal cells in the L5 ventral horn contribute to generating the rhythms and patterns of locomotor-like activity by activated CPG networks in the first to fifth lumbar spinal cord.

Mask wearing increases eye involvement during smiling: a facial EMG study.

The use of face masks has become ubiquitous. Although mask wearing is a convenient way to reduce the spread of disease, it is important to know how the mask affects our communication via facial expression. For example, when we are wearing the mask and meet a friend, are our facial expressions different compared to when we are not? We investigated the effect of face mask wearing on facial expression, including the area around the eyes. We measured surface electromyography from zygomaticus major, orbicularis oculi, and depressor anguli oris muscles, when people smiled and talked with or without a mask. Only the actions of the orbicularis oculi were facilitated by wearing the mask. We thus concluded that mask wearing may increase the recruitment of the eyes during smiling. In other words, we can express joy and happiness even when wearing a face mask.

Neural substrates of shared visual experiences: a hyperscanning fMRI study.

Sharing experience is a fundamental human social cognition. Since visual experience is a mental state directed toward the world, we hypothesized that sharing visual experience is mediated by joint attention (JA) for sharing directedness and mentalizing for mental state inferences. We conducted a hyperscanning functional magnetic resonance imaging with 44 healthy adult volunteers to test this hypothesis. We employed spoken-language-cued spatial and feature-based JA tasks. The initiator attracts the partner's attention by a verbal command to a spatial location or an object feature to which the responder directs their attention. Pair-specific inter-individual neural synchronization of task-specific activities was found in the right anterior insular cortex (AIC)-inferior frontal gyrus (IFG) complex, the core node of JA and salience network, and the right posterior superior temporal sulcus, which represents the shared categories of the target. The right AIC-IFG also showed inter-individual synchronization of the residual time-series data, along with the right temporoparietal junction and dorsomedial prefrontal cortex-the core components for mentalization and the default mode network (DMN). This background synchronization represents sharing the belief of sharing the situation. Thus, shared visual experiences are represented by coherent coordination between the DMN and salience network linked through the right AIC-IFG.

Frequency-specific task modulation of human brain functional networks: A fast fMRI study.

How coherent neural oscillations are involved in task execution is a fundamental question in neuroscience. Although several electrophysiological studies have tackled this issue, the brain-wide task modulation of neural coherence remains uncharacterized. Here, with a fast fMRI technique, we studied shifts of brain-wide neural coherence across different task states in the ultraslow frequency range (0.01-0.7 Hz). First, we examined whether the shifts of the brain-wide neural coherence occur in a frequency-dependent manner. We quantified the shift of a region's average neural coherence by the inter-state variance of the mean coherence between the region and the rest of the brain. A clustering analysis based on the variance's spatial correlation between frequency components revealed four frequency bands (0.01-0.15 Hz, 0.15-0.37 Hz, 0.37-0.53 Hz, and 0.53-0.7 Hz) showing band-specific shifts of the brain-wide neural coherence. Next, we investigated the similarity of the inter-state variance's spectra between all pairs of regions. We found that regions showing similar spectra correspond to those forming functional modules of the brain network. Then, we investigated the relationship between identified frequency bands and modules' inter-state variances. We found that modules showing the highest variance are those made up of parieto-occipital regions at 0.01-0.15 Hz, while it is replaced with another consisting of frontal regions above 0.15 Hz. Furthermore, these modules showed specific shifting patterns of the mean coherence across states at 0.01-0.15 Hz and above 0.15 Hz, suggesting that identified frequency bands differentially contribute to neural interactions during task execution. Our results highlight that usage of the fast fMRI enables brain-wide investigation of neural coherence up to 0.7 Hz, which opens a promising track for assessment of the large-scale neural interactions in the ultraslow frequency range.

Structural and functional connectivity from the dorsomedial hypothalamus to the ventral medulla as a chronological amplifier of sympathetic outflow.

Psychological stress activates the hypothalamus, augments the sympathetic nervous output, and elevates blood pressure via excitation of the ventral medullary cardiovascular regions. However, anatomical and functional connectivity from the hypothalamus to the ventral medullary cardiovascular regions has not been fully elucidated. We investigated this issue by tract-tracing and functional imaging in rats. Retrograde tracing revealed the rostral ventrolateral medulla was innervated by neurons in the ipsilateral dorsomedial hypothalamus (DMH). Anterograde tracing showed DMH neurons projected to the ventral medullary cardiovascular regions with axon terminals in contiguity with tyrosine hydroxylase-immunoreactive neurons. By voltage-sensitive dye imaging, dynamics of ventral medullary activation evoked by electrical stimulation of the DMH were analyzed in the diencephalon-lower brainstem-spinal cord preparation of rats. Although the activation of the ventral medulla induced by single pulse stimulation of the DMH was brief, tetanic stimulation caused activation of the DMH sustained into the post-stimulus phase, resulting in delayed recovery. We suggest that prolonged excitation of the DMH, which is triggered by tetanic electrical stimulation and could also be triggered by psychological stress in a real life, induces further prolonged excitation of the medullary cardiovascular networks, and could contribute to the pathological elevation of blood pressure. The connectivity from the DMH to the medullary cardiovascular networks serves as a chronological amplifier of stress-induced sympathetic excitation. This notion will be the anatomical and pathophysiological basis to understand the mechanisms of stress-induced sustained augmentation of sympathetic activity.

Blockade of astrocytic activation delays the occurrence of severe hypoxia-induced seizure and respiratory arrest in mice.

Seizures are induced when subjects are exposed to severe hypoxia. It is followed by ventilatory fall-off and eventual respiratory arrest, which may underlie the pathophysiology of death in patients with epilepsy and severe respiratory disorders. However, the mechanisms of hypoxia-induced seizures have not been fully understood. Because astrocytes are involved in various neurological disorders, we aimed to investigate whether astrocytes are operational in seizure generation and respiratory arrest in a severe hypoxic condition. We examined the effects of astrocytic activation blockade on responses of EEG and ventilation to severe hypoxia. Adult mice were divided into two groups; in one group (n = 24) only vehicle was injected, and in the other group (n = 24) arundic acid, an inhibitory modulator of astrocytic activation, was administered before initiation of recording. After recording EEG and ventilation by whole body plethysmography in room air, the gas in the recording chamber was switched to 5% oxygen (nitrogen balanced) until a seizure and ventilatory depression occurred, followed by prompt switch back to room air. Severe hypoxia initially increased ventilation, followed by a seizure and ventilatory suppression in all mice examined. Fourteen mice without arundic acid showed respiratory arrest during loading of hypoxia. However, 22 mice pretreated with arundic acid did not suffer from respiratory arrest. Time from the onset of hypoxia to the occurrence of seizures was significantly longer in the group with arundic acid than that in the group without arundic acid. We suggest that blockade of astrocytic activation delays the occurrence of seizures and prevents respiratory arrest.

Teacher-learner interaction quantifies scaffolding behaviour in imitation learning.

Teachers often believe that they take into account learners' ongoing learning progress in their teaching. Can behavioural data support this belief? To address this question, we investigated the interactive behavioural coordination between teachers and learners during imitation learning to solve a puzzle. The teacher manually demonstrated the puzzle solution to a learner who immediately imitated and learned it. Manual movements of teachers and learners were analysed using a bivariate autoregressive model. To identify bidirectional information exchange and information shared between the two agents, we calculated causality and noise covariance from the model. Information transfer observed from teacher to learner in the lateral component of their motion indicated imitation of the spatial information of the puzzle solution. Information transfer from learner to teacher in the vertical component of their motion indicated the monitoring process through which teachers adjust their timing of demonstration to the learner's progress. The shared information in the lateral component increased as learning progressed, indicating the knowledge was shared between the two agents. Our findings demonstrated that the teacher interactively engaged in and contingently supported (i.e. scaffolded) imitation. We thus provide a behavioural signature of the teacher's intention to promote learning indispensable for understanding the nature of teaching.

What Makes Eye Contact Special? Neural Substrates of On-Line Mutual Eye-Gaze: A Hyperscanning fMRI Study.

Automatic mimicry is a critical element of social interaction. A salient type of automatic mimicry is eye contact characterized by sharing of affective and mental states among individuals. We conducted a hyperscanning functional magnetic resonance imaging study involving on-line (LIVE) and delayed off-line (REPLAY) conditions to test our hypothesis that recurrent interaction through eye contact activates the limbic mirror system, including the anterior cingulate cortex (ACC) and anterior insular cortex (AIC), both of which are critical for self-awareness. Sixteen pairs of human adults participated in the experiment. Given that an eye-blink represents an individual's attentional window toward the partner, we analyzed pairwise time-series data for eye-blinks. We used multivariate autoregression analysis to calculate the noise contribution ratio (NCR) as an index of how a participant's directional attention was influenced by that of their partner. NCR was greater in the LIVE than in the REPLAY condition, indicating mutual perceptual-motor interaction during real-time eye contact. Relative to the REPLAY condition, the LIVE condition was associated with greater activation in the left cerebellar hemisphere, vermis, and ACC, accompanied by enhanced functional connectivity between ACC and right AIC. Given the roles of the cerebellum in sensorimotor prediction and ACC in movement initiation, ACC-cerebellar activation may represent their involvement in modulating visual input related to the partner's movement, which may, in turn, involve the limbic mirror system. Our findings indicate that mutual interaction during eye contact is mediated by the cerebellum and limbic mirror system.

Neural correlates of online cooperation during joint force production.

During joint action, two or more persons depend on each other to accomplish a goal. This mutual recursion, or circular dependency, is one of the characteristics of cooperation. To evaluate the neural substrates of cooperation, we conducted a hyperscanning functional MRI study in which 19 dyads performed a joint force-production task. The goal of the task was to match their average grip forces to the target value (20% of their maximum grip forces) through visual feedback over a 30-s period; the task required taking into account other-produced force to regulate the self-generated one in real time, which represented cooperation. Time-series data of the dyad's exerted grip forces were recorded, and the noise contribution ratio (NCR), a measure of influence from the partner, was computed using a multivariate autoregressive model to identify the degree to which each participant's grip force was explained by that of their partner's, i.e., the degree of cooperation. Compared with the single force-production task, the joint task enhanced the NCR and activated the mentalizing system, including the medial prefrontal cortex, precuneus, and bilateral posterior subdivision of the temporoparietal junction (TPJ). In addition, specific activation of the anterior subdivision of the right TPJ significantly and positively correlated with the NCR across participants during the joint task. The effective connectivity of the anterior to posterior TPJ was upregulated when participants coordinated their grip forces. Finally, the joint task enhanced cross-brain functional connectivity of the right anterior TPJ, indicating shared attention toward the temporal patterns of the motor output of the partner. Since the posterior TPJ is part of the mentalizing system for tracking the intention of perceived agents, our findings indicate that cooperation, i.e., the degree of adjustment of individual motor output depending on that of the partner, is mediated by the interconnected subdivisions of the right TPJ.

Role of the right anterior insular cortex in joint attention-related identification with a partner.

Understanding others as intentional agents is critical in social interactions. We perceive others' intentions through identification, a categorical judgment that others should work like oneself. The most primitive form of understanding others' intentions is joint attention (JA). During JA, an initiator selects a shared object through gaze (initiative joint attention, IJA), and the responder follows the direction of the initiator's gaze (reactive joint attention, RJA). Therefore, both participants share the intention of object selection. However, the neural underpinning of shared intention through JA remains unknown. In this study, we hypothesized that JA is represented by inter-individual neural synchronization of the intention-related activity. Additionally, JA requires eye contact that activates the limbic mirror system; therefore, we hypothesized that this system is involved in shared attention through JA. To test these hypotheses, participants underwent hyperscanning fMRI while performing JA tasks. We found that IJA-related activation of the right anterior insular cortex of participants was positively correlated with RJA-related activation of homologous regions in their partners. This area was activated by volitional selection of the target during IJA. Therefore, identification with others by JA is likely accomplished by the shared intentionality of target selection represented by inter-individual synchronization of the right anterior insular cortex.

Development of a low-cost EMG biofeedback device kit as an educational tool for physical therapy students.

[Purpose] Electromyography biofeedback therapy is applied to various diseases during physical therapy for motor learning. Our aim was to develop a low-cost electromyography biofeedback device kit that students could build by themselves in class and to evaluate whether this kit was an adequate educational tool for physical therapy students. [Subjects and Methods] This study included 34 volunteers from a 3 year physical therapy vocational school and a 4 year university course. All students were tasked with: 1) completing a pre-questionnaire; 2) attending basic lectures on electromyography biofeedback therapy and how to build the device; 3) building the device; and 4) completing a post-questionnaire. [Results] Mean time required to build the device was 50.8 ± 34.1 minutes for the vocational course students and 27.4 ± 8.8 minutes for university students. For both groups, there was a significant increase in the number of students stating "have an interest in," "be involved with," and "have knowledge of electromyography biofeedback" when pre- and post-questionnaires were compared. In the post questionnaire, the frequency of the "knowledge increased" response was higher. [Conclusion] Physical therapy students can easily build our new device in a classroom, and this kit is a useful educational tool to motivate learning in electromyography biofeedback.

Brain networks of social action-outcome contingency: The role of the ventral striatum in integrating signals from the sensory cortex and medial prefrontal cortex.

Social interactions can be facilitated by action-outcome contingency, in which self-actions result in relevant responses from others. Research has indicated that the striatal reward system plays a role in generating action-outcome contingency signals. However, the neural mechanisms wherein signals regarding self-action and others' responses are integrated to generate the contingency signal remain poorly understood. We conducted a functional MRI study to test the hypothesis that brain activity representing the self modulates connectivity between the striatal reward system and sensory regions involved in the processing of others' responses. We employed a contingency task in which participants made the listener laugh by telling jokes. Participants reported more pleasure when greater laughter followed their own jokes than those of another. Self-relevant listener's responses produced stronger activation in the medial prefrontal cortex (mPFC). Laughter was associated with activity in the auditory cortex. The ventral striatum exhibited stronger activation when participants made listeners laugh than when another did. In physio-physiological interaction analyses, the ventral striatum showed interaction effects for signals extracted from the mPFC and auditory cortex. These results support the hypothesis that the mPFC, which is implicated in self-related processing, gates sensory input associated with others' responses during value processing in the ventral striatum.

Interaction between novel oscillation within the ventromedial hypothalamus and the sympathetic nervous system.

The ventromedial hypothalamus (VMH) is known to play an important role in feeding behavior and the control of sympathetic nerve activity (SNA). We report the identification of novel neuron groups that showed oscillations on both sides of the VMH in hypothalamus slice preparations from juvenile rats of postnatal days 5-14. We detected spontaneous rhythmic burst activity with a frequency of around 0.06Hz typically in the dorsolateral region of the VMH (i.e., VMH oscillation) using optical recordings (voltage and calcium imaging), field potential recordings and intracellular membrane potential recordings. The oscillation was also confirmed after isolation of the VMH from other hypothalamic structures. The frequency of oscillation was increased by lowering the glucose concentration of the superfusate. To evaluate the relation between VMH oscillation and SNA, we simultaneously recorded VMH oscillation, SNA from the thoracic sympathetic nerve trunk and phrenic nerve discharge (Phr) in the decerebrate and arterially perfused in situ preparation from juvenile rats of postnatal days 5-11. Power spectral analysis in the arterially perfused in situ rat preparation revealed similar peak values to those of slice preparations within the low-frequency range between the VMH oscillation and sympathetic nerve trunk activity. In addition, we analyzed cross-correlations between the VMH, SNA and Phr. The results revealed that a predominant positive correlation of the VMH activity with the SNA existed with an average time lag of 2.4s, suggesting the presence of functional couplings between the VMH and SNA (and respiratory center) in the lower brainstem and spinal cord. We hypothesize that the VMH oscillation might be involved in low-frequency modulation of the SNA.

Neural substrates of shared attention as social memory: A hyperscanning functional magnetic resonance imaging study.

During a dyadic social interaction, two individuals can share visual attention through gaze, directed to each other (mutual gaze) or to a third person or an object (joint attention). Shared attention is fundamental to dyadic face-to-face interaction, but how attention is shared, retained, and neutrally represented in a pair-specific manner has not been well studied. Here, we conducted a two-day hyperscanning functional magnetic resonance imaging study in which pairs of participants performed a real-time mutual gaze task followed by a joint attention task on the first day, and mutual gaze tasks several days later. The joint attention task enhanced eye-blink synchronization, which is believed to be a behavioral index of shared attention. When the same participant pairs underwent mutual gaze without joint attention on the second day, enhanced eye-blink synchronization persisted, and this was positively correlated with inter-individual neural synchronization within the right inferior frontal gyrus. Neural synchronization was also positively correlated with enhanced eye-blink synchronization during the previous joint attention task session. Consistent with the Hebbian association hypothesis, the right inferior frontal gyrus had been activated both by initiating and responding to joint attention. These results indicate that shared attention is represented and retained by pair-specific neural synchronization that cannot be reduced to the individual level.

Unintentional Interpersonal Synchronization Represented as a Reciprocal Visuo-Postural Feedback System: A Multivariate Autoregressive Modeling Approach.

People's behaviors synchronize. It is difficult, however, to determine whether synchronized behaviors occur in a mutual direction--two individuals influencing one another--or in one direction--one individual leading the other, and what the underlying mechanism for synchronization is. To answer these questions, we hypothesized a non-leader-follower postural sway synchronization, caused by a reciprocal visuo-postural feedback system operating on pairs of individuals, and tested that hypothesis both experimentally and via simulation. In the behavioral experiment, 22 participant pairs stood face to face either 20 or 70 cm away from each other wearing glasses with or without vision blocking lenses. The existence and direction of visual information exchanged between pairs of participants were systematically manipulated. The time series data for the postural sway of these pairs were recorded and analyzed with cross correlation and causality. Results of cross correlation showed that postural sway of paired participants was synchronized, with a shorter time lag when participant pairs could see one another's head motion than when one of the participants was blindfolded. In addition, there was less of a time lag in the observed synchronization when the distance between participant pairs was smaller. As for the causality analysis, noise contribution ratio (NCR), the measure of influence using a multivariate autoregressive model, was also computed to identify the degree to which one's postural sway is explained by that of the other's and how visual information (sighted vs. blindfolded) interacts with paired participants' postural sway. It was found that for synchronization to take place, it is crucial that paired participants be sighted and exert equal influence on one another by simultaneously exchanging visual information. Furthermore, a simulation for the proposed system with a wider range of visual input showed a pattern of results similar to the behavioral results.

Brain networks of affective mentalizing revealed by the tear effect: The integrative role of the medial prefrontal cortex and precuneus.

Affective mentalizing involves the integration of various social signals in order to infer the affective states of others. Previous neuroimaging studies have shown that the medial prefrontal cortex, the precuneus/posterior cingulate cortex, and the temporo-parietal junction constitute the core affective mentalizing network. However, the relative contributions of these regions to affective mentalizing remain unclear. We used functional magnetic resonance imaging to investigate which of these nodes are involved in the integration of two social signals: emotional tears and facial expressions. We assumed that this integration would produce a supra-additive effect, indicated by greater activity than the sum of the effects of the individual social signals. Female subjects rated the sadness of faces with either tears or tear-like circles, and either sad or neutral expressions. We observed the supra-additive effect in the medial prefrontal cortex and precuneus/posterior cingulate cortex but not in the temporo-parietal junction. These results indicate that the medial prefrontal cortex and precuneus/posterior cingulate cortex play an important role in integrating tears and facial expressions during affective mentalizing.

Sleep is associated with offline improvement of motor sequence skill in children.

In adults, sleep is necessary for the offline improvement of certain skills, such as sequential finger tapping, but whether children show a similar effect is still debatable. Here, we tested whether sleep is associated with offline performance improvement in children. Nine- and 11-year-old children trained on an explicit sequential finger tapping task. On the night following training, their parents observed and recorded the duration of each child's sleep. The following day, all children performed a surprise retest session on the previously trained sequence. In both 9- and 11-year-old children, skill performance was significantly improved during the first retest session relative to the end of training on the previous day, confirming the offline improvement in performance. There was a significant correlation between the degree of improvement and sleep duration the night after training, suggesting that in children, as in adults, sleep is associated with offline skill enhancement.

Principal component analysis reveals differential attentional modulation of the vocal response to pitch perturbation.

The auditory-vocal system modifies voice fundamental frequency (F0) with auditory feedback. The responses to F0 changes in auditory feedback are known to depend on the task. The hypothesis explored in this study is that the task dependency is the result of multiple components of the F0 responses differently modulated with different tasks. Attention to audition was manipulated by task condition by the instruction to ignore or to count the number of the F0 shifts heard during vocalization. A synthetic voice with pitch shifts was used as auditory pseudo-feedback. The upward and downward shifts evoked very similar vocal F0 response patterns with polarity reversal. Attention to the auditory feedback caused a reduction in the grand-average response amplitude. By decomposing the F0 responses with principal component analysis (PCA), three principal components (PCs) with different peak latencies were found to have contributions above the criterion of 5%, totaling to 74%. All three PCs contributed to a compensatory response under the "ignore" condition. The slowest PC changed its polarity and the intermediate PC was reduced to almost zero under the "count" condition. Thus, the task-dependency of the F0 response to auditory feedback can be described in terms of different sensitivities of components to attention.

Social rewards enhance offline improvements in motor skill.

Motor skill memory is first encoded online in a fragile form during practice and then converted into a stable form by offline consolidation, which is the behavioral stage critical for successful learning. Praise, a social reward, is thought to boost motor skill learning by increasing motivation, which leads to increased practice. However, the effect of praise on consolidation is unknown. Here, we tested the hypothesis that praise following motor training directly facilitates skill consolidation. Forty-eight healthy participants were trained on a sequential finger-tapping task. Immediately after training, participants were divided into three groups according to whether they received praise for their own training performance, praise for another participant's performance, or no praise. Participants who received praise for their own performance showed a significantly higher rate of offline improvement relative to other participants when performing a surprise recall test of the learned sequence. On the other hand, the average performance of the novel sequence and randomly-ordered tapping did not differ between the three experimental groups. These results are the first to indicate that praise-related improvements in motor skill memory are not due to a feedback-incentive mechanism, but instead involve direct effects on the offline consolidation process.