首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Consolidation of motor memories associated with skilled practice can occur both online, concurrent with practice, and offline, after practice has ended. The current study investigated the role of dorsal premotor cortex (PMd) in early offline motor memory consolidation of implicit sequence‐specific learning. Thirty‐three participants were assigned to one of three groups of repetitive transcranial magnetic stimulation (rTMS) over left PMd (5 Hz, 1 Hz or control) immediately following practice of a novel continuous tracking task. There was no additional practice following rTMS. This procedure was repeated for 4 days. The continuous tracking task contained a repeated sequence that could be learned implicitly and random sequences that could not. On a separate fifth day, a retention test was performed to assess implicit sequence‐specific motor learning of the task. Tracking error was decreased for the group who received 1 Hz rTMS over the PMd during the early consolidation period immediately following practice compared with control or 5 Hz rTMS. Enhanced sequence‐specific learning with 1 Hz rTMS following practice was due to greater offline consolidation, not differences in online learning between the groups within practice days. A follow‐up experiment revealed that stimulation of PMd following practice did not differentially change motor cortical excitability, suggesting that changes in offline consolidation can be largely attributed to stimulation‐induced changes in PMd. These findings support a differential role for the PMd in support of online and offline sequence‐specific learning of a visuomotor task and offer converging evidence for competing memory systems.  相似文献   

2.
Implicit motor learning is preserved after stroke, but how the brain compensates for damage to facilitate learning is unclear. We used a random effects analysis to determine how stroke alters patterns of brain activity during implicit sequence‐specific motor learning as compared to general improvements in motor control. Nine healthy participants and nine individuals with chronic, right focal subcortical stroke performed a continuous joystick‐based tracking task during an initial functional magnetic resonance images (fMRI) session, over 5 days of practice, and a retention test during a separate fMRI session. Sequence‐specific implicit motor learning was differentiated from general improvements in motor control by comparing tracking performance on a novel, repeated tracking sequence during early practice and again at the retention test. Both groups demonstrated implicit sequence‐specific motor learning at the retention test, yet substantial differences were apparent. At retention, healthy control participants demonstrated increased blood oxygenation level dependent (BOLD) response in left dorsal premotor cortex (PMd; BA 6) but decreased BOLD response left dorsolateral prefrontal cortex (DLPFC; BA 9) during repeated sequence tracking. In contrast, at retention individuals with stroke did not show this reduction in DLPFC during repeated tracking. Instead implicit sequence‐specific motor learning and general improvements in motor control were associated with increased BOLD response in the left middle frontal gyrus BA 8, regardless of sequence type after stroke. These data emphasize the potential importance of a prefrontal‐based attentional network for implicit motor learning after stroke. This study is the first to highlight the importance of the prefrontal cortex for implicit sequence‐specific motor learning after stroke. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.  相似文献   

3.
Implicit and explicit memory systems for motor skills compete with each other during and after motor practice. Primary motor cortex (M1) is known to be engaged during implicit motor learning, while dorsal premotor cortex (PMd) is critical for explicit learning. To elucidate the neural substrates underlying the interaction between implicit and explicit memory systems, adults underwent a randomized crossover experiment of anodal transcranial direct current stimulation (AtDCS) applied over M1, PMd or sham stimulation during implicit motor sequence (serial reaction time task, SRTT) practice. We hypothesized that M1‐AtDCS during practice will enhance online performance and offline learning of the implicit motor sequence. In contrast, we also hypothesized that PMd‐AtDCS will attenuate performance and retention of the implicit motor sequence. Implicit sequence performance was assessed at baseline, at the end of acquisition (EoA), and 24 h after practice (retention test, RET). M1‐AtDCS during practice significantly improved practice performance and supported offline stabilization compared with Sham tDCS. Performance change from EoA to RET revealed that PMd‐AtDCS during practice attenuated offline stabilization compared with M1‐AtDCS and sham stimulation. The results support the role of M1 in implementing online performance gains and offline stabilization for implicit motor sequence learning. In contrast, enhancing the activity within explicit motor memory network nodes such as the PMd during practice may be detrimental to offline stabilization of the learned implicit motor sequence. These results support the notion of competition between implicit and explicit motor memory systems and identify underlying neural substrates that are engaged in this competition.  相似文献   

4.
Median nerve stimulation (MNS) has been shown to change brain metaplasticity over the somatosensory networks, based on a bottom‐up mechanism and may improve motor learning. This exploratory study aimed to test the effects of MNS on implicit and explicit motor learning as measured by the serial reaction time task (SRTT) using a double‐blind, sham‐controlled, randomized trial, in which participants were allocated to one of three groups: (a) online active MNS during acquisition, (b) offline active MNS during early consolidation and (c) sham MNS. SRTT was performed at baseline, during the training phase (acquisition period), and 30 min after training. We assessed the effects of MNS on explicit and implicit motor learning at the end of the training/acquisition period and at retest. The group receiving online MNS (during acquisition) showed a significantly higher learning index for the explicit sequences compared to the offline group (MNS during early consolidation) and the sham group. The offline group also showed a higher learning index as compared to sham. Additionally, participants receiving online MNS recalled the explicit sentence significantly more than the offline MNS and sham groups. MNS effects on motor learning have a specific effect on type of learning (explicit vs. implicit) and are dependent on timing of stimulation (during acquisition vs. early consolidation). More research is needed to understand and optimize the effects of peripheral electrical stimulation on motor learning. Taken together, our results show that MNS, especially when applied during the acquisition phase, is a promising tool to modulate motor leaning.  相似文献   

5.
In this study, the time course of the procedural learning of a visuomotor sequence skill was followed over a 24-hour and a 1-week time period in children with and without specific language impairment (SLI). Two aspects of memory consolidation in implicit sequence learning were examined: the evolution of post-training gains in sequence knowledge (Experiment 1) and the susceptibility to interference (Experiment 2). In the first experiment, 18 children with SLI and 17 control children matched for sex, age, and nonverbal intelligence completed a serial reaction-time (SRT) task and were tested 24 hours and 1 week after practicing. The two groups of children attained an equal level of sequence knowledge in the training session, but the children with SLI lacked the consolidation gains displayed by the control children in the two post-training sessions. Working with a new group of children, 17 with SLI and 17 control peers, Experiment 2 examined resistance to interference by introducing a second sequence 15 min after the first training session. Similar results were obtained for the performance of both groups in the training session. However, although the performance of the control group improved in the post-training sessions, the performance of the SLI group deteriorated significantly during the consolidation phase due to the interfering sequence. These findings suggest that the consolidation phase of sequence learning is impaired in children with SLI.  相似文献   

6.
Towards adaptive classification for BCI   总被引:1,自引:0,他引:1  
Non-stationarities are ubiquitous in EEG signals. They are especially apparent in the use of EEG-based brain-computer interfaces (BCIs): (a) in the differences between the initial calibration measurement and the online operation of a BCI, or (b) caused by changes in the subject's brain processes during an experiment (e.g. due to fatigue, change of task involvement, etc). In this paper, we quantify for the first time such systematic evidence of statistical differences in data recorded during offline and online sessions. Furthermore, we propose novel techniques of investigating and visualizing data distributions, which are particularly useful for the analysis of (non-)stationarities. Our study shows that the brain signals used for control can change substantially from the offline calibration sessions to online control, and also within a single session. In addition to this general characterization of the signals, we propose several adaptive classification schemes and study their performance on data recorded during online experiments. An encouraging result of our study is that surprisingly simple adaptive methods in combination with an offline feature selection scheme can significantly increase BCI performance.  相似文献   

7.
There is a continuing need to improve understanding of the central nervous system control of learning. Specifically, there is a need to examine the characteristics of cortical and sub-cortical activity linked to the stages of motor learning, including those occurring within a single-session. In this study we sought to design and investigate a visuomotor task to determine its ability to assess the component of motor learning occurring during a single session of fMRI (i.e., the 'online' improvement in motor performance). Fourteen healthy control subjects performed a visuomotor task requiring a combination of bilateral grip force to accurately move a cursor towards a target. We assessed online motor learning by comparing behavioural measures (accuracy and error magnitude) and the extent of spatial activation in specific brain regions of interest (ROIs) using fMRI pre- and post-training. Results showed a training-related improvement in performance based on increased accuracy (p<0.0125) and decreased error magnitude (p<0.0125) from pre- to post-training. Decreases in the extent of spatial activation from pre- to post-training in the majority of ROIs supported a training-related attenuation in brain activity associated with online motor learning. Importantly, decreases in error magnitude across conditions (p<0.05) confirmed that improvements in performance continued over the entire course of the experiment. Establishing this task may permit more extensive study of the neural correlates of single-session, online learning in healthy individuals and those with motor control challenges. Information obtained from such studies may provide an opportunity to improve interventions in neurological rehabilitation.  相似文献   

8.
The development of avoidance learning depends on dopamine release in forebrain regions. Previous studies indicated that rewarding brain stimulation facilitated two-way active avoidance learning. However, it is not clear whether the temporal relationship of brain stimulation to the training session (before, during or after) is important. To investigate the role of stimulation condition (no stimulation, self-stimulation only, or self-stimulation plus avoidance stimulation) and sequence of self-stimulation training (before or after avoidance training), we used a 3 × 2 factorial design, in which every level of stimulation was paired with every level of sequence for a total of 6 different groups. The results suggest that self-stimulation either before or after avoidance learning improved acquisition performance, but acquisition was maximal when stimulation was also given during acquisition trials. Importantly, the sequence of self-stimulation (before or after each acquisition session) was irrelevant to this beneficial effect. However, stimulation had no apparent effect on long-term retention when tested 10 days later under conditions of no stimulation, except that the performance of the group that had previously received avoidance-contingent stimulation deteriorated over the course of 60 trials. This may reflect frustration from the omission of expected reward. These results are relevant for optimizing brain stimulation to improve learning.  相似文献   

9.
BackgroundResearch involving incapacitated persons with dementia entails complex scientific, legal, and ethical issues, making traditional surveys of layperson views on the ethics of such research challenging. We therefore assessed the impact of democratic deliberation (DD), involving balanced, detailed education and peer deliberation, on the views of those responsible for persons with dementia.MethodsOne hundred and seventy-eight community-recruited caregivers or primary decision-makers for persons with dementia were randomly assigned to either an all-day DD session group or a control group. Educational materials used for the DD session were vetted for balance and accuracy by an interdisciplinary advisory panel. We assessed the acceptability of family-surrogate consent for dementia research (“surrogate-based research”) from a societal policy perspective as well as from the more personal perspectives of deciding for a loved one or for oneself (surrogate and self-perspectives), assessed at baseline, immediately post-DD session, and 1 month after DD date, for four research scenarios of varying risk-benefit profiles.ResultsAt baseline, a majority in both the DD and control groups supported a policy of family consent for dementia research in all research scenarios. The support for a policy of family consent for surrogate-based research increased in the DD group, but not in the control group. The change in the DD group was maintained 1 month later. In the DD group, there were transient changes in attitudes from surrogate or self-perspectives. In the control group, there were no changes from baseline in attitude toward surrogate consent from any perspective.ConclusionsIntensive, balanced, and accurate education, along with peer deliberation provided by democratic deliberation, led to a sustained increase in support for a societal policy of family consent in dementia research among those responsible for dementia patients.  相似文献   

10.
Adult rats chronically implanted with supradural electrodes were telemetrically EEG recorded during a baseline session, a training session for a two-way active avoidance task, and a retention session. Rats were assigned to a fast learning (FL), slow learning (SL) and non learning (NL) group if they achieved criterion during the training session, the retention session, or in neither session. High-resolution EEG analyses indicated that intergroup differences were present in the low frequency range of waking baseline power spectra. Moreover, baseline delta emissions directly correlated with freezings, and inversely correlated with avoidances, while emissions at 7-10 Hz directly correlated with avoidances and inversely correlated with freezings. Interestingly, during the first training period, waking delta emission selectively increased in FL rats in concomitance with a marked performance improvement; instead, SL and NL rats displayed increments at 7-9 Hz. In addition, freezings scored during the first two training periods directly correlated with post-training waking emission at 2 Hz, and inversely correlated with emission at 7-10 Hz. Conversely, escapes and avoidances directly correlated with waking emission at 7-10 Hz. The data indicate that (i) waking baseline power spectra differ among behavioral groups, and correlate with behavioral performance the following day; (ii) selective modifications of waking power spectra occur in each behavioral group during training; and (iii) behavioral responses during training correlate with post-training waking power spectra. Notably, the delta increment selectively occurring in training FL rats is assumed to reflect online memory processing leading to better performance. The latter observation supports the primary involvement of delta waves in learning.  相似文献   

11.
Gabay Y  Schiff R  Vakil E 《Neuropsychologia》2012,50(10):2435-2441
Motor sequence learning has been studied extensively in Developmental dyslexia (DD). The purpose of the present research was to examine procedural learning of letter names and motor sequences in individuals with DD and control groups. Both groups completed the Serial Search Task which enabled the assessment of learning of letter names and motor sequences independently of each other. Control participants learned both the letter names as well as the motor sequence. In contrast, individuals with DD were impaired in learning of the letter names sequence and showed a reliable transfer of the motor sequence. Previous studies proved that motor sequence learning is impaired in DD. The present study demonstrated that this deficit is more pronounced when the task to be learned involves linguistic units. This result implies that the procedural learning system of language is more deficient than the motor procedural learning system in individuals with DD. The dissociation between motor and letter names sequence learning in those with DD also implies that the systems underlying these two tasks are separable.  相似文献   

12.
Practice-induced improvements in skilled performance reflect "offline " consolidation processes extending beyond daily training sessions. According to visual learning theories, an early, fast learning phase driven by high-level areas is followed by a late, asymptotic learning phase driven by low-level, retinotopic areas when higher resolution is required. Thus, low-level areas would not contribute to learning and offline consolidation until late learning. Recent studies have challenged this notion, demonstrating modified responses to trained stimuli in primary visual cortex (V1) and offline activity after very limited training. However, the behavioral relevance of modified V1 activity for offline consolidation of visual skill memory in V1 after early training sessions remains unclear. Here, we used neuronavigated transcranial magnetic stimulation (TMS) directed to a trained retinotopic V1 location to test for behaviorally relevant consolidation in human low-level visual cortex. Applying TMS to the trained V1 location within 45 min of the first or second training session strongly interfered with learning, as measured by impaired performance the next day. The interference was conditional on task context and occurred only when training in the location targeted by TMS was followed by training in a second location before TMS. In this condition, high-level areas may become coupled to the second location and uncoupled from the previously trained low-level representation, thereby rendering consolidation vulnerable to interference. Our data show that, during the earliest phases of skill learning in the lowest-level visual areas, a behaviorally relevant form of consolidation exists of which the robustness is controlled by high-level, contextual factors.  相似文献   

13.
The aim of this randomized double blinded sham‐controlled study was to determine the effect of cerebellar anodal transcranial direct current stimulation (a‐tDCS) on online and offline motor learning in healthy older individuals. Thirty participants were randomly assigned in experimental (n = 15) or sham tDCS (n = 15) groups. Participants in experimental group received 2 mA cerebellar a‐tDCS for 20 min. However, the tDCS was turned off after 30 seconds in sham group. Response time (RT) and error rate (ER) in serial RT test were assessed before, during 35 minutes and 48 h after the intervention. Reduction of RT and ER following the intervention session was considered as short‐term (35 min post intervention) and long‐term offline learning (48 h post intervention), respectively. Online RT and ER reduction were similar in both groups (P > 0.05). RT was significantly reduced 48 hours post intervention in cerebellar a‐tDCS group (P = 0.03). Moreover, RT was significantly increased after 35 minutes and 48 hours in sham tDCS group (P = 0.03, P = 0.007), which indicates a lack of short‐term and long‐term offline learning in older adults. A‐tDCS on cerebellar region produced more short‐term and long‐term offline improvement in RT (P = 0.014, P = 0.01) compared to sham tDCS. In addition, online, short‐term and long‐term (48 h) offline error reduced in cerebellar a‐tDCS as compared to sham‐control group, although this reduction was not significant (P > 0.05). A deficit suggests that a direct comparison to a younger group was made. The findings suggested that cerebellar a‐tDCS might be useful for improvement of offline motor learning in older individuals.  相似文献   

14.
It has been proposed that an impairment of procedural memory underlies a range of linguistic, cognitive and motor impairments observed in developmental dyslexia (DD). However, studies designed to test this hypothesis using the implicit sequence learning paradigm have yielded inconsistent results. A fundamental aspect of procedural learning is that it takes place over an extended time-period that may be divided into distinct stages based on both behavioural characteristics and neural correlates of performance. Yet, no study of implicit sequence learning in children with DD has included learning stages beyond a single practice session. The present study was designed to fill this important gap by extending the investigation to include the effects of overnight consolidation as well as those of further practice on a subsequent day. The results suggest that the most pronounced procedural learning impairment in DD may emerge only after extended practice, in learning stages beyond a single practice session.  相似文献   

15.
Decreased long-range temporal correlations (LRTC) in brain signals can be used to measure cognitive effort during task execution. Here, we examined how learning a motor sequence affects long-range temporal memory within resting-state functional magnetic resonance imaging signal. Using the Hurst exponent (HE), we estimated voxel-wise LRTC and assessed changes over 5 consecutive days of training, followed by a retention scan 12 days later. The experimental group learned a complex visuomotor sequence while a complementary control group performed tightly matched movements. An interaction analysis revealed that HE decreases were specific to the complex sequence and occurred in well-known motor sequence learning associated regions including left supplementary motor area, left premotor cortex, left M1, left pars opercularis, bilateral thalamus, and right striatum. Five regions exhibited moderate to strong negative correlations with overall behavioral performance improvements. Following learning, HE values returned to pretraining levels in some regions, whereas in others, they remained decreased even 2 weeks after training. Our study presents new evidence of HE's possible relevance for functional plasticity during the resting-state and suggests that a cortical subset of sequence-specific regions may continue to represent a functional signature of learning reflected in decreased long-range temporal dependence after a period of inactivity.  相似文献   

16.
The Procedural Deficit Hypothesis (PDH) posits that Specific Language Impairment (SLI) can be largely explained by abnormalities of brain structures that subserve procedural memory. The PDH predicts impairments of procedural memory itself, and that such impairments underlie the grammatical deficits observed in the disorder. Previous studies have indeed reported procedural learning impairments in SLI, and have found that these are associated with grammatical difficulties. The present study extends this research by examining consolidation and longer-term procedural sequence learning in children with SLI. The Alternating Serial Reaction Time (ASRT) task was given to children with SLI and typically developing (TD) children in an initial learning session and an average of three days later to test for consolidation and longer-term learning. Although both groups showed evidence of initial sequence learning, only the TD children showed clear signs of consolidation, even though the two groups did not differ in longer-term learning. When the children were re-categorized on the basis of grammar deficits rather than broader language deficits, a clearer pattern emerged. Whereas both the grammar impaired and normal grammar groups showed evidence of initial sequence learning, only those with normal grammar showed consolidation and longer-term learning. Indeed, the grammar-impaired group appeared to lose any sequence knowledge gained during the initial testing session. These findings held even when controlling for vocabulary or a broad non-grammatical language measure, neither of which were associated with procedural memory. When grammar was examined as a continuous variable over all children, the same relationships between procedural memory and grammar, but not vocabulary or the broader language measure, were observed. Overall, the findings support and further specify the PDH. They suggest that consolidation and longer-term procedural learning are impaired in SLI, but that these impairments are specifically tied to the grammatical deficits in the disorder. The possibility that consolidation and longer-term learning are problematic in the disorder suggests a locus of potential study for therapeutic approaches. In sum, this study clarifies our understanding of the underlying deficits in SLI, and suggests avenues for further research.  相似文献   

17.
《Brain stimulation》2014,7(4):532-540
BackgroundNoninvasive electrical brain stimulation (NEBS) with transcranial direct current (tDCS) or random noise stimulation (tRNS) applied to the primary motor cortex (M1) can augment motor learning.ObjectiveWe tested whether different types of stimulation alter particular aspects of learning a tracing task over three consecutive days, namely skill acquisition (online/within session effects) or consolidation (offline/between session effects).MethodsMotor training on a tracing task over three consecutive days was combined with different types and montages of stimulation (tDCS, tRNS).ResultsUnilateral M1 stimulation using tRNS as well as unilateral and bilateral M1 tDCS all enhanced motor skill learning compared to sham stimulation. In all groups, this appeared to be driven by online effects without an additional offline effect. Unilateral tDCS resulted in large skill gains immediately following the onset of stimulation, while tRNS exerted more gradual effects. Control stimulation of the right temporal lobe did not enhance skill learning relative to sham.ConclusionsThe mechanisms of action of tDCS and tRNS are likely different. Hence, the time course of skill improvement within sessions could point to specific and temporally distinct interactions with the physiological process of motor skill learning. Exploring the parameters of NEBS on different tasks and in patients with brain injury will allow us to maximize the benefits of NEBS for neurorehabilitation.  相似文献   

18.
On-line Assessment of Statistical Learning by Event-related Potentials   总被引:1,自引:0,他引:1  
Abstract We investigated the neural processes involved in on-line statistical learning and word segmentation. Auditory event-related potentials (ERPs) were recorded while participants were exposed to continuous, nonlinguistic auditory sequences, the elements of which were organized into "tritone words" that were sequenced in random order, with no silent spaces between them. After listening to three 6.6-min sessions of sequences, the participants performed a behavioral choice test, in which they were instructed to indicate the most familiar tone sequence in each test trial by pressing buttons. The participants were divided into three groups (high, middle, and low learners) based on their behavioral performance. The overall mean performance was 74.4%, indicating that the tone sequence was segmented and that the participants learned the tone words statistically. Grand-averaged ERPs showed that word onset (initial tone) elicited the largest N100 and N400 in the early learning session of high learners, but in middle learners, the word-onset effect was elicited in a later session, and there was no effect in low learners. The N400 amplitudes significantly differed between the three learning sessions in the high- and middle-learner groups. The results suggest that the N400 effect indicates not only on-line word segmentation but also the degree of statistical learning. This study provides insight into the neural mechanisms underlying on-line statistical learning processes.  相似文献   

19.
《Brain stimulation》2021,14(4):873-883
BackgroundSkill learning engages offline activity in the primary motor cortex (M1). Sensorimotor cortical activity oscillates between excitatory trough and inhibitory peak phases of the mu (8–12 Hz) rhythm. We recently showed that these mu phases influence the magnitude and direction of neuroplasticity induction within M1. However, the contribution of M1 activity during mu peak and trough phases to human skill learning has not been investigated.ObjectiveTo evaluate the effects of phase-dependent TMS during mu peak and trough phases on offline learning of a newly-acquired motor skill.MethodsOn Day 1, three groups of healthy adults practiced an explicit motor sequence learning task with their non-dominant left hand. After practice, phase-dependent TMS was applied to the right M1 during either mu peak or mu trough phases. The third group received sham TMS during random mu phases. On Day 2, all subjects were re-tested on the same task to evaluate offline learning.ResultsSubjects who received phase-dependent TMS during mu trough phases showed increased offline skill learning compared to those who received phase-dependent TMS during mu peak phases or sham TMS during random mu phases. Additionally, phase-dependent TMS during mu trough phases elicited stronger whole-brain broadband oscillatory power responses than phase-dependent TMS during mu peak phases.ConclusionsWe conclude that sensorimotor mu trough phases reflect brief windows of opportunity during which TMS can strengthen newly-acquired skill memories.  相似文献   

20.
Abstract Objective. Borderline personality disorder (BPD) is defined as a pervasive pattern of instability in emotion, mood and interpersonal relationships, with a comorbidity between PBD and depressive disorders (DD). A key competence for successful management of interpersonal relationships is emotional intelligence (EI). Given the low EI of patients suffering from BPD, the present study aimed at investigating the effect on both emotional intelligence and depression of training emotional intelligence in patients with BPD and DD. Methods. A total of 30 inpatients with BPD and DD (53% females; mean age 24.20 years) took part in the study. Patients were randomly assigned either to the treatment or to the control group. Pre- and post-testing 4 weeks later involved experts' rating of depressive disorder and self-reported EI. The treatment group received 12 sessions of training in components of emotional intelligence. Results. Relative to the control group, EI increased significantly in the treatment group over time. Depressive symptoms decreased significantly over time in both groups, though improvement was greater in the treatment than the control group. Conclusion. For inpatients suffering from BPD and DD, regular skill training in EI can be successfully implemented and leads to improvements both in EI and depression. Results suggest an additive effect of EI training on both EI and depressive symptoms.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号