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| Author | Friedman, J.; Korman, M. | ||||
| Title | Offline Optimization of the Relative Timing of Movements in a Sequence Is Blocked by Retroactive Behavioral Interference | Type | Journal Article | ||
| Year | 2016 | Publication | Frontiers in Human Neuroscience | Abbreviated Journal | Front. Hum. Neurosci. |
| Volume | 10 | Issue | Pages  |
623 | |
| Keywords | learning; interference; consolidation; finger movements; kinematics | ||||
| Abstract | Acquisition of motor skills often involves the concatenation of single movements into sequences. Along the course of learning, sequential performance becomes progressively faster and smoother, presumably by optimization of both motor planning and motor execution. Following its encoding during training, “how-to” memory undergoes consolidation, reflecting transformations in performance and its neurobiological underpinnings over time. This offline post-training memory process is characterized by two phenomena: reduced sensitivity to interference and the emergence of delayed, typically overnight, gains in performance. Here, using a training protocol that effectively induces motor sequence memory consolidation, we tested temporal and kinematic parameters of performance within (online) and between (offline) sessions, and their sensitivity to retroactive interference. One group learned a given finger-to-thumb opposition sequence (FOS), and showed robust delayed (consolidation) gains in the number of correct sequences performed at 24 h. A second group learned an additional (interference) FOS shortly after the first and did not show delayed gains. Reduction of touch times and inter-movement intervals significantly contributed to the overall offline improvement of performance overnight. However, only the offline inter-movement interval shortening was selectively blocked by the interference experience. Velocity and amplitude, comprising movement time, also significantly changed across the consolidation period but were interference-insensitive. Moreover, they paradoxically canceled out each other. Current results suggest that shifts in the representation of the trained sequence are subserved by multiple processes: from distinct changes in kinematic characteristics of individual finger movements to high-level, temporal reorganization of the movements as a unit. Each of these processes has a distinct time course and a specific susceptibility to retroactive interference. This multiple-component view may bridge the gap in understanding the link between the behavioral changes, which define online and offline learning, and the biological mechanisms that support those changes. | ||||
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| ISSN | 1662-5161 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 83 | |||
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| Author | Merdler, T.; Liebermann, D.G.; Levin, M.F.; Berman, S. | ||||
| Title | Arm-plane representation of shoulder compensation during pointing movements in patients with stroke | Type | Journal Article | ||
| Year | 2013 | Publication | Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology | Abbreviated Journal | J Electromyogr Kinesiol |
| Volume | 23 | Issue | 4 | Pages |
938–947 |
| Keywords | Kinematics; Arm movement; Rehabilitation | ||||
| Abstract | Improvements in functional motor activities are often accompanied by motor compensations to overcome persistent motor impairment in the upper limb. Kinematic analysis is used to objectively quantify movement patterns including common motor compensations such as excessive trunk displacement during reaching. However, a common motor compensation to assist reaching, shoulder abduction, is not adequately characterized by current motion analysis approaches. We apply the arm-plane representation that accounts for the co-variation between movements of the whole arm, and investigate its ability to identify and quantify compensatory arm movements in stroke subjects when making forward arm reaches. This method has not been previously applied to the analysis of motion deficits. Sixteen adults with right post-stroke hemiparesis and eight healthy age-matched controls reached in three target directions (14 trials/target; sampling rate: 100Hz). Arm-plane movement was validated against endpoint, joint, and trunk kinematics and compared between groups. In stroke subjects, arm-plane measures were correlated with arm impairment (Fugl-Meyer Assessment) and ability (Box and Blocks) scores and were more sensitive than clinical measures to detect mild motor impairment. Arm-plane motion analysis provides new information about motor compensations involving the co-variation of shoulder and elbow movements that may help to understand the underlying motor deficits in patients with stroke. | ||||
| Address | Department of Industrial Engineering and Management, Ben-Gurion University of the Negev, Beer-Sheva, Israel | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 1050-6411 | ISBN | Medium | ||
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| Notes | PMID:23566477 | Approved | no | ||
| Call Number | Serial | 69 | |||
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| Author | Harel Arzi; Tal Krasovsky; Moshe Pritsch; Dario G. Liebermann | ||||
| Title | Movement control in patients with shoulder instability: a comparison between patients after open surgery and nonoperated patients | Type | Journal Article | ||
| Year | 2014 | Publication | Journal of Shoulder and Elbow Surgery | Abbreviated Journal | |
| Volume | 23 | Issue | 7 | Pages |
982–992 |
| Keywords | Smoothness; kinesthesis; arm kinematics; shoulder instability; open surgery | ||||
| Abstract | Background Open surgery to correct shoulder instability is deemed to facilitate recovery of static and dynamic motor functions. Postoperative assessments focus primarily on static outcomes (e.g., repositioning accuracy). We introduce kinematic measures of arm smoothness to assess shoulder patients after open surgery and compare them with nonoperated patients. Performance among both groups of patients was hypothesized to differ. Postsurgery patients were expected to match healthy controls. Methods All participants performed pointing movements with the affected/dominant arm fully extended at fast, preferred, and slow speeds (36 trials per subject). Kinematic data were collected (100 Hz, 3 seconds), and mixed-design analyses of variance (group, speed) were performed with movement time, movement amplitude, acceleration time, and model-observed similarities as dependent variables. Nonparametric tests were performed for number of velocity peaks. Results Nonoperated and postsurgery patients showed similarities at preferred and faster movement speeds but not at slower speed. Postsurgery patients were closer to maximally smoothed motion and differed from healthy controls mainly during slow arm movements (closer to maximal smoothness, larger movement amplitude, shorter movement time, and lower number of peaks; i.e., less movement fragmentation). Conclusions Arm kinematic analyses suggest that open surgery stabilizes the shoulder but does not necessarily restore normal movement quality. Patients with recurrent anterior shoulder instability (RASI) seem to implement a “safe” but nonadaptive mode of action whereby preplanned stereotypical movements may be executed without depending on feedback. Rehabilitation of RASI patients should focus on restoring feedback-based movement control. Clinical assessment of RASI patients should include higher order kinematic descriptors. |
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| Notes | Approved | no | |||
| Call Number | Serial | 74 | |||
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| Author | Wilf, M.; Korakin, A.; Bahat, Y.; Koren, O.; Galor, N.; Dagan, O.; Wright, W.G.; Friedman, J.; Plotnik, M. | ||||
| Title | Using virtual reality-based neurocognitive testing and eye tracking to study naturalistic cognitive-motor performance | Type | Journal Article | ||
| Year | 2024 | Publication | Neuropsychologia | Abbreviated Journal | Neuropsychologia |
| Volume | 194 | Issue | Pages |
108744 | |
| Keywords | Humans; Aged; *Eye-Tracking Technology; Cognition; Executive Function; *Virtual Reality; Aging; Color trails test; Fall risk; Hand kinematics; Pupil; Virtual reality | ||||
| Abstract | Natural human behavior arises from continuous interactions between the cognitive and motor domains. However, assessments of cognitive abilities are typically conducted using pen and paper tests, i.e., in isolation from “real life” cognitive-motor behavior and in artificial contexts. In the current study, we aimed to assess cognitive-motor task performance in a more naturalistic setting while recording multiple motor and eye tracking signals. Specifically, we aimed to (i) delineate the contribution of cognitive and motor components to overall task performance and (ii) probe for a link between cognitive-motor performance and pupil size. To that end, we used a virtual reality (VR) adaptation of a well-established neurocognitive test for executive functions, the 'Color Trails Test' (CTT). The VR-CTT involves performing 3D reaching movements to follow a trail of numbered targets. To tease apart the cognitive and motor components of task performance, we included two additional conditions: a condition where participants only used their eyes to perform the CTT task (using an eye tracking device), incurring reduced motor demands, and a condition where participants manually tracked visually-cued targets without numbers on them, incurring reduced cognitive demands. Our results from a group of 30 older adults (>65) showed that reducing cognitive demands shortened completion times more extensively than reducing motor demands. Conditions with higher cognitive demands had longer target search time, as well as decreased movement execution velocity and head-hand coordination. We found larger pupil sizes in the more cognitively demanding conditions, and an inverse correlation between pupil size and completion times across individuals in all task conditions. Lastly, we found a possible link between VR-CTT performance measures and clinical signatures of participants (fallers versus non-fallers). In summary, performance and pupil parameters were mainly dependent on task cognitive load, while maintaining systematic interindividual differences. We suggest that this paradigm opens the possibility for more detailed profiling of individual cognitive-motor performance capabilities in older adults and other at-risk populations. | ||||
| Address | Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Israel; Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. Electronic address: Meir.Plotnik@sheba.health.gov.il | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 0028-3932 | ISBN | Medium | ||
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| Notes | PMID:38072162 | Approved | no | ||
| Call Number | Serial | 123 | |||
| Permanent link to this record | |||||