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Author | Friedman, J.; Amiaz, A.; Korman, M. | ||||
Title | The online and offline effects of changing movement timing variability during training on a finger-opposition task | Type | Journal Article | ||
Year | 2022 | Publication ![]() |
Scientific Reports | Abbreviated Journal | Sci Rep |
Volume | 12 | Issue | 1 | Pages | 13319 |
Keywords | Fingers; Humans; *Learning; *Motor Skills; Movement; Psychomotor Performance; Upper Extremity | ||||
Abstract | In motor learning tasks, there is mixed evidence for whether increased task-relevant variability in early learning stages leads to improved outcomes. One problem is that there may be a connection between skill level and motor variability, such that participants who initially have more variability may also perform worse on the task, so will have more room to improve. To avoid this confound, we experimentally manipulated the amount of movement timing variability (MTV) during training to test whether it improves performance. Based on previous studies showing that most of the improvement in finger-opposition tasks comes from optimizing the relative onset time of the finger movements, we used auditory cues (beeps) to guide the onset times of sequential movements during a training session, and then assessed motor performance after the intervention. Participants were assigned to three groups that either: (a) followed a prescribed random rhythm for their finger touches (Variable MTV), (b) followed a fixed rhythm (Fixed control MTV), or (c) produced the entire sequence following a single beep (Unsupervised control MTV). While the intervention was successful in increasing MTV during training for the Variable group, it did not lead to improved outcomes post-training compared to either control group, and the use of fixed timing led to significantly worse performance compared to the Unsupervised control group. These results suggest that manipulating MTV through auditory cues does not produce greater learning than unconstrained training in motor sequence tasks. | ||||
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Language | English | Summary Language | Original Title | ||
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Series Volume | Series Issue | Edition | |||
ISSN | 2045-2322 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:35922460; PMCID:PMC9349301 | Approved | no | ||
Call Number | Serial | 115 | |||
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Author | Lowenthal-Raz, J.; Liebermann, D.G.; Friedman, J.; Soroker, N. | ||||
Title | Kinematic descriptors of arm reaching movement are sensitive to hemisphere-specific immediate neuromodulatory effects of transcranial direct current stimulation post stroke | Type | Journal Article | ||
Year | 2024 | Publication ![]() |
Scientific Reports | Abbreviated Journal | Sci Rep |
Volume | 14 | Issue | 1 | Pages | 11971 |
Keywords | Humans; *Transcranial Direct Current Stimulation/methods; Male; Female; Middle Aged; *Stroke/physiopathology/therapy; Biomechanical Phenomena; Aged; *Arm/physiopathology; *Movement/physiology; *Stroke Rehabilitation/methods; Single-Blind Method; Cross-Over Studies | ||||
Abstract | Transcranial direct current stimulation (tDCS) exerts beneficial effects on motor recovery after stroke, presumably by enhancement of adaptive neural plasticity. However, patients with extensive damage may experience null or deleterious effects with the predominant application mode of anodal (excitatory) stimulation of the damaged hemisphere. In such cases, excitatory stimulation of the non-damaged hemisphere might be considered. Here we asked whether tDCS exerts a measurable effect on movement quality of the hemiparetic upper limb, following just a single treatment session. Such effect may inform on the hemisphere that should be excited. Using a single-blinded crossover experimental design, stroke patients and healthy control subjects were assessed before and after anodal, cathodal and sham tDCS, each provided during a single session of reaching training (repeated point-to-point hand movement on an electronic tablet). Group comparisons of endpoint kinematics at baseline-number of peaks in the speed profile (NoP; smoothness), hand-path deviations from the straight line (SLD; accuracy) and movement time (MT; speed)-disclosed greater NoP, larger SLD and longer MT in the stroke group. NoP and MT revealed an advantage for anodal compared to sham stimulation of the lesioned hemisphere. NoP and MT improvements under anodal stimulation of the non-lesioned hemisphere correlated positively with the severity of hemiparesis. Damage to specific cortical regions and white-matter tracts was associated with lower kinematic gains from tDCS. The study shows that simple descriptors of movement kinematics of the hemiparetic upper limb are sensitive enough to demonstrate gain from neuromodulation by tDCS, following just a single session of reaching training. Moreover, the results show that tDCS-related gain is affected by the severity of baseline motor impairment, and by lesion topography. | ||||
Address | Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel. nachum@soroker.online | ||||
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Publisher | Place of Publication | Editor | |||
Language | English | Summary Language | Original Title | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2045-2322 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:38796610; PMCID:PMC11127956 | Approved | no | ||
Call Number | Serial | 125 | |||
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Author | Salzer, Y.; Friedman, J. | ||||
Title | Reaching trajectories unravel modality-dependent temporal dynamics of the automatic process in the Simon task: a model-based approach | Type | Journal Article | ||
Year | 2020 | Publication ![]() |
Psychological Research | Abbreviated Journal | Psychol Res |
Volume | 84 | Issue | 6 | Pages | 1700-1713 |
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Abstract | The Simon effect represents a phenomenon in which the location of the stimuli affects the speed and accuracy of the response, despite being irrelevant for the task demands. This is believed to be due to an automatic activation of a response corresponding to the location of the stimuli, which conflicts with the controlled decision process based on relevant stimuli features. Previously, differences in the nature of the Simon effect (i.e., the pattern of change of the effect across the distribution of response times) between visual and somatosensory stimuli were reported. We hypothesize that the temporal dynamics of visual and somatosensory automatic and controlled processes vary, thus driving the reported behavioral differences. While most studies have used response times to study the underlying mechanisms involved, in this study we had participants reach out to touch the targets and recorded their arm movements using a motion capture system. Importantly, the participants started their movements before a final decision was made. In this way, we could analyze the movements to gain insights into the competition between the automatic and controlled processes. We used this technique to describe the results in terms of a model assuming automatic activation due to location-based evidence, followed by inhibition. We found that for the somatosensory Simon effect, the decay of the automatic process is significantly slower than for the visual Simon effect, suggesting quantitative differences in this automatic process between the visual and somatosensory modalities. | ||||
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Language | English | Summary Language | Original Title | ||
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Series Volume | Series Issue | Edition | |||
ISSN | 0340-0727 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:30980236 | Approved | no | ||
Call Number | Serial | 97 | |||
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Author | Finkbeiner, Matthew; Friedman, Jason | ||||
Title | The flexibility of nonconsciously deployed cognitive processes: Evidence from masked congruence priming | Type | Journal Article | ||
Year | 2011 | Publication ![]() |
PLoS ONE | Abbreviated Journal | |
Volume | 6 | Issue | 2 | Pages | e17095 |
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Abstract | Background It is well accepted in the subliminal priming literature that task-level properties modulate nonconscious processes. For example, in tasks with a limited number of targets, subliminal priming effects are limited to primes that are physically similar to the targets. In contrast, when a large number of targets are used, subliminal priming effects are observed for primes that share a semantic (but not necessarily physical) relationship with the target. Findings such as these have led researchers to conclude that task-level properties can direct nonconscious processes to be deployed exclusively over central (semantic) or peripheral (physically specified) representations. Principal Findings We find distinct patterns of masked priming for “novel” and “repeated” primes within a single task context. Novel primes never appear as targets and thus are not seen consciously in the experiment. Repeated primes do appear as targets, thereby lending themselves to the establishment of peripheral stimulus-response mappings. If the source of the masked priming effect were exclusively central or peripheral, then both novel and repeated primes should yield similar patterns of priming. In contrast, we find that both novel and repeated primes produce robust, yet distinct, patterns of priming. Conclusions Our findings indicate that nonconsciously elicited cognitive processes can be flexibly deployed over both central and peripheral representations within a single task context. While we agree that task level properties can influence nonconscious processes, our findings sharply constrain the extent of this influence. Specifically, our findings are inconsistent with extant accounts which hold that the influence of task-level properties is strong enough to restrict the deployment of nonconsciously elicited cognitive processes to a single type of representation (i.e. central or peripheral). |
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Notes | Approved | no | |||
Call Number | Penn State @ write.to.jason @ | Serial | 22 | ||
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Author | Friedman, J.; Korman, M. | ||||
Title | Kinematic Strategies Underlying Improvement in the Acquisition of a Sequential Finger Task with Self-Generated vs. Cued Repetition Training | Type | Journal Article | ||
Year | 2012 | Publication ![]() |
PLoS one | Abbreviated Journal | PLoS One |
Volume | 7 | Issue | 12 | Pages | e52063 |
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Abstract | Many motor skills, such as typing, consist of articulating simple movements into novel sequences that are executed faster and smoother with practice. Dynamics of re-organization of these movement sequences with multi-session training and its dependence on the amount of self-regulation of pace during training is not yet fully understood. In this study, participants practiced a sequence of key presses. Training sessions consisted of either externally (Cued) or self-initiated (Uncued) training. Long-term improvements in performance speed were mainly due to reducing gaps between finger movements in both groups, but Uncued training induced higher gains. The underlying kinematic strategies producing these changes and the representation of the trained sequence differed significantly across subjects, although net gains in speed were similar. The differences in long-term memory due to the type of training and the variation in strategies between subjects, suggest that the different neural mechanisms may subserve the improvements observed in overall performance. | ||||
Address | Department of Cognitive Science, Macquarie University, Sydney, Australia ; ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia | ||||
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Language | English | Summary Language | Original Title | ||
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Series Volume | Series Issue | Edition | |||
ISSN | 1932-6203 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | PMID:23272210 | Approved | no | ||
Call Number | Serial | 41 | |||
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