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| Author | Friedman, Jason; Brown, Scott; Finkbeiner, Matthew | ||||
| Title | Linking cognitive and reaching trajectories via intermittent movement control | Type | Journal Article | ||
| Year | 2013 | Publication | Journal of Mathematical Psychology | Abbreviated Journal | |
| Volume | 57 | Issue | 3-4 | Pages | 140-151 |
| Keywords | Decision making; Diffusion model; Reaction times; Arm movements; Submovements | ||||
| Abstract | Theories of decision-making have traditionally been constrained by reaction time data. A limitation of reaction time data, particularly for studying the temporal dynamics of cognitive processing, is that they index only the endpoint of the decision making process. Recently, physical reaching trajectories have been used as proxies for underlying mental trajectories through decision space. We suggest that this approach has been oversimplified: while it is possible for the motor control system to access the current state of the evidence accumulation process, this access is intermittent. Instead, we demonstrate how a model of arm movements that assumes intermittent, not continuous, access to the decision process is sufficient to describe the effects of stimulus quality and viewing time in curved reaching movements. | ||||
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Approved | no | |||
| Call Number | Serial | 70 | |||
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| Author | Dario G. Liebermann; Larry Katz; and Ruth Morey Sorrentino | ||||
| Title | Experienced Coaches’ Attitudes Towards Science and Technology | Type | Journal Article | ||
| Year | 2005 | Publication | International Journal of Computer Science in Sport | Abbreviated Journal | |
| Volume | 4 | Issue | 1 | Pages | 21-28 |
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| Abstract | In this study, the attitude of experienced coaches towards technologies and sport sciences was assessed. A questionnaire was used to evaluate three areas: (1) Attitudes towards technology and sport science in coaching, (2) Technology and scientific knowledge in practice, and (3) Perceived importance of technology and science in enhancing sport results. A group of 27 highly experienced coaches completed the questionnaire. The questionnaire consisted of three parts, starting with demographic information, followed by a series of 27 questions with answers on a Likert scale ranging from strongly agree to strongly disagree, and finally, coaches were requested to rank 14 well-defined ‘coaching goals’ from 1 (most important) to 14 (least important). Results showed that top-level coaches rated having a good relationship with the athletes’ as a major goal. Overall, members of this group of experienced coaches seem to recognize the general importance of sport sciences, and appear to be positive about the use of sport technologies, but do not necessarily translate these positive attitudes into actual practice within their competitive sport environments, even when they all use information technology for other activities. According to these results, sport science researchers and technology developers need to adapt their strategies. Coaching education should encourage coaches to incorporate technologies as part of their coaching routines. Developing innovative resources and incorporating them in coaching education, as is done in some countries, may be a starting point. However, placing the emphasis on educating successful coaches on the practical use of technology and scientific knowledge is suggested as a short-term goal. This may allow for a more immediate effect on the attitude and practice of less senior coaches that tend to adopt methods and training routines through following the personal example provided by top-level coaches. |
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Approved | no | |||
| Call Number | Serial | 66 | |||
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| Author | Frenkel-Toledoa, S.; Bentin, S.; Perry, A.; Liebermann, D. G.; Soroker, N. | ||||
| Title | Mirror-neuron system recruitment by action observation: Effects of focal brain damage on mu suppression | Type | Journal Article | ||
| Year | 2014 | Publication | NeuroImage | Abbreviated Journal | |
| Volume | 87 | Issue | Pages | 127-137 | |
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| Abstract | Mu suppression is the attenuation of EEG power in the alpha frequency range (8-12 Hz), recorded over the sensorimotor cortex during execution and observation of motor actions. Based on this dual characteristic it is thought to signalize activation of a human analogue of the mirror neuron system (MNS) found in macaque monkeys, though much uncertainty remains concerning its specificity and full significance. To further explore the hypothesized relationship between mu suppression and MNS activation, we investigated how it is affected by damage to cortical regions, including areas where the MNS is thought to reside. EEG was recorded in 33 first-event stroke patients during observation of video-clips showing reaching and grasping hand movements. We examined the modulation of EEG oscillations at central and occipital sites, and analyzed separately the lower (8-10 Hz) and higher (10-12 Hz) segments of the alpha/mu range. Suppression was determined relative to observation of a non-biological movement. Normalized lesion data were used to investigate how damage to regions of the fronto-parietal cortex affects the pattern of suppression. The magnitude of mu suppression during action observation was significantly reduced in the affected hemisphere compared to the unaffected hemisphere. Differences between the hemispheres were significant at central (sensorimotor) sites but not at occipital (visual) sites. Total hemispheric volume loss did not correlate with mu suppression. Suppression in the lower mu range in the unaffected hemisphere (C3) correlated with lesion extent within the right inferior parietal cortex. Our lesion study supports the role of mu suppression as a marker of MNS activation, as suggested by findings gathered in previous studies in normal subjects. | ||||
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Approved | no | |||
| Call Number | Serial | 71 | |||
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| Author | Park, J.; Pazin, N.; Friedman, J.; Zatsiorsky, V.M.; Latash, M.L. | ||||
| Title | Mechanical properties of the human hand digits: Age-related differences | Type | Journal Article | ||
| Year | 2014 | Publication | Clinical Biomechanics | Abbreviated Journal | |
| Volume | 29 | Issue | 2 | Pages | 129–137 |
| Keywords | hand; aging; friction; apparent stiffness; damping | ||||
| Abstract | Background Mechanical properties of human digits may have significant implications for the hand function. We quantified several mechanical characteristics of individual digits in young and older adults. Methods Digit tip friction was measured at several normal force values using a method of induced relative motion between the digit tip and the object surface. A modified quick-release paradigm was used to estimate digit apparent stiffness, damping, and inertial parameters. The subjects grasped a vertical handle instrumented with force/moment sensors using a prismatic grasp with four digits; the handle was fixed to the table. Unexpectedly, one of the sensors yielded leading to a quick displacement of the corresponding digit. A second-order, linear model was used to fit the force/displacement data. Findings Friction of the digit pads was significantly lower in older adults. The apparent stiffness coefficient values were higher while the damping coefficients were lower in older adults leading to lower damping ratio. The damping ratio was above unity for most data in young adults and below unity for older adults. Quick release of a digit led to force changes in other digits of the hand, likely due to inertial hand properties. These phenomena of “mechanical enslaving” were smaller in older adults although no significant difference was found in the inertial parameter in the two groups. Interpretations The decreased friction and damping ratio present challenges for the control of everyday prehensile tasks. They may lead to excessive digit forces and low stability of the grasped object. |
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| ISSN | 0268-0033 | ISBN | Medium | ||
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Approved | no | |||
| Call Number | Serial | 73 | |||
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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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