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Author Noy, L.; Alon, U.; Friedman, J.
Title Corrective jitter motion shows similar individual frequencies for the arm and the finger Type Journal Article
Year 2015 Publication Experimental Brain Research Abbreviated Journal Exp Brain Res
Volume 233 Issue 4 Pages (up) 1307-1320
Keywords
Abstract A characteristic of visuomotor tracking of non-regular oscillating stimuli are high-frequency jittery corrective motions, oscillating around the tracked stimuli. However, the properties of these corrective jitter responses are not well understood. For example, does the jitter response show an idiosyncratic signature? What is the relationship between stimuli properties and jitter properties? Is the jitter response similar across effectors with different inertial properties? To answer these questions, we measured participants' jitter frequencies in two tracking tasks in the arm and the finger. Thirty participants tracked the same set of eleven non-regular oscillating stimuli, vertically moving on a screen, once with forward-backward arm movements (holding a tablet stylus) and once with upward-downward index finger movements (with a motion tracker attached). Participants' jitter frequencies and tracking errors varied systematically as a function of stimuli frequency and amplitude. Additionally, there were clear individual differences in average jitter frequencies between participants, ranging from 0.7 to 1.15 Hz, similar to values reported previously. A comparison of individual jitter frequencies in the two tasks showed a strong correlation between participants' jitter frequencies in the finger and the arm, despite the very different inertial properties of the two effectors. This result suggests that the corrective jitter response stems from common neural processes.
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0014-4819 ISBN Medium
Area Expedition Conference
Notes PMID:25630905 Approved no
Call Number Serial 76
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Author Liebermann, D.G.; Goodman, D.
Title Effects of visual guidance on the reduction of impacts during landings Type Journal Article
Year 1991 Publication Ergonomics Abbreviated Journal Ergonomics
Volume 34 Issue 11 Pages (up) 1399-1406
Keywords Adult; Analysis of Variance; Biomechanics; *Cues; Humans; Male; Motor Activity/*physiology; Psychomotor Performance/physiology; Vision, Ocular/*physiology
Abstract While a common view is that vision is essential to motor performance, some recent studies have shown that continuous visual guidance may not always be required within certain time constraints. This study investigated a landing-related task (self-released falls) to assess the extent to which visual information enhances the ability to reduce the impacts at touchdown. Six individuals performed six blocked trials from four height categories in semi-counterbalanced order (5-10, 20-25, 60-65, and 90-95 cm) in vision and no-vision conditions randomly assigned. A series of two-way ANOVA with repeated measures were carried out separately on each dependent variable collapsed over six trials. The results indicated that vision during the flight did not produce softer landings. Indeed, in analysing the first peak (PFP) a main effect for visual condition was revealed in that the mean amplitude was slightly higher when vision was available (F(1,5) = 6.57; p less than 0.05), thus implicating higher forces at impact. The results obtained when the time to the first peak (TFP) was applied showed no significant differences between conditions (F(1,5) less than 1). As expected, in all cases, the analyses yielded significant main effects for the height categories factor. It appears that during self-initiated falls in which the environmental cues are known before the event, visual guidance is not necessary in order to adopt a softer landing strategy.
Address Research Department, Wingate Institute, Israel
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0014-0139 ISBN Medium
Area Expedition Conference
Notes PMID:1800107 Approved no
Call Number Serial 55
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Author Krasovsky, T.; Keren-Capelovitch, T.; Friedman, J.; Weiss, P.L.
Title Self-feeding kinematics in an ecological setting: typically developing children and children with cerebral palsy Type Journal Article
Year 2021 Publication IEEE Transactions on Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society Abbreviated Journal IEEE Trans Neural Syst Rehabil Eng
Volume 29 Issue Pages (up) 1462-1469
Keywords
Abstract Assessment of self-feeding kinematics is seldom performed in an ecological setting. In preparation for development of an instrumented spoon for measurement of self-feeding in children with cerebral palsy (CP), the current work aimed to evaluate upper extremity kinematics of self-feeding in young children with typical development (TD) and a small, age-matched group of children with CP in a familiar setting, while eating with a spoon. METHODS: Sixty-five TD participants and six children diagnosed with spastic CP, aged 3-9 years, fed themselves while feeding was measured using miniature three-dimensional motion capture sensors (trakStar). Kinematic variables associated with different phases of self-feeding cycle (movement time, curvature, time to peak velocity and smoothness) were compared across age-groups in the TD sample and between TD children and those with CP. RESULTS: Significant between-age group differences were identified in movement times, time to peak velocity and curvature. Children with CP demonstrated slower, less smooth self-feeding movements, potentially related to activity limitations. CONCLUSIONS: The identified kinematic variables form a basis for implementation of self-feeding performance assessment in children of different ages, including those with CP, which can be deployed via an instrumented spoon.
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1534-4320 ISBN Medium
Area Expedition Conference
Notes PMID:34280104 Approved no
Call Number Serial 110
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Author Thorpe, A.; Friedman, J.; Evans, S.; Nesbitt, K.; Eidels, A.
Title Mouse Movement Trajectories as an Indicator of Cognitive Workload Type Journal Article
Year 2022 Publication International Journal of Human-Computer Interaction Abbreviated Journal International Journal of Human-Computer Interaction
Volume 38 Issue 15 Pages (up) 1464-1479
Keywords
Abstract Assessing the cognitive impact of user interfaces is a shared focus of human-computer interaction researchers and cognitive scientists. Methods of cognitive assessment based on data derived from the system itself, rather than external apparatus, have the potential to be applied in a range of scenarios. The current study applied methods of analyzing kinematics to mouse movements in a computer-based task, alongside the detection response task, a standard workload measure. Sixty-five participants completed a task in which stationary stimuli were tar;geted using a mouse, with a within-subjects factor of task workload based on the number of targets to be hovered over with the mouse (one/two), and a between-subjects factor based on whether both targets (exhaustive) or just one target (minimum-time) needed to be hovered over to complete a trial when two targets were presented. Mouse movement onset times were slower and mouse movement trajectories exhibited more submovements when two targets were presented, than when one target was presented. Responses to the detection response task were also slower in this condition, indicating higher cognitive workload. However, these differences were only found for participants in the exhaustive condition, suggesting those in the minimum-time condition were not affected by the presence of the second target. Mouse movement trajectory results agreed with other measures of workload and task performance. Our findings suggest this analysis can be applied to workload assessments in real-world scenarios.
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Series Volume Series Issue Edition
ISSN 1044-7318 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 117
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Author Awasthi, B.; Williams, M.A.; Friedman, J.
Title Examining the role of red background in magnocellular contribution to face perception Type Journal Article
Year 2016 Publication PeerJ Abbreviated Journal PeerJ
Volume 4 Issue Pages (up) e1617
Keywords
Abstract This study examines the role of the magnocellular system in the early stages of face perception, in particular sex categorization. Utilizing the specific property of magnocellular suppression in red light, we investigated visually guided reaching to low and high spatial frequency hybrid faces against red and grey backgrounds. The arm movement curvature measure shows that reduced response of the magnocellular pathway interferes with the low spatial frequency component of face perception. This finding provides behavioral evidence for magnocellular contribution to non-emotional aspect of face perception.
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Language en Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2167-8359 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 81
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