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| Author | Awasthi, B.; Sowman, P.F.; Friedman, J.; Williams, M.A. | ||||
| Title | Distinct spatial scale sensitivities for early categorisation of Faces and Places: Neuromagnetic and Behavioural Findings | Type | Journal Article | ||
Year  |
2013 | Publication | Frontiers in Human Neuroscience | Abbreviated Journal | |
| Volume | 7 | Issue | 91 | Pages | |
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| Abstract | Research exploring the role of spatial frequencies in rapid stimulus detection and categorisation report flexible reliance on specific spatial frequency bands. Here, through a set of behavioural and magnetoencephalography (MEG) experiments, we investigated the role of low spatial frequency (LSF)(25 cpf) information during the categorisation of faces and places. Reaction time measures revealed significantly faster categorisation of faces driven by LSF information, while rapid categorisation of places was facilitated by HSF information. The MEG study showed significantly earlier latency of the M170 component for LSF faces compared to HSF faces. Moreover, the M170 amplitude was larger for LSF faces than for LSF places, whereas the reverse pattern was evident for HSF faces and places. These results suggest that spatial frequency modulates the processing of category specific information for faces and places. | ||||
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| ISSN | 1662-5161 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 67 | |||
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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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| Notes | Approved | no | |||
| Call Number | Serial | 70 | |||
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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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| Series Volume | Series Issue | Edition | |||
| ISSN | 0268-0033 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 73 | |||
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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 | 1307-1320 |
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| 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 | Portnoy, S.; Rosenberg, L.; Alazraki, T.; Elyakim, E.; Friedman, J. | ||||
| Title | Differences in Muscle Activity Patterns and Graphical Product Quality in Children Copying and Tracing Activities on Horizontal or Vertical Surfaces | Type | Journal Article | ||
| Year |
2015 | Publication | Journal of Electromyography and Kinesiology | Abbreviated Journal | Journal of Electromyography and Kinesiology |
| Volume | 25 | Issue | 3 | Pages | 540�547 |
| Keywords | Motor equivalence; Electromyography; Tablet; Occupational Therapy; Muscle fatigue; Motor control | ||||
| Abstract | The observation that a given task, e.g. producing a signature, looks similar when created by different motor commands and different muscles groups is known as motor equivalence. Relatively little data exists regarding the characteristics of motor equivalence in children. In this study, we compared the level of performance when performing a tracing task and copying figures in two common postures: while sitting at a desk and while standing in front of a wall, among preschool children. In addition, we compared muscle activity patterns in both postures. Specifically, we compared the movements of 35 five- to six-year old children, recording the same movements of copying figures and path tracing on an electronic tablet in both a horizontal orientation, while sitting, and a vertical orientation, while standing. Different muscle activation patterns were observed between the postures, however no significant difference in the performance level was found, providing evidence of motor equivalence at this young age. The study presents a straightforward method of assessing motor equivalence that can be extended to other stages of development as well as motor disorders. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1050-6411 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 77 | |||
| Permanent link to this record | |||||