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Author Dempsey-Jones, H.; Wesselink, D.B.; Friedman, J.; Makin, T.R. pdf  url
doi  openurl
  Title Organized Toe Maps in Extreme Foot Users Type Journal Article
  Year 2019 Publication (up) Cell Reports Abbreviated Journal Cell Reports  
  Volume 28 Issue 11 Pages 2748-2756.e4  
  Keywords  
  Abstract Although the fine-grained features of topographic maps in the somatosensory cortex can be shaped by everyday experience, it is unknown whether behavior can support the expression of somatotopic maps where they do not typically occur. Unlike the fingers, represented in all primates, individuated toe maps have only been found in non-human primates. Using 1-mm resolution fMRI, we identify organized toe maps in two individuals born without either upper limb who use their feet to substitute missing hand function and even support their profession as foot artists. We demonstrate that the ordering and structure of the artists’ toe representation mimics typical hand representation. We further reveal “hand-like” features of activity patterns, not only in the foot area but also similarly in the missing hand area. We suggest humans may have an innate capacity for forming additional topographic maps that can be expressed with appropriate experience.  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2211-1247 ISBN Medium  
  Area Expedition Conference  
  Notes doi: 10.1016/j.celrep.2019.08.027 Approved no  
  Call Number Serial 99  
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Author Nahab, Fatta; Kundu, Prantik; Gallea, Cecile; Kakareka, John; Pursley, Randy; Pohida, Tom; Miletta, Nathaniel; Friedman, Jason; Hallett, Mark pdf  doi
openurl 
  Title The neural processes underlying self-agency Type Journal Article
  Year 2011 Publication (up) Cerebral Cortex Abbreviated Journal  
  Volume 21 Issue 1 Pages 48-55  
  Keywords  
  Abstract Self-agency (SA) is the individual’s perception that an action is the consequence of his/her own intention. The neural networks underlying SA are not well understood. We carried out a novel, ecologically valid, virtual-reality experiment using BOLD-fMRI where SA could be modulated in real-time while subjects performed voluntary finger movements. Behavioral testing was also performed to assess the explicit judgment of SA. Twenty healthy volunteers completed the experiment. Results of the behavioral testing demonstrated paradigm validity along with the identification of a bias that led subjects to over- or underestimate the amount of control they had. The fMRI experiment identified two discrete networks. These leading and lagging networks likely represent a spatial and temporal flow of information, with the leading network serving the role of mismatch detection and the lagging network receiving this information and

mediating its elevation to conscious awareness, giving rise to SA.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Penn State @ write.to.jason @ Serial 21  
Permanent link to this record
 

 
Author Park, J.; Pazin, N.; Friedman, J.; Zatsiorsky, V.M.; Latash, M.L. pdf  url
doi  openurl
  Title Mechanical properties of the human hand digits: Age-related differences Type Journal Article
  Year 2014 Publication (up) 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.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  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 Raveh, E.; Friedman, J.; Portnoy, S. pdf  url
doi  openurl
  Title Evaluation of the effects of adding vibrotactile feedback to myoelectric prosthesis users on performance and visual attention in a dual-task paradigm Type Journal Article
  Year 2018 Publication (up) Clinical Rehabilitation Abbreviated Journal Clin Rehabil  
  Volume 99 Issue 11 Pages 2263-2270  
  Keywords  
  Abstract Objective: To evaluate the effects of adding vibrotactile feedback to myoelectric prosthesis users on the performance time and visual attention in a dual-task paradigm.

Design: A repeated-measures design with a counterbalanced order of two conditions.

Setting: Laboratory setting.

Subjects: Transradial amputees using a myoelectric prosthesis with normal or corrected eyesight (N=12, median age=65 ± 13 years). Exclusion criteria were orthopedic or neurologic problems.

Interventions: Subjects performed grasping tasks with their prosthesis, while controlling a virtual car on a road with their intact hand. The dual task was performed twice: with and without vibrotactile feedback.

Main measures: Performance time of each of the grasping tasks and gaze behavior, measured by the number of times the subjects shifted their gaze toward their hand, the relative time they applied their attention to the screen, and percentage of error in the secondary task.

Results: The mean performance time was significantly shorter (P=0.024) when using vibrotactile feedback (93.2 ± 9.6 seconds) compared with the performance time measured when vibrotactile feedback was not available (107.8 ± 20.3seconds). No significant differences were found between the two conditions in the number of times the gaze shifted from the screen to the hand, in the time the subjects applied their attention to the screen, and in the time the virtual car was off-road, as a percentage of the total game time

(51.4 ± 15.7 and 50.2 ± 19.5, respectively).

Conclusion: Adding vibrotactile feedback improved performance time during grasping in a dual-task paradigm. Prosthesis users may use vibrotactile feedback to perform better during daily tasks, when multiple cognitive demands are present.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0269-2155 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Penn State @ write.to.jason @ Serial 89  
Permanent link to this record
 

 
Author Awasthi, Bhuvanesh; Friedman, Jason; Williams, Mark A pdf  doi
openurl 
  Title Reach Trajectories Reveal Delayed Processing of Low Spatial Frequency Faces in Developmental Prosopagnosia Type Journal Article
  Year 2012 Publication (up) Cognitive Neuroscience Abbreviated Journal  
  Volume 3 Issue 2 Pages 120-130  
  Keywords  
  Abstract Developmental prosopagnosia (DP) is characterized by a selective deficit in face recognition despite normal cognitive and neurological functioning. Previous research has established configural processing deficits in DP subjects. Low spatial frequency (LSF) information subserves configural face processing. Using hybrid stimuli, here we examined the evolution of perceptual dynamics and integration of LSF information by DP subjects while they pointed to high spatial frequency (HSF) face targets. Permutation analysis revealed a 230-ms delay in LSF processing by DP subjects as compared to controls. This delayed processing is likely to contribute to the difficulties associated with face recognition in DP subjects and is reflective of their alleged reliance on local rather than global features in face perception. These results suggest that quick and efficient processing of LSF information is critical for the development of normal face perception.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Penn State @ write.to.jason @ Serial 27  
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