University of Southern California
University of Southern California
Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy
Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy
Redesigning Lives Globally
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Faculty
Faculty

John Margetis OTD, OTR/L

John Margetis

Assistant Professor of Clinical Occupational Therapy

Room: CHP 133
Phone: (323) 442-5370
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Biography

John Margetis specializes in neurologic and critical care rehabilitation with clinical interests in vascular/acquired brain injury, stroke, neuroimaging and neurocognitive dysfunction. In addition to providing direct patient care, Dr. Margetis mentors fellow faculty members, doctoral residents and Levels I and II fieldwork students. During his doctoral residency he authored a position paper defining the role of occupational therapy in acute care settings, and has been an invited lecturer on congenital amputations at USC and Children's Hospital Los Angeles.

Education

Doctorate of Occupational Therapy (OTD)
University of Southern California
2013

Master of Arts (MA) in Occupational Therapy
University of Southern California
2012

Bachelor of Science (BS) in Occupational Therapy
University of Southern California
2011

Bachelor of Arts (BA) in Sociology
University of Southern California
2011

Publications

Journal Articles

Liew, S. L., Sheng, T., Margetis, J. L., & Aziz-Zadeh, L. S. (2013). Both novelty and expertise increase action observation network activity. Frontiers in Human Neuroscience, 7, 541. doi:10.3389/fnhum.2013.00541. Link to full text Abstract →← Abstract 

Our experiences with others affect how we perceive their actions. In particular, activity in bilateral premotor and parietal cortices during action observation, collectively known as the action observation network (AON), is modulated by one's expertise with the observed actions or individuals. However, conflicting reports suggest that AON activity is greatest both for familiar and unfamiliar actions. The current study examines the effects of different types and amounts of experience (e.g., visual, interpersonal, personal) on AON activation. fMRI was used to scan 16 healthy participants without prior experience with individuals with amputations (novices), 11 experienced occupational therapists (OTs) who had varying amounts of experience with individuals with amputations, and one individual born with below-elbow residual limbs (participant CJ), as they viewed video clips of goal-matched actions performed by an individual with residual limbs and by an individual with hands. Participants were given increased visual exposure to actions performed by both effectors midway through the scanning procedure. Novices demonstrated a large AON response to the initial viewing of an individual with residual limbs compared to one with hands, but this signal was attenuated after they received visual exposure to both effectors. In contrast, OTs, who had moderate familiarity with residual limbs, demonstrated a lower AON response upon initial viewing-similar to novices after they received visual exposure. At the other extreme, CJ, who has extreme familiarity with residual limbs both visually and motorically, shows a largely increased left-lateralized AON response, exceeding that of novices and experienced OTs, when viewing the residual limb compared to hand actions. These results suggest that a nuanced model of AON engagement is needed to explain how cases of both extreme experience (CJ) and extreme novelty (novices) can result in the greatest AON activity.