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Dissertation defense for Geo Kartheiser to be held September 25, 2018

To:      Students, Faculty and Staff

From:  Gaurav Mathur, Ph.D., Dean of the Graduate School

Re:       Dissertation Defense for Geo Kartheiser

It is my pleasure to announce that George Scott Kartheiser, a Ph.D. candidate in the Ph.D. in Educational Neuroscience (PEN) Program, will defend his dissertation on “Neuroplasticity of spatial working memory in signed language processing” on Tuesday, September 25 at 9 a.m. in the Kellogg Conference Hotel Boardroom.  The first 45 minutes of the dissertation defense are open to the Gallaudet community.

Spatial cognition has been shown to be enhanced in early-exposed deaf signers of signed languages, possibly because signed languages are spatial in nature. However, spatial cognition is generally considered malleable across the lifespan. This raises the question of how age of language exposure impacts the brain’s neural systems when processing a signed language (typically impacted by the age of language exposure)—a language that occurs in space and involves spatial cognition (typically not presumed to be impacted by age of exposure). Mr. Kartheiser’s study addresses whether the age of exposure and proficiency in American Sign Language (ASL) impacts the neural activity related to aspects of spatial working memory required in the processing of signed language. Three groups of hearing, adult signers participated in this study: native signers (adults who had early exposure to ASL); proficient signers (adults with strong signing skills irrespective of age of ASL exposure), and new signers (adults learning ASL for the first time). Participants were recorded with functional Near Infrared Spectroscopy (fNIRS) brain recording while completing a working memory n-back task. As expected, all three groups showed equal behavioral performance (as measured by accuracy) across all n-back conditions. However, only native, early- exposed signers, showed significantly greater brain activity in the left dorsolateral prefrontal cortex, a key brain site for spatial working memory especially with n-back tests, across all n-back conditions and in the right ventrolateral prefrontal cortex for 1-back when compared with proficient and new signers. Taken together, these results show that early exposure to a visuospatial language impacts the way the brain processes spatial information—a finding that suggests that spatial cognition may be vulnerable to sensitive periods in development. The work also carries Educational Neuroscience implications for transformative translation in the possibility that early exposure to a signed language may be used as a way to improve spatial cognition abilities in the general population.

The members of Mr. Kartheiser’s dissertation committee are Professor Laura-Ann Petitto, Ph.D. Program in Educational Neuroscience and Department of Psychology, chair of the dissertation committee; Professor Deborah Chen Pichler, Department of Linguistics; Dr. Clifton Langdon, Ph.D. Program in Educational Neuroscience; Professor Pilar Piñar, World Languages and Cultures Department; and Professor David Uttal, Department of Psychology, Northwestern University.

Since enrolling in the PEN program at its inception in Fall 2013, Mr. Kartheiser has been a graduate research assistant in Dr. Petitto’s Brain & Language Laboratory for Neuroimaging (BL2) and a student-scholar in the National Science Foundation (NSF) Science of Learning Center for Visual Language and Visual Learning (VL2). While in the PEN program, he co-authored three peer-reviewed journal publications and two book chapters. He also co-authored and presented at 15 national and international scientific meetings, including prestigious invited public science lectures at the University of Hong Kong and eight peer-reviewed professional presentations around the world. He is certified in the use of functional near infrared spectroscopy (fNIRS) neuroimaging with infants, children, and adults and in advanced neuroimaging data analysis. He also has also led pioneering work in BL2 on integrating fNIRS with other state-of-the-art scientific technology (eye tracking, thermal imaging to measure human attention and emotional engagement) in order to answer new scientific questions about language acquisition and reading development in infants and children with different language experiences. The findings from some of his pioneering work in BL2 led to the creation of the revolutionary translational learning tool for young babies who are deprived of early-life language input, called RAVE.

Mr. Kartheiser’s neuroimaging training was supported by two grants to his primary advisor, Professor Petitto: a W. M. Keck Foundation grant (“Seeing the rhythmic temporal beats of human language,” Petitto, PI) and a NSF INSPIRE grant (“The RAVE revolution for children with minimal language exposure,” Petitto, PI, IIS-1547178). Additional funding that supported Mr. Kartheiser’s graduate studies came from a NSF VL2 subaward to Professor Petitto (“The impact of early visual language experience on visual attention and visual sign phonology processing,” Petitto, PI, SBE-1041725) and VL2 graduate student research scholarships (Petitto & Allen, CO-PIs, SBE-1041725). Mr. Kartheiser’s dissertation study was supported by a NIH NRSA F31 Individual Predoctoral Fellowship (“Neuroplasticity of Spatial Working Memory in Signed Language Processing”, 5F31DC014230) and a scholarship made possible by the Florence Foederer Fellows Fund at Gallaudet University.

Posted by Elizabeth Gibbons | Posted September 13, 2018 at 12:58 PM

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Gallaudet

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Washington, DC 20002