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Behavioral and fMRI Measures of Crossmodal Plasticity Induced by Auditory Sensory Substitution

Citation

Stiles, Noelle Rebecca Barry (2015) Behavioral and fMRI Measures of Crossmodal Plasticity Induced by Auditory Sensory Substitution. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9N29TZP. http://resolver.caltech.edu/CaltechTHESIS:11072014-145237990

Abstract

Thirty nine million people are blind worldwide. Sensory Substitution (SS) attempts to aid the blind by translating images into sound and thereby restoring visual function. Previous studies have found that training on SS generates crossmodal neural changes allowing for activation in early visual regions in response to SS sounds. Unfortunately, training on auditory sensory substitution to become proficient at basic visual tasks takes 1 week to 3 months and even then is slow, inaccurate, and attention-intensive. In this thesis it was studied if SS interpretation could be performed by entirely naive users automatically, and if the crossmodal plasticity engendered through training could be engaged automatically. In contrast to the top-down SS interpretation, we have found that SS interpretation can be effortless and automatic in entirely naive individuals when crossmodally intuitive stimuli that contain crossmodal mappings are used. Crossmodal mappings are pre-existing associations in all individuals of images and sounds that were found to be used for entirely naive interpretation of SS. This result indicates that SS could potentially be made more useful to the blind with appropriate training and translation algorithms. We also studied if the crossmodal plasticity generated by SS training can also be activated automatically in trained blind and sighted device users. We found that crossmodal plasticity engendered through a week of training could be triggered automatically by SS stimuli. This indicates that crossmodal plasticity does not require an attention-intensive task be used and therefore is not entirely top-down cognitive. It might be possible to tap into this automatic processing in visual cortex of SS stimuli to make SS interpretation less effortful and more perceptual following the appropriate training. Overall, this thesis attempts to use SS to understand crossmodal neural processing and plasticity, and to through this broadened knowledge restore some visual function to the entirely blind.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Crossmodal Plasticity; Vision; Audition; Blind
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Computation and Neural Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Shimojo, Shinsuke
Thesis Committee:
  • O'Doherty, John P. (chair)
  • Lester, Henry A.
  • Tsao, Doris Y.
  • Shimojo, Shinsuke
Defense Date:23 September 2014
Funders:
Funding AgencyGrant Number
NSF Graduate Research Fellowship ProgramUNSPECIFIED
Mary Louise Remy Endowed Scholar Award (Philanthropic Educational Organization)UNSPECIFIED
University of Southern California Discovery Scholars PrizeUNSPECIFIED
Caltech Graduate Office Travel AwardsUNSPECIFIED
Della Martin Fund for Discoveries in Mental IllnessUNSPECIFIED
NIH1R21EY023796-01
Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologyUNSPECIFIED
Record Number:CaltechTHESIS:11072014-145237990
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:11072014-145237990
DOI:10.7907/Z9N29TZP
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8720
Collection:CaltechTHESIS
Deposited By: Noelle Stiles
Deposited On:07 Mar 2017 19:42
Last Modified:02 Oct 2017 20:07

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