• About
  • Policies
  • What is open access
  • Library
  • Contact
Advanced search
      View Item 
      •   BUIR Home
      • University Library
      • Bilkent Theses
      • Theses - Graduate Program in Neuroscience
      • Graduate Program in Neuroscience - Master's degree
      • View Item
      •   BUIR Home
      • University Library
      • Bilkent Theses
      • Theses - Graduate Program in Neuroscience
      • Graduate Program in Neuroscience - Master's degree
      • View Item
      JavaScript is disabled for your browser. Some features of this site may not work without it.

      Temporal and spatial nonlinearities in FMRI BOLD response in human primary visual cortex

      Thumbnail
      View / Download
      33.1 Mb
      Author(s)
      Benar, Cem
      Advisor
      Boyacı, Hüseyin
      Date
      2019-08
      Publisher
      Bilkent University
      Language
      English
      Type
      Thesis
      Item Usage Stats
      122
      views
      45
      downloads
      Abstract
      It is generally assumed that fMRI BOLD response (i.e., functional magnetic resonance imaging blood-oxygen-level-dependent signal) is linear and time-invariant. In this study, we investigated spatial and temporal nonlinearities in fMRI BOLD response at different flickering durations (nearly instantaneous and 1 s). We presented participants two successive flickering checkerboard wedge stimuli with stimulus onset asynchrony (SOA) of 0 s, 0.5 s, 1.5 s, and 6 s. The spatial locations of the stimuli were categorized as the same location in the same hemifield, adjacent locations in the same hemifield, and between hemifields. We demonstrated that fMRI BOLD response behaves nonlinearly when the successive stimuli spatially and temporally were close to each other for both flickering durations. Nonlinearity between the successive stimuli was the highest for the same location in the same hemifield, higher in adjacent locations in the same hemifield, and the lowest in between hemifields. In addition, nonlinearity at the shorter SOAs (0 s, 0.5 s, and 1.5 s) was found to be higher than nonlinearity at SOA 6.
      Keywords
      Spatial nonlinearity
      Spatial summation
      Temporal nonlinearity
      Temporal summation
      fMRI BOLD
      Primary visual cortex
      Permalink
      http://hdl.handle.net/11693/52297
      Collections
      • Graduate Program in Neuroscience - Master's degree 38
      Show full item record

      Browse

      All of BUIRCommunities & CollectionsTitlesAuthorsAdvisorsBy Issue DateKeywordsTypeDepartmentsThis CollectionTitlesAuthorsAdvisorsBy Issue DateKeywordsTypeDepartments

      My Account

      LoginRegister

      Statistics

      View Usage StatisticsView Google Analytics Statistics

      Bilkent University

      If you have trouble accessing this page and need to request an alternate format, contact the site administrator. Phone: (312) 290 1771
      © Bilkent University - Library IT

      Contact Us | Send Feedback | Off-Campus Access | Admin | Privacy