Changes in FMRI resting state networks due to audiovisual association induced effects on visual motion perception
Author(s)
Advisor
Kafalıgönül, Hacı HulusiDate
2016-08Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Associative learning, the process by which an association between two stimuli or
a behavior and a stimulus is learned, is one of today's exciting and important
topics of neuroscience. The in
uence of multisensory associations on perceptual
experience has revealed unexpected levels of sensory plasticity in the adult brain.
By using an audiovisual association paradigm, we designed experiments to assess
motion perception and BOLD activity under various associative learning conditions.
Eleven subjects (3 males) participated in the audiovisual association
training followed by resting state fMRI scans. Before and after the association
training, random-dot motion with varying coherence values and static tones of
distinct frequencies were presented. Subjects were required to indicate the direction
of random-dot motion. During the association phase, random-dots moving
up or down with 100% coherence was paired with either high or low frequency
static tone. The behavioral data showed that the perception of random-dot motion
with low coherence was signi cantly changed in favor of exposed audiovisual
association. The analyses on resting state functional data indicated that identi-
ed canonical networks (i.e., visual, auditory, sensory, motor, executive, memory,
and default mode) did not di er signi cantly between pre- and post- association
training, and inter-hemispheric coherence values between early stage visual
motion areas were not increased. On the other hand, the connectivity strength
between auditory and visual networks increased signi cantly after the acquired
audiovisual association. Accordingly, these ndings suggest that even brief association
training can lead to changes in connectivity between low-level sensory
areas.
Keywords
Multisensory associationResting state
Functional connectivity
Motion discrimination
Sensory plasticity