Poster No:
431
Submission Type:
Abstract Submission
Authors:
Josiane Mukahirwa1, Qianli Meng1, Keith Schneider1
Institutions:
1University of Delaware, Newark, DE
First Author:
Co-Author(s):
Introduction:
The magnocellular system theory of developmental dyslexia suggests a pervasive dysfunction of the magnocellular system, specialized for temporal processing, throughout the brain (Stein, 2019). However, this has only been extensively investigated in the visual system (Livingston et al.,1991). Here, we measure the contributions of the magnocellular system in the auditory cortex in people with dyslexia compared to normal readers.
Methods:
Using fMRI at 3T, we imaged whole-brain responses in 10 subjects with dyslexia and 11 normal readers as they passively listened to sustained and transient non-linguistic sounds in a block of ~8 s during 8– 40 functional ~5 min runs. Trial-wise estimates for individual subjects were used to perform multi-voxel pattern analyses (MVPA) to discriminate between the sustained and transient responses in localized regions (searchlight) in the whole brain. The results were compared to contrasts between the stimuli obtained with a general linear model (FSL FEAT).
Results:
MVPA group results showed that in the normal readers, regions surrounding Heschl's gyrus (primary auditory cortex) were able to consistently (FWE, p < .05, TFCE) discriminate between the sustained and transient stimuli. In contrast, the subjects with dyslexia exhibited no regions that discriminated above the threshold, although there was consistent subthreshold discriminability in the auditory cortex. However, there were no significant differences between the groups. The GLM contrasts did not exhibit any significant differences between the sustained and transient stimuli or between groups, but there were large areas in the auditory cortex with subthreshold activity within groups.
Conclusions:
Our findings indicate that in normal readers, MVPA but not GLM analyses revealed significant discrimination in the auditory cortex between transient and sustained auditory stimuli, whereas no discrimination exceeded the statistical threshold in the dyslexia group. However, the discrimination differences between groups were not reliable in our small sample.
Disorders of the Nervous System:
Neurodevelopmental/ Early Life (eg. ADHD, autism) 1
Language:
Reading and Writing
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI)
Multivariate Approaches 2
Perception, Attention and Motor Behavior:
Perception: Auditory/ Vestibular
Keywords:
Cortex
FUNCTIONAL MRI
Multivariate
Perception
Univariate
Other - Dyslexia; magnocellular system; transient auditory sounds
1|2Indicates the priority used for review
Provide references using author date format
J. Stein (2019), “The current status of the magnocellular theory of developmental dyslexia,” Neuropsychologia, vol. 130, no. September 2017, pp. 66–77, doi: 10.1016/j.neuropsychologia.2018.03.022.
M. S. Livingstone, G. D. Rosen, F. W. Drislane, and A. M. Galaburda (1991), “Physiological and anatomical evidence for a magnocellular defect in
developmental dyslexia,” Proceedings of the National Academy of Sciences., vol. 88, no. 18, pp.7943–7947, doi: 10.1073/pnas.88.18.7943.