title: Dyslexics' faster decay of implicit memory for sounds and words is manifested in their shorter neural adaptation.
abstract: Dyslexia is a prevalent reading disability whose underlying mechanisms are still disputed. We studied the neural mechanisms underlying dyslexia using a simple frequency-discrimination task. Though participants were asked to compare the two tones in each trial, implicit memory of previous trials affected their responses. We hypothesized that implicit memory decays faster among dyslexics. We tested this by increasing the temporal intervals between consecutive trials, and by measuring the behavioral impact and ERP responses from the auditory cortex. Dyslexics showed a faster decay of implicit memory effects on both measures, with similar time constants. Finally, faster decay of implicit memory also characterized the impact of sound regularities in benefitting dyslexics' oral reading rate. Their benefit decreased faster as a function of the time interval from the previous reading of the same non-word. We propose that dyslexics' shorter neural adaptation paradoxically accounts for their longer reading times, since it reduces their temporal window of integration of past stimuli, resulting in noisier and less reliable predictions for both simple and complex stimuli. Less reliable predictions limit their acquisition of reading expertise.
authors.affiliation: Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.|Department of Psychology, Princeton University, Princeton, United States.
authors.forename: Sagi
authors.identifier: 0000-0002-8759-6980
authors.initials: S
authors.lastname: Jaffe-Dax
authors.affiliation: Psychology Department, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Or
authors.initials: O
authors.lastname: Frenkel
authors.affiliation: Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.|Psychology Department, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Merav
authors.initials: M
authors.lastname: Ahissar
mesh_terms: D000328:Adult; D001307:Auditory Perception; D004410:Dyslexia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D010364:Pattern Recognition, Visual; D011932:Reading; D013016:Sound; D055815:Young Adult
keywords: adaptation; auditory perception; dyslexia; event related potential; human; implicit memory; neuroscience