Scientific Article
previous document  unige:25804  next document
add to browser collection

Altered low-γ sampling in auditory cortex accounts for the three main facets of dyslexia

Lehongre, Katia
Ramus, Franck
Villiermet, Nadège
Schwartz, Denis
Published in Neuron. 2011, vol. 72, no. 6, p. 1080-90
Abstract It has recently been conjectured that dyslexia arises from abnormal auditory sampling. What sampling rate is altered and how it affects reading remains unclear. We hypothesized that by impairing phonemic parsing abnormal low-gamma sampling could yield phonemic representations of unusual format and disrupt phonological processing and verbal memory. Using magnetoencephalography and behavioral tests, we show in dyslexic subjects a reduced left-hemisphere bias for phonemic processing, reflected in less entrainment to ≈30 Hz acoustic modulations in left auditory cortex. This deficit correlates with measures of phonological processing and rapid naming. We further observed enhanced cortical entrainment at rates beyond 40 Hz in dyslexics and show that this particularity is associated with a verbal memory deficit. These data suggest that a single auditory anomaly, i.e., phonemic oversampling in left auditory cortex, accounts for three main facets of the linguistic deficit in dyslexia.
Keywords Acoustic Stimulation/methodsAuditory Cortex/physiologyAuditory Perception/physiologyBrain Waves/physiologyDyslexia/diagnosis/physiopathologyElectroencephalography/methodsHumansReaction Time/physiology
PMID: 22196341
Full text
Article (Published version) (857 Kb) - public document Free access
(ISO format)
LEHONGRE, Katia et al. Altered low-γ sampling in auditory cortex accounts for the three main facets of dyslexia. In: Neuron, 2011, vol. 72, n° 6, p. 1080-90. doi: 10.1016/j.neuron.2011.11.002

465 hits



Deposited on : 2013-01-22

Export document
Format :
Citation style :