Turning visual shapes into sounds: Early stages of reading acquisition revealed in the ventral occipitotemporal cortex
2014
NeuroImage
90: 298-307
Authors: 
Perrone-Bertolotti M.
Vidal J.R.
de Palma R.
Hamame C.M.
Ossandon T.
Kahane P.
Minotti L.
Bertrand O.
Lachaux J.P.

The exact role of the left ventral occipitotemporal cortex (VOTC) during the initial stages of reading acquisition is a hotly debated issue, especially regarding the comparative effect of learning on early stimulus-dependent vs. later task-dependent processes. We show that this controversy can be solved with high-temporal resolution intracerebral EEG recordings of the VOTC. We measured High-Frequency Activity (50-150Hz) as a proxy of population-level spiking activity while participants learned Japanese Katakana symbols, and found that learning primarily affects top-down/task-dependent neural processing, after a few minutes only. In contrast, adaptation of early bottom-up/stimulus-dependent processing takes several days to adapt and provides the basis for fluent reading. Such evidence that two consecutive stages of neural processing, stimulus- and task-dependent are differentially affected by learning, can reconcile seemingly opposite hypotheses on the role of the VOTC during reading acquisition.