Neuronal response specificity as a marker of reading proficiency: two-fold nature of the N170 revealed after massive repetition.

Reading demands precise and efficient letter and word processing. This event-related potentials (ERP) study utilized massive repetition of visually presented single letters to trigger neuronal adaptation. Our aim was to explore whether the adaptation pattern of the N170 ERP component, serving as an indicator of neuronal response specificity, would differ for two reader groups. Forty German students, divided at the median into slow and fast readers, accomplished a visual oddball paradigm. ERPs of standard stimuli were computed separately for the first, second, and third part of the experiment. ERP waveforms and independent component analyses showed two subcomponents within the N170 time window. For both reader groups, the ERP amplitudes decreased over the time course of the experiment; however, only faster readers showed a subcomponent-specific adaptation response, restricted to the earlier N170 part. Results may reflect different degrees of neuronal response specificity in slow and fast readers, which might serve as a promising indicator for interindividual differences in visual recognition tasks such as reading.