Alpha suppression and connectivity modulations in left temporal and parietal cortices index partial awareness of words.
Neuroimage June 1, 2016 Lorenzo Magazzini, Philipp Ruhnau, Nathan Weisz
The partial awareness hypothesis proposes that people can become conscious of distinct properties of an object independently, from low-level features to complex forms. In a visual word masking experiment adjusted to each participant's perception threshold, participants perceived individual letters but not whole words in about half of trials, corresponding to partial awareness. Magnetoencephalography (MEG) recordings showed that partial awareness, compared to no awareness, involved suppression of alpha oscillations in left temporal and parietal cortices. Functional connectivity analysis revealed strong connections between the temporal seed and other language network regions. The findings suggest that engagement of language regions, indexed by alpha power suppression, establishes and maintains conscious representations of pre-lexical units.