Brain indices associated with semantic cues prior to and after a word in noise

It is well established that identification of words in noise improves when it is preceded by a semantically related word, but comparatively little is known about the effect of subsequent context in guiding word in noise identification. We build on the findings of a previous behavioural study (Chan & Alain, 2019) by measuring neuro-electric brain activity while manipulating the semantic content of a cue that either preceded or followed a word in noise. Participants were more accurate in identifying the word in noise when it was preceded or followed by a cue that was semantically related. This gain in accuracy coincided with a late positive component, which was time-locked to the word in noise when preceded by a cue and time-locked to the cue when it followed the word in noise. Distributed source analyses of this positive component revealed different patterns in source activity between the two temporal conditions. The effects of relatedness also generated an event-related potential modulation around 400 ms (N400) that was present at cue presentation when it followed the word in noise, but not for the word in noise when preceded by the cue, consistent with findings regarding its sensitivity to signal degradation. Exploratory analyses examined a subset of data based on participants' subjective perceived clarity, which revealed a posterior deflection over the left hemisphere that showed a relatedness effect. We discuss these findings in light of research on prediction as well as a reflective attention framework.