Listeners with congenital amusia are sensitive to context uncertainty in melodic sequences

International audienceIn typical listeners, the perceptual salience of a surprising auditory event depends on the uncertainty of its context. For example, in melodies, pitch deviants are more easily detected and generate larger neural responses when the context is highly predictable than when it is less so. However, it is not known whether amusic listeners with abnormal pitch processing are sensitive to the degree of uncertainty of pitch sequences and, if so, whether they are to a different extent than typical listeners. To answer this question, we manipulated the uncertainty of short melodies while participants with and without congenital amusia underwent EEG recordings in a passive listening task. Uncertainty was manipulated by presenting melodies with different levels of complexity and familiarity, under the assumption that simpler and more familiar patterns would enhance pitch predictability. We recorded mismatch negativity (MMN) responses to pitch, intensity, timbre, location, and rhythm deviants as a measure of auditory surprise. We found reduced MMN amplitudes and longer peak latencies for all sound features with increasing levels of complexity, and putative familiarity effects only for intensity deviants. No significant group-by-complexity or group-byfamiliarity interactions were detected. However, in amusics, pitch MMN responses peaked later and were disrupted in high complexity and unfamiliar melodies. Our results indicate that amusics are sensitive to the uncertainty of melodic sequences and hint at pitch-specific impairments in this population when uncertainty is high. As previous research has linked amusia with abnormal frontotemporal connectivity, our findings potentially suggest that processing pitch under high uncertainty conditions requires an intact frontotemporal loop