![]() ![]() These findings have led to the proposal that amusics have normal implicit processing of pitch information, but lack conscious access to it ( Norman-Haignere et al., 2016 Peretz, 2016). This is supported by EEG research showing intact early preattentive responses to pitch deviants in amusics, but diminished late responses associated with higher order processing and conscious perception ( Moreau et al., 2013 Peretz et al., 2005, 2009 Zendel et al., 2015). Previous research has linked congenital amusia with disrupted functional and structural connections between temporal and frontal areas implicated in auditory sequence processing ( Albouy et al., 2013 Hyde et al., 2011 Loui et al., 2009). This question is of particular interest given the neural profile of the condition. ![]() Given the pitch specificity of this condition, the question arises: do amusic listeners encode the uncertainty of pitch sequences and, if so, do they do it differently than normal listeners? ![]() Amusic listeners are impaired in pitch discrimination, pitch memory, and pitch production ( Ayotte et al., 2002 Graves et al., 2019 Peretz et al., 2002). One population of interest in this regard are listeners with congenital amusia, a condition that disrupts the processing of pitch information. Studying this type of listeners is of relevance because it could provide valuable information about the auditory processes that underlie the encoding of uncertainty and its modulatory effects. However, very little is known about how this ability changes in listeners with abnormal auditory function. This modulatory effect of uncertainty is often seen as a precision-weighting mechanism that adjusts the balance between top-down predictions and bottom-up sensory signals according to their reliability ( Clark, 2013 Feldman & Friston, 2010 Hohwy, 2012).Ī growing body of evidence suggests that listeners encode the degree of uncertainty of auditory signals ( Barascud et al., 2016 Bianco et al., 2019, 2020 Garrido et al., 2013 Hsu et al., 2015 Lumaca et al., 2019 Quiroga-Martinez et al., 2019a, 2019b Sohoglu & Chait, 2016 Southwell & Chait, 2018). In the example above, this implies that a wrong or out-of-tune note would be heard more prominently if the melody were repetitive and thus highly predictable. Crucially, the salience of a surprising sound and the strength of the neural responses that it generates are dependent on the uncertainty of the context ( Quiroga-Martinez et al., 2019a, 2019b). When contradicted, these expectations give rise to prediction error responses in the brain, which are taken to reflect the update of its internal model of the auditory signal ( Friston, 2005 Friston et al., 2020 Vuust et al., 2018). When hearing a melody, for example, we constantly generate expectations about the features of upcoming sounds ( Huron, 2006). Prediction plays an important role in listening. ![]() However, our findings also hint at pitch-specific impairments in this population when uncertainty is high, thus suggesting that pitch processing under high uncertainty conditions requires an intact frontotemporal loop. The present results thus indicate that amusics are sensitive to the uncertainty of melodic sequences and that preattentive auditory change detection is greatly spared in this population across sound features and levels of predictability. However, in contrast to previous studies, pitch MMN responses in amusics were disrupted in high complexity and unfamiliar melodies. No significant group-by-complexity or group-by-familiarity interactions were detected. In both participant groups, we observed reduced MMN amplitudes and longer peak latencies for all sound features with increasing levels of complexity, and putative familiarity effects only for intensity deviants. We recorded mismatch negativity (MMN) responses to pitch, intensity, timbre, location, and rhythm deviants as a measure of auditory surprise. 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. 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. 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 non-musician listeners. 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. In typical listeners, the perceptual salience of a surprising auditory event depends on the uncertainty of its context. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |