Neuromagnetic brain activities associated with perceptual categorization and sound-content incongruency: a comparison between monosyllabic words and pitch names

Effects of syllable name change on pitch comparison

Previous research has found that musicians’ pitch judgments, unlike non-musicians’, are influenced by syllable names. Although non-musicians fail to identify absolute pitches, they acknowledge the direction of pitch change. The present experiment investigated whether non-musicians’ judgments of pitch change can be influenced by the direction of syllable name change. Moreover, we examined the spatial, magnitudinal and sequential nature of pitches and syllable names. Participants ( N = 33) were asked to hear two successive tones sung by syllable name and to judge the direction of pitch change by pressing vertically arranged buttons. Participants’ accuracy of pitch change judging was found to be influenced by the direction of syllable name change. However, the response location was not found to interact with pitch change or syllable name change. The distance effect was found in pitches but not in syllable names. A sequence effect was found that trials with early-in-sequence syllable names were responded faster than trials with late-in-sequence syllable names. These results suggest that syllable names can influence non-musicians’ pitch judgments in a relative context. We suggest that it is the sequential order of syllable names that is the product of cultural activities that interfere with the judgment of pitch change.

Music models aberrant rule decoding and reward valuation in dementia

Aberrant rule- and reward-based processes underpin abnormalities of socio-emotional behaviour in major dementias. However, these processes remain poorly characterized. Here we used music to probe rule decoding and reward valuation in patients with frontotemporal dementia (FTD) syndromes and Alzheimer's disease (AD) relative to healthy age-matched individuals. We created short melodies that were either harmonically resolved ('finished') or unresolved ('unfinished'); the task was to classify each melody as finished or unfinished (rule processing) and rate its subjective pleasantness (reward valuation). Results were adjusted for elementary pitch and executive processing; neuroanatomical correlates were assessed using voxel-based morphometry. Relative to healthy older controls, patients with behavioural variant FTD showed impairments of both musical rule decoding and reward valuation, while patients with semantic dementia showed impaired reward valuation but intact rule decoding, patients with AD showed impaired rule decoding but intact reward valuation and patients with progressive non-fluent aphasia performed comparably to healthy controls. Grey matter associations with task performance were identified in anterior temporal, medial and lateral orbitofrontal cortices, previously implicated in computing diverse biological and non-biological rules and rewards. The processing of musical rules and reward distils cognitive and neuroanatomical mechanisms relevant to complex socio-emotional dysfunction in major dementias.