TY - JOUR T1 - Reduced functional connectivity between left frontal and right auditory cortices during speech perception in congenital amusia JF - bioRxiv DO - 10.1101/834366 SP - 834366 AU - Kyle Jasmin AU - Fred Dick AU - Lauren Stewart AU - Adam Tierney Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/11/08/834366.abstract N2 - Congenital amusia is a condition characterized by disordered perception of and memory for pitch. Investigations of amusia’s neural basis have typically used musical or tonal tasks to demonstrate reduced connectivity between frontal and auditory cortices within the right hemisphere. However, pitch is not only a musical property, but is also an important aspect of spoken language — one which amusics, presumably because of their impairment, tend to rely on less than non-amusic adults. It is an open question whether amusics’ decreased reliance on pitch for speech shares the same right hemispheric neural substrate as their music-related deficits. Here we used functional magnetic resonance imaging to scan 15 individuals with amusia and 15 non-amusic controls while they performed a speech categorization task (intonational phrase boundary detection). On each trial, participants matched auditory and visual sentences by relying on pitch cues, duration cues, or both combined. We used a data-driven analysis to identify the strongest functional connectivity differences between the amusics and controls. Group differences in global functional connectivity (Control > Amusia) were strongest in four regions in lateral prefrontal cortex. Connectivity with these ‘seed’ regions was examined with respect to the rest of the brain. Participants with amusia showed prominent decreases in functional connectivity between language-related regions (left inferior and middle frontal gyrus/DLPFC) and pitch-related regions (right auditory and anterior insular cortex). No connectivity differences between the cue conditions were detected and no condition-by-group interactions were found, suggesting that decreased functional connectivity in amusia persisted irrespective of which acoustic cues judgments were based on. There were also no group differences in degree of task-related activation. We conclude that functional connectivity between left—as well as right—frontal cortex and pitch-related right hemisphere regions is decreased in amusia, and suggest this decreased connectivity may reflect amusics’ strategic downweighting of pitch information during processing of spoken language. Our results also suggest that individual differences in auditory abilities relating to specific dimensions (such as pitch) are reflected in differential functional connectivity between regions that process those dimensions. ER -