Neural systems involved when attending to a speaker

Abstract

Rememberingwhat a speaker said depends on attention. During conversational speech, the emphasis is onworkingmemory, but listening to a lecture encourages episodicmemory encoding.With simultaneous interference from background speech, the need for auditory vigilance increases.We recreated these context-dependent demands on auditory attention in 2ways. The firstwas to require participants to attend to one speaker in either the absence or presence of a distracting background speaker. The second was to alter the task demand, requiring either an immediate or delayed recall of the content of the attended speech. Across 2 fMRI studies, common activated regions associated with segregating attended from unattended speech were the right anterior insula and adjacent frontal operculum (aI/FOp), the left planum temporale, and the precuneus. In contrast, activity in a ventral right frontoparietal systemwas dependent on both the task demand and the presence of a competing speaker. Additionalmultivariate analyses identified other domain-general frontoparietal systems, where activity increased during attentive listening but was modulated little by the need for speech stream segregation in the presence of 2 speakers. These results make predictions about impairments in attentive listening in different communicative contexts following focal or diffuse brain pathology.