TY - JOUR T1 - Neural decoding of bistable sounds reveals an effect of intention on perceptual organization JF - bioRxiv DO - 10.1101/206417 SP - 206417 AU - Alexander J. Billig AU - Matthew H. Davis AU - Robert P. Carlyon Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/01/22/206417.abstract N2 - Auditory signals arrive at the ear as a mixture that the brain must decompose into distinct sources, based to a large extent on acoustic properties of the sounds. An important question concerns whether listeners have voluntary control over how many sources they perceive. This has been studied using pure tones H and L presented in the repeating pattern HLH-HLH-, which can form a bistable percept, heard either as an integrated whole (HLH-) or as segregated into high (H-H-) and low (-L—) sequences. Although instructing listeners to try to integrate or segregate sounds affects reports of what they hear, this could reflect a response bias rather than a perceptual effect. We had human listeners (15 males, 12 females) continuously report their perception of such sequences and recorded neural activity using magneto-encephalography. During neutral listening, a classifier trained on patterns of neural activity distinguished between periods of integrated and segregated perception. In other conditions, participants tried to influence their perception by allocating attention either to the whole sequence, or to a subset of the sounds. They reported hearing the desired percept for a greater proportion of time than when listening neutrally. Critically, neural activity supported these reports; stimulus-locked brain responses in auditory cortex were more likely to resemble the signature of segregation when participants tried to hear segregation than when attempting to perceive integration. These results indicate that listeners can influence how many sound sources they perceive, as reflected in neural responses that track both the input and its perceptual organization.Significance Statement Can we consciously influence our perception of the external world? We address this question using sound sequences that can be heard either as coming from a single source, or as two distinct auditory streams. Listeners reported spontaneous changes in their perception between these two interpretations while we recorded neural activity to identify signatures of such integration and segregation. They also indicated that they could, to some extent, choose between these alternatives. This claim was supported by corresponding changes in responses in auditory cortex. By linking neural and behavioral correlates of perception we demonstrate that the number of objects we perceive can depend not only on the physical attributes of our environment, but also on how we intend to experience it.This research was supported by a Medical Research Council Doctoral Training Award Studentship for Alexander J. Billig and by Medical Research Council grant number MC-A060-5PQ70 for Robert P. Carlyon. Alexander J. Billig is currently affiliated with UCL Ear Institute, University College London, United Kingdom, and thanks Timothy D. Griffiths and Ingrid S. Johnsrude for continuing financial support while he wrote this paper. ER -