Emergence of neural encoding of auditory objects while listening to competing speakers

• DOI: 10.1073/pnas.1205381109
• Publication Date: 2012-07-03T02:45:15Z
• Authors: Nai Ding; Jonathan Z. Simon
• Keywords: Magnetoencephalography; Neural adaptation; Auditory scene analysis; Selective auditory attention; Representation

A visual scene is perceived in terms of objects. Similar ideas have been proposed for the analogous case auditory analysis, although their hypothesized neural underpinnings not yet established. Here, we address this question by recording from subjects selectively listening to one two competing speakers, either different or same sex, using magnetoencephalography. Individual representations are seen speech with each being phase locked rhythm corresponding stream and which can be exclusively reconstructed temporal envelope that stream. The representation attended dominates responses (with latency near 100 ms) posterior cortex. Furthermore, when intensity background speakers separately varied over an 8-dB range, adapts only speaker but speaker, suggesting object-level gain control. In summary, these results indicate concurrent objects, even if spectrotemporally overlapping resolvable at periphery, neurally encoded individually cortex emerge as fundamental representational units top-down attentional modulation bottom-up adaptation.