Neural generators underlying concurrent sound segregation

Abstract

Although an object-based account of auditory attention has become an increasingly popular model for understanding how temporally overlapping sounds are segregated, relatively little is known about the cortical circuit that supports such ability. In the present study, we applied a beamformer spatial filter to magnetoencephalography (MEG) data recorded during an auditory paradigm that used inharmonicity to promote the formation of multiple auditory objects. Using this unconstrained, data-driven approach, the evoked field component linked with the perception of multiple auditory objects (i.e., the objectrelated negativity; ORNm), was found to be associated with bilateral auditory cortex sources that were distinct from those coinciding with the P1m, N1m, and P2m responses elicited by sound onset. The right hemispheric ORNm source in particular was consistently positioned anterior to the other sources across two experiments. These findings are consistent with earlier proposals of multiple auditory object detection being associated with generators in the auditory cortex and further suggest that these neural populations are distinct from the long latency evoked responses reflecting the detection of sound onset. Research highlightsThe ORN is an evoked response that indexes perceptual parsing of concurrent sounds. Using ER-SAM source imaging, the ORN generator was localized. The ORN generator in the right hemisphere was spatially distinct (anterior) from the P1m, N1m, and P2m sources. Distinct neural events index sound onset and concurrent sound segregation.

Stimulus Phase Locking of Cortical Oscillation for Auditory Stream Segregation in Rats

“…8 B ). In addition, there are other possible candidates of the neural correlates of auditory streaming, such as auditory mismatch negativity [75]–[77], object-related negativity [77], [78], stimulus-specific, multiple-time-scale adaptations [79], and stimulus-induced but non-stimulus-locked concerted activities by neuronal ensemble across auditory cortical fields [80], [81]. Furthermore, interactions between cortical and subcortical activities via cortico-fugal connections should be also taken into account [29].…”

Similar sound intensity dependence of the N1 and P2 components of the auditory ERP: Averaged and single trial evidence

“…This time/energy dependent activity suggests that N1 activity is related with the detection and orientation to changes in the auditory environment. This is corroborated by the fact that it is possible to elicit N1-like responses using both the onset and the offset of a given auditory stimulus (Arnott et al, 2011;Hari et al, 1987). At the neuroanatomical level, the N1 was suggested to be a composite wave reflecting the summation of at least three distinct underlying components (McCallum and Curry, 1980;Näätänen and Picton, 1987).…”

“…The P2 is thought to index some aspects of stimulus classification, reflecting primary processes of attentional allocation, perceptual learning, and even memory (Arnott et al, 2011). It has also been suggested that its fronto-central prominence is related to inhibitory processes for interference caused by irrelevant stimulation (Crowley and Colrain, 2004;Dempster, 1992).…”

Effects of age-related hearing loss and background noise on neuromagnetic activity from auditory cortex

“…We chose to model the N1m wave because it was the largest and most reliable deflection from the AEF elicited by the harmonic complex tones. The analysis was performed on the grand average across stimulus types to enhance signal-to-noise ratio and because the differences in source location between the N1m elicited by tuned and mistuned stimuli were expected to be small (Arnott et al, 2011). Peak amplitude and latency were determined as the largest positivity (P) or negativity (N) in the individual source waveforms during a specific interval.…”