Decision making and ambiguity in auditory stream segregation

Abstract

Researchers of auditory stream segregation have largely taken a bottom-up view on the link between physical stimulus parameters and the perceptual organization of sequences of ABAB sounds. However, in the majority of studies, researchers have relied on the reported decisions of the subjects regarding which of the predefined percepts (e.g., one stream or two streams) predominated when subjects listened to more or less ambiguous streaming sequences. When searching for neural mechanisms of stream segregation, it should be kept in mind that such decision processes may contribute to brain activation, as also suggested by recent human imaging data. The present study proposes that the uncertainty of a subject in making a decision about the perceptual organization of ambiguous streaming sequences may be reflected in the time required to make an initial decision. To this end, subjects had to decide on their current percept while listening to ABAB auditory streaming sequences. Each sequence had a duration of 30 s and was composed of A and B harmonic tone complexes differing in fundamental frequency (ΔF). Sequences with seven different ΔF were tested. We found that the initial decision time varied non-monotonically with ΔF and that it was significantly correlated with the degree of perceptual ambiguity defined from the proportions of time the subjects reported a one-stream or a two-stream percept subsequent to the first decision. This strong relation of the proposed measures of decision uncertainty and perceptual ambiguity should be taken into account when searching for neural correlates of auditory stream segregation.

Task rule and choice are reflected by layer-specific processing in rodent auditory cortical microcircuits

“…Some studies have suggested layer-specific differences in the representation of auditory information along the vertical axis of the auditory cortex (Bandyopadhyay et al, 2010;Li et al, 2014;Tischbirek et al, 2019). In agreement, a growing body of human imaging studies has shown attention and task-related modulation of auditory processing in the A1 (Deike et al, 2015;Häkkinen and Rinne, 2018;Petkov et al, 2004;Puschmann et al, 2017) based on gross neural or metabolic response measures. However, how the canonical principles of the columnar processing are reflected in the aforementioned multiplexed function of the A1 is very much unknown (Ohl, 2015;King et al, 2018).…”

Auditory stream segregation of iterated rippled noises by normal-hearing and hearing-impaired listeners

“…This pattern of buildup of streaming decisions was not supported, however, by Deike et al (2012) for complex tone stimuli. The ambiguity region of frequency difference may be influenced by more cognitive than sensory factors, such as interpretation of instructions or attentional influences (Carlyon et al, 2001;Micheyl and Oxenham, 2010;Deike et al, 2015). Most studies of auditory stream segregation have focused on the effects of variable stimulus parameters and task demands on the streaming tendencies of normal-hearing listeners.…”

Task rule and choice are reflected by layer-specific processing in rodent auditory cortical microcircuits

“…Some studies have suggested layer-specific differences in the representation of auditory information along the vertical axis of the auditory cortex, with granular layers revealing more accurate tonotopic response properties due to the dominant lemniscal inputs compared to supragranular and infragranular layers [13][14][15] . In addition, a growing body of human imaging studies has shown attention and task-related modulation of auditory processing in the A1 [16][17][18][19] based on gross neural or metabolic response measures. However, how the canonical principles of the columnar processing are reflected in the aforementioned multiplexed function of the A1 is very much unknown 9,20 .…”