Sustained neural activity correlates with rapid perceptual learning of auditory patterns

Abstract

Recurring structures forming regular patterns are common in sounds. Learning such patterns is thought to be crucial for accurate auditory perceptual organization (scene analysis) and efficient recognition and prediction of sounds. The current study investigated the behavioral and neural signatures of rapid perceptual learning of regular patterns in sounds. In six behavioral and EEG experiments with over 120 human participants from both sexes, we show that individuals are faster to detect regular patterns, are more sensitive to pattern deviations, and are more accurate at judging the temporal order of pattern onset relative to a visual stimulus when patterns are repeated compared to novel. Sustained neural activity indexed perceptual learning in two ways. First, sustained activity increased earlier for repeated compared to novel regular patterns when participants attended to sounds, but not when they ignored them; this earlier response increase mirrored the rapid perceptual learning we observed behaviorally. Second, the magnitude of sustained activity was reduced for repeated compared to novel patterns, independent of whether participants attended to or ignored sounds. The reduction in the magnitude of sustained activity appeared only for later stimulus presentations, suggesting it is not directly related to perceptual learning, but to processes enabled by learning. Our study thus reveals neural markers of perceptual learning of auditory patterns, and of processes that may be related to reduced novelty or better prediction of learned auditory patterns.

A Neural Signature of Regularity in Sound is Reduced in Older Adults

“…For both younger and older adults, we observed that sustained neural activity increased after the onset of a sound pattern relative to sounds without a pattern. Previous work in younger adults has revealed similar increases in sustained activity for different types of patterns, including tone sequences such as those we have utilized here (Gutschalk et al, 2002; Ross et al, 2002; Keceli et al, 2012; Barascud et al, 2016; Sohoglu and Chait, 2016; Teki et al, 2016; Southwell et al, 2017; Herrmann and Johnsrude, 2018b; Southwell and Chait, 2018; Herrmann et al, 2019; Herrmann et al, 2021).…”

“…It is clear from previous work that temporally regular – and thus predictable – structure in sounds that forms a pattern elicits sustained neural activity (Gutschalk et al, 2002; Barascud et al, 2016; Herrmann and Johnsrude, 2018b). However, additional work suggests that the magnitude of pattern-related sustained activity is related to the degree of novelty or predictability of a pattern, such that sustained activity decreases when a pattern is frequently, compared to infrequently, heard (Gutschalk et al, 2007; Herrmann et al, 2021). A reduction in sustained activity in older adults may thus result from reduced processing of the pattern as well as from reduced novelty of the pattern, but further behavioral research is needed to investigate the perceptual consequences of the altered cortical sensitivity observed here.…”

“…Acoustic stimuli were 4-s long sequences that each consisted of 96 pure-tone pips arranged in twelve sets of eight tones each (see also Barascud et al, 2016; Herrmann and Johnsrude, 2018b; Southwell and Chait, 2018; Herrmann et al, 2021). Each set had a duration of 0.333 s. Pips were 0.0417 s in duration with attack and decay times of 0.007 s, and no gap between tones, or sets.…”

“…The detection of a regular pattern in a sound is associated with an increase in a sustained, low-frequency, DC power offset in cortical electroencephalography (EEG) and magnetoencephalography (MEG) recordings (Barascud et al, 2016; Southwell et al, 2017; Herrmann and Johnsrude, 2018b). Sustained neural activity manifests as soon as a pattern, such as repetition of a set of tones, is present (Southwell et al, 2017; Herrmann and Johnsrude, 2018b; Southwell and Chait, 2018; Herrmann et al, 2021). It also manifests for spectrally coherent chord fluctuations (Teki et al, 2016), complex sounds made of isochronous tone sequences (Sohoglu and Chait, 2016), and repeated amplitude or frequency modulations (Gutschalk et al, 2002; Ross et al, 2002; Herrmann and Johnsrude, 2018b; Herrmann et al, 2019).…”