Biology subjects

Bury, G.

Publications and source records attributed to Bury, G..

4 recordsLinked to original sources

bioRxiv2025

Distinctive neurophysiological correlates of sound onset and offset perception in humans

Accurate detection of sound onsets and offsets is vital for speech perception. Sound-onset event-related potentials (ERPs) have been well-characterised in electroencephalography (EEG) studies, but the characteristics of sound-offset ERPs have often been obscured by temporal confounds in experimental design. Here, two EEG studies were conducted in human listeners performing an interval duration discrimination task with (i) noise intervals in silence or (ii) silent intervals (gaps) in noise. Stimuli used in the active task were also presented under passive listening conditions. This design enabled us to investigate whether features of the offset ERP could be masked by task demands, and whether the usual temporal precedence of the onset cue in a sound influences the relative magnitude and shape of onset and offset ERPs. The morphology of the offset ERP was distinct from that of the onset ERP in both noise and silent interval duration discrimination tasks, even though the roles of onset and offset cues as initial versus final markers of interval duration were reversed. This observation corroborates evidence from animal studies that there are fundamental differences in brain mechanisms of onset and offset perception. In all experimental conditions, the amplitude of the offset ERP was one-third to one-half that of the onset ERP. Differences between active and passive listening conditions were largely explained by enhancement of ERPs for whichever cue (onset or offset) marked the end of the intervals compared in the duration discrimination task. However, this context dependence emerged in earlier ERP waves for offset than onset responses. Key points summaryO_LIOnset and offset event-related potentials (ERPs) differ in morphology and amplitude C_LIO_LIFor both onset and offset ERPs, P200 and later waves depend on behavioural context C_LIO_LIFor offset ERPs only, P100/N100 waves also depend on behavioural context C_LIO_LIEngagement in duration discrimination alters ERPs primarily for end-interval cues C_LI

neuroscience↗

bioRxiv2020

Sustained pupil responses are modulated by predictability of auditory sequences

The brain is highly sensitive to auditory regularities and exploits the predictable order of sounds in many situations, from parsing complex auditory scenes, to the acquisition of language. To understand the impact of stimulus predictability on perception, it is important to determine how the detection of predictable structure influences processing and attention. Here we use pupillometry to gain insight into the effect of sensory regularity on arousal. Pupillometry is a commonly used measure of salience and processing effort, with more perceptually salient or perceptually demanding stimuli consistently associated with larger pupil diameters. In two experiments we tracked human listeners pupil dynamics while they listened to sequences of 50ms tone pips of different frequencies. The order of the tone pips was either random, contained deterministic (fully predictable) regularities (experiment 1, n = 18, 11 female) or had a probabilistic regularity structure (experiment 2, n = 20, 17 female). The sequences were rapid, preventing conscious tracking of sequence structure thus allowing us to focus on the automatic extraction of different types of regularities. We hypothesized that if regularity facilitates processing by reducing processing demands, a smaller pupil diameter would be seen in response to regular relative to random patterns. Conversely, if regularity is associated with heightened arousal and attention (i.e. engages processing resources) the opposite pattern would be expected. In both experiments we observed a smaller sustained (tonic) pupil diameter for regular compared with random sequences, consistent with the former hypothesis and confirming that predictability facilitates sequence processing. Significance statementThe brain is highly sensitive to auditory regularities. To appreciate the impact that detecting predictability has on perception, we need to better understand how a predictable structure influences processing and attention. We recorded listeners pupil responses to sequences of tones that followed either a predictable or unpredictable pattern, as the pupil can be used to implicitly tap into these different cognitive processes. We found that the pupil showed a smaller sustained diameter to predictable sequences, indicating that predictability eased processing rather than boosted attention. The findings suggest that the pupil response can be used to study the automatic extraction of regularities, and that the effects are most consistent with predictability helping the listener to efficiently process upcoming sounds.

neuroscience↗

bioRxiv2019

Pupillometry as an objective measure of sustained attention in young and older listeners

The ability to sustain attention on a task-relevant sound-source whilst avoiding distraction from other concurrent sounds is fundamental to listening in crowded environments. To isolate this aspect of hearing we designed a paradigm that continuously measured behavioural and pupillometry responses during 25-second-long trials in young (18-35 yo) and older (63-79 yo) participants. The auditory stimuli consisted of a number (1, 2 or 3) of concurrent, spectrally distinct tone streams. On each trial, participants detected brief silent gaps in one of the streams whilst resisting distraction from the others. Behavioural performance demonstrated increasing difficulty with time-on-task and with number/proximity of distractor streams. In young listeners (N=20), pupillometry revealed that pupil diameter (on the group and individual level) was dynamically modulated by instantaneous task difficulty such that periods where behavioural performance revealed a strain on sustained attention, were also accompanied by increased pupil diameter. Only trials on which participants performed successfully were included in the pupillometry analysis. Therefore, the observed effects reflect consequences of task demands as opposed to failure to attend.\n\nIn line with existing reports, we observed global changes to pupil dynamics in the older group, including decreased pupil diameter, a limited dilation range, and reduced temporal variability. However, despite these changes, the older group showed similar effects of attentive tracking to those observed in the younger listeners. Overall, our results demonstrate that pupillometry can be a reliable and time-sensitive measure of the effort associated with attentive tracking over long durations in both young and (with some caveats) older listeners.

neuroscience↗

bioRxiv2018

Cardiac afferent activity modulates early neural signature of error detection during skilled performance

Behavioral adaptations during performance rely on predicting and evaluating the consequences of our actions through action monitoring. Previous studies revealed that proprioceptive and exteroceptive signals contribute to error-monitoring processes, which are implemented in the posterior medial frontal cortex. Interestingly, errors trigger changes in autonomic nervous system activity such as pupil dilation or heartbeat deceleration. Yet, the contribution of implicit interoceptive signals of bodily states to error-monitoring during ongoing performance has been overlooked. This is more surprising given the evidence on the relevance of interoceptive signals for the modulation of perceptual, affective and cognitive processes.\n\nWe investigated whether cardiovascular interoceptive signals influence the neural correlates of error processing during performance, with an emphasis on the early stages of error processing. We recorded participants electroencephalography and electrocardiogram during the performance of highly-trained music pieces in musicians. Previous event-related potential (ERP) studies revealed that pitch errors during skilled musical performance are preceded by an error detection signal, the pre-error-negativity (preERN), and followed by a later error positivity (PE). In this study, by combining ERP, source localization and multivariate pattern classification analysis, we found that the error-correct ERP waveform had a larger amplitude within 40-100 ms following errors in the systolic period of the cardiac cycle. This component could be decoded from single-trials, was dissociated from the preERN and PE, and stemmed from the inferior parietal cortex, which is a region implicated in cardiac autonomic regulation. In addition, the cardiac phase influenced behavioral alterations resulting from errors, with a smaller post-error slowing and less perturbed velocity in keystrokes following pitch errors in the systole phase of the cardiac cycle. This study provides the first evidence of preconscious visceral information modulating neural and behavioral responses related to early error monitoring during skilled performance.

neuroscience↗