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Online speech processing imposes significant computational demands on the listening brain, the underlying mechanisms of which remain poorly understood. Here, we exploit the perceptual “pop-out” phenomenon (i.e. the dramatic improvement of speech intelligibility after receiving information about speech content) to investigate the neurophysiological effects of prior expectations on degraded speech comprehension. We recorded electroencephalography (EEG) and pupillometry from 21 adults while they rated the clarity of noise-vocoded and sine-wave synthesized sentences. Pop-out was reliably elicited following visual presentation of the corresponding written sentence, but not following incongruent or neutral text. Pop-out was associated with improved reconstruction of the acoustic stimulus envelope from low-frequency EEG activity, implying that improvements in perceptual clarity were mediated via top-down signals that enhanced the quality of cortical speech representations. Spectral analysis further revealed that pop-out was accompanied by a reduction in theta-band power, consistent with predictive coding accounts of acoustic filling-in and incremental sentence processing. Moreover, delta-band power, alpha-band power, and pupil diameter were all increased following the provision of any written sentence information, irrespective of content. Together, these findings reveal distinctive profiles of neurophysiological activity that differentiate the content-specific processes associated with degraded speech comprehension from the context-specific processes invoked under adverse listening conditions.

During pregnancy, a woman will attribute increased abdominal sensations to foetal movement. Surprisingly, many women report anecdotallythat they feel kick-like sensations long after the pregnancy. However, this experience had never been reported in the scientific literature. We designed this survey to obtain a first impression of how common these subjective experiences of phantom kicks are in the Australian community. Results are reported in: Sasan et al. (2021). “Phantom Kicks: Women’s subjective experience of fetal kicks after the postpartum period. Journal of Women’s Health, 30 (1), 36-44. http://doi.org/10.1089/jwh.2019.8191 Please cite the above paper and this listing in Zenodo when using this material. Sasan et al. (2021). “Phantom Kicks: Women’s subjective experience of fetal kicks after the postpartum period. Journal of Women’s Health, 30 (1), 36-44. http://doi.org/10.1089/jwh.2019.8191 Sasan, Ward, Nash, Orchard, Farrell, Hohwy, Jamadar (2021). The phantom kicks survey: Subjective experiences of foetal kicks during and after pregnancy. Zenodo doi:10.5281/zenodo.5595552 &nbsp

A disproportionate amount of research on impulsivity has focused on trait-related aspects rather than state fluctuations. As a result, the relationship between state impulsivity and moment-to-moment behaviour is unclear. Impulsivity is assumed to negatively affect self-control, but an alternative explanation, yet to be tested, could be that changes in state impulsivity and its homeostatic drivers influence the intensity of urges. We tested whether state impulsivity and hunger affected behaviour through a dual-process model, affecting both the experience of various urges, and self-control, using a smartphone-based experience sampling approach. We found that state impulsivity is associated with stronger urges, but we found no evidence of an association with diminished self-control. Being hungry amplifies urges across different types of urges, and both hunger and late hours are negatively related to the likelihood of controlling urges. These findings imply that the influence of hunger is not limited to the food domain, and provide new insight into the role of state impulsivity in daily life. [Abstract copyright: Copyright © 2022 Elsevier Ltd. All rights reserved.]

Perceptual awareness depends upon the way in which we engage with our sensorium. This notion is central to active inference, a theoretical framework that treats perception and action as inferential processes. This variational perspective on cognition formalizes the notion of perception as hypothesis testing and treats actions as experiments that are designed (in part) to gather evidence for or against alternative hypotheses. The common treatment of perception and action affords a useful interpretation of certain perceptual phenomena whose active component is often not acknowledged. In this article, we start by considering Troxler fading – the dissipation of a peripheral percept during maintenance of fixation, and its recovery during free (saccadic) exploration. This offers an important example of the failure to maintain a percept without actively interrogating a visual scene. We argue that this may be understood in terms of the accumulation of uncertainty about a hypothesized stimulus when free exploration is disrupted by experimental instructions or pathology. Once we take this view, we can generalize the idea of using bodily (oculomotor) action to resolve uncertainty to include the use of mental (attentional) actions for the same purpose. This affords a useful way to think about binocular rivalry paradigms, in which perceptual changes need not be associated with an overt movement.

Perception likely results from the interplay between sensory information and top-down signals. In this electroencephalography (EEG) study, we utilised the hierarchical frequency tagging (HFT) method to examine how such integration is modulated by expectation and attention. Using intermodulation (IM) components as a measure of nonlinear signal integration, we show in three different experiments that both expectation and attention enhance integration between top-down and bottom-up signals. Based on a multispectral phase coherence (MSPC) measure, we present two direct physiological measures to demonstrate the distinct yet related mechanisms of expectation and attention, which would not have been possible using other amplitude-based measures. Our results link expectation to the modulation of descending signals and to the integration of top-down and bottom-up information at lower levels of the visual hierarchy. Meanwhile, the results link attention to the modulation of ascending signals and to the integration of information at higher levels of the visual hierarchy. These results are consistent with the predictive coding account of perception., Perception is believed to result from the integration of sensory information with pre-existing information available in the brain. This study provides direct neurophysiological evidence showing how expectation and attention increase such integration of top-down and bottom-up neural signals in perception.

In visual search of natural scenes, differentiation of briefly fixated but task-irrelevant distractor items from incidental memory is often comparable to explicit memorization. However, many characteristics of incidental memory remain unclear, including the capacity for its conscious retrieval. Here, we examined incidental memory for faces in either upright or inverted orientation using Rapid Serial Visual Presentation (RSVP). Subjects were instructed to detect a target face in a sequence of 8-15 faces cropped from natural scene photographs (Experiment 1). If the target face was identified within a brief time window, the subject proceeded to an incidental memory task. Here, subjects used incidental memory to discriminate between a probe face (a distractor in the RSVP stream) and a novel, foil face. In Experiment 2 we reduced scene-related semantic coherency by intermixing faces from multiple scenes and contrasted incidental memory with explicit memory; a condition where subjects actively memorised each face from the sequence without searching for a target. In both experiments, we measured objective performance (Type 1 AUC) and metacognitive accuracy (Type 2 AUC) revealing sustained and consciously accessible incidental memory for upright and inverted faces. In novel analyses of face categories, we examined whether accuracy or metacognitive judgements are affected by shared semantic features (i.e., similarity in gender, race, age). Similarity enhanced the accuracy of incidental memory discriminations but did not influence metacognition. We conclude that incidental memory is sustained and consciously accessible, is not reliant on scene contexts, and not enhanced by explicit memorization.