From speech and talkers to the social world: The neural processing of human spoken language

Human speech perception is a paradigm example of the complexity of human linguistic processing; however, it is also the dominant way of expressing vocal identity and is critically important for social interactions. Here, I review the ways that the speech, the talker, and the social nature of speech interact and how this may be computed in the human brain, using models and approaches from nonhuman primate studies. I explore the extent to which domain-general approaches may be able to account for some of these neural findings. Finally, I address the importance of extending these findings into a better understanding of the social use of speech in conversations

The neural control of volitional vocal production-from speech to identity, from social meaning to song

The networks of cortical and subcortical fields that contribute to speech production have benefitted from many years of detailed study, and have been used as a framework for human volitional vocal production more generally. In this article, I will argue that we need to consider speech production as an expression of the human voice in a more general sense. I will also argue that the neural control of the voice can and should be considered to be a flexible system, into which more right hemispheric networks are differentially recruited, based on the factors that are modulating vocal production. I will explore how this flexible network is recruited to express aspects of non-verbal information in the voice, such as identity and social traits. Finally, I will argue that we need to widen out the kinds of vocal behaviours that we explore, if we want to understand the neural underpinnings of the true range of sound-making capabilities of the human voice. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part II)'

Poetry and Neuroscience: : An Interdisciplinary Conversation

Dialogues and collaborations between scientists and non-scientists are now widely understood as important elements of scientific research and public engagement with science. In recognition of this, the authors, a neuroscientist and a poet, use a dialogical approach to extend questions and ideas first shared during a lab-based poetry residency. They recorded a conversation and then expanded it into an essayistic form, allowing divergent disciplinary understandings and uses of experiment, noise, voice and emotion to be articulated, shared and questioned

Careful whispers: when sounds feel like a touch

There are anatomical and functional links between auditory and somatosensory processing. We suggest that these links form the basis for the popular internet phenomenon where people enjoy a sense of touch from auditory (and often audiovisual) stimuli

Error in the Superior Temporal Gyrus? A Systematic Review and Activation Likelihood Estimation Meta-Analysis of Speech Production Studies

Evidence for perceptual processing in models of speech production is often drawn from investigations in which the sound of a talker's voice is altered in real time to induce “errors.” Methods of acoustic manipulation vary but are assumed to engage the same neural network and psychological processes. This paper aims to review fMRI and PET studies of altered auditory feedback and assess the strength of the evidence these studies provide for a speech error correction mechanism. Studies included were functional neuroimaging studies of speech production in neurotypical adult humans, using natural speech errors or one of three predefined speech manipulation techniques (frequency altered feedback, delayed auditory feedback, and masked auditory feedback). Seventeen studies met the inclusion criteria. In a systematic review, we evaluated whether each study (1) used an ecologically valid speech production task, (2) controlled for auditory activation caused by hearing the perturbation, (3) statistically controlled for multiple comparisons, and (4) measured behavioral compensation correlating with perturbation. None of the studies met all four criteria. We then conducted an activation likelihood estimation meta-analysis of brain coordinates from 16 studies that reported brain responses to manipulated over unmanipulated speech feedback, using the GingerALE toolbox. These foci clustered in bilateral superior temporal gyri, anterior to cortical fields typically linked to error correction. Within the limits of our analysis, we conclude that existing neuroimaging evidence is insufficient to determine whether error monitoring occurs in the posterior superior temporal gyrus regions proposed by models of speech production

Pre-SMA activation and the perception of contagiousness and authenticity in laughter sounds

Functional near-infrared spectroscopy and behavioural methods were used to examine the neural basis of the behavioural contagion and authenticity of laughter. We demonstrate that the processing of laughter sounds recruits networks previously shown to be related to empathy and auditory-motor mirror networks. Additionally, we found that the differences in the levels of activation in response to volitional and spontaneous laughter could predict an individual's perception of how contagious they found the laughter to be

Correction to: ‘Robert Provine: the critical human importance of laughter, connections and contagion’ (2022) by Scott et al

One of the authors' names was spelt incorrectly as Addsion Billing instead of Addison Billing. This has now been corrected on the publisher's website

Pushing the envelope: Evaluating speech rhythm with different envelope extraction techniques

The amplitude of the speech signal varies over time, and the speech envelope is an attempt to characterise this variation in the form of an acoustic feature. Although tacitly assumed, the similarity between the speech envelope-derived time series and that of phonetic objects (e.g., vowels) remains empirically unestablished. The current paper, therefore, evaluates several speech envelope extraction techniques, such as the Hilbert transform, by comparing different acoustic landmarks (e.g., peaks in the speech envelope) with manual phonetic annotation in a naturalistic and diverse dataset. Joint speech tasks are also introduced to determine which acoustic landmarks are most closely coordinated when voices are aligned. Finally, the acoustic landmarks are evaluated as predictors for the temporal characterisation of speaking style using classification tasks. The landmark that performed most closely to annotated vowel onsets was peaks in the first derivative of a human audition-informed envelope, consistent with converging evidence from neural and behavioural data. However, differences also emerged based on language and speaking style. Overall, the results show that both the choice of speech envelope extraction technique and the form of speech under study affect how sensitive an engineered feature is at capturing aspects of speech rhythm, such as the timing of vowels

An Alternative Method to Niskin Sampling for Molecular Analysis of the Marine Environment

The development of low-cost, open-source Remotely Operated Vehicle (ROV) systems has provided almost unrestricted access for researchers looking to monitor the marine environment in ever greater resolution. Sampling microbial communities from the marine environment, however, still usually relies on Niskin-bottle sampling (ROV or Conductivity-Temperature-Depth sampler (CTD) based), a method which introduces an inaccuracy and variability that is incompatible with metatranscriptomic analysis, for example. Here, we describe a versatile, easily-replicated platform which achieves in situ mRNA preservation, via the addition of RNAlater to filtered microbial cells, to enhance ROV or CTD functionality