Biology subjects

Skipper, J. I.

Publications and source records attributed to Skipper, J. I..

23 records · Page 2Linked to original sources

bioRxiv2020

A 'Naturalistic Neuroimaging Database' for understanding the brain using ecological stimuli

Neuroimaging has advanced our understanding of human psychology using reductionist stimuli that often do not resemble information the brain naturally encounters. It has improved our understanding of the network organization of the brain mostly through analyses of resting-state data for which the functions of networks cannot be verifiably labelled. We make a Naturalistic Neuroimaging Database (NNDb v1.0) publically available to allow for a more complete understanding of the brain under more ecological conditions during which networks can be labelled. Eighty-six participants underwent behavioural testing and watched one of 10 full-length movies while functional magnetic resonance imaging was acquired. Resulting timeseries data are shown to be of high quality, with good signal-to-noise ratio, few outliers and low movement. Data-driven functional analyses provide further evidence of data quality. They also demonstrate accurate timeseries/movie alignment and how movie annotations might be used to label networks. The NNDb can be used to answer questions previously unaddressed with standard neuroimaging approaches, progressing our knowledge of how the brain works in the real world.

neuroscience↗

bioRxiv2020

More than words: The online orchestration of word predictability, prosody, gesture, and mouth movements during natural language comprehension

The ecology of human language is face-to-face interaction, comprising cues, like prosody, cospeech gestures, and mouth movements. Yet, the multimodal context is usually stripped away in experiments as dominant paradigms focus on linguistic processing only. In two studies we presented video-clips of an actress producing naturalistic passages to participants whose electroencephalographic activity was recorded. We quantified each cue and determined their effect on a well-established electroencephalographic marker of cognitive load in comprehension (N400). We found that brain responses to words were affected by informativeness of co-occurring multimodal cues, indicating that comprehension relies on linguistic and non-linguistic cues. Moreover, brain responses were affected by interactions between the multimodal cues, indicating that the impact of each cue dynamically changes based on the informativeness of other available cues. Thus, results show that multimodal cues are integral to comprehension, hence, our theories must move beyond the limited focus on speech and linguistic processing.

neuroscience↗

bioRxiv2018

Measuring narrative engagement: The heart tells the story

Stories play a fundamental role in human culture. They provide a mechanism for sharing cultural identity, imparting knowledge, revealing beliefs, reinforcing social bonds and providing entertainment that is central to all human societies. Here we investigated the extent to which the delivery medium of a story (audio or visual) affected conscious and subconscious engagement with the narrative. Although participants self-reported greater involvement for watching video relative to listening to auditory scenes, stronger physiological responses were recorded for auditory stories. Sensors placed at their wrists showed higher and more variable heart rates, greater electrodermal activity, and even higher body temperatures. We interpret these findings as physiological evidence that the stories were more cognitively and emotionally engaging when presented in an auditory format. This may be because listening to a story, rather than watching a video, is a more active process of co-creation, and that this imaginative process in the listeners mind is detectable on the skin at their wrist.

neuroscience↗

bioRxiv2017

A Core Speech Circuit Between Primary Motor, Somatosensory, And Auditory Cortex: Evidence From Connectivity And Genetic Descriptions

What adaptations allow humans to produce and perceive speech so effortlessly? We show that speech is supported by a largely undocumented core of structural and functional connectivity between the central sulcus (CS or primary motor and somatosensory cortex) and the transverse temporal gyrus (TTG or primary auditory cortex). Anatomically, we show that CS and TTG cortical thickness covary across individuals and that they are connected by white matter tracts. Neuroimaging network analyses confirm the functional relevance and specificity of these structural relationships. Specifically, the CS and TTG are functionally connected at rest, during natural audiovisual speech perception, and are coactive over a large variety of linguistic stimuli and tasks. Importantly, across structural and functional analyses, connectivity of regions immediately adjacent to the TTG are with premotor and prefrontal regions rather than the CS. Finally, we show that this structural/functional CS-TTG relationship is mediated by a constellation of genes associated with vocal learning and disorders of efference copy. We propose that this core circuit constitutes an interface for rapidly exchanging articulatory and acoustic information and discuss implications for current models of speech.

neuroscience↗

bioRxiv2017

Brain reorganization in anticipation of predictable words

How is speech understood despite the lack of a deterministic relationship between the sounds reaching auditory cortex and what we perceive? One possibility is that unheard words that are unconsciously activated in association with listening context are used to constrain interpretation. We hypothesized that a mechanism for doing so involves reusing the ability of the brain to predict the sensory effects of speaking associated words. Predictions are then compared to signals arriving in auditory cortex, resulting in reduced processing demands when accurate. Indeed, we show that sensorimotor brain regions are more active prior to words predictable from listening context. This activity resembles lexical and speech production related processes and, specifically, subsequent but still unpresented words. When those words occur, auditory cortex activity is reduced, through feedback connectivity. In less predictive contexts, activity patterns and connectivity for the same words are markedly different. Results suggest that the brain reorganizes to actively use knowledge about context to construct the speech we hear, enabling rapid and accurate comprehension despite acoustic variability.

neuroscience↗