Biology subjects

Vuillaume, L.

Publications and source records attributed to Vuillaume, L..

4 recordsLinked to original sources

bioRxiv2019

SSVEP as a no-report paradigm to capture phenomenal experience of complex visual images

This study is part of a larger attempt to explore how the brain produces conscious experience. Our main objective here was to take advantage of a neural signature conveyed by the steady-state visual evoked potentials (SSVEP) technique (1) to explore the extent to which complex visual images can be processed in the absence of consciousness and (2) to determine whether this tool can be used to shed light on participants phenomenal experience of these images. To this end, we embedded faces within sequences of non-face stimuli and manipulated their contrast to create a subliminal condition. Our results were threefold. First, we show that a significant brain activation can be delineated with the SSVEP tool even when participants report being unable to see the stimuli. In this subliminal condition, the brain response was confined to the back of the scalp. Second, we observe that the face signal increases in magnitude and propagates bilaterally along a posterior-to-anterior axis as image contrast increases. Third, we suggest that SSVEP could be used as a novel instance of a no-report paradigm because it requires no overt behavioural response, and because at some contrast levels and electrodes, its outputs (signal magnitude and scalp topography) predict peoples self-reported phenomenal experience.

neuroscience↗

bioRxiv2019

Comparing self- and hetero-metacognition in the absence of verbal communication

The ability to infer how confident other people are in their decisions is crucial for regulating social interactions. It is unclear whether one can read others confidence in absence of verbal communication and whether one can infer it as accurately as for ones own confidence. To address these questions, we used an auditory task in which participants had to guess the confidence of someone else performing the task or to judge their own confidence in different conditions (i.e., while performing the task themselves or while watching themselves performing the task on a pre-recorded video). Results show that participants are able to guess the confidence of other people as accurately as when judging their own. Crucially, we show that hetero-metacognition is a flexible mechanism relying on different cues according to the context. Our results support the idea that metacognition leverages the same inference mechanisms as involved in theory of mind.

neuroscience↗

bioRxiv2018

Sensorimotor conflicts alter perceptual and action monitoring

Bodily self-consciousness is defined as a set of prereflective representations of integrated bodily signals giving rise to self-identification, self-location and first-person perspective. While bodily self-consciousness is known to modulate perception, little is known about its influence on higher-level cognitive processes. Here, we manipulated bodily self-consciousness by applying sensorimotor conflicts while participants performed a perceptual task followed by confidence judgments. Results showed that sensorimotor conflicts altered perceptual monitoring by decreasing metacognitive performance. In a second experiment, we replicated this finding and extended our results by showing that sensorimotor conflicts also altered action monitoring, as measured implicitly through intentional binding. In a third experiment, we showed that effects on perceptual monitoring were induced specifically by sensorimotor conflicts related to the trunk and not to the hand. Taken together, our results suggest that bodily self-consciousness may serve as a scaffold for perceptual and action monitoring.

neuroscience↗

bioRxiv2018

Waving goodbye to contrast: Self-generated hand movements attenuate visual sensitivity

It is well known that the human brain continuously predicts the sensory consequences of its own body movements, which typically results in sensory attenuation. Yet, the extent and exact mechanisms underlying sensory attenuation are still debated. To explore this issue, we asked participants to decide which of two visual stimuli was of higher contrast in a virtual reality situation where one of the stimuli could appear behind the participants invisible moving hand or not. Over two experiments, we measured the effects of such \"virtual occlusion\" on first-order sensitivity and on metacognitive monitoring. Our findings show that self-generated hand movements reduced the apparent contrast of the stimulus. This result can be explained by the active inference theory. Moreover, sensory attenuation seemed to affect only first-order sensitivity and not (second-order) metacognitive judgments of confidence.

neuroscience↗