First-person body view modulates the neural substrates of episodic memory and autonoetic consciousness: A functional connectivity study

Episodic memory (EM) is classically conceived as a memory for events, localized in space and time, and characterized by autonoetic consciousness (ANC) allowing to mentally travel back in time and subjectively relive an event. Building on recent evidence that the first-person visual co-perception of one's own body during encoding impacts EM, we used a scene recognition task in immersive virtual reality (VR) and measured how first-person body view would modulate peri-encoding resting-state fMRI, EM performance, and ANC. Specifically, we investigated the impact of body view on post-encoding functional connectivity in an a priori network of regions related either to EM or multisensory bodily processing and used these regions in a seed-to-whole brain analysis. Post-encoding connectivity between right hippocampus (rHC) and right parahippocampus (rPHC) was enhanced when participants encoded scenes while seeing their body. Moreover, the strength of connectivity between the rHC, rPHC and the neocortex displayed two main patterns with respect to body view. The connectivity with a sensorimotor fronto-parietal network, comprising primary somatosensory and primary motor cortices, correlated with ANC after - but not before - encoding, depending on body view. The opposite change of connectivity was found between rHC, rPHC and the medial parietal cortex (from being correlated with ANC before encoding to an absence of correlation after encoding), but irrespective of body view. Linking immersive VR and fMRI for the study of EM and ANC, these findings suggest that seeing one's own body during encoding impacts the brain activity related to EM formation by modulating the connectivity between the right hippocampal formation and the neocortical regions involved in the processing of multisensory bodily signals and self-consciousness.

Underlying mechanisms of episodic autobiographical memory and self-consciousness

Lucie Bréchet

Cognitive neuroscience has been examining consciousness associated with the subject, that is the self of the conscious experience and its related multisensory processing of bodily signals, the so-called bodily self-consciousness. Different line of research has highlighted the concept of the autobiographical self in memory and the associated autonoetic consciousness, that is the human ability to mentally travel in time. The subjective re-experiencing of past episodes is often described as re-living them from a viewpoint and location that is similar to the initial encoding. In the first part of my thesis, I have studied how self-relevant bodily cues and personal memories influence our sense of self. In the second part, I have examined how the self is involved in spontaneous thoughts. Through a collection of four studies, I will argue here that it is possible to explore the underlying characteristics of self-consciousness and its relation to bodily signals and memory by a number of cognitive neuroscience approaches, including virtual reality (VR), electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). First, I investigated how the presence or absence of multisensory bodily cues influences long-term episodic autobiographical memory by using immersive VR environment. Second, I examined the underlying brain mechanisms of bodily-self and autobiographical-self by combining a meta-analytical approach with recent fMRI results from (a) patients suffering with out-of-body experiences and (b) healthy participants with induced illusory states of bodily self. Third, I explored how the immersive VR technology can be used to selectively and retroactively strengthen episodic autobiographical memory. Fourth, I examined whether it is possible to capture the inner, self-relevant conscious thoughts and record them with both fMRI and EEG methods. The results from my thesis indicate that (a) the bodily cues fundamentally influence the autobiographical memory and (b) it is possible to manipulate the self-related nature of conscious thoughts. I will discuss my findings with reference to current understanding of bodily-self, autobiographical-self and their links to theories of self-consciousness. Finally, based on my results, I will suggest what should be the following, future step towards memory prosthesis.

EPFL2019

First-person view of one’s body in immersive virtual reality: Influence on episodic memory

Jane Aspell, Olaf Blanke, Lucie Bréchet, Baptiste Gauthier, Bruno Herbelin, Robin Mange, Andrea Serino, Quentin Antoine Marie Theillaud

Episodic memories (EMs) are recollections of contextually rich and personally relevant past events. EM has been linked to the sense of self, allowing one to mentally travel back in subjective time and re-experience past events. However, the sense of self has recently been linked to online multisensory processing and bodily self-consciousness (BSC). It is currently unknown whether EM depends on BSC mechanisms. Here, we used a new immersive virtual reality (VR) system that maintained the perceptual richness of life episodes and fully controlled the experimental stimuli during encoding and retrieval, including the participant’s body. Our data reveal a classical EM finding, which shows that memory for complex real-life like scenes decays over time. However, here we also report a novel finding that delayed retrieval performance can be enhanced when participants view their body as part of the virtual scene during encoding. This body effect was not observed when no virtual body or a moving control object was shown, thereby linking the sense of self, and BSC in particular, to EMs. The present VR methodology and the present behavioral findings will enable to study key aspects of EM in healthy participants and may be especially beneficial for the restoration of self-relevant memories in future experiments.

2019

First-person view of one’s body in immersive virtual reality: Influence on episodic memory

Olaf Blanke, Lucie Bréchet, Baptiste Gauthier, Bruno Herbelin, Robin Mange, Andrea Serino, Quentin Antoine Marie Theillaud

2019

Underlying mechanisms of episodic autobiographical memory and self-consciousness

Lucie Bréchet

EPFL2019