Relationship between electroencephalographic data and comfort perception captured in a Virtual Reality design environment of an aircraft cabin

Successful aircraft cabin design depends on how the different stakeholders are involved since the first phases of product development. To predict passenger satisfaction prior to the manufacturing phase, human response was investigated in a Virtual Reality (VR) environment simulating a cabin aircraft. Subjective assessments of virtual designs have been collected via questionnaires, while the underlying neural mechanisms have been captured through electroencephalographic (EEG) data. In particular, we focused on the modulation of EEG alpha rhythm as a valuable marker of the brain's internal state and investigated which changes in alpha power and connectivity can be related to a different visual comfort perception by comparing groups with higher and lower comfort rates. Results show that alpha-band power decreased in occipital regions during subjects' immersion in the virtual cabin compared with the relaxation state, reflecting attention to the environment. Moreover, alpha-band power was modulated by comfort perception: lower comfort was associated with a lower alpha power compared to higher comfort. Further, alpha-band Granger connectivity shows top-down mechanisms in higher comfort participants, modulating attention and restoring partial relaxation. Present results contribute to understanding the role of alpha rhythm in visual comfort perception and demonstrate that VR and EEG represent promising tools to quantify human-environment interactions

Spectral and Anatomical Patterns of Large-Scale Synchronization Predict Human Attentional Capacity

The capacity of visual attention determines how many visual objects may be perceived at any moment. This capacity can be investigated with multiple object tracking (MOT) tasks, which have shown that it varies greatly between individuals. The neuronal mechanisms underlying capacity limits have remained poorly understood. Phase synchronization of cortical oscillations coordinates neuronal communication within the fronto-parietal attention network and between the visual regions during endogenous visual attention. We tested a hypothesis that attentional capacity is predicted by the strength of pretarget synchronization within attention-related cortical regions. We recorded cortical activity with magneto- and electroencephalography (M/EEG) while measuring attentional capacity with MOT tasks and identified large-scale synchronized networks from source-reconstructed M/EEG data. Individual attentional capacity was correlated with load-dependent strengthening of theta (3-8 Hz), alpha (8-10 Hz), and gamma-band (30-120 Hz) synchronization that connected the visual cortex with posterior parietal and prefrontal cortices. Individual memory capacity was also preceded by crossfrequency phase-phase and phase-amplitude coupling of alpha oscillation phase with beta and gamma oscillations. Our results show that good attentional capacity is preceded by efficient dynamic functional coupling and decoupling within brain regions and across frequencies, which may enable efficient communication and routing of information between sensory and attentional systems.Peer reviewe

Structural and functional neuroplasticity in posttraumatic stress disorder: fear learning and context processing

In this thesis, structural and functional brain differences are investigated in three studies between patients with posttraumatic stress disorder (PTSD) and healthy trauma (TC) or non-trauma exposed (HC) control subjects and results are discussed within a common psychobiological model of PTSD. In this work, we provide a meta-analysis including 30 studies with 1,700 participants on structural white matter differences, investigate white and gray matter alterations in PTSD (154 subjects) and examine behavioral and psychophysiological alterations during contextual fear processing using virtual reality in a functional magnetic resonance imaging study (63 subjects). In summary, this work suggests that patients with PTSD show alterations in structural and functional brain activity that can both be associated to fear learning and context processing. Our work proposes above all that lower volume and activity within the prefrontal cortex in combination with functional alterations in the hippocampi can be associated with deficient contextual fear processing

Visual perception and attention and their neurochemical and microstructural brain correlates in healthy and pathological ageing

Visual perception and attention declines with normal ageing, however their neural and cognitive mechanisms in healthy and pathological ageing are yet to be fully understood. This thesis aimed to provide a characterisation of normal age-related differences across the visual perception and attention hierarchy, identify their underlying neural correlates, and assess how normal ageing contrasts with pathological ageing in Dementia with Lewy bodies (DLB)