Altering Consciousness through Sensory Stimulation: Effects of Nasal Airflow and Flicker Light Exposure on Functional Connectivity and Subjective Experience

This thesis offers an in-depth investigation into how different sensory stimulations influence states of consciousness, combining resting-state functional connectivity analyses with retrospective, self-report phenomenological measures. The study is grounded in contemporary theories of consciousness, exploring both the neurobiological and phenomenological aspects of altered states. After contemporary theories in consciousness research, three studies are presented. The first experiment examined the effects of slow artificial nasal stimulation on brain connectivity and participants’ subjective experience, identifying stimulation-induced functional connectivity changes and associated shifts in participants’ phenomenological reports. The second study comprised the analysis of a previously published fMRI dataset by Amaya et al. 2023. This re-analysis explored the effects induced by flicker-light stimulation on Default Mode and Ventral Attention networks, as well as frequency-dependent functional connectivity alterations in visual areas. The third experiment investigated the differential effects of breathing routes (mouth versus nasal slow breathing) on conscious experience and brain connectivity, highlighting the role of slow-paced nasal breathing in inducing enhanced inward-directed attention and increased functional connectivity between regions of the Dorsal Attention, Salience and Sensorimotor networks.