Towards understanding human consciousness: How internal brain states and environmental context shape our subjective experience

Introduction

Consciousness is subjective experience, the ‘what it is likeness’, for example to perceive a certain scene or to feel joy. In the last three decades, tremendous progress has been made in identifying the neural correlates of consciousness at the level of whole brain regions.

Advances in Related Fields

Meanwhile, outside the field of consciousness, rapid progress has been made in understanding neural, biochemical, and psychological factors that have to be accounted for to further understand human consciousness. Most importantly, we know much more about:

1. The neurotransmitter systems underlying basic sensory processes in animals (e.g. neurobiology).
2. The mechanisms responsible for fluctuations in wakefulness and arousal (e.g. anesthetics/neurobiology).
3. How perception is constructed by the brain’s predictions about regularities in the world (e.g. neuroscience/psychology).

This research has, however, been performed in relative isolation from studies of human consciousness, and clear opportunities to link these different fields remain largely unexplored.

Research Objectives

Here I will establish this crucial link by combining state-of-the-art neuroimaging techniques with pharmacological interventions and computational modeling in humans performing novel experimental tasks gauging subjective perceptual experience. My project has three main aims:

1. I will first test the hypothesis that excitatory and inhibitory neurotransmitters play central, albeit different roles in recurrent neural processes, crucial for conscious experience.
2. Second, I will test how subjective experience is shaped by spontaneous fluctuations in arousal and levels of physical activity.
3. Third, I will test how conscious experience is modulated by the interplay between predictions and sensory input.

Expected Outcomes

This research promises to provide an integrative framework for understanding the neural and biochemical mechanisms of consciousness, and will reveal how it is shaped and determined by being a human agent that interacts with, acts in, and predicts its environment.