Accounting for distinct sources of behavioural variability through physiological measures

Cognitive performance and behaviour are continually in flux across both short and long timescales even under the most carefully controlled experimental conditions. Standard models tend to attribute such variability to 'noise' but this belies the fact that multiple distinct brain processes can contribute to behavioural variability and that parsing them is critical to our understanding of normal and abnormal cognition. In this talk we describe work that leverages physiological measurements and mathematical modelling to parse the distinct brain processes driving this moment-to-moment variability. Specifically, we will outline recent work showing that behaviour is modulated by respiratory phase. In addition, we highlight new electrophysiological data which makes it possible to track fluctuations in decision boundaries and attentional engagement. We will also discuss recent modelling work that attempts to systematically account for such variations in participants' arousal state over time.