Professor O'Leary studies regulatory control in the nervous system using engineering approaches and experimental physiology. He is interested in the general principles and mechanisms that allow biological nervous systems to develop, self-organise, adapt and store information. There is overwhelming evidence that nervous systems are highly variable and in constant flux, to a far higher degree than one might expect given its intricate functions. Understanding the sources and consequences of this variability and what it implies about regulatory mechanisms is a key goal in his research, relevant to basic questions in neuroscience as well as a better understanding of disease.