Research in the O’Connell lab is seeking to understand the neural mechanisms underpinning high-level cognition. This work comprises both basic and translational research and employs a range of psychophysiological techniques including EEG, fMRI, autonomic system measurement and transcranial stimulation. Our primary research interests include:
Perceptual Decision Making
One of the central challenges for the field of neuroscience is to understand how the brain allows us to make reliable categorical decisions from the noisy sensory information it receives. Recently, in collaboration with Simon Kelly of the City College of New York, we devised a novel paradigm that makes it possible to isolate and continuously track the key information processing stages intervening between sensation and action during simple perceptual decisions in discrete human brain signals (see O’Connell, Dockree & Kelly, 2012). This technique is now allowing us to explore the mechanisms that influence the timing and accuracy of perceptual decision making in both clinical (e.g. mild cognitive impairment, ADHD) and non-clinical populations.
The brain possesses specialized systems for continually monitoring our performance and for adjusting our behaviour if an error is detected. Occasionally however, this monitoring system fails us and an error can go unnoticed, depriving us of a crucial opportunity to take remedial action. Such failures of self-awareness can cause significant functional impairment in a range of clinical populations. Our group is currently exploring the neural processes that determine whether or not a performance error will enter consciousness (e.g. Murphy et al 2012).
Our research is also directed toward understanding how, why and when attention levels fluctuate. Lapses of attention are a leading cause of human error and a major focus of our work has been to develop laboratory tests that mimic real life situations and make it possible to continuously track neural signatures of spatial and non-spatial attention over time. In collaboration with Mark Bellgrove of Monash University, we are utilizing pharmacological and genetic analysis techniques to probe the neurochemical influences on visuospatial and vigilant attention.
European Research Council (Starting Grant)
Human Decisions project – funded by the European Research Council (Starting Grant 2015-2020)
How do we make reliable decisions given sensory information that is often weak or ambiguous? Current theories center on the idea that even in the case of very simple perceptual decisions, the brain acts much like a court room judge, sampling and accumulating sensory ‘evidence’ until a sufficient degree of certainty or belief has been reached in favour of one of the choice alternatives. Neural signals fitting this role have been identified in monkey electrophysiology but efforts to study the neural dynamics underpinning human decision making have been hampered by technical challenges associated with non-invasive recording methods. The Human Decisions project builds on a recent paradigm breakthrough that enables parallel tracking of neural signals that can be unambiguously linked to the three key information processing stages necessary for simple perceptual decisions: sensory encoding, decision formation and motor preparation. Chief among these is a freely-evolving decision variable signal which builds at an evidence-dependent rate up and precisely predicts the timing and accuracy of perceptual reports at the single-trial level. This provides an unprecedented neurophysiological window onto the distinct parameters of the human decision process such that the underlying mechanisms of several major behavioral phenomena can finally be investigated. The goal of the Human Decisions Project is to develop a systems-level understanding of perceptual decision making in the human brain by tackling three core questions: 1) what are the neural adaptations that allow us to deal with speed pressure and variations in the reliability of the physically presented evidence? 2) What neural mechanism determines our subjective confidence in a decision? and 3) How does aging impact on the distinct neural components underpinning perceptual decision making?