Just a phase? Causal probing reveals spurious phasic dependence of sustained attention
M. Vinao-Carl,
Y. Gal-Shohet,
E. Rhodes,
J. Li,
A. Hampshire,
D. Sharp,
N. Grossman
Affiliations
M. Vinao-Carl
Department of Brain Sciences, Imperial College London, London, UK; UK Dementia Research Institute, (UK DRI), Imperial College London, London, UK
Y. Gal-Shohet
Department of Medical Physics and Engineering, University College London, London, UK
E. Rhodes
Department of Brain Sciences, Imperial College London, London, UK; UK Dementia Research Institute, (UK DRI), Imperial College London, London, UK
J. Li
Department of Brain Sciences, Imperial College London, London, UK; UK Dementia Research Institute, (UK DRI), Imperial College London, London, UK
A. Hampshire
Department of Brain Sciences, Imperial College London, London, UK
D. Sharp
Department of Brain Sciences, Imperial College London, London, UK; UK Dementia Research Institute, (UK DRI), Imperial College London, London, UK; UK Dementia Research Institute, Care Research and Technology Centre (UK DRI-CRT), Imperial College London, London, UK
N. Grossman
Department of Brain Sciences, Imperial College London, London, UK; UK Dementia Research Institute, (UK DRI), Imperial College London, London, UK; Corresponding author at: Division of Brain Sciences, Imperial College London, London, UK.
For over a decade, electrophysiological studies have reported correlations between attention / perception and the phase of spontaneous brain oscillations. To date, these findings have been interpreted as evidence that the brain uses neural oscillations to sample and predict upcoming stimuli. Yet, evidence from simulations have shown that analysis artefacts could also lead to spurious pre-stimulus oscillations that appear to predict future brain responses. To address this discrepancy, we conducted an experiment in which visual stimuli were presented in time to specific phases of spontaneous alpha and theta oscillations. This allowed us to causally probe the role of ongoing neural activity in visual processing independent of the stimulus-evoked dynamics. Our findings did not support a causal link between spontaneous alpha / theta rhythms and behaviour. However, spurious correlations between theta phase and behaviour emerged offline using gold-standard time-frequency analyses. These findings are a reminder that care should be taken when inferring causal relationships between neural activity and behaviour using acausal analysis methods.
