The respiratory phase modulates task-related neural representations of visual stimuli

We investigate how respiration influences cognition by examining the interaction between respiratory phase and task-related brain activity during two visual categorization tasks. While prior research shows that cognitive performance varies along the respiratory cycle, the underlying neurophysiological mechanisms remain poorly understood. Though some studies have shown that large-scale neural activity reflecting changes in the excitation-inhibition balance is co-modulated with the respiratory cycle, it remains unclear whether respiration directly shapes the quality by which task-relevant sensory information is encoded. We address this gap by applying single-trial multivariate analyses to EEG data obtained in humans, allowing us to track how respiration modulates the sensory evidence in this neurophysiological signal. Confirming previous studies, our data show that participants performance varies with the respiratory phase prior and during a trial. Importantly, they also suggest that respiration directly influences the sensory evidence carried by parieto-occipital processes emerging around 300 to 200 ms prior to participants responses. Hence, respiration and sensory-cognitive processes are not only highly intertwined but respiration directly facilitates the representation of behaviourally-relevant signals in the brain.