Evidence That Respiratory Phase May Modulate 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 for example changes in the excitation-inhibition balance is comodulated with the respiratory cycle, it remains unclear whether respiration directly shapes the neural signatures reflecting the encoding of task-specific external signals. We address this gap by applying single-trial multivariate analyses to EEG data obtained in humans (n = 25, any gender), allowing us to track how respiration relates to the sensory evidence reflected in this neurophysiological signal. Confirming previous studies, our data show that participant's performance varies with the respiratory phase prior and during a trial. Importantly, they suggest that respiration may directly influence the sensory evidence carried by neurophysiological processes emerging ∼300-200 ms prior to participant's responses. Hence, respiration and sensory-cognitive processes are not only highly intertwined but respiration may directly facilitate the representation of behaviorally relevant signals in the brain.