Bianca M van Kemenade^1,2, Lars F Muckli²; ¹Justus Liebig University Giessen, ²University of Glasgow

Self-generated stimuli are often perceptually and neurally attenuated. This sensory attenuation is considered the result of predictions made using the efference copy, a copy of the motor command. However, several studies have shown that action can sometimes lead to enhancement instead of attenuation. It is currently still unclear which factors determine which effect action has on perception and neural processing. In the current study, we investigated whether the effect of action depends on the visibility of the sensory action outcomes. Participants completed both a behavioural and an fMRI experiment to test effects on both perception and neural processing. In both experiments, they had to perform an orientation discrimination task on two sequentially presented gratings. In active conditions, participants elicited the presentations by a button press, whereas in passive conditions, the gratings were presented automatically. We manipulated the visibility of the stimuli by embedding the gratings in noise during low visibility blocks. In high visibility blocks, the gratings were clear to see. Behavioural results showed significantly better performance for active compared to passive conditions. The Action x Visibility interaction showed a trend, with better performance for active conditions slightly more pronounced in the low visibility condition. This matched our univariate fMRI results, showing a significant Action x Visibility interaction in visual cortex, where an enhanced BOLD-response for active compared to passive conditions was present in low visibility conditions only. However, preliminary multivariate analyses showed no differences in decoding accuracy between active and passive conditions, neither in high nor low visibility conditions. Overall, these results suggest that action can boost both perception and the amplitude, but not precision, of neural responses particularly when the sensory action outcomes are noisy. This supports the idea that the effect of action on perception is dynamically modulated depending on context.

Acknowledgements: DFG (SFB/TRR 135, Project A10)