Whisker pad stimulation elicits brain-wide cross-sensory activation in awake rats measured with zero echo time fMRI

Motivation: Sensory research has typically focused on one system at a time, and basic mechanisms related to interactions between sensory systems remain poorly understood. Goal(s): To detect and characterize brain-wide cross-sensory interplay, and to study how non-core circuits react to varying input into the core circuit. Approach: Classical whisker pad stimulation in head-fixed awake and anesthetized rats in combination with a large number of fMRI measurements. Results: We detected cross-sensory brain-wide activations to whisker pad stimulation. The activation profile of many non-core regions differed from that of the core circuit. Importantly, some features of cross-sensory interplay were not visible under anesthesia. Impact: Cross-sensory activations are gaining increasing attention in imaging studies. Previously, multisensory interplay may have gone unnoticed, as the focus has been in the primary pathway. Our results also emphasize the importance of avoiding anesthesia in preclinical cross-sensory research.