Physiopy/phys2bids: BIDS formatting of physiological recordings

The BOLD fMRI signal contains multiple subject-dependent sources of physiological origin. This fact can be exploited to capture physiological states (e.g. cerebrovascular reactivity) [1,6], or physiological fluctuations can be treated as noise and removed to improve activation or connectivity mapping [2,4]. In both cases, it is necessary to measure physiological signals (e.g. cardiac pulse, chest volume, exhaled CO2 and O2, skin conductance). It is becoming common practice in the neuroimaging community to share collected data on public platforms that rely on Brain Imaging Data Structure (BIDS [3]). However, due to (I) the high variability in the experimental setup and measurement process, (II) the lack of tools to convert such data into BIDS format, and (III) the lack of consensus guidelines for how to use such data in neuroimaging pipelines, few centres or researchers routinely collect and utilize physiological data and even fewer share them. Here, we introduce the development of physiopy: a user-friendly, community-driven bundle of tools that aim to help researchers collect, share, and prepare physiological data for neuroimaging analysis.