Simple and Efficient 3D-Printed Superfusion Chamber for Electrophysiological and Neuroimaging RecordingsIn Vivo

Abstract

In vitroandin vivoexperimentation in the central nervous system are effective approaches to study its functioning. Manipulationsin vitroare characterized by easy experimental control and stable experimental conditions. However, transferring these advantages toin vivoresearch remains technically and ethically challenging, preventing many research teams from acquiring critical recordings in their animal models. In order to transfer the benefits ofin vitroexperimentation toin vivoexperimentation, we developed a suite of 3D-printed tools (a superfusion chamber with an independent brain presser and animal stand). Using the immature rat barrel cortex as a model, we show that our set of tools (further “superfusion preparation”) provides stable conditions for electrophysiological and neuroimaging recordings in the neonatal rat neocortexin vivo. Highly correlated intracellular and extracellular activity was recorded during spontaneous and evoked cortical activity, supporting the possibility of simultaneous long-lasting electrophysiological recordings from a single cortical columnin vivo. The optical intrinsic signal of evoked cortical responses was also recorded from the skull-free neocortex, suggesting the effective combination of the superfusion preparation with neuroimaging approaches. Modulation of immature activity by epicortical application of pharmacological agents via superfusion equally supports the use of the superfused cortex preparation in pharmacological screening. In addition to high efficiency (in affordability, reliability, and ease of usein vivo), the 3D-printed set of tools developed should reduce animal use, supporting the 3Rs principle (Replacement, Reduction, and Refinement) of ethical use of animals.