Abstract
In vitro and in vivo experimentation in the central nervous system are effective approaches to study its functioning. Manipulations in vitro are characterized by easy experimental control and stable experimental conditions. However, transferring these advantages to in vivo research remains technically and ethically challenging, preventing many research teams from acquiring critical recordings in their animal models. In order to transfer the benefits of in vitro experimentation to in vivo experimentation, 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 neocortex in vivo. Highly correlated intra- and extracellular activity was recorded during spontaneous and evoked cortical activity, supporting the possibility of simultaneous long-lasting electrophysiological recordings from a single cortical column in 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 use in vivo), the 3d printed set of tools developed should reduce animal use, supporting the 3Rs principle of ethical use of animals.
Significance statement
This study describes a 3d printed superfused chamber developed for extra-/intracellular and neuroimaging cortical recordings in vivo. The device consists of a set of independent parts (a superfusion chamber with an independent brain presser and animal stand) that serve for stable, unified, and well-controlled experimental manipulations in the living rat. In addition to facilitating experimental procedures, the proposed superfusion chamber allows drug screening that also supports the 3Rs principle (Replacement, Reduction, and Refinement).
Footnotes
The authors report no conflict of interest.
The project leading to this publication received funding from France 2030, the French Government program managed by the French National Research Agency (ANR-16-CONV-0001), from the Excellence Initiative of Aix-Marseille University - A*MIDEX (DS), and from RSF grant 22-25-00225 (VSh, VS, single-cell recordings in vivo and their analysis) and was within the Program of competitive growth at Kazan Federal University (publication fees).
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
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