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

Electrophysiological extracellular recordings using the superfused cortex preparation. A, B, Scheme and picture of the superfused cortex preparation with a presser fixed on the rodent head. C, Evoked and spontaneous neuronal network activity recorded in the barrel cortex with (black trace) and without (gray trace) the superfusion chamber. Expanded episodes of evoked (left) and spontaneous (right) activity marked by a single and doubled asterisk on the traces are shown below. Lines correspond to the fluctuations of LFP, while vertical bars are MUA. D, Group data of spontaneous activity occurrence recorded with and without the superfusion chamber. E, F, Group data of MUA rate during episodes of evoked activity and its duration recorded with and without the superfusion chamber. G, Power spectral density of evoked activity recorded with and without the superfusion chamber. H, Group data of evoked activity spectral peak distribution in the β and γ frequency ranges recorded with and without the superfusion chamber. Filled circles represent the results of individual experiments; red circles, mean values; red whiskers, confidence intervals based on t Student’s criteria.

Electrophysiological intracellular and extracellular recordings using the superfusion chamber. A, Picture of simultaneous intracellular and extracellular recording using superfusion chamber. B, Simultaneously recorded evoked EPSCs (red trace), IPSCs (blue trace), and corresponding extracellular LFP responses (black trace) recorded in one cortical column of the barrel cortex. Note that spontaneous activity is also observed both extracellular and intracellularly. C, Cross-correlation between extracellular and intracellular activity recorded using the superfusion chamber. Cross-correlation centered on LFP troughs. D, LFP (black line), EPSC (red line), and IPSC (blue line) spectrum of the evoked response during PW stimulation. E, Group data for the spectrum peak frequencies in the β (left) and γ (right) frequency range. Peak frequency values of the evoked and spontaneous response for the EPSC (light red filled and empty circles, respectively), IPSC (light blue filled and empty circles, respectively), and LFP (light gray filled and empty circles, respectively) are shown. Black filled circles represent mean values; black whiskers, confidence intervals based on the t Student’s criteria.

Optical intrinsic signal recordings using the superfusion chamber. A, Experimental scheme of OIS recordings in vivo. B, Field of view of the cortical surface fixed under the presser recorded using the green illumination shown on the left. Expanded view of the presser with clearance (red) and crosspiece (blue). C, OIS evoked by whisker stimulation from the experiment shown in B. Note the crosspiece and clearance zones are over the barrel cortex. D, Comparison of the dynamics of the OISs recorded under the clearance (red), crosspiece (blue), and that recorded through the skull (gray). The shaded area corresponds to the SD of the OIS. E, Group data for the OIS amplitude under the clearance (red), crosspiece (blue), and recorded through the skull (gray). F, Group data for OIS onset in the zone of clearance (red), crosspiece (blue), and through the skull (gray). G, Group data for OIS duration under the clearance (red), crosspiece (blue), and through the skull (gray). Black filled circles represent mean values, black whiskers, confidence intervals based on the t Student’s criteria.