In-vivo Neural Recordings in Rodents

Neural signals were acquired and amplified by multifunction input/output cards (PCI-6259, National Instruments, Austin, US) in rats or an electrophysiological recording system (RHD2000, Intan Technologies, Los Angeles, USA) in mice and digitized at 20 kHz. To increase the single unit yield, in case of the rat recordings, we waited 30 min for the tissue to stabilize after implantation, while implants in mice were inserted slowly (2 μm/s for MS, ~10 μm/s for CA1) with a motorized micromanipulator (Robot Stereotaxic, Neurostar, Tübingen, Germany) to minimize tissue damage^{163 (link)}. We carried out 30-min-long recordings in rats with 100 µm dorso-ventral separation, and 15-min-long recordings in mice at three distinct dorso-ventral positions within in the MS. Theta oscillations were induced by tail pinch (3 times 1 min in rats; once for 5 mins in mice).