TITLE: SPARC - Gastrointestinal myoelectric recordings from the behaving ferret
AUTHORS: Charles C. Horn, Derek M. Miller, Stephanie Fulton, Bill J. Yates, Lee E. Fisher, Ameya C. Nanivadekar

[DESCRIPTION]
<div class = "text-blocks"><div class = "text-block">This protocol provides the steps for recording the gastrointestinal myoelectric responses and stimulation of the abdominal vagus nerve from the behaving ferret. These tests occur after an animal is surgically implanted with gastrointestinal and vagus nerve electrodes (see the protocol "SPARC - Chronic implantation of gastrointestinal and vagus nerve electrodes in the ferret" for implantation methods).</div><div class = "text-block">Funding: This protocol was developed with funding from the NIH Common Fund’s Stimulating Peripheral Activity to Relieve Conditions (SPARC) program (Award U18TR002205). To learn more about the SPARC program, visit https://sparc.science.</div></div>

[STEPS]
?. [Room setup]
Cover floor of behavioral test chamber with layer of Alpha-dri bedding. The floor of the plexiglas chamber is 51 x 51 cm (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3348962/)
?. [Room setup]
Turn off all lights except lamp over testing chamber.
?. [Room setup]
Keep the room quiet during recording except for white noise.
?. [Room setup]
Set up video camera directly above chamber so that entire area is visible with minimal shadows. Set up a second camera to view the feeding tube from the side for feeding trials to track volume consumed.
?. [Room setup]
Suspend tether ~50 cm above chamber and secure with rubber bands to provide elasticity as the animal moves.
?. [Animal]
Animal should be fasted 3 hours before starting recording.
?. [Animal]
Place animal in chamber and allow 10 minutes for acclimation.
?. [Animal]
Connect animal to tether.
?. [Animal]
During testing, hold the tether straight above the animal out of its reach, but with some slack. If the animal tries to grab the tether, especially during adaptation, a plastic straw can be inserted through the breathing holes in the side of the chamber to distract the animal from the tether.
?. [Recording: Baseline control]
Record electrode impedances before the recording begins.
?. [Recording: Baseline control]
Electrophysiological recording and video recording should be started at the same time.
?. [Recording: Baseline control]
Record 1 h of baseline data for control days.
?. [Recording: Feeding]
For feeding trials, introduce Ensure liquid diet in a graduated tube (100 ml Richter glass feeding tube) attached to the side of the chamber at 10 min after the start of recording. Remove the feeding tube 45 min after presentation. Finish with 10 min of baseline recording.
?. [Recording: Feeding with vagus stimulation]
For feeding with stimulation trials, introduce Ensure at the same time as in Step 13. Start stimulation 2 minutes after food introduction. Stop stimulation and remove food at the same time, i.e., minute 45 in the recording. Finish with 10 minutes of baseline
?. [Recording: Emetiine (emesis testing)]
For emetine trials, begin infusion at the 10 min in the recording. Infusion rate is 10ml/min. Record for 1 hour after infusion has ended.
?. [Recording: Emetiine (emesis testing)]
After recording is done, animal should be monitored until there is no further emesis.
?. [Recording: Water control]
For water control trials, follow Step 15.
?. [End]
Stop electrophysiological and video recordings at the same time.
?. [End]
Measure impedances at the end of each recording.