UCSD_MED Autonomous Operant Conditioning Chamber for Rodent Cognitive Testing

Background: 

NEATLabs is a cognitive research lab that studies both human and animal behavior; they utilize neural-engineering methods in order to target and repair identified circuit deficits due to psychiatric disorders. In this experiment, NEATLabs is studying a rat’s ability to perform a task in order to better understand a rat’s ability to display response inhibition and executive function tasks. Once this behavioral task is validated, they will be able to understand which networks are involved with those cognitive functions and how these perturbations affect behavior.  This animal testing is very valuable because it is highly translational and mirror tests done in their human lab. Currently, the three different types of implants used for the test include a Bilateral LFP Implant, Optical Stimulant Implant, and a Chemical Stimulant Implant, which can be seen below.

Objective:

Currently, the rats live in a housing chamber and are transported into the behavioral chamber for an hour a day for pre-training. The main goal is to automate the pre-training process, so that the rats always have access to the testing chamber and are able to passively train themselves 24 hours a day. We plan to achieve this goal by connecting the home chamber to the testing chamber. This new chamber set-up should require less interaction from the lab technicians when pre-training the rats.                      

Current Home Chambers

Current Behavioral Chamber

Final Design: 

The design for this Autonomous Operant Conditioning Chamber is made up of two main chambers that are connected by a bridge. The first chamber is the home chamber, which is a normal home cage that the rats are currently stored in when they are not being tested on. The second chamber is the behavioral chamber, where the rats will be participating in a Go / NoGo stimulus response test with a monitor on the wall. These two chambers are then connected with a PVC tube that acts as a bridge to allow the rats to come and go into either chamber as they please. In order to account for the slight 4° angle from the vertical on the home chamber, an adaptor was made that is able to slide into place. This adaptor allows the PVC bridge to slide in and out of two vertical walls more easily. Additionally, a new automated water delivery system will be implemented into the home chamber. This new water delivery system is a button operated Arduino system that will deliver 15 mL from a water reservoir, through a peristaltic pump, and into a 15mL tube that is connected to a drinking valve. Previously, the lab technicians had to manually measure out 15 mL a day for each rat. In addition to the time they spend measuring this out, the lab technicians also expressed their frustration with having to account for the error in the water bottles when the water bottles were not perfectly vertical. Implementing this new water delivery system saves the lab technicians time and frustration everyday.

CAD of Final Design

Picture of Final Design

The water delivery system will be implemented by using the same water bottle holder that is currently used on the home cage. We will instead hold our water in a 15mL tube that leads to a drinking valve that does not leak when the rats are not drinking from it. The tube allows the water to be stored in case they don't want to drink the water right away. This system can be seen below.

Water Delivery system implemented into chamber