Integrated Reward Block

A project completed with Benjamin Tan.

Time Frame: September 2011 to April 2012

The Problem: Existing off-the-shelf reward blocks have inadequate designs that are not compatible with many laboratory environments. A device needs to be created that allows test animals easy access to food and that can be adjusted to fit to any test environment.

Requirements:

Accept 45 mg food pellets, delivered through a tube from an electronically controlled dispenser
Make food tray safe and easily accessible by the test subjects, i.e. rats
Illuminate pellet delivery area, controlled by TTL pulse.
Actively remove pellets when required through TTL pulse input
Compatible with the software control system currently in use
Detect entry of test subject into feeding area via sensor and transmit TTL pulse output to a NI digital I/O board
Detect presence of the delivered pellet via sensor, i.e. pellet remains vs. eaten
Detect broken pellet and/or failed delivery via sensor with TTL pulse output
Robust design with smooth, chew-resistant material choice, and prevent test subject access to vulnerable components such as plastic tube and/or employ modular design with easily replaceable components
Have a modular design that would allow it to be used in different environments
Device could be easily cleaned to maintain test area hygiene
Minimize electrical and operational noise and transients that can interfere with recording of neural data and irritate the test subject
Ensure food pellets dispensed individually in a consistent manner and deliver in the same exact location
Ability to automatically correct the number of food pellets delivered if a commanded delivery fails

Concepts:
A number of concepts were generated for this device. The following are a few examples.

Clamps would allow researchers to position the reward block anywhere on the experimental platform they require.

Pellets drop from the tube connected to the back of the device, LEDs illuminate the feeding area, the circular bowl is safe for test subjects to interact with and slows down pellets as they drop from the tube. A sliding door opens and closes to remove uneaten pellets into a cabinet on bottom of the device.

The Prototype: