This week was very fun for me in the lab. The rats reached learning criteria on the Linear Track (which I talked about in week 2) and moved on to the next stage, the W-Maze Alternation Task.
The completion of the W-maze Alternation Task demonstrates how the hippocampus and pre-frontal cortex (PFC) interact. An animal must access memories from previous trials which is dependent on the hippocampus. Then, an animal must utilize this information to guide a choice between the two side arms of the track which is dependent on the PFC.
The rats are tested on the W-track for 14 consecutive days, so there are 14 sessions.
Here is a digital sketch of the w-maze/track from the research protocol:
In the research protocol, the W-maze is decribed as an automated system controlled by the Arduino Uno microcontroller. It consists of three solenoids, three feeder dishes, tubing, and three infrared motion sensors hooked up to the microcontroller. On the end of each arm of the maze, there is a food dish and an infrared motion sensor. When the rat breaks the plane of the sensor, it will trigger the opening of the solenoid to dispense vanilla Ensure into the feeder dish. Ensure is the same food reward the rats recieved on the Linear Track.
A computer application, coded by my very smart research advisor, tells the experimenter how many correct patterns (laps) were completed and how many errors were made. Also, a camera mounted on the ceiling records video data for future behavioral analysis. This camera system is also helpful because I get to live-watch the rat in action on the track/maze instead of standing in the room as that woud distract the rat.
Correct Patterns would look like:
Given that this was the first week, many incorrect patterns were made. Incorrect patterns are when the rats go in a u-pattern (two arms) in a row instead of a w-pattern (three arms). Another incorrect pattern could be going back and forth on the same arm twice. The goal is that each day the rat will improve because it can retrieve memories to make correct choices. This again highlights how the hipocampus and PFC are involved.
Last week I mentioned that we recieved new rats to add to our experiment. These new rats have yet to complete the Linear Track and the W-maze. In my next post I will be talking about what I did with the new rats this week!