Place and Response Learning in the Open-field Tower Maze

The overall goal of this procedure is to train rats in the open field tower Maze Task. This is accomplished by first building the maze apparatus. The second step is to pair, house and handle the rats.

Next rats are acclimated to and pre-trained in the maze. The final step is to administer response or place training and testing procedures. Ultimately, the percent of first choice correct responses for each rat is recorded to determine its rate and magnitude of learning in the maze.

The main advantage of this technique over existing mazes is that the open field tower maze is a non aversive repetitive task. Therefore, stress is eliminated as a potential intervening variable. This method can help answer key questions in the behavioral neuroscience field, such as what effects hormones have on learning and memory processes.

In the absence of stress, Though this method can provide insight into the neural mechanisms of learning and memory in the adult rat. It can be used with other model systems such as mice and rodents of different ages. After constructing the circular maze, decorate the interior surface using four distinct black and white patterns.

Next, build four food towers and secure them to the maze floor. In addition, build three pre-training towers and tape them in place for use. During the pre-training phase, glue black plastic food cups to the top of each food tower, top each food cup with a screw top lid ventilated with three small holes.

Lastly, hang a 60 watt bulb to dimly illuminate the maze room and mount a digital video camera to the ceiling to record sessions for later analysis before training. Each experimenter should handle all rats performance a day for a total of seven days. To motivate the rats to retrieve rewards, place them on a food restricted diet that allows one hour of free feeding per day.

Double house female rats throughout the duration of the experiment to promote lower levels of anxiety. To begin the pre-training procedure, bait each uncapped food cup on the seven towers with a food reward. When ready, place a rat into the maze in a random location, allow the rat to explore until it finds and consumes all seven food rewards.

If the rat does not retrieve all of the food rewards within 10 minutes, remove it from the maze and repeat this procedure the following day. If a rat does not retrieve and consume all seven food rewards within the first two days, allow it additional 30 minute sessions until the food rewards are retrieved. First, assign each rat to two of four start locations.

Counterbalance the start location type of learning, the correct tower for place learners, and the correct turn for response learners. At the start of each training day, turn on a noise machine and open the video recording program bait all four towers and cover three out of the four food cups, leaving the food reward on the correct tower exposed. When ready, start video recording and place the rat in the maze at its assigned Start location.

Move behind a curtain to observe the rat's behavior on a computer monitor immediately after it retrieves the reward. Or after three minutes, remove the rat and stop video recording place. Learning requires solving the maze by finding a specific location.

Using spatial cues, always use the same correct food tower and place the rat in one of two start locations. For example, bait tower D and release the rat from start location two or three for response learning rats. Switch the correct food tower depending on the start location response learners solve the maze by learning to make a specific turn regardless of its starting location in the maze.

For example, bait tower D and release the rat from start location three or bait tower B, and release that same rat from start. Location two, administer 48 training trials across 12 days with four trials per day. After all the rats perform at their asymptotic level, carry out a start location switch test to test the persistence of the learned behavior.

First counterbalance novel. Start locations for each rat. Then follow the procedures for each training trial demonstrated earlier with the new start locations.

For a place learning rat that was originally released from location two or three, place the rat in either of the new start locations, one or four while still bathing Tower D for a response. Learning rat that learned to turn right and was originally released from locations two or three. Place the rat in either of the new start locations, one or four and bait either tower A or C respectively.

Administer eight. Start location switch test trials across two days with four trials per day. A novel experimenter blinded to the treatment groups should score the videotape trials.

Begin by the number of attempts a rat makes to find the correct tower on each trial. Next, calculate the likelihood that a rat finds the reward on its first choice within each training day. Construct learning curves using this percentage across training days.

Lastly, exclude rats from the analysis if their performance across the trials fails to reach a predetermined set of criterion. Rats given cycling estradiol replacement required fewer trials to reach acquisition criteria during place learning. While response learning rates were similar between treatment groups, performance levels improved throughout the training trials during place training for all treatment groups.

However, rats given cycling estradiol treatment had higher percentages of first choice, correct trials over overall performance also increased throughout response training for all treatment groups. In this case, treatment type had no significant effect on the rate of response learning. After switching the start location place, learners were initially impaired regardless of treatment.

However, the difference in performance between vehicle treated and estradiol treated rats became larger. On the second trial block, all rats returned to Prewitt test levels when they were subsequently trained on their original start location Response learners were impaired when given the switch start location test. However, pairwise comparisons revealed that performance in estradiol treated rats were covered to Prewitt levels.

On the second trial block. All rats returned to Prewitt test levels of performance when they were subsequently tested with their original start location. While attempting this procedure, it is important to remember to keep the mace conditions constant throughout the duration of the experiment and avoid stressing the rats when handling them.

Following this procedure, other methods like stereotactic surgery and drug administrations can be performed in order to identify the brain regions important for acquisition expression and retention of response and place learning. After watching this video, you should have a good understanding of how to train and test adult rats in the open field tower maze.