Knowledge Base

Acquiring Data

Protocol

The following protocol tests for basic working memory (the subject learns not to re-enter a baited arm).

Habituation (Pre-Training)

In a typical radial 8-arm maze test, first a pre-training session is carried out in which the animal is allowed to freely visit all arms for 10 to 15 minutes per day. Also, the doors are regularly opened and closed to habituate the animal.

Training Trials

In this phase, the animal is exposed to where the food is, and this is what the later tested memory is based on. Animals are trained one session per day, for approx. one week.

Typically, all arms are baited in this phase. At the start of the trial, the animal is placed in the center of the maze, facing the same direction on every trial, everyday.

Stop the trial when:

1. All eight arms have been visited
2. 10 minutes have passed since the start of the trial
3. 2 minutes have passed since the animal's last arm entry

Performance

Among the variables commonly used for the analysis of performance are:

• The number of errors in each session (entering an arm that has been visited previously counted as an error) and the total number of errors across eight sessions
• The number of correct choices in the first eight arm entries of each session

Reference Memory Errors

While the previous protocol is primarily sensitive to impairments in working memory, an alternate protocol allows a disassociation to be achieved between working and reference types of memory.

In this protocol, four arms are baited for the training phase. The same maze arms are baited each day and, across sessions, the animal learns to ignore the other arms, which never contain a reward. This is the reference memory component of the task. In the test phase, food items are placed in the same arms as they were on the memory trials that day. It is recorded when the animal gets 100% correct on his memory trials. When the animal enters an arm that is not baited, it is marked as an error.

Reference: Wenk, G.L. (2004). Current Protocols in Neuroscience, 8.5A.1-8.5A.12.

Source: EthoVision XT 18 - Application Manual, Noldus Information Technology