In this video, we will walk you through how exactly mice learn to self head-fix using the self head-restraining platform. The concept is quite simple and relies on operant or classical conditioning principles. Mice learn head-fixation by walking through the narrow corridor of the chamber past a set of rails that latch the head plate in place allowing the mouse to receive a water reward.
The rails are locked into place once the photo beam sensors, located on the corridor, are triggered when the mouse has reached the correct position. The rails can be set to lock for a specified amount of time, while the mouse performs a behavioral task.
In this case, the timer has been set to 10 min. After 10min the rails will automatically release, allowing the mouse to return to its home cage.
The most critical step in learning self-latching is the habituation phase.
During the habituation process, which typically takes between 1-2 weeks, a habituation tube with a similar non-locking rail system is placed in the home cage and attached to a water reward. At this time, mice should be placed on water restriction so that they are motivated to seek water. Mice gradually approach and enter the tube, following the rail system until they are able to obtain water.
The key difference between habituation and the actual task is that during habituation the rails do not automatically lock so the mouse can exit at any point. This allows mice to get comfortable with having their head plates in the rail system but also gives them the opportunity to voluntarily escape.
After habituation, once mice are comfortable entering the corridor and sliding their head plate into the rails they easily learn to self-latch using the self head-restraining platform and can then be trained to perform operant behaviors while head-fixed.