Mice Learn Voluntary Head-Fixation

Mice Learn Voluntary Head-Fixation

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.

Questions?

How to Get the Most out of Your Operant Training Chambers

How to Get the Most out of Your Operant Training Chambers

In this post, we describe four common tasks you can use with your operant training chambers, and what exactly they measure. All of these tasks are easy to program with our Touch Panel operant chambers and TaskStudio software.

Learn more about our chambers and their unique specifications here.

Two-Choice Visual Discrimination Task:

This task involves learning that one of the two shapes displayed on the screen is correct. Touching the correct stimuli is rewarded and touching the incorrect stimuli is punished with a timeout where the mouse or rat cannot start another trial. Once the mouse or rat learns the correct stimuli, they are reversed so that the previously rewarded stimuli now results in punishment. This type of reversal learning requires the mouse or rat to inhibit automatic responses that require the prefrontal cortex. This task is a great measure of cognitive flexibility and is a great tool for examining animal models of many neuropsychiatric disorders.

Example of the two-choice visual discrimination task.

Paired Associate Learning (PAL)

In this task, mice or rats learn and remember which of three objects goes in which of three spatial locations. On each trial, two different objects are presented; one is in the correct location; the other in the incorrect location. The rat or mouse must choose which stimulus is in the correct location. This task relies on the hippocampus and can be used to test hippocampal dysfunction as seen in Alzheimer’s disease.

Visuomotor Conditional Learning (VMCL)

This task is a stimulus-response task. The rat or mouse must learn that two stimuli go with two different locations. When stimulus A is presented the rat or mouse must always respond to location A. If stimulus B is presented, the rat or mouse must always respond to location B. This type of test is useful for examining motor dysfunction in rat and mouse models of Parkinson’s disease and Huntington’s disease.

5-Choice Serial Reaction Time (5CSRT)

This task requires the rodent to respond to a brief visual stimuli presented randomly in one of 5 locations. It is used to measure attention span and impulsivity control in mice and rats and is useful for animal models of ADHD.

Questions?

Image simultaneously during behavior with the TaskForcer

Image simultaneously during behavior with the TaskForcer

The TaskForcer and Imaging Adapter Base Mount were designed for simultaneous neural imaging during operant behavior. What’s unique about the imaging adapter base mount is that you can adjust x y and z positions, which allows you to adjust the TaskForcer angle under the 2-photon microscope. This is especially important for making sure the cranial window of the experimental test subject is parallel to the objective. Even slight changes to the angle of the cranial window can offset regions of interest in the imaging window and sacrifice data collection.

The base mount contains mm markings so you can precisely align the TaskForcer unit across experimental sessions that may be spaced days or weeks apart
Although the mount was designed for the TaskForcer, it is sold separately and is compatible with a variety of behavioral setups. For more information about the imaging adapter base mount and the TaskForcer check out our TaskForcer product page.

Running Multiple Behavioral Tests?

Running Multiple Behavioral Tests?

The Free Maze, our reconfigurable modular maze, has you covered!

With the Free Maze, all components are reconfigurable, meaning you can easily disassemble and reassemble your maze with unique specifications. This allows you to create different mazes for different behavioral assays using the same piece of equipment, instead of having to purchase individual mazes for each assay you want to run.

The standard setup is the T-Maze, but individual corridor components can be mixed and matched to build your custom maze. 

This reconfigurable modular maze was designed to offer users flexibility instead of being constrained to a single maze type. Ultimately, the maze design is up to the user’s imagination.

Examples of different corridor types offered with the Free Maze

The reconfigurable modular maze system also comes with photo beam sensors that can be placed anywhere along the maze to record the animal’s position. Breaks in photo beam sensors are also used to trigger automatic doors that open up new pathways for the animal while they use the maze.

Not only can users disassemble corridors to construct different maze types, but they can also move the location of the photo beam sensors and door units, to change the trajectory of the animal’s path within the same maze. Corridors are sized separately for both mice and rats.

Our reconfigurable modular maze system is ideal for learning and memory experiments assessing:

  • Spatial memory
  • Basic working memory
  • Differences between working and reference memory
  • Impairments in the working memory

The reconfigurable modular maze is also completely automated. Photobeam sensors, doors, and reward dispensers are controlled by TaskStudio software. With this software, users can create and save tasks specific to each maze type, using the Trial Builder. The software makes it easy to run through different trials within the same session or across sessions.

Performing in vivo electrophysiology or optical imaging in freely moving animals? The maze is also compatible with in vivo electrophysiology and optical imaging techniques.

Learn more about the Free Maze by visiting our product page or connecting with an expert.

Price Comparison of 3 Neurotransmitter Detection Methods

Price Comparison of 3 Neurotransmitter Detection Methods

When it comes to neurotransmitter detection such as Dopamine, Serotonin, Norepinephrine, Glutamate, GABA, Acetylcholine, etc., in microdialysis samples, tissue homogenates, blood plasma, and others, there are three (3) main methods; LC-Mass Spectrometry (LC-MS), HPLC-ECD (Electrochemical Detection) & ELISA/Radioimmunoassays.

The first option is LCMS, it provides the highest sensitivity and specificity to the detecting neurotransmitters and also the most expensive option. The price range is between US$200,000 to $600,000.

The second method is HPLC-ECD which is much more cost affordable while offering great sensitivity. The price range is between US$20,000 to $60,000.

The third method is ELISA or Radioimmunoassays which offers less sensitivity. There is also a concern of selectivity due to cross-talk among antibodies.

Therefore, when choosing which method would work best for you, we would recommend HPLC-ECD.

A solution for precise optical imaging during head-fixed behavior

A solution for precise optical imaging during head-fixed behavior

Cranial window implants in head-fixed mice offer stable optical access to large areas of the cortex over extended periods of time. Window preparations can be combined viral preparations (or in genetically modified mice) to monitor, map or manipulate neuronal activity (eg. using optogenetics) in awake behaving animals. This makes them extremely useful for studying relationships between neuronal activity and behavior.

A major roadblock with the cranial window and optical imaging approach.

The main difficulty with the cranial window and optical imaging approach is the alignment of the mouse or other experimental subjects under the microscope. Due to the curvature of the subject animal’s skull, cranial windows are almost always angled. However, for the most precise optical access, windows should be aligned parallel to the imaging objective. Even minor changes to the window angle can offset neuropil in the axial direction under the microscope and sacrifice data collection. This issue becomes compounded when you repeat experiments over time. Minor changes in the window angle across sessions can distort or change the location of neuropil within the same imaging region, making it challenging to draw significant conclusions from your data.

How can you precisely align the mouse under the microscope each time?

One of AMUZA’s tools, the Imaging Adapter Base Mount on the TaskForcer, overcomes this challenge.

While the mount was made for the TaskForcer unit, it can be made to fit any behavioral rig and enables a more precise fit of your behavioral setup under the microscope.

The Imaging Adapter Base mount can be rotated in X, Y and Z directions to change the angle of your behavioral setup so that you can precisely align the head of the mouse underneath the microscope.

The base mount also contains mm markings, allowing you to get the exact same fit each time you place your behavioral rig under the microscope. This greatly minimizes the chance that observable changes to neuropil are due from distortion of the imaging location under the microscope and greatly improves the quality of your data.

If you are imaging over a wide field of view, the Imaging Adapter Base Mount can be readjusted to align each separate imaging location parallel with your objective. This ensures a consistent level of accuracy across each imaging location.

Each Imaging Adapter Base Mount is custom built to fit your microscope to ensure that you are getting the best product tailored to your specific needs.

In an era of Neuroscience where reproducibility of data is crucial, the Imaging Adapter Base Mount and TaskForcer unit offer stable precision for the most accurate results. You can learn more about this product, and the TaskForcer on our TaskForcer webpage.

Imaging Adapter Base Mount (left) and TaskForcer with base mount (right)