Deart Julien  Artinian,

What you choose to do is up to you but you have to give references to other researchers who did the same or provide an explanation why you modified the protocol. Record your lights and noise so that another researcher can follow your detailed description of your method in your paper and end up with the same result. Everything about Barnes maze is given at this site:

http://www.nature.com/protocolexchange/protocols/349#/equipment

"EQUIPMENT SETUP:

The maze:

The paradigm consists of a circular platform (92 cm of diameter) with 20 equally spaced holes (5 cm diameter ; 7.5 cm between holes) along the perimeter and is elevated 105 cm above the floor. The colour of the maze depends on the strain to be tested (white or black). Provide enough contrast between mice and the open surface so that the computer tracking software is able to recognize them.

In the Barnes maze, animals receive reinforcement to escape from the open platform surface to a small dark recessed chamber located under the platform called a “target box”. Mice can access the target box through an escape tunnel (transparent plastic tube 50 cm long, 5 cm diameter), which is located under the target hole (28×22 x 21 cm). A ramp is placed under the target hole so that mice may reach the escape tunnel easily. From the centre of the maze all holes should look identical and the ramp should not be visually discriminated from the other holes from most points on the maze, even if it is difficult to ensure no visual discrimination once the mouse is situated adjacent to the escape hole.18

Stimulus/reinforcement

Several reinforcements have been used as stimulus to complete the task: bright light, noise and/or a fan. We suggest using only aversive noise as reinforcement because using a fan may be too stressful for mice and noise is considered an appropriate stimulus in the system used.

In addition, the use of bright light may be a problem if a video camera, computer and tracking software are used to record performance; most tracking systems are sensitive to light reflections from the lit surface.

Use aversive noise of 85 dB as a motivator by an electronic metronome (IMT-400, Intelli) as a buzzer for the experiments; it is very useful because you have timbre, pitch and volume settings to choose. The same parameters have to be used during the whole experiments.

Room configuration: Visual cues (use different colours and shapes: triangle, rectangle, circle and/or a cross) should be prepared and placed surrounding the maze. Animals will have spatial visual cues endogenous to the room (for example a door, a desk or a computer) and intentional (prepared by the experimenter). These cues should not be moved during the whole experiment as these are the animal’s reference points for locating the target hole.

Video-tracking system: TiBe Split software for the BM was designed for our laboratory. Primary and total latency as well as primary and total path length during training days and probe trial can be analysed. Primary and total errors should be manually calculated as software approach is not efficient enough to distinguish between head deflection and or just approximation to the holes. "

The used Video Tracking System TiBe was developed by Imagination Computer Services GesmbH in cooperation with the University of Veterinary Medicine

Vienna. More information on TiBe can be found at: http://www.imagination.at/en/?Products:Science

Thanks for your reply Béatrice.

Of course I knew the protocol from Sunyer, but I wanted to get more details, examples and advices. For example, they are one of the only group I know not using curtains around the maze... But thanks anyway.

I have never seen curtains in any laboratory I have visisted.

I double checked the litterature and I can't find again the ref... so it means you are very right, no curtains around the maze !

I did a lot of watermaze experiments and for this test, people use curtains for different reasons, such as standardization of the environment with 4 cardinal directions, but also to visually isolate the experimenter. Without curtains, mice (C57Bl/6) tended to be attracted by me and to scratch the wall of the maze, floatting and waiting for me...

Do you think the visual presence of the experimenter in the room can add a bias in the Barnes maze ? Anyway it will simplify my setup without curtains !

Many thanks Béatrice.

Everything can add an bias but the conditions are equal for all mice so it does not really matter

Here you have our well-functioning linear maze. Look at the picture. very useful, no water and the like needed:

Thanks for this Béatrice, I'm gonna have a look on this maze.

My question from an uneducated Librarian is "WHY THE HELL DO YOU WANT TO KNOW THIS">>emojiiiii emojjjjj ha.ha,