Von Frey Testing on mice is Difficult…
And that’s why we designed Mousemet. For algometry at higher force ranges, please visit our parent website, www.topcatmetrology.co.uk and click on the Prod!
Uncomfortable
The mouse runs around, the bars of the floor get in the way and you have to crouch and look upwards to do it.
Delicate
The forces are tiny: the smallest amount of hand tremor affects the reading and, with most electronic systems, the measurement is a small proportion of the range of the instrument.
Operator Sensitive
Technique is all important: changing the operator during a study can seriously affect the data.
Time Consuming
With filaments or an electronic system, it takes a long time and the percentage of invalid tests tends to be high.
Mousemet is our solution
Click here for a PDF of the initial evaluation, performed at Newcastle University and presented at the autumn meeting of the AVA in Liverpool last year.
Ergonomic
The mouse is contained in a “one-dimensional run”. This enclosure is wide enough for the mouse to feel comfortable in, thereby ensuring natural behaviour, but not wide enough to turn round in without standing up. So, for the vast majority of the test session (after the initial exploratory behaviour), the mouse will be pointing left to right (or right to left). Mousemet is supplied with one run as standard. Additional runs may be purchased to save time; the next mouse can be exploring while you test the current one. The runs are suitable for laboratory sterilisation procedures.
He (or she) will also be standing on bars which are sized and spaced specifically for his paws allowing him to grip the bars comfortably with his toes, but allowing the maximum plantar area for testing. The run also has a lid; to remove the mouse, just take off the lid and then lift the entire run off the two vertical legs. The mouse may then be decanted safely back into his cage.
Designed for scientists
So that’s got the mouse where we want him. Now we need to make the scientist comfortable. We do this by making the supports adjustable, in 2cm click steps so that, when you are sitting at the bench with your elbows on the table (using the elbow pads provided) the bars of the run will be at eye level.
The run is transparent, so you have a clear view of the mouse’s paws and the probe. It also means that your hands will be at the right height to operate MouseMet.
Easy to Use
MouseMet is a highly sensitive rotary force transducer with a measurement range of 0.1-5g. The innovative design makes it insensitive to slight hand tremor; forces down to 0.1g can be applied without any difficulty.
Comfortable
To apply a force with MouseMet, hold the instrument with the probe arm horizontal, touch the probe tip onto the plantar surface, and then rotate the black handles while keeping the arm horizontal. This is intrinsically easy and comfortable with your forearms properly supported and gives you full control over the placement of the probe tip.
Repeatable between operators
The force ramp is displayed immediately on the notebook computer and the peak force calculated for you. Reject tests are inevitable, because the mouse moved, the probe slipped or just because the scientist wasn’t sure if it was a valid response.
MouseMet allows you to select immediately via a thumbswitch. Press the switch within 5 seconds of the test, and that ramp is stored. Otherwise it’s ignored. Similarly, we’ve watched people trying to achieve a pre-determined force ramp rate, by watching guide lights, or symbols on a computer screen. This really isn’t practical; you should be watching the mouse. So MouseMet allows you to preset the force ramp rate that you’re aiming for, and overlays it onto the test result displayed. The ramp on the right here is a good one.
Efficient measurement
With a little bit of practise, it’s easy to be consistent. The ramp rate window in the graph on the left is set to 1gf/second and this test is clearly a reject; the rate is too high and also there is no dwell time at or near the peak force. it’s doubtful whether the mouse would have time to feel it.
After the test series, MouseMet’s software allows you to select the ramps you want to keep and then exports the results to Excel.
Free 30 Day Trial
MouseMet is available for a free 30 day trial. If you’d like to know more please call Mike on +44 (0)7739913696 or email mike@mousemet.co.uk.