Here is a question for everyone.
Mechanical sensibility is measured primarily in two ways:
(1) Threshold method “up-down” (Chaplan 1994)
(2) Frequency response method (for example, see Simonetti 2014 below)
While the threshold ‘up-down’ method seems predominant in the literature, I’ve come to prefer the frequency-response method, in that I find it more consistent between animals between days. Moreover, because it is normally distributed(?), parametric stats can be used appropriately.
Here is the question.
Do you do the applications of a fiber to a single subject sequentially (1st, 2nd, 3rd, 4th, etc.) or do you do an application to all subjects, and then the next and then the next. In other words:
Let’s say you have 3 mice in a group.
Round 1: Mouse 1 (first application) -> Mouse Two (first application) -> Mouse Three First application
Round 2: Mouse 1 (second application)…
Round 3 Mouse 1 (third application).
Both ways are used by different experimenters, but it’s never clear in the literature. My interpretation is that it is more common to perform all applications of a given fiber to a single subject before moving to the next. Some interval (5 seconds?) is given between applications so as to not sensitize or cause anticipation, but the all-at-once seems more common.
What do you do? And what are the virtues of each way? And does it matter?