Has anyone tried conditioned place aversion (CPA) with pain?


#1

I saw this CPA assay in a paper from Cheng et al. (2017)

07 PM

This looks laborious but useful.

To measure the negative valence effect associated with brush-evoked dynamic mechanical hypersensitivity, we used a biased compartment-assignment proce- dure, in which we measured the influence of VT3Lbx1 neurons on the time of mice spending in the dark compartment receiving conditional stimulations. The CPA apparatus consisted of two chambers (10 × 10 × 15 cm per compartment), one dark (A) and one bright (B), with a metal mesh floor (i.e., the chambers, which had no floor, were placed onto a metal mesh used as the floor). The center was an inserted black (facing compartment A) and white (facing compartment B) plas- tic wall with a rectangular hole in the bottom center (4 × 8 cm; Fig. 4a). Mouse movement was recorded by a Sony camcorder. The amount of time a mouse spent in chamber A was evaluated by the experimenter after recording. On day 1, each mouse was placed in the bright compartment (B) and allowed to freely explore between chambers A and B for 15 min (pre-test). With this apparatus design, most if not all naive mice showed an initial preference for the dark chamber. Mice were conditioned over a 4-d period. On days 2 and 4, the hole in the central wall was blocked with a dark film on the A compartment side. The mouse was put in the bright chamber for 20 min. On days 3 and 5, the hole in the central wall was blocked with dark film on the B compartment side. The mouse was then placed in chamber A, and the injured hindpaw was brushed with the paintbrush from heel to toe for 20 min at ~2-s intervals. On day 6 the hole in the central wall was unblocked. The mice were tested for their compartment preference by placing them in the bright compartment first and allowing them to freely explore the entire apparatus for 15 min (post-test). The aversion score was measured as the difference in time (in s) spent in the dark compartment during pre-test versus during post-test (i.e., aver- sion score = (pre-test time in dark chamber) – (post-test time in dark chamber)).

Has anyone done this, or something like it, and have success? Any tips?

@ShanTan @LegakisL @ram_kandasamy @Benjamin @liz @thicunha @TSheahan

We discussed this here in the past in some capacity, and it seems like CPA might not be very easy to do with mice in pain assays:


#2

And from a recent paper, here is one with optogenetic stimuli to induce aversion. Also, make note of the setup. It’s basically two cardboard boxes taped togehter. Low-tech and cheap, but gets the job done.


#3

#4

An update. A box modeled on Cheng 2017. This depends on the niceness preferring the dark (red) side. We’ll see. I would have preferred that the red side were more a semi-transparent dark red.


#5

https://photos.app.goo.gl/WSsV4MjYgYbNM1Cm2

I built the cage as it was described in the paper. The mice don’t seem to prefer the dark side. Any thoughts?


#6

We use CPA with optogenetics similar to the Beaudry paper linked above and it has been working well in a mouse masseter tendon ligation model.

In my previous lab I tried doing the light-dark box test a handful of times with a handful of different genetic models (DISC1, NPAS3, UBE3A, etc.) and think the most preference I ever saw for the dark box was 55-60%. I gave up on the test but decided if I were to ever do it again I was going to get a bright lamp and have it shining on the light side. Not sure if it would help but the standard lighting in the room was not able to motivate the mice to move on the Barnes maze (mice are in the open on a circular maze and searching for a dark box underneath the maze). The bright lamp was enough to get that test to work so figured that could be an issue in the LD box test.


#7

Hi,
Thanks for your insights.

I’ve been doing a real-time place aversion with different optogenetics lines, as in this paper and it’s been excellent. Not a huge amount of work and immediate results.

In my previous lab I tried doing the light-dark box test a handful of times with a handful of different genetic models (DISC1, NPAS3, UBE3A, etc.) and think the most preference I ever saw for the dark box was 55-60%. I gave up on the test but decided if I were to ever do it again I was going to get a bright lamp and have it shining on the light side. Not sure if it would help but the standard lighting in the room was not able to motivate the mice to move on the Barnes maze (mice are in the open on a circular maze and searching for a dark box underneath the maze). The bright lamp was enough to get that test to work so figured that could be an issue in the LD box test.

Interesting. The paradigm I was trying to follow was the one in Cheng et. al 2017, where they want to have a preference for the dark side first. That probably helps to create larger differences that are easier to see, but the truth is, many people do CPP/CPA where at baseline, there is nearly equal preference for the boxes. That’s more typical in fact. So I think I should just do that if I want to do a conditioned test. Maybe the ambient light is not strong enough in the light box to induce the movement.