Ipsilateral vs. Contralateral (Within-subject) vs. Sham/Vehicle Control for Unilateral Pain Models

What are your feelings regarding the controls for unilateral pain models such as inflammatory (CFA/Zymosan) or neuropathic (SNI)? Ipsi-Contra controls have the advantage of needing fewer subjects and also using the same mouse as its own control (within-subject), minimizing variability between subjects (potentially). The downside is that unilateral treatments might have contralateral effects, as some studies show. There isn’t consistency in this regard.

What do you think?

@tberta @liz @runDRG @ShanTan @jmogil

Mirror hypersensitivity is extremely common, and depending on the strain, extremely robust. I think it’s a big mistake to not have pre-injury baselines and (where appropriate) sham surgery groups.

1 Like

Thanks @jmogil
I agree entirely with pre-injury baseline(s). And I’ve always done a sham or vehicle. But i see some studies in good journals sometimes using ipsi contra instead of sham. So I thought I’d ask.

I’d definitely be worried about “cross-over” effects, but I think how worried you should be depends on your model. If you’re modeling chronic pain, or looking in the brain, it’s likely a bigger issue than if you’re looking acutely in the periphery.