SUMMARY: Part One: There are two separate areas of the insula. One is involved with generalized sensory magnitude integration, and the other is specialized in evaluating nociceptive stimulus properties including a weaker estimation of magnitude.
Student: And what is giving you such a puzzled look?
Professor: I am confused! Some experts have highly criticized one of my favorite research studies.
- In a recent blog post, I wrote about an apparently well designed study by Baliki et al. (2009) demonstrating that the insula was highly involved in dyspnea magnitude estimation (click to see post).
- But even more recently I found a review in which Moayedi & Weissman-Fogel (2009) meticulously critiqued the methods, results, and conclusions of the Baliki et al study.
METHODS AND RESULTS FROM BALIKI ET AL. (2009)
Professor: To be fair to Baliki et al. and Moayedi & Weissman-Fogel, this post will be in two parts, and the parts are detailed. Let’s begin with the design that Baliki et al. actually used in their study:
- Using a finger-span device, the subjects rated thermal pain during an fMRI scan.
- The investigators created lines on slides having lengths identical to each of the subjects’ thermal ratings.
- During a subsequent scan, the subjects rated these lines as they varied in length, i.e., made visual ratings, which unbeknownst to them were the same values as their heat pain ratings.
- To determine how much magnitude variability there was in each participant’s ratings, they
calculated the variance both for their pain ratings and for their visual length ratings.
Student: Please show Part A of their Figure 1 and its original legend from the article by Baliki et al. (2009):
