Archive for December, 2014

What does Pain Salience have to do with Pain Intensity? Part 1

December 18th, 2014

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.


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:

  1. Using a finger-span device, the subjects rated thermal pain during an fMRI scan.
  2. The investigators created lines on slides having lengths identical to each of the subjects’ thermal ratings.
  3. 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.
  4. 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):

Click to read more