This 2015 California human study was of the dorsal anterior cingulate cortex (dACC):
“No neural region has been associated with more conflicting accounts of its function than the dACC.
The best psychological description of dACC function was related to pain processing—not executive, conflict, or salience processing.
We conclude by considering that physical pain may be an instance of a broader class of survival-relevant goals monitored by the dACC, in contrast to more arbitrary temporary goals, which may be monitored by the supplementary motor area.”
A related brain area – the paracingulate sulcus (PCS) – and its impact on the study’s findings was discussed in the supplementary material:
“The PCS is present in a subset of the population and thus extends the dACC further in the dorsal direction. This possible additional sulcus is relevant because, for some individuals, the ventral portion of the SMA [supplementary motor area]/pre-SMA may actually be the PCS.
The vast majority of fMRI studies overlook most individual differences in neuroanatomy and depend on the probabilistic neuroanatomy averaged across a group of participants and then on standard atlases that typically don’t take these individual differences into account.
There are two structural forms of PCS. The “prominent” form extends through the entire dACC region; however the “present” form begins in the rostral ACC and ends near the anterior border of the dACC.
Men are significantly more likely than women to have unilateral or bilateral PCS.
Additionally, six morphology studies have indicated the existence of a PCS that is left-lateralized.”
How about that? A brain area that:
- Assists in monitoring pain in the contexts of survival goals;
- Size, form, and placement varies widely among individuals;
- Is missing in some people!
Here’s a long critique of the study that included dialog with the authors:
“If you observe activation in dACC..your single best guess as to what process might be involved..should be ‘motor’ by a landslide. You could also guess ‘reward’ or ‘working memory’ with about the same probability as ‘pain.’
Of course, the more general message you should take away from this is that it’s probably a bad idea to infer any particular process on the basis of observed activity.”
And the authors’ “last comment”:
“Based on Neurosynth evidence, is more of the dACC selective for pain than for attention, autonomic, avoidance, conflict, emotion, error, executive, fear, negative affect, response inhibition, response selection, reward, and salience? Absolutely.”
http://www.pnas.org/content/112/49/15250.full “The dorsal anterior cingulate cortex is selective for pain: Results from large-scale reverse inference”