14 DAY TRIAL // A headache makes you inefficient. No matter what are you trying to do, the pain captures all of your resources. It is normal, this is how we survived during our evolution in a painful world. Now, a German team at the University Medical Center Hamburg-Eppendorf led by Ulrike Bingel has found the brain nucleus that decreases your cognitive processing while in pain. This pain-related brain nucleus differs from the one linked to cognitive processing interference connected to a distracting memory task.
In their investigation, the scientists asked the subjects to perform a cognitive task of distinguishing images, but also a working memory task involving remembering images. The volunteers made all this while experiencing various levels of pain provoked by the zapping of their hands by a harmless laser beam. While they experienced these sensations, the subjects' brains were scanned employing functional magnetic resonance imaging (fMRI), which reveals blood flow across the brain, linked to brain activity.
The team found a brain nucleus called the lateral occipital complex (LOC) as the cognitive-related area connected by both "working memory load" and pain, which was not a surprise as the LOC was previously discovered to be linked to image processing. Next, the researchers looked for the brain area affecting the activity on the LOC. The best candidate was the rostral anterior cingulate cortex (rACC), linked to the brain's pain processing. This is also part of the anterior cingulate cortex (in the connection area between the two hemispheres), involved in "executive" functions like the attentional control.
Indeed, the fMRI scans revealed that the rACC was the brain nucleus activated when pain affected the LOC. A working memory load induced changes in the LOC activity through a different nucleus, the inferior parietal cortex.
Visual modulation by pain - as shown by fMRI scans - is behaviorally relevant, as the researchers also noticed a parallel impairment of accuracy in the subjects' ability to recognize images.