In the famous Milgram Experiment, it only took commands from a purported authority figure to get people to subject another study participant to electric shocks up to 450 volts (about a quarter of the voltage used to execute people in the electric chair). In reality, the other participant was an actor, and there were no actual shocks. Nevertheless, the experiment revealed how easily influenced people are by authority, even when that authority has little real power. If that’s how ordinary people react to an unrelated authority, graduate students have no chance to resist their advisor’s commands. That was the situation faced by Andrew Jahn, who graduated from IU with his PhD in 2015. While a member of the Cognitive Control Lab at IU, he completed a project in which participants were shocked inside a brain scanner, to watch what happened inside the brains of the research participants. (Humorous allusions aside, the electric shocks in this case were much smaller and calibrated to be tolerable by the participants).
Functional magnetic resonance imaging (fMRI, a.k.a brain scanning) is a technique for determining which brain regions change their patterns of activity in response to particular conditions. You may be surprised to learn that we still know remarkably little about how the brain is organized. We know that different brain regions do somewhat different things, but at the same time, there is a substantial degree of overlap and cooperation that has not yet been fully mapped out.
Typically, we use a special projector to show participants in the MRI machine images from a computer. In experiments probing cognition, these images typically consist of simple shapes, numbers, and words indicating information relevant to decision making, like an amount of reward for successful performance. These types of experiments allow us to look at how the brain responds to many interesting variables such as risk, reward, and loss. Though these concepts certainly play important roles in the real world, they are quite abstract. How does the brain respond to much more visceral stimuli, like pain?
This question is particularly relevant in light of a provocative 2015 paper claiming that one particularly well-studied brain region, the anterior cingulate, responds solely to pain. Proving that no community is immune to internet drama, the publication of this paper provoked a storm of tweets and blog posts in the cognitive neuroscience world, an eruption that was soon dubbed #cingulategate.
Part of the reason Cingulategate was so dramatic was that plenty of past work had shown that the anterior cingulate cortex responds reliably to response conflict. Response conflict occurs when you can only make one response, but two responses are competing for expression. This can occur during emotional and motivational conflict such as when you simultaneously want to reach for that cookie and also want to resist, but it can also occur in more abstract situations.
This brings us to why Dr. Jahn was shocking participants in the scanner. He wanted to compare the responses in the cingulate to conflict, surprise, and pain all in one study rather than look at differences across separate studies. Each trial of the task showed a cue, consisting of a colored rectangle or circle, followed by either an electric shock or a simple button pressing task. The cue indicated whether the shock was likely to be big or small, or whether the button pressing task would evoke high or low response conflict. Sometimes the outcome didn’t match the cue, eliciting surprise.
He found strong responses in the cingulate for all three factors, though not all in the same regions. The lowest (or most ventral, for all you anatomy buffs) part of the cingulate showed the strongest pain response while higher (more dorsal) regions responded most strongly to the more cognitive variables of conflict and surprise. This pattern indicates that the paper which sparked Cingulategate certainly overstated the specificity of the pain response. However, it did contain a kernel of truth in that there does seem to be a region of the anterior cingulate that is particularly sensitive to pain.
This research and similar work in cognitive science will help us better map out the functional architecture of the brain, allowing us to better understand how it works. Stay tuned for reports on more work going on in the Cognitive Control Lab, including adding nicotine vapor to the repertoire of novel MRI stimuli!