A sixth sense for danger
While some scientists discount the existence of a sixth sense for danger, new research from Washington University in St. Louis has identified a brain region that clearly acts as an early warning system -- one that monitors environmental cues, weighs possible consequences and helps us adjust our behavior to avoid dangerous situations.
"Our brains are better at picking up subtle warning signs than we previously thought," said Joshua Brown, Ph.D., a research associate in psychology in
the Arts and Sciences department of Washington University, and co-author of a study on these findings in the Feb. 18 issue of the journal “Science.”
The findings offer scientific evidence for a new way of conceptualizing the complex executive control processes taking place in and around the anterior cingulate cortex (ACC), a brain area located near the top of the frontal lobes and along the walls that divide the left and right hemispheres.
"In the past, we found activity in the ACC when people had to make a difficult decision among mutually exclusive options, or after they made a mistake," Brown said. "But now we find that this brain region can actually learn to recognize when you might make a mistake, even before a difficult decision has to be made. So the ACC appears to act as an early warning system -- it learns to warn us in advance when our behavior might lead to a negative outcome.”
Implications for mental illness
The ACC has been the focus of intensive scientific research in recent years because it plays a critical role in the brain's processing of especially complex
and challenging cognitive tasks. Abnormalities in the region are associated
with a host of mental problems, including schizophrenia and obsessive-compulsive disorder.
"Our results suggest how impairment of the ACC mechanisms in schizophrenia can lead to breakdowns in the early warning system, so that the brain fails to pre-empt or control inappropriate behavior," Brown said. "On the other hand, in individuals with obsessive-compulsive disorder, the ACC might warn of an impending problem even when no problem is imminent."
"Interestingly, we also found evidence that the same neurotransmitter involved in drug addiction and Parkinson's disease, namely dopamine, seems to play a key role in training the ACC to recognize when to send the early warning signal," he added.
Known to be an important component of the brain's control system, the ACC
is believed to help mediate between fact-based reasoning and emotional responses, such as love, fear or anticipation.
"For a long time we've been interested in how the brain figures out how to integrate cognitive information about the world with our emotions, how we feel about something," Brown said. "For many reasons, people think the ACC might be the brain structure responsible for converging these different signals. It seems to be an area that's involved in deciding what information gets prioritized in the decision-making process.”
New paradigm for brain's "whoops center"
Recent studies have documented spikes of activity in the ACC just as people realize that they've made a mistake of some kind, a sensation some describe as the "whoops" moment.
Theories based on these findings suggest that the primary role of the ACC is to help detect and subsequently correct mistakes or, alternatively, to detect the state of high-conflict that often accompanies mistakes".
Brown's study, co-authored with Todd Braver, Ph.D., an associate professor
of psychology in Arts and Sciences at the same university, offers compelling evidence that the ACC is better understood as a pre-emptive early warning system, one that is actively working to help us anticipate the potential for mistakes and thus avoid them altogether.
"We started with the premise that perhaps the cingulate was not responding to the detection of an error or state of conflict, but maybe instead what the cingulate is detecting is the likelihood of making an error," Brown said. "We wanted to see if the cingulate would become more active even in situations where no conflict is presented and no errors are made, but the potential for error is still higher than normal.”
To test their hypothesis, Brown and Braver developed an experiment requiring healthy young people to respond to a series of cues on a computer screen.
Participants were presented with either a white or a blue dash, which soon changed into a small arrow pointing either right or left.
They were instructed to quickly push one of two buttons depending on the arrow's direction. To simulate conflict, researchers occasionally slipped in a larger second arrow that required participants to change gears and push the opposite button.
"The idea is that at some point you have these competing tendencies – to push the right or left button -- and both are active in brain at same time, which creates conflict," explains Brown. "Some theories suggest that whenever you see these two arrows, then that drives this state of conflict and it's the state of conflict that is being detected by the cingulate."
By increasing the delay before presentation of the larger second arrow, researchers raised the odds that an individual would reach "the point of no return" and thus be unable to change gears in time to avoid pushing the wrong button.
They then adjusted the delay time over many trials so that each participant eventually exhibited error rates of about 50 percent when provided with an initial blue priming dash, compared with error rates of only 4 percent when presented with a white priming dash.
Using functional magnetic resonance imaging (fMRI), researchers captured images of brain activity at 2.5-second intervals throughout the experiment.
"We didn't tell them that the white or blue cue offered any clue about their likelihood of making an error on any particular trial, but by the end of the
session, some of them had begun to figure it out, at least on a subconscious level," Brown said.
Even among those who remained relatively unaware of the blue cue's significance, researchers found that simply showing the blue color was eventually enough to spark increased activity in the cingulate, and that this effect strengthened over time as the subject became more familiar with the task.
Thus, brain imaging confirmed that the ACC had "learned" the significance
of the blue cue, and had begun, at least subconsciously, to adjust behaviors accordingly, the study found.
"It appears that this area of the brain is somehow figuring out things without you necessarily having to be consciously aware of it," Brown said. "It makes sense that this mechanism exists because there are plenty of situations in our everyday lives that require the brain to monitor subtle changes in our environment and adjust our behavior, even in cases where we may not be necessarily aware of the conditions that prompted the adjustment. In some cases, the brain's ability to monitor subtle environmental changes and make adjustments may actually be even more robust if it takes place on a subconscious level."
Shown/Header image: A new theory suggests that the anterior cingulate cortex, described by some scientists as part of the brain's "whoops center," may actually function as an early warning system -- one that works at a subconscious level to help us recognize and avoid high-risk situations.
Shown/Header image: Researchers provided study participants with a series of blue or white cues and asked them to push one button or another depending on the direction of arrows. Brain imaging suggested that an area of the brain had "learned" to recognize that blue cues indicated a greater potential for error, thus providing an early warning signal that the ongoing behavior might result in negative consequences. Image credit(s): Joshua Brown, WUSTL
Get more info: Washington University, (314) 935-6375
Read additional sci-tech stories in the FEB/MAR 2005 issue of "Arte Six."