Neuroscientists using functional Magnetic Resonance Imaging (fMRI) brain scans have discovered a connection between two parts of the brain that allows one part of the brain to dampen down emotional conflicts so that the brain's ability to think does not become impaired.
New York, NY (Sept. 20, 2006) – Columbia University Medical Center researchers have identified an emotional control circuit in the human brain which keeps emotionally intense stimuli from interfering with mental functioning. These results significantly enhance understanding of the neurobiology underlying psychiatric disorders involving emotional control, such as post traumatic stress disorder (PTSD) or depression.
The ability to prevent PTSD and depression would eliminate the brain damage that those mental diseases cause and therefore cause a substantial portion of the population to function at a higher level than would otherwise be the case.
Negative emotions are processed by the amygdala and the scientists decided to figure out which part of the brain exerted a dampening effect upon feelings of fear. They previously had found that people who are more anxious tend to react more to fearful stimuli if they are not consciously aware that they see something fearful.
The current findings extend on a previous Neuron paper (Dec 16, 2004) in which Drs. Etkin, Kandel and Hirsch found that anxious individuals show more activity in the amygdala, a central brain region involved in the processing of negative emotions, when unconsciously perceiving fearful stimuli (please click here to read the Columbia press release). When these stimuli were perceived consciously, however, the amygdalas of subject with both high and low levels of anxiety responded similarly.
Dr. Hirsch explained that this previous finding suggested that subjects were somehow able to control their conscious emotional responses, but that their unconscious responses may be more automatic. “Following the discovery of the amygdala’s role in fear response, we decided to explore the finer points of the neurocircuitry of fear – how it is regulated and controlled in the brain,” said Dr. Hirsch.
The scientists were able to identify the brain circuitry that resolves emotional conflicts.
To study emotional regulation, Dr. Etkin collaborated with Tobias Egner, Ph.D., a post-doctoral fellow in Dr. Hirsch’s lab, who has used fMRI to study non-emotional forms of attentional control. In the 2006 Neuron paper, subjects were asked to identify the facial expressions in photos shown to them as either happy or fearful. Across each face were the words FEAR or HAPPY, and were either congruent or conflicting from the facial expressions. When the word and face clashed, subjects experienced an emotional conflict, which slowed their performance and made them less accurate in identifying facial expressions.
Using a clever behavioral trick, however, the researchers were able to discriminate between brain circuitry that detected this emotional conflict from circuitry that resolved this conflict. They found that the amygdala generates the signal telling the brain that an emotional conflict is present; this conflict then interferes with the brains ability to perform the task. The rostral anterior cingulate cortex, a region of the frontal lobe, was activated to resolve the conflict. Critically, the rostral cingulate dampened activity in the amygdala, so that the emotional response did not overwhelm subjects’ performance, thus achieving emotional control.
Do people with anxiety problems have smaller or less active rostral anterior cingulate cortexes? Or is the connection from that region to the amygdala smaller?
Seems to me this study suggests where we could intervene in the brain to reduce distractions caused by emotional conflicts. Imagine a brain stimulator device that sends a signal to the amygdala saying "chill out dude".
The greater our understanding of human emotions becomes the better we'll be able to manipulate our own emotions. Will most people decide to function under the influence of biotechnologically manipulated emotions?
If people decide to manipulate their emotions which types of manipulations will they choose? On the one hand, I can see competitive pressures for people to manipulate their emotions so that they work harder and get more done. On the other hand, I can imagine a future in which very large numbers of people manipulate their emotions so that they do not feel the need to compete and so that they feel happy and satisfied with less material goods and lower social statuses.
|Share |||Randall Parker, 2006 October 01 07:14 PM Brain Emotions|