The human brain weighs only three pounds but is estimated to have about 100 billion cells, according to the clinical neuropsychologist Glen Johnson in his book "The Traumatic Brain Injury Survival Guide." As with other organs in the body, each part of the brain works to control specific processes. Among many other tasks, your brain manufactures, processes and controls your emotions.
The Limbic System
An NIH Teacher's Guide titled "The Brain: What's Going on in There," states the limbic system, which includes the amygdala and hippocampus, is involved in regulating emotions and motivations. In particular, the limbic system is involved in generating emotions that relate to survival like fear and anger, as well as feelings of pleasure related to such things as eating and sex. When you do something related to survival, such as eating, a circuit of specialized nerve cells located at the top of the brainstem works to relay messages to the limbic system. Fibers in these cells reach the frontal region of the cerebral cortex, which then sends a message of pleasure. Once this feeling of pleasure is received, the limbic system processes it and reminds the body to repeat this activity (in this case, eating) again.
Lobotomy and its Effect on Emotions
During the early twentieth century, lobotomy surgeries were conducted on people who were considered extremely violent or agitated. According to a Psychosurgery.org article about the history of lobotomies, the idea was that if nerves connecting the frontal lobes to the rest of the brain could be damaged or severed, they might regenerate and form new, healthy connections. Unfortunately, this did not occur.
Doctors of the era viewed lobotomy as a way to stop behavioral problems and eliminate violent emotions, because most patients became passive and nonviolent following the surgery. Lobotomies, however, also had unforeseen effects. Many patients stopped completing even basic activities of daily living and lost interest in everything around them. Most lacked motivation, acted with little or no emotion, and experienced difficulty performing even simple tasks that required multiple steps.
The ACC/Amygdala Relationship
According to a 2006 article titled "How The Brain Controls Emotions" appearing on the website Medical News Today, researchers believe an area of the brain's cortex known as the anterior cingulate cortex (ACC), is able to prevent emotions from interfering with mental functioning. The study piggybacked onto previous research that found the ACC was in fact connected to the amygdala in the brain's limbic system. Conducted by Amit Etkin, Joy Hirsch and colleagues and published in the September 21, 2006, issue of the journal Neuron, the study found that "emotional stimuli activated the amygdala as expected." In addition, when subjects were presented with "incongruent" images the ACC exerted control over the amygdala. Etkin and colleagues asked study participants to indicate whether a face image was happy or fearful, while being instructed to ignore written labels that read "fear" or "happy" written across each face. Their studies concluded that portions of the cortex were in fact able to ignore written labels and focus solely on reading the emotions of the picture.
The Role of Frontal Lobes
Frontal lobes play a critical role in controlling emotions, according to Glen Johnson. Located at the front of the brain, the frontal lobe is responsible for "managing" the emotions produced in other sections of the brain, according to Johnson. He explains that the frontal lobes are built with a control switch of sorts that can stop a person from acting on an emotion. When working properly, therefore, the frontal lobes will tell the body not to act on an impulse despite the emotion and message being generated.
