Sad Brain, Happy Brain

So Happy (and Sad) Together
The common emotions of sadness and happiness are a problem for researchers. Depression and mania are core areas of study for a neuroscientist. But everyday ups and downs are so broadly defined that researchers have a hard time figuring out what exactly to study. They note activity in virtually every part of the brain. Last year Drs. Peter J. Freed and J. John Mann, publishing in The American Journal of Psychiatry, reported on the literature of sadness and the brain. In 22 studies, brain scans were performed on nondepressed but sad volunteers. Sadness was mostly induced (subjects were shown sad pictures or films, asked to remember a sad event), although, in a couple of studies, subjects had recently experienced a loss. In the aggregate, sadness appeared to cause altered activity in more than 70 different brain regions. The amygdala and hippocampus both show up on this list, as do the front part of the brain (prefrontal cortex) and the anterior cingulate cortex. A structure called the insula (which means "island") also appears here—it is a small region of cortex beneath the temporal lobes that registers body perceptions and taste.

The authors believe this complicated picture makes sense. The brain regions on their list process conflict, pain, social isolation, memory, reward, attention, body sensations, decision making and emotional displays, all of which can contribute to feeling sad. Sadness triggers also vary—for example, the memory of a personal loss; a friend stressing over a work conflict; seeing a desolate film.

In the brain, happiness is as widely distributed as sadness. In his book "This Is Your Brain on Music," Dr. Daniel Levitin (page 58) notes that music simultaneously enlists many parts of the brain. We listen and respond to sounds and rhythms (auditory, sensory and motor cortex, cerebellum). We interpret (sensory cortex) and reason (prefrontal cortex). Music pulls on memories for experience and emotion (amygdala and hippocampus). If the music is working for you, it is probably triggering the reward system (nucleus accumbens). And if you're playing it, as Dr. Levitin does, you also get to throw satisfaction into the mix. This may or may not be a description of happiness, but it certainly coincides with the notion of flow, described by the author Dr. Mihály Csíkszentmihályi: concentrated attention and the absence of self-consciousness. A neuroscientist might say that a life that fully engages your brain in these ways is a life worth living.

Faith, Love and Understanding
The challenge to cognitive neuroscientists becomes greater as we go up the ladder to more-complicated emotional states. And the stakes become higher, too, because research into such highly valued and personal mental processes can be easily misunderstood.

Empathy is more than being nice. It is the ability to feel what another person feels, and in its most refined form it is the capacity to deeply understand another person's point of view. The brain's empathic powers actually begin with fear detection. Most of us are extraordinarily skilled face readers. We readily act on the emotions communicated to us through facial expression. And the grammar of facial expression, in some instances, is plain. We are masters at telling when a smile is insincere by the absence of wrinkles (called Duchenne lines) around the smiler's eyes. In a spontaneous smile, the corners of the mouth curl up and muscles around the eyes contract. Duchenne lines are almost impossible to fake.

In the Marx Brothers movie "Duck Soup," Groucho encounters his brother Chico in a doorway, dressed like him in a nightshirt and cap and a fake mustache. They perform a famous version of the mirror routine, Chico copying Groucho's actions. The humor may derive, at least in part, from humans' highly developed skill as copycats. When you observe someone eating ice cream or stubbing a toe, the brain regions that are activated in the eater and the stubber are also activated in you.