The brain is the mind is the brain. One hundred billion nerve cells, give or take, none of which individually has the capacity to feel or to reason, yet together generating consciousness. For about 400 years, following the ideas of French philosopher René Descartes, those who thought about its nature considered the mind related to the body, but separate from it. In this model—often called “dualism” or the mind-body problem—the mind was “immaterial,” not anchored in anything physical. Today neuroscientists are finding abundant evidence . . . that separating mind from brain makes no sense. Nobel Prize-winning psychiatrist-neuroscientist Eric Kandel stated it directly in a watershed paper published in 1998: “All mental processes, even the most complex psychological processes, derive from operations of the brain.”
Neuroscientists consider it settled that the mind arises from the cooperation of billions of interconnected cells that, individually, are no smarter than amoebae. But it’s a shocking idea to some that the human mind could arise out of such an array of mindlessness. Many express amazement that emotions, pain, sexual feelings or religious belief could be a product of brain function. They are put off by the notion that such rich experiences could be reduced to mechanical or chemical bits. Or they worry that scientific explanations may seduce people into a kind of moral laziness that provides a ready excuse for any human failing: “My brain made me do it.” Our brains indeed do make us do it, but that is nonetheless consistent with meaningful lives and moral choices. Writing for the President’s Council on Bioethics earlier this year, philosopher Daniel Dennett made the point that building knowledge about the biology of mental life may improve our decision making, even our moral decision making. And it could enhance our chances of survival as a species, too.
. . . . The brain is responsible for most of what you care about—language, creativity, imagination, empathy and morality. And it is the repository of all that you feel. The endeavor to discovery the biological basis for these complex human experiences has given rise to a relatively new discipline: cognitive neuroscience. . . .
. . . .Neuroscientists . . . have a rapidly growing appreciation of the emotional brain and are beginning to look closely at these subjective states, which were formerly the province of philosophers and poets. It is complex science that holds great promise for improving the quality of life. Fortunately, understanding basic principles does not require an advanced degree.
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Fear is a good place to start, because it is one of the emotions that cognitive neuroscientists understand well. It is an unpleasant feeling, but necessary to our survival; humans would not have lasted very long in the wilderness without it. Two deep brain structures called the amygdalae manage the important task of learning and remembering what you should be afraid of.
Each amygdala, a cluster of nerve cells named after its almond shape (from the Greek amugdale), sits under its corresponding temporal lobe on either side of the brain. Like a network hub, it coordinates information from several sources. It collects input from the environment, registers emotional significance and—when necessary—mobilizes a proper response. It gets information about the body’s response to the environment (for example, heart rate and blood pressure) from the hypothalamus. It communicates with the reasoning areas in the front of the brain. And it connects with the hippocampus, an important memory center.
The fear system is extraordinarily efficient. It is so efficient that you don’t need to consciously register what is happening for the brain to kick off a response. If a car swerves into your lane of traffic, you will feel the fear before you understand it. Signals travel between the amygdala and your crisis system before the visual part of your brain has a chance to “see.” Organisms with slower responses probably did not get the opportunity to pass their genetic material along.
Fear is contagious because the amygdala helps people not only recognize fear in the faces of others, but also to automatically scan for it. People or animals with damage to the amygdala lose these skills. Not only is the world more dangerous for them, the texture of life is ironed out; the world seems less compelling to them because their “excitement” anatomy is impaired.
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[We’ve excluded, here, interesting overviews of how the brain experiences with anger, happiness, sadness, and empathy.]
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But empathy depends on more than an ability to mirror actions or sensations. It also requires what some cognitive neuroscientists call mentalizing, or a “theory of mind.” Simon Baron-Cohen, a leading researcher in the study of autism, has identified the inability to generate a theory of mind as a central deficit in that illness. He has coined the term “mindblindness” to designate that problem. The corollary, “mindsightedness,” requires healthy function in several areas of the brain. The processing and remembering of subtle language cues take place toward the ends of the temporal lobes. At the junction of the temporal and parietal lobes, the brain handles memory for events, moral judgment and biological motion (what we might call body language). And the prefrontal cortex handles many complex reasoning functions involved in feelings of empathy.
Not surprisingly, love also engages a whole lot of brain. Areas that are deeply involved include the insula, anterior cingulate, hippocampus and nucleus accumbens—in other words, parts of the brain that involve body and emotional perception, memory and reward. There is also an increase in neurotransmitter activity along circuits governing attachment and bonding, as well as reward (there’s that word again). And there’s scientific evidence that love really is blind; romantic love turns down or shuts off activity in the reasoning part of the brain and the amygdala. In the context of passion, the brain’s judgment and fear centers are on leave. Love also shuts down the centers necessary to mentalize or sustain a theory of mind. Lovers stop differentiating you from me.
Faith is also being studied. Earlier this year the Annals of Neurology published an article by Sam Harris and colleagues exploring what happens in the brain when people are in the act of either believing or disbelieving. In an accompanying editorial, Oliver Sachs and Joy Hirsch underscored the significance of what the researchers found. Belief and disbelief activated different regions of the brain. But in the brain, all belief reactions looked the same, whether the stimulus was relatively neutral: an equation like (2+6)+8=16, or emotionally charged: “A Personal God exists, just as the Bible describes.”
By putting a big religious idea next to a small math equation, some readers might think the researchers intend to glibly dismiss it. But a discovery about brain function does not imply a value judgment. And understanding the reality of the natural world—how the brain works—shouldn’t muddle the big questions about human experience. It should help us answer them.
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