WillSpirit!

Today I am filling in at the local Suicide Hot Line. Since this time of day tends to be slow, I’ll probably have time to complete a post. As I planned this essay, knowing where I’d be writing it, the topic of suicide naturally suggested itself to me. But after giving it more thought, I decided to write about something a little less depressing.

In the book Buddha’s Brain, Rick Hanson explains that dwelling on negative memories and feelings strengthens them. If we habitually focus on unhappy topics, and especially if we simultaneously harbor unpleasant emotions, then we increase the neural circuits that promote misery. The converse is also true: dwelling on happy topics and pleasant feelings leads to brain changes that foster contentment.

My goal these days is to improve my mental balance, and spend less time obsessed with depressing topics. Since my childhood was loaded with trauma and my adulthood has brought huge disappointments, negativity is already well entrenched in my brain. It will take the rest of my life to build in enough positive memory and feeling to counterbalance that burden of loss. Reliving my suicidal feelings and remembering the suicides of loved ones seem like counterproductive exercises. They can wait for some future day; no doubt depression will eventually descend despite my best efforts, and such subjects will be on my mind already.

Two readers have requested posts about neuroplasticity; since I’ve already introduced the idea by mentioning Hanson’s book, I might as well develop it further. Neuroplasticity has become a hot topic in neuroscience, but it is actually something we make use of every day. If we wanted to be less technical, we could replace the fancy jargon with the word learning without losing much meaning. Both terms refer to long-term changes in the brain.

One of the first and most striking demonstrations of neuroplasticity came from the research of V.S. Ramachandran. He showed that after an amputation, the brain regions that used to handle the sensory input from the lost limb do not simply go silent. Instead, adjacent functions spread into the unused area. So if an arm is amputated, the sensory system of the face expands into the area that once served the severed limb. As a result, people have odd phantom limb experiences, such as touch to the cheek causing ‘feeling’ in a hand that no longer exists. More elegant examples include the expansion of brain representation of fingers in musicians, or the larger memory modules of London taxi drivers, who have to memorize maps of the entire city.

The outer and most evolutionary recent part of the brain is the neocortex. In effect, it is a flat sheet of nerve tissue that has been folded and balled up to fit inside the skull. Although different parts of the cortex have somewhat different structural details, in every region the sheet is layered. In the visual cortex there are six layers, with some receiving input, some primarily performing internal processing, and some creating output to other regions. The number of layers and the specific appearance varies from place to place on the neocortical sheet, but one is struck by the overall uniformity. Regions that handle functions as diverse as vision, language, touch, movement, and judgment all look more or less the same, and areas with similar functions can appear identical. Thus, the sensory area serving the arm is indistinguishable in appearance from that serving the face.

This makes it easy for cortical regions to take up new functions. In people who are blinded, and especially those blinded from birth, hearing functions encroach on the visual cortex. This expands the processing space for auditory signals, and probably partly explains why people who are blind often hear better than those with sight. Enlarging the cortical space for fingers in musicians presumably increases manual dexterity.

These are large-scale changes that demonstrate the brain’s impressive ability to reorganize itself in response to need. Restructuring on that scale takes time, but smaller shifts in brain structure and function happen every instant. Every thought is accompanied by a ripple of neuronal activity that forms an organized ensemble and then dissipates. Every time a memory is created, new connections are established between nerve cells. The brain is changing all the time as we learn new skills, see new things, and think new thoughts. As we live we learn, and as we learn we change our brains. This is the essence of neuroplasticity.

We should feel both sobered and empowered by the fact that everything we think and do sculpts our neurons. Sobered, because every single thought leaves traces that accumulate; a lifetime of negative thinking strengthens the neural foundations of stress, fear, and sadness. If we clumsily allow our minds to obsess on whatever attracts attention, no matter how discouraging or counterproductive, we will develop brains prone to unhappiness. Empowerment comes from recognizing the opposite principle: fostering positive thoughts, memories, and feelings will gradually increase our ability to remain contented.