“We grieve by calling up one memory at a time, reliving it, and then letting it go. At a brain level we are turning on each of the neural networks that were wired together to form our perception of the person, experiencing the memory with exceptional vividness, then saying goodbye one network at a time. In grief, we learn to live without the one we love, but the reason this lesson is so hard is that we first must unlearn the idea that he person exists and can still be relied on.”
“… massive neuronal reorganization occurs at two life stages: when we fall in love and when we begin parenting.”
“Whereas dopamine induces excitement, puts us into high gear, and triggers sexual arousal, oxytocin induces a calm, warm mood that increases tender feelings and attachment and may lead us to lower our guard.”
“One reason we can change our brains simply by imagining is that, from a neuroscientific point of view, imagining an act and doing it are not as different as they sound. When people close their eyes and visualize a simple object, such as the letter a, the primary visual cortex lights up, just as it would if the subjects were actually looking at the letter a. Brain scans show that in action and imagination many of the same parts of the brain are activated. That is why visualizing can improve performance.”
“As the scientist Gerald Edelman has pointed out, the human cortex alone has 30 billion neurons and is capable of making 1 million billion synaptic connections. Edelman writes, “If we considered the number of possible neural circuits, we would be dealing with hyperastronomical numbers: 10 followed by at least a million zeros. (There are 10 followed by 79 zeros, give or take a few, of particles in the known universe.)” These staggering numbers explain why the human brain can be described as the most complex known object in the universe, and why it is capable of ongoing, massive microstructural change, and capable of performing so many different mental functions and behaviors, including our different cultural activities.”
