. . . Progress has also been made in mapping which brain systems control which kinds of operations (my own field of research): One system is responsible for lifting your foot, another senses the pain when you stub your toe; one system helps you to solve arithmetic problems, another enjoys "La Bohème." A new approach to studying brains and individual differences involves making maps of how neurons connect to one another. Following the term genome, these are called connectomes. . . .
. . .The human brain contains 100 million neurons, and each neuron makes thousands of connections on average. If we assume that each distinct connection pattern gives rise to a distinct brain state—like the effervescent sensation after that first kiss—the number of brain states exceeds the number of known particles in the universe. Your experiences, memories, personality and thoughts are thus encoded in the ways your neurons connect to one another. The next big frontier is mapping those trillions of neural connection patterns to their brain states. By observing a particular network of neurons firing, researchers should know (in theory) whether you are thinking about love or money, beer or burgers. . .
. . .The levels of various chemicals in our brains can clearly be altered pharmaceutically. They are also influenced by diet, exercise, stress and normal biological cycles. Even if we know how the neurons are connected and the strength of their synapses, the amount of dopamine, for example, that is available in the brain at any given moment will influence firing patterns. This could cause the same neural network (a group of connected neurons) to give rise to different thoughts or different networks to give rise to similar thoughts. . . .
Perhaps due to my having been an English major the first time around, I find the neologism "connectome" unfortunate as the suffix makes me of the word "lobotomy" every time I see it and pronounce it in my mind, but as a way of understanding the way the brain works it looks to be a terrific tool.