"My notion of personality is pretty simple: it's that your 'self,' the essence of who you are, reflects patterns of interconnectivity between neurons in your brain. Connections between neurons, known as synapses, are the main channels of information flow and storage in the brain. Most of what the brain does is accomplished by synaptic transmission between neurons, and by calling upon the information encoded by past transmission across synapses.
"Given the importance of synaptic transmission in brain function, it should be practically a truism to say that the self is synaptic. What else could it be? Not everyone, however, will be happy with this conclusion. Many will surely counter that the self is psychological, social, moral, aesthetic, or spiritual, rather than neural, in nature ... even a partial understanding of the synaptic basis of who we are is, for me, an acceptable goal. For seeking knowledge about the brain is not only a valid scientific pursuit; it can also improve the quality of life, as when it uncovers new ways of treating neurological or psychiatric disorders."
-- Joseph LeDoux, 'Synaptic Self' (2002), p. 2-3.