Peter Kalivas is Professor of Neuroscience and Psychiatry at the Medical University of South Carolina and a world leader in studying the role of neuroplasticity in addiction.
I wrote Peter after I discussed his work on addiction, glutamate and learning in the post Addiction & Learning: More Than Glutamate and Dopamine, where I was critical of a biological determinist view of addiction but hopeful about how anthropology and neuroscience can combine to better understand the role of learning and memory in addiction.
Peter was kind enough to leave a long comment on that post, and I want to highlight it here so that everyone gets a chance to read his insights. I’ve done some light editing, mostly to make it more readable online.
Most of us understand that neither dopamine nor glutamate explain addiction. Two points to make along these lines:
1) The day we understand the brain as an organ in reductionist terms, we might be able to provide a tight linear cause and effect analysis from gene to transmitter to circuit to a complex behavior like addiction. That holy grail is slipping through the fingers of my generation of scientists, it’s a long game. However, I think those of us trying to explain behavior from the bottom up believe that unlike the search for the holy grail, our journey will eventually get us an explanation that is workable in terms of explaining human behavior and curing behavioral pathologies.
2) The reason behind our penchant to build magic molecular bullets to explain complex behavior is simple and political (sounds depressingly like a Tea Party). We are trying to find a pharmacotherapy, and the current FDA-approved state of the art is usually a single molecular target. Do we believe that a single molecule defines a behavior like addiction, of course not. Do interest rates define an economy, no, but adjusting them can fix a problem (perhaps not with the current economy, bad example).
A final thought on learning and memory, and neuroanthropology. I think that the most accurate and utilitarian understanding of human behavior in our lifetimes will arise from iterative processing between fields like anthropology and neurobiology. Learning and memory is in the gun sights of reductionist experimentation, and we are likely to have some pretty solid molecular/circuitry explanations in 10-20 years (maybe less), perhaps at the level we now understand the heart (literally, not as Shakespeare might think of the heart).
However, even a process like learning is little more than an automatic function, largely pre-programmed as a tool to help us navigate. By developing more accurate top-down models of the development and expression of integrated behaviors, an anthropological context gives neurobiologists the framework by which we will design experiments to determine how learning and memory underpin complex behaviors and behavioral pathologies. Conversely, I like to think that our ill-formed certitude of how one or another highly reduced process in the brain influences behavior might help you frame complex behaviors.