Phrenological thinking, a popular pseudoscientific practice in the 1800’s suggested that the structure of the head and underlying brain held the clues to understanding human behavior. Today, amidst the ongoing convergence of developmental science, molecular & biochemical science and systems-dynamical science (to name just a few), there is – of course – no single or agreed-upon level of analysis that can provide all the answers. Circuit dynamics are wonderfully correlated with behavior, but they can be regulated by synaptic weights. Also, while developmental studies reveal the far reaching beauty of neuronal circuitry, such elegant wiring is of little benefit without healthy and properly regulated synaptic connections. Genes too, can be associated with circuit dynamics and behavior, but what do these genes do? Perchance encode proteins that help to form and regulate synapses? Synapses, synapses, synapses. Perhaps there is a level of analysis – or a nexus – where all levels of analysis intersect? What do we know about synapses and how these essential aspects of brain function are formed and regulated?
With this in mind I’ve been exploring the nanosymposium, “Molecular Dynamics and Regulation at Synapses” to learn more about the latest findings in this important crossroads of neurobiology. If you’re like me, you sort of take synapses for granted and think of them as being very tiny and sort of generic. Delve a while into the material presented at this symposium and you may come to view the lowly synapse – a single synapse – as a much larger, more complex, ever changing biochemical world unto itself. The number of molecular players under scrutiny by the groups presenting in this one session is staggering. GTPase activating proteins, kinases, molecular motors, receptors, proteases, cell adhesive proteins, ion channels and many others must interact according to standard biochemical and thermodynamic laws. At this molecular-soup level, it seems rather miraculous that the core process of vessicle-to-cell membrane fusion can happen at all – let alone in the precise way needed to maintain the proper oscillatory timing needed for Hebbian plasticity and higher-level circuit properties associated with attention and memory.
For sure, this is one reason why the brain and behavior are hard to understand. Synapses are very complex!