Thomas C. Südhof

I started doing experiments because I was fascinated by the question of how neurons in the brain communicate to process sensory information and transform it into a motor response. It was clear from the very beginning that understanding this question required insight into the molecular machinery that underlies synaptic transmission, the process by which a signal is transferred at a synapse. At a synapse, a presynaptic neuron signals to a postsynaptic cell (usually another neuron) by secreting a chemical neurotransmitter that is then recognized by the postsynaptic cell. Our work has focused on how presynaptic neurons secrete neurotransmitters. Neurotransmitter secretion is triggered by calcium in an unusually fast and tightly regulated reaction and is positioned precisely in front of the postsynaptic cell by virtue of a transsynaptic cell-adhesion apparatus. In dissecting neurotransmitter secretion we have identified molecular mechanisms that mediate the calcium control of secretion and couple it to the postsynaptic cell. These initial results provide a platform for deciphering the complete machinery that integrates the molecular components of synapses into a functional "minicomputer" for information processing by the brain, a question I am very interested in pursuing.