Study reveals a protein’s key contribution to heterogeneity of neuron Tomosyn’ sight regulation of neurotransmitter release distinguishes functions of two neuron classes at the fly neuromuscular junction. Human brain and cognitive abilities – artist’s impression. Image credit: Max Pixel , CC0 Public Domain The versatility of the nervous system comes from not only the diversity of ways in which neurons communicate in circuits, but also their “plasticity,” or ability to change those connections when new information has to be remembered, when their circuit partners change, or other conditions emerge. A new study by neuroscientists at The Picower Institute for Learning and Memory of MIT shows how just one protein situated on the front lines of neural connections, or synapses, can profoundly change how some neurons communicate and implement plasticity. The team found that expression of the tomosyn protein is a major determining factor in whether the “presynaptic” neurons that send signal