This simplified diagram shows how the neurons in our brain form connections known as synapses. A family of proteins called neurexins, shown here as blue beaded structures, help to form the synaptic connections that allow the brain to do different tasks. Defects in neurexins were found to be associated with neurological conditions like autism. Neuroscientists think that slightly different forms, or isoforms, of neurexins may create different types of synaptic connections, and thus enable our brains to perform so many different tasks. In the first comprehensive survey of this important protein family, Stanford researchers observed more than 450 variants of neurexins, and estimate that this protein family may have 2,500 or more isoforms.