Origin
Emily was living with her grandfather and brother when they were exposed to Terrigen Mists and were engulfed in cocoons. Emily broke out of her cocoon, along with her grandfather, but her brother remained inside his. Emily discovered that the she now had enhanced speed and strength, as well as telepathic powers.
Creation
Synapse was created by Gerry Duggan and Ryan Stegman and first appeared in Uncanny Avengers Vol.3 issue 1 (2015).
Major Story Arcs
Part of the Uncanny Avengers
Assuming the name Synapse, Emily decided to became a hero and used her powers alongside the Avengers Unity Squad. When a villian called the Shredded Man tries to take over New York Emily eventually learns that it is her grandfather. With Cable and the rest of the Unity Squad they defeat the Shredded Man. Afterwords Emily takes a leave of absence from the team to mourn the loss of her grandfather.