Many thanks to replicasmovieofficial for sharing a still from Replicas featuring Keanu on instagram. The following comment about Keanu by the director was posted with the photo:
“Keanu has a phenomenal work ethic. I knew his reputation for preparing for physical roles (such as the stunts in John Wick) but I was impressed at how that preparation extends even into the research for a role like this. He was constantly reading up on neuro-science and bringing new ideas for scenes and for the science underlying our story. Obviously, we can’t yet map the human mind, but there is a tremendous amount of existing research on the function of the brain and Keanu read a great deal about it,” says Nachmanoff.
Many thanks to @replicas_movie for sharing clip of Keanu and Thomas Middleditch speaking about Replicas here, here, and here.