No. They're impact protection. An anti-concussive helmet would look bigger and softer, like this early example: https://helmets.org/concussionhelmet.htmAnd as many people have said: helmets prevent concussion, don't they??
Some suspect helmets have made riders continuing with concussion more likely because without helmets, skull lacerations or fractures would have been obvious to the doctors and got the rider stopped. Unintended consequences strike again?
Ian Boswell has done some good interviews on concussion but I think he's still expecting an improved helmet to help, which it might not, or it might have some other unintended consequence.