I'm trying to identify a movie I saw in the late 60s. It was about a man fatally injured in a car crash, but they are able to keep his brain alive in a liquid filled tank. It was in color IIRC. The car crash was shown through the use of miniatures. When the car crashes, it catches fire. The flames are very obviously too small. The car was a futuristic looking one with, I think, curved body parts traveling through a miniature roadway landscape. The scientists are able to communicate with the brain and learn the crash was not an accident. With the help of the brain they try to learn who the killer was. I'm not sure about this part. They determine who the killer was and the brain dies, satisfied.
It's not The Brain AKA Vengeance AKA A Dead Man Seeks His Murderer with Anne Heywood and Peter van Eyck. That one is set in contemporary times, not the future, unless the German version was set in the future. I saw it at the U.S. Air Force base theatre in Germany, so it may have been a dubbed European film. Loosely based on Donovan's Brain, but there have been many adaptations of the story. My brother saw it back in the 70s on US TV, but can't remember the title or anything else about it either.