Felipe Massa's condition is improving and doctors at the Budapest hospital where he is have said they are reassured about the progress he is making.
The Ferrari driver suffered a skull fracture and concussion when he crashed during qualifying for the Hungarian Grand Prix. The accident was caused when he was hit on the head by a spring that had come off Rubens Barrichello's car.
After an emergency operation on Saturday afternoon, Massa was put in an induced coma to help his recovery - and since then he has been making good progress.
Hungarian defence ministry spokesman Istvan Bocskai said that tests carried out on Massa were 'reassuring' about his condition. He could also move his hands and his legs - which were positive signs that there was no damage to his brain.
Bocskai told Hungarian television MTV: "Felipe has spent the night calmly. A few hours ago he had do undergo an ultrasonic test, because after impacts like the one he had sometimes water builds up in the bowels.
"In his case the situation was not so bad, the results were reassuring. Today they will also do another CT-scan on him to control the results from yesterday.
"He's woken up (from sedation) more and more often now and he's able to communicate passively, that is, he reacts when he's talked to, which I think is certainly a good sign. We are optimistic, in our hope a slow recovery is beginning."
When asked if he suffered any lasting damage to his brain, Bocskai said: "I think the results of the CT-scans have been encouraging. The doctors haven't seen any worrying signs which might indicate this, but I think in this phase it would be too soon to declare anything.
"What I have mentioned just now, that he was able to passively communicate when woken up, that he could move his legs and arms, all seemed to show there was no particular damage. The situation is encouraging, but we are not yet at the point in his recovery where we could say anything for certain."
He added: "Every single moment is important now. The doctors and nurses who are taking care of him are doing everything that is possible to help his recovery. He is in good hands. The hospital he is in has all the neccessary diagnostic tools, it is probably one of the most up to date hospitals in Europe.
"There are experienced army soldiers in the medical team that is working around him. The doctors who completed the operation had experiences with some really extreme injuries, amongst them Colonel (Lajos) Zsiros, who has attended many military missions. He is the leading surgeon of the Hungarian Defence Forces.
"And Peter Bazso, the medical director of the hospital is also a very experienced neurosurgeon. These circumstances are all helping him to make a recovery. We are hopeful, but I think we cannot yet state anything for certain, it would't be appropriate."
Ferrari president Luca di Montezemolo is flying to Budapest on Monday to be with Massa, who has also had visits from F1 supremo Bernie Ecclestone, Barrichello and members of Ferrari including team principal Stefano Domenicali.