Boston (CNN) -- Dzhokhar Tsarnaev, the surviving suspect in the Boston Marathon bombings, lies in a hospital with a gunshot wound to the side of his neck, sedated and intubated, sources say. 

But he could be brought out of sedation in minutes so he could answer questions from law enforcement officials, doctors tell CNN. 

Intubated and sedated patients are often put on "sedation holidays." 

What we know about the suspects 

Under normal circumstances, doctors use these holidays, which last anywhere from a few minutes to a few hours, so they can ask patients questions to assess neurological and cognitive functioning. 

The patients can't talk, since they have a tube down their throats, but they can write. 

"They're still pretty out of it on these holidays, pretty confused and sleepy, but they could be able to understand what's being said to them," said Dr. Albert Wu, an internist and attending physician at Johns Hopkins Hospital. 

While many patients are groggy during these holidays, others are quite awake and thoughtful. 

Did one brother brainwash the other? 

Tsarnaev, who has been hospitalized since his capture on Friday, has been communicating with officials, two sources told CNN. 

"They have been questioning him since yesterday," a senior law enforcement source said. "There is some form of communication between law enforcement and the suspect." 

Neither source would divulge what Tsarnaev has been communicating. 

Dr. Corey Siegel, a gastroenterologist and professor at Dartmouth-Hitchcock Medical Center, remembers visiting his grandmother in the intensive care unit while she was intubated and sedated. 
For what reason?
Under normal circumstances, doctors use these holidays, which last anywhere from a few minutes to a few hours, so they can ask patients questions to assess neurological and cognitive functioning. 