The scan, which detects certain brain injuries but not concussions, was negative.
Disease, too, can rob memory, as with Alzheimer's or certain brain tumors.
For example, he said, the brain might be thought of as a biological system, but "certain brain problems may not be solvable by taking a biological approach.
A fourth study reported here, by doctors at the Mayo Clinic, found a mutation that indicates certain brain tumors will be more aggressive and chances of survival lower.
The precise mechanism by which the drug controls seizures is unknown but researchers have theorized that it dampens an excessive buildup of electrical activity in certain brain cells.
Innercool has Food and Drug Administration approval for inducing hypothermia during certain brain operations, and Radiant has approval for warming patients after cardiovascular surgery.
He also observed that the fine inner structure of the nerves in certain brain regions was disrupted, forming "tangles" made up of a protein later called tau.
BrPCs might also be causally involved in certain brain diseases.
It's possible that normal brain development depends on certain brain regions maturing in synchrony, Schlaggar says.
That's still true, but new research shows that certain brain cells bypass the synapse altogether.
Although the bug doesn't make us sick, it does seem to slow certain brain activities.
