14 DAY TRIAL // Scientists have discovered that the brain and skull have a lot in common with latex and toothpaste, at least when it comes to electrical conductivity.
The new find would help efforts to diagnose, understand and monitor epilepsy, comas and other disorders related to brain activity as well as researching the normal brain activity.
The brain and skull conductivity are behind the techniques commonly used to scan brain activity.
The existence of brain's conductivity was already known, but precisely how conductive the skull is in living organisms have puzzled the researchers for years.
The brain is, of course, more conductive than the skull because the brain holds billions of electrically conductive brain cells called neurons. "Old data used for 30 years estimated the brain was 80 times more conductive than the skull, which is about how much more conductive liquid latex is than crushed cranberries," explained biomedical engineer Bin He at the University of Minnesota. "One of the more recent experiments suggest the brain is 25 times more conductive than the skull, which is about how much more conductive latex fluid is than New York City water," he explained.
The electrical conductivity of liquid latex is about 1,750 microsiemens per centimeter, hundreds of millions of times less conductive than copper (580 billion microsiemens per centimeter).
To find how conductive the skull is, the research team investigated two children undergoing possible surgery for epilepsy. Previously, investigators identified the specific seizure responsible brain areas with electrodes introduced deep into the brain.
In the new approach, the team measured the brain activity of the children from the outside using electrodes placed on their scalps. "Computer models built of their heads based off nearly 50 sets of electrical measurements found the brain is only about 18.7 times more conductive than the skull, or about how much more conductive latex fluid is than toothpaste," said Bin He. The discovery could lead to "the possibility of much accurate brain surgical outcomes" in the future.