Try to get this through your head.

That could get easier soon.

One of the biggest challenges in treating neurological conditions such as Parkinson's and Alzheimer's disease is finding safe and non-invasive ways to enable drugs to penetrate the brain's natural defense -- the blood-brain barrier. Now scientists have developed a way to temporarily open a very small part of that barrier using focused ultrasound. They hope this precise targeting will allow drugs to enter specific parts of the brain -- without exposing the rest of the brain and without damaging the barrier or surrounding neuronal tissue in the process. [...]

The blood-brain barrier protects the brain, which is why it can be difficult for drugs to penetrate it. The barrier consists of endothelial cells that line the small blood vessels in the brain. These cells are tightly packed to create a wall between most parts of the brain and the rest of the circulatory system, blocking bacteria and all but the smallest molecules.

Focused ultrasound works by directing sound waves toward a point in space. Individually, the waves are not powerful enough to affect the tissue, but when targeted, their collective intensity is much greater. High-intensity focused ultrasound (HIFU), which applies more intense sound waves, has been used to destroy tumors through heating, a process known as ablation. When targeting the brain, though, Konofagou's team used much lower-intensity levels, similar to those applied in diagnostic ultrasound, the technology used during a pregnancy sonogram. While researchers don't know exactly how this technique is able to open the barrier, they say it's not through heating.

Unlike tumor ablation --and this distinction is key -- Konofagou's technique appears to be reversible. Using an MRI contrast agent, she was able to show that the barrier closed up after about four hours. [...]

It is important to start applying this technique to animal models that simulate specific diseases, he says, just as Konofagou is doing, although he adds that the skulls of mice are extremely thin, unlike those of humans. Konofagou says she's now working on using higher-frequency ultrasound waves, which she believes will be able to penetrate human skulls.