Ultrasound may help unlock brain's secrets

Ultrasound may help scientists to unlock the brain's secrets noninvasively, and perhaps create new treatments for illnesses, new research suggests.

Neurons - the cells that make up the brain, nerves, and spinal cord - communicate with each other using electrical pulses known as action potentials, but their interactions are complicated and hard to understand.

Just getting access to the brain itself is difficult: inserting devices through the skull into the brain requires surgery, researchers said.

But work by Technion professors Eitan Kimmel and Shy Shoham, and PhD student Misha Plaksin, may advance our ability to unlock the brain's secrets noninvasively using sound, and perhaps create new treatments for illnesses.

Scientists have known for a while that ultrasonic waves can affect cells in many ways. For instance, physicians use ultrasound to stimulate the production of blood vessels and bone; it's also used in heat therapy.

When applied to neurons, ultrasonic waves can change how the neurons generate and transmit electrical signals.

According to Kimmel's model, when the ultrasonic waves encounter a cell, the two layers of the cellular membrane begin to vibrate.

Cell membranes also act as capacitors, storing electrical charge. As the layers vibrate, the membrane's electrical charge also moves, creating an alternating current that leads to a charge accumulation.

The longer the vibrations continue, the more charge builds up in the membrane. Eventually, enough charge builds up that an action potential is created.

The team was able to use the model to predict experimental results that were then verified using brain stimulation experiments performed in mice.

According to Shoham, this is "the first predictive theory of ultrasound stimulation."

All of these results mean that scientists might be on the verge of finally understanding how ultrasound affects nerve cells, researchers said.

The findings were published in the journal Physical Review X.