Week in Review: Control

UNC-TV Science Week in Review: September, 5 2013


Scientific research is often geared towards controlling the world around us. The discovery of fire allowed early humans to control cold and darkness. The internal combustion engine demonstrated a mastery of fire, harnessing it to create electricity and make vehicles move. Now as climate changes, scientists seek to subjugate the products of our controls (greenhouse gases and pollution) for cleaner air and a cooler planet.

This week, North Carolina scientists focused on control, whether that be in our heads or our blood, but also demonstrated the majesty of things we can’t control.

Turning Down the Volume
Here’s a riddle for you. If someone yells six inches from your ear, it’s really really loud. Maybe even loud enough to hurt. If someone shouts to you from across a field, you hear a much quieter noise. If you shout back to them, the noise is loud but certainly not a volume you can’t handle. 

But why? Your mouth is no more than six inches from your ear, and you’re yelling loudly enough for someone to hear you across a field, so why doesn’t your shout hurt the same as someone else’s?

The answer is that your brain actually turns down the volume when it realizes you’re going to scream. Scientists have theorized this for decades but this week, researchers from Duke discovered the mechanism by which the brain controls audio levels.

When you speak a part of your brain called the secondary motor cortex issues a command for your jaw to move. The command travels through neurons to the spinal cord and to the jaw. But the secondary motor cortex also sends a little signal to the auditory cortex, which controls hearing and interprets sounds. The auditory cortex then turns itself down.

The researchers tested this with thin slices of mouse brains, and found that when they stimulated the secondary motor cortex, the auditory cortex was less active. This discovery is a useful insight into some forms of psychosis where patients can’t tell their own voices from the voices of others. The researchers from this study think the cause might be a severed connection between the auditory and secondary motor cortexes. The findings appeared in the journal Neuroscience.

New Possibilities to Prevent Heart Attacks and Strokes
Blood consists of a few basic parts: plasma (the liquid), red blood cells (to carry oxygen), white blood cells (to fight infections), and platelets. Platelets are short-lived cell fragments. They don’t reproduce, die off every 5-9 days and have one famous function:  clotting.

When you cut yourself, you begin to bleed, but as more platelets crowd into the area, they stick to each other, building something like a less organized brick-wall of cells, called a clot, to stop you from losing blood. Too few platelets can make paper cuts deadly, but too many can leave clots in your blood vessels, causing heart attacks and strokes.

This week, doctors from UNC School of Medicine used a technique often used to study cancer to identify some of the mechanisms that cause platelets to form clots, opening new avenues of treatment and prevention of heart attacks and strokes. The technique is called an “activity based protein profile” and it determines the proteins at work in a cell at any given time. Doctors often use it to determine what proteins are causing cancer cells to multiply but the UNC doctors used it to examine which proteins were helping the platelets hold onto each other when forming a clot. 

Based on the proteins in action, the researchers identified several new chemicals that can interrupt the clotting process, adding more weapons to the arsenal of anticoagulants (anti-clotting drugs) doctors already use. They also found a signaling protein which acts like an “on-off switch” for clotting. Their findings appeared in the journal Chemistry and Biology.

Moon to Pass Venus on Sunday Night
Stargazers and astronomy buffs may want to look to the West in the evening twilight, for a special twist on a monthly event. The moon will pass by Venus from our point of view on Earth. This happens once a month, as the moon orbits Earth. What’s special about Sunday’s event is that due to how Venus is currently aligned with Earth, Venus and the moon will appear extremely close to each other, within a moon’s diameter from our point of view.

How this event appears to us on Earth is actually somewhat counterintuitive. Venus and the moon will appear to be right on top of each other, but in reality they are about 100 million miles apart. Even though Venus is roughly the size of Earth and much larger than the moon, it will look like an extremely bright star. This is because the moon is only 230,000 miles from Earth whereas Venus is 100 miles away. Even the moon passing Venus is a trick, as the moon moves more slowly than Venus, and every other planet for that matter. We only see the moon pass by the planets because it orbits Earth while the planets orbit the sun.

Despite all the apparent contradictions, look West in the evening twilight on Sunday and you will be able to see Venus just above the moon.

- Daniel Lane

Daniel Lane covers science, medicine and the environment as a reporter/writer. He is currently pursuing a master's degree in medical and science journalism at UNC - Chapel Hill.