Why you get carsick when reading

Do you get carsick when you try to read in the car? It’s very annoying for someone who really likes to bury their nose in a book. There’s this time in the car going somewhere—maybe a couple of hours. Why waste that time just staring out the window, when you could be reading? But once you start reading, your stomach tells you, in no uncertain terms, that you’re going to be sick soon.

Why?

Well, it has to do with how your body interprets mixed messages. Your vestibular system in the ears is constantly telling your brain that you’re moving. At the same time, your eyes are looking at a book that isn’t moving. These mixed messages tell your brain that something’s wrong. And the only thing that leads to this kind of mixed messages—at least the only thing for many millions of years of evolution—is that you’ve been poisoned. The body’s reaction to thinking that it has swallowed something really nasty is to un-swallow it. You know, throwing up.

This doesn’t affect everyone to the same degree, which is just individual variation. Maybe you have genes that don’t get as upset about this. That’s good if you like reading in the car. But it doesn’t bode well if you inadvertently swallow some poison.

Brain Dissections

While I teach general science, my schools Gifted and Talented teacher goes into more advanced work with some of the students. Today she brought in a biology expert to do sheep brain dissection in my classroom.

Students were finding the parts of the brain they’ve learned about, from the pituitary gland to the olfactory lobes to the optic nerve crossover. Looking at the gray matter and the white matter.

Some parents came in to do this with their kids. Most kids had fun, but one or two were kind of squeamish.

Sheep brain

Sheep brain

Walking on ice is hard

Researchers at the Salk Institute have found where nerve signals are preprocessed to help the brain maintain balance on slippery surfaces. They think a group of nerves in the spinal cord called RORα serve as a link between the brain and the feet. Studies with mice showed that mice without the RORα nerves had trouble maintaining balance.

“We think these neurons are responsible for combining all of this information to tell the feet how to move,” says Steeve Bourane, a postdoctoral researcher in Goulding’s lab and first author on the new paper. “If you stand on a slippery surface for a long time, you’ll notice your calf muscles get stiff, but you may not have noticed you were using them. Your body is on autopilot, constantly making subtle corrections while freeing you to attend to other higher-level tasks.”


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Tasting the light

This one is old, but since I just wrote one post on neuroplasticity, I thought I’d write another.

Back in 2009, scientists made a special digital camera for the blind. This camera sent its picture to a small array of electrodes. These electrodes were on a small “lollipop” that the blind person put in his/her mouth. The small electric signals were picked up by the tongue. They said it felt like pop-rocks, or champagne bubbles.

It took only about 15 minutes for the blind user’s brain to start interpreting the input as vision.

Seiple works with four patients who train with the BrainPort once a week and notes that his patients have learned how to quickly find doorways and elevator buttons, read letters and numbers, and pick out cups and forks at the dinner table without having to fumble around. “At first, I was amazed at what the device could do,” he said. “One guy started to cry when he saw his first letter.”

While the sensor can only work in black and white, and is fairly low resolution, it is amazing that the brain can rewire itself so quickly to take input from the tongue and interpret it as vision.

Nervous system may be more distributed than we thought

Your nervous system might be more sophisticated than we thought. Classically, nerves send signals to the brain for processing. The brain does all the heavy lifting of figuring out what was observed.

That may not be the case. Researchers at Umeå University in Sweden have found that the nerves in skin do some preprocessing of the signals before they send them to the brain.

Our work has shown that two types of first-order tactile neurons that supply the sensitive skin at our fingertips not only signal information about when and how intensely an object is touched, but also information about the touched object’s shape

In particular, they found that the neurons in the skin perform the same type of calculations that the cerebral cortex does.

Rats show regret

RatNo, not for the black death. That wasn’t rats fault, it was parasites living on rats. Instead, researchers examined how rats reacted and how they felt after making poor choices. The orbitofrontal cortex and the ventral striatum parts of the brain are used when expressing regret. People with damaged orbitofrontal cortexes don’t experience regret.

The scientists put electrodes in the brains of rats, and ran them through a choice maze. This maze has 4 openings that lead to different kinds of food, some taste, others no so. After choosing a path the rats hear a tone indicates how long they’ll have to wait before getting the food (1 – 45 seconds). They can choose to take another path or stay where they are. If they skip this food, and end up with a worse food (bummer, no chocolate), 2 things happen: the rats look back at the path they were in, and the regret portion of the brain would be used.

What’s more, “just like humans,” says Redish, the rats were more likely to take a “bad deal”—or wait longer than they normally would for their next piece of food—after a regretful decision. The rats would also hastily consume food that stemmed from a bad choice, spending only about five seconds with the treat. Normally the rats would spend about 20 seconds grooming themselves and eating their food.

Deep brain stimulation may one day help restore memories

DARPA is working on brain implants that can help restore memories. This work is aimed at helping soldiers, but it may also work for Alzheimer’s patients. We can already use deep brain stimulation to help reduce tremors in Parkinson’s patients, and help patients with epilepsy. This may help restore more normal brain function in people. But, there are ethical considerations. Changing the way the brain works is changing the very heart of our identity. How much about the person’s personality would be changed?

New neurons may hurt old memories

The brain can make new neurons throughout your life. For a long time it was accepted that you’re born with all the neurons you’ll ever have, but that’s not true. New neurons form mostly in the hippocampusolfactory bulb, subventricular zone, and possibly in the cerebral cortex.

But all is not rosy with getting new brain cells. It turns out that new neurons in the hippocampus, the main part of the brain associated with memory, disrupt older memories. While the new neurons make it easier to learn new things, they make it harder to remember older things already known.