Nuts and Volts - July/August 2018

Messin’ with Brain Cells

For decades, sci-fi movies and TV shows have portrayed characters whose brains have been erased or reprogrammed by evil-doers. This fictitious process is so common that it doesn’t particularly terrify most of us anymore. Maybe it should now, because UC Berkeley ( www.berkeley.edu) neuroscientists are getting closer to making it a reality.

Under development is a system that uses holographic projection to activate or deactivate brain activity, thereby allowing it to “edit the sensations we feel, paste in our brain pictures that we never saw, cut out unwanted pain, or insert nonexistent scents into memory.” Recently, a chunk of mouse brain was treated with a protein that when hit with a flash of light turns the cell on and creates a spike of activity. To function properly, the system needs enough accuracy to “shoot the very specific sets of neurons you want to activate and do it at the characteristic scale and the speed at which they normally work.” Apparently, they have achieved that.

The researchers have already tested the prototype on mice as they walk on a treadmill, acting on the touch, So, how long until they are able to work with live human brains? Who knows? Maybe they already can. Maybe they already have.

Are you absolutely certain you were at the Snake Pit Bar and Grill last night? ▲

ADVANCED TECHNOLOGY

Say No More

You may not have thought about it, but when engaged in silent reading, you think the words as you read them and hear them in your mind. This is known as “subvocalization,” and the phenomenon has been under consideration since the mid 1800s. In 1899, a researcher named Curtis concluded that silent reading was, in fact, the only mental activity that caused significant movements of the larynx.

Half a century later, A. W. Edfeldt devised an electrical instrument that could record this movement. His device was too primitive to correlate movements with specific words, but he did conclude that silent speech reinforces learning and is therefore a good thing.

Other researchers have come to the opposite conclusion: that subvocalization should be minimized. After all, if you have to subvocalize everything you read, you can’t read any faster than you can speak (about 150 to 250 words per minute). It’s therefore widely considered to be a hindrance to learning, and speed readers are trained to avoid it as much as possible.

Researchers at the MIT Media Lab ( www.media.mit.edu) have now created a wearable device that picks up neuromuscular signals in the face and jaw and feeds them to a machine-learning system that can associate the signals with specific words. The “AlterEgo” system includes a pair of bone-conduction headphones that transfer sound vibrations through the face bones to the inner ear, bypassing the ear canal completely.

In one experiment, subjects used the system to report opponents’ moves in a chess game and receive a computer’s recommended moves, all soundlessly. In another, 10 subjects used the system to execute computations, and it turned out to be about 92 percent accurate. Accuracy should improve as data about more complicated conversations is collected.

Researchers speculate that the system could be valuable in both extremely noisy environments and one where silence is mandatory (e.g., special ops). It could also allow disabled people who can’t speak normally to communicate with others. ▲