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Thursday, February 25, 2016

Scientists identify the brain's fear frequency

Ever wondered why you get chills down your spine each time you sit in the dentist’s chair or strap yourself into a rollercoaster? They're produced by a conditioned fear response, which can be learned following a bad experience and recalled whenever certain stimuli relating to that event present themselves. While this concept is certainly nothing new, scientists have for the first time identified a particular brainwave that appears to regulate this response, potentially opening the door to new treatments for conditions such as post-traumatic stress disorder.

The brain’s ability to learn and recall conditioned behaviors was famously illustrated by Ivan Pavlov and his slobbery dogs in the 19th century, and numerous subsequent studies have revealed how this phenomenon can be manipulated to elicit fear as well as hunger. Rodents, for instance, can easily be trained to freeze upon hearing a tone that they have come to associate with an aversive experience such as pain.

Monday, February 1, 2016

Scientists have found a method to decode what a person is perceiving

Neuroscientists have developed a new technique that enables them to decode what people are perceiving just by looking at a readout of their brain signals. This ability to spontaneously decipher human consciousness in real-time could have wide-ranging implications, potentially leading to novel treatments for brain injuries or helping people with locked-in syndrome to communicate.
The researchers collaborated with seven epilepsy patients at a hospital in Seattle, who had a number of electrodes called electrocorticographic (ECoG) arrays implanted into their brains. These targeted the temporal and occipital lobes of the brain's cortex, concerned with hearing and vision, respectively.
Patients were each shown a series of grayscale images of faces and houses, which flashed up on a screen in a random order for 400 milliseconds each. Using a novel framework for interpreting subjects’ brain activity data, the researchers were able to tell exactly when each patient had seen an image, and what that image contained. A report of this process has been published in the journal PLOS Computational Biology.
Lead researcher Kai Miller told IFLScience that “there have been other studies where scientists have been able to tell when a patient is looking at one type of an image or another, but the timing of this stimulus had always been known ahead of time.
“However, we were able to decode spontaneously from the signal, so we were able to look at the brain signal and say at this point in time they saw this particular type of image.” To achieve this, the team focused on two types of brain signals: event-related potentials (ERPs) and broadband.

Electrodes were implanted into the temporal and occipital lobes of epilepsy patients, and used to measure their brain activity when viewing a series of images. Kai Miller, Stanford University