Scientists captured the decision-making brain activity in macaques down to the millisecond.
There’s an area in your brain, called the orbitofrontal cortex, which plays a key role in the decisions you make. When it’s damaged, it can lead to poor choices and impulsivity.
Neuroscientists at UC Berkeley recorded the real-time deliberations by macaque monkeys, enabling them to capture the dynamics of decision-making down to the millisecond in the brain’s orbitofrontal cortex. In theory, the new insights will help researchers figure out how to help people pick a healthier choice over a more toxic one.
"If we can measure a decision in real time, we can potentially also manipulate it," study senior author Jonathan Wallis, a UC Berkeley neuroscientist and professor of psychology, said in a press statement.
In the experiment, electrodes were implanted in the monkeys’ brains, allowing researchers to track the neural activity as the macaques weighed the pros and cons of the images they were presented with.
The monkeys looked at a series of four different images of abstract shapes, each of which delivered a different amount of juice to the monkey. With a computational algorithm, the scientists tracked the orbitofrontal activity as the monkeys looked from image to image, deciding which would yield the greatest reward.
The researchers used a pattern-recognition algorithm, called linear discriminant analysis, to look at the patterns of neural activity and pin down which picture the monkey was fixated on.
Next, the monkeys were presented with two of the before-seen images, and the researchers were able to watch the primates’ neural patterns as they switched back and forth deciding between two options in which the amounts of juice only differed slightly.
"Effectively we could now see the decision unfold and make predictions about the animal's choice," Wallis said.
The researchers say that the findings, which have been published in the journal Nature Neuroscience, offer new insight into the internal decision-making process — particularly habitual behaviors — and help researchers create implants to target neural circuits and treat neuropsychiatric disorders like addiction, anxiety, and depression.
"Now that we can see when the brain is considering a particular choice, we could potentially use that signal to electrically stimulate the neural circuits involved in the decision and change the final choice," Wallis said.
"For example, a device could be created that detects when an addict is about to choose a drug and instead bias their brain activity towards a healthier choice.”
For now, this idea remains hypothetical, and there would certainly be some ethical concerns to smooth out before implanting a brain device that could sway a person’s decisions. Nonetheless, it’s always a triumph in neuroscience when we can gain new insights into the workings of the brain.
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