Scientists have uncovered for the first time what happens in animals brains when they learn from subconscious, visual stimuli. The study was conducted by KU Leuven, Massachusetts General Hospital and Harvard were published in Neuron. This research could help in treatments for a number of conditions.
Brains learns from stimuli
Previous research has shown that when people are rewarded during the presentation of visual stimuli that are not consciously perceivable, they can still perceive these stimuli afterwards. Although this is a known phenomenon, researchers were unsure as to how exactly this unconscious perceptual learning comes about. Professor Wim Vanduffel and his colleagues studied the brains of two rhesus monkeys before and after they were exposed to subconscious visual stimuli.
In the study, the researchers activated part of the reward system at the base of the brain stem, the ventral tegmental area. The researchers included cells that produce dopamine, a molecule that is also released when you receive a reward. Wim Vanduffel said, “Dopamine is a crucial messenger molecule of our motor and reward systems, and is extremely important for learning and enjoyment.” They activated the ventral tegmental area, released dopamine, among other things. He added, “By stimulating the brain area directly, we can causally link the activity in that area to perception or complex cognitive behaviour.”
Researchers uncovered what happens when the brain learns from unconscious, visual stimuli ð The discovery helps scientists understand, among others, what happens in the brains of people with Parkinson’s disease ð§ https://t.co/EtbmevUF6e
— KU Leuven (@KU_Leuven) March 15, 2021
The monkeys were shown virtually invisible images of human faces and bodies while the brain area was activated. The monkeys were not able to perceive the images as they were blurry and the monkey had to perform the different task at the same time. Researchers followed the same procedure for the control test. When the monkeys received subconscious visual stimuli while the ventral tegmental area was stimulated, they knew details about those images afterwards. The researchers also made a brain scan of the animals before and after the test. The scans showed that the task caused activity in the visual cortex of the brain and in areas important for memory. The researchers were able to see blood flow in the brain that gave an indication of neurons being active.
“With this data, we can zoom in to find out what is happening exactly at a neuronal level in these brain areas, in future experiments,” he added.
Disturbances in the dopaminergic system can lead to numerous psychiatric and motor disorders, such as depression, addiction and Parkinson’s disease. A better understanding of how this system works, in various forms of learning, is therefore crucial to developing targeted therapies for these conditions. This insight is also useful in situations such as trauma, ageing or oncological problems where an increase in brain plasticity, i.e. the ability to change, could be very useful. “By stimulating areas of the brain that produce dopamine, we could, for example, enable people to regain their speech more quickly or improve their motor skills after an accident or illness. Vandufeel explained that this could be done through medication but for that, there is a long way to go.