Scientists find how the brain gains from subconscious stimuli


Researchers discover how the brain learns from subconscious stimuli The ventral tegmental area consists of, among others, cells that produce dopamine. Credit: Neuron Researchers discovered for the first time what occurs in animals ‘brains when they learn from subconscious, visual stimuli. In time, this understanding can cause brand-new treatments for a variety of conditions. The research study, a collaboration in between KU Leuven, Massachusetts General Medical Facility, and Harvard was published in Neuron.

A knowledgeable birdwatcher acknowledges a lot more information in a bird’s plumage than the normal individual. Thanks to comprehensive training, he or she can recognize specific functions in the plumage. This knowing procedure is not only dependent on mindful processes. Previous research study has actually revealed that when people are rewarded during the discussion of visual stimuli that are not purposely perceivable, they can still view these stimuli later on.

Although this is a known phenomenon, scientists were uncertain as to how exactly this unconscious perceptual knowing comes about. To discover, Professor Wim Vanduffel and coworkers studied the brains of 2 rhesus monkeys prior to and after they were exposed to subconscious visual stimuli.


The researchers triggered part of the benefit system at the base of the brain stem, the ventral tegmental location. This includes cells that produce dopamine, a molecule that is likewise released when you get a benefit. “Dopamine is an important messenger molecule of our motor and reward systems, and is extremely essential for learning and enjoyment,” states Vanduffel. Triggering the forward tegmental area launched dopamine, to name a few things. “By promoting the brain area directly, we can causally connect the activity in that area to understanding or complex cognitive behavior,” discusses Vanduffel.

While the brain location was triggered, the monkeys were shown essentially unnoticeable images of human faces and bodies. Because the images were very blurred and the monkeys needed to perform a very various and difficult task at the same time, they might not knowingly perceive these images. The very same process was followed during the control tests, however the brain was not promoted.

When the monkeys got subconscious visual stimuli while the ventral tegmental location was stimulated, they knew information about those images afterwards. For instance, they knew whether the bodies shown were relied on the left or to the right. This was not the case when there had actually been no brain stimulation.

“Thanks to this experiment, we can demonstrate for the first time a direct causal relationship in between this brain region and, as a result, also the likely link in between dopamine and the subconscious knowing of intricate visual stimuli.”

The scientists also made a brain scan of the animals before and after the test. “We can see the blood flow in the brain, which provides a sign of which nerve cells are active. The more blood flow, the more activity,” explains Vanduffel. The scans revealed that the job triggered activity in the visual cortex of the brain and in areas crucial for memory. “With this information, we can focus to find out what is occurring exactly at a neuronal level in these brain locations, in future experiments.”

“Given that Freud’s insights in the 20th century, the clinical community has actually been questioning how subconscious sensations can impact us. Thanks to today awareness that there is a strong resemblance between human beings and monkeys, and new and innovative technologies, we can lastly map such procedures physiologically.”

Parkinson’s disease

Disturbances in the dopaminergic system can lead to various psychiatric and motor disorders, such as depression, addiction and Parkinson’s illness. A better understanding of how this system works, in different kinds of learning, is therefore important to developing targeted treatments for these conditions.

“Parkinson’s is a motor disorder and is triggered by dopamine-producing neurons passing away off. However, current dopamine treatments may produce side effects due to the fact that they likewise set off the entire benefit system, which not just lowers motor symptoms but can likewise result in addicting habits.” Essential research into the functioning of these brain areas will ultimately cause more targeted treatments with fewer adverse effects.


This insight is likewise useful in circumstances such as trauma, aging or oncological problems where an increase in brain plasticity, i.e. the ability to change, could be extremely helpful. “By stimulating locations of the brain that produce dopamine, we could, for instance, enable people to regain their speech more quickly or enhance their motor abilities after a mishap or disease. This might even be done through medication, although we are still a long way from that,” discusses Vanduffel.

Insights about our brain and the conditions under which we and other primates visually form our world are for that reason important, because, as Vanduffel concludes: “you need to understand how a vehicle’s engine works before you can repair an issue with it.”

Scientists reversibly disable brain pathway in primates More details: Sjoerd R. Murris et al, Electrical stimulation of the macaque forward tegmental location drives category-selective learning without attention, Neuron (2021 ). DOI: 10.1016/ j.neuron.2021.02.013

Citation: Researchers find how the brain learns from subconscious stimuli (2021, March 15) retrieved 15 March 2021 from

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