Brain structure that filters identified consciousness

Scientists identify brain structures that filter consciousness

by Smriti Mallapaty & Nature Magazine

For the first time, neuroscientists have observed how deep structures in the brain are activated when the brain recognizes its own thoughts known as conscious perception.

The brain is Continuously fired There are sights, sounds, and other stimuli, but people only recognize bars of the world around them. For example, the taste of chocolate or the sound of someone else's voice. Researchers have long known that the outer layer of the brain, known as the brain cortex, is involved in this experience of recognizing a particular idea.

The involvement of deeper brain structures was much more difficult to understand, as they were only accessible through invasion surgery. Designing experiments to test animal concepts is also difficult. But studying these areas allows researchers to broaden their theory of consciousness beyond the outer packaging of the brain, the researchers say.

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“The Field of the ” Consciousness research Liad Mudrik, a neuroscientist at Tel Aviv University in Israel, said: Investigate awarenessshe says.

Whether you notice it

In research published in Science Today, Minger Chang, a neuroscientist at Beijing Normal University, focuses on the thalamus. This area at the heart of the brain is involved in the processing of sensory information and working memory, and is thought to play a role in conscious perception.

Participants were already receiving treatment for severe persistence headachethey had thin electrodes that were injected deeply into the brain. This allowed Zhang and his colleagues to study brain signals and measure conscious perceptions.

Participants were asked to move their eyes in a specific way, depending on whether the icon flashed to the previous screen. The icon is designed so that participants only recognize about half of their appearance.

During the task, the researchers recorded neural activity in multiple regions of the brain, including the thalamus and cortex. Christopher White, a systems neuroscientist at the University of Sydney in Australia, said this is the first time such a simultaneous recording has been made to people performing tasks related to the science of consciousness. The work is “very amazing,” he says. This is because teams can see how the timing of neural activity in different regions changes.

Gatekeeper

Participants' thalamic and prefrontal cortex activities differed significantly from those when they were aware of the appearance of the icons. The activity that recognized the icon appeared to be stronger in the thalamus section than in the cortical section and adjusted in two regions. This suggests that the thalamus acts as a filter and controls which thoughts are guided by awareness and not, says Mac Shine, a systems neuroscientist at the University of Sydney.

Previous animal studies support these findings. In a 2020 paper, researchers used magnets to move individual mice whiskers enough to allow the mice to notice about half the time. Animals were trained to lick from a spurt of water when they felt movement. Researchers discovered cells in the cerebral cortex that mice were activated when they noticed that mice were projected into deeper brain regions of the brain regions, including the thalamus.

The latest research is “one of the most elaborate and extensive investigations into the role of the thalamus in consciousness,” says Mudrik. However, there are still questions as to whether the task truly captured neural activity associated with conscious experiences or paid attention to stimuli that are not necessarily consciously recognized, she says.

Zhang plans to conduct more experiments on people and investigate brain activity in detail in macaque monkeys.

This article was reproduced with permission and was First published April 3, 2025.