A group of scientists has discovered specific areas of the brain that become active when individuals gain awareness of themselves and their thoughts. This complex process appears to be managed by the thalamus, which is a central brain region known for its role as a mediator between sensory signals and the cerebral cortex. The cerebral cortex is responsible for higher-level functions such as memory, thought, and personality.
Conscious perception is defined as the human ability to become aware of stimuli sensed by the body. This state is distinct from merely being awake, where sensations are processed automatically without deliberate thought. Conscious perception involves a detailed, voluntary analysis of external stimuli. For instance, individuals can breathe unconsciously, but they can also consciously focus on their breathing and alter its rhythm. Similarly, when listening to music, individuals can distinctly identify and focus on different instruments.
In recent efforts, neurologists have been trying to pinpoint the area of the brain where this perceptual change takes place. Historically, the cerebral cortex was suspected to control this function due to its role in advanced brain processing. Although the thalamus was never completely dismissed from its involvement in conscious perception, it was generally considered to play a secondary role as an intermediary that readies sensory information for the cortex. A new study published in Science redefines this understanding, highlighting the thalamus as an active participant in conscious perception.
Previous studies exploring the thalamus’s role in consciousness have often faced doubt, either because they lacked compelling observational data or due to questions about the methods used to obtain such data. To determine whether brain regions become active during conscious attention, it is necessary for subjects to be consciously aware of stimuli while undergoing brain monitoring through invasive methods.
However, the team from Beijing Normal University in China utilized participants who already had thin electrodes implanted in their brains for experimental headache treatment, thereby avoiding ethical concerns related to conducting invasive procedures solely for research purposes.
These researchers conducted a visual perception test with the participants. A blinking object was displayed on a screen, disappearing half of the time. This setup required participants to actively focus and realign their gaze, fostering conscious perception. The pre-existing electrodes recorded the corresponding brain activity.
The researchers claim that this study represents one of the first simultaneous recordings of conscious perception. The collected data strongly supports the hypothesis that the thalamus functions as a gateway to conscious perception. According to the authors, “The findings indicate that the intralaminar and medial thalamic nuclei regulate conscious perception. This conclusion represents a significant advance in our understanding of the network that forms the basis of visual consciousness in humans.”
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