New research conducted by scientists from the USA and France has uncovered the key role played by the brain stem in maintaining wakefulness and human consciousness. This discovery offers insight into altered states of consciousness, such as coma and vegetative state.
Previous studies have suggested that consciousness can be divided into two aspects: arousal (or wakefulness) and awareness. A study in 2016 by Harvard Medical School researchers first highlighted the link between the brain stem, responsible for regulating arousal, and other parts of the brain associated with awareness.
In a recent study involving experts from MIT and the University of Tour in France, scientists focused on exploring the brain’s “default mode network,” a state in which the brain is not actively engaged in a task but is still capable of processing information. This network, known as the “default-awake network” (DAAN), operates without requiring active input.
The study used MRI scans of three donated brains and analyzed MRI data from 84 healthy individuals as part of the “Human Connectome” project, which aims to map neural connections in the brain. The researchers paid particular attention to the midbrain, where they identified the ventral tegmental area (VTA). The VTA was found to have strong connections with other nodes in the DAAN network, indicating its role in conscious perception.
This new discovery highlights the importance of the VTA, previously thought to only influence behavior and cognition. Scientists now believe that the VTA also contributes to maintaining wakefulness and, subsequently, awareness. Additionally, researchers identified two direct connections between the brain stem and the cortex, linking wakefulness and awareness.
Although the researchers acknowledge the limitations of their study, they suggest that future research may uncover further insights into the complex nature of consciousness. With numerous possible interpretations and the topic’s inherent ambiguity, continued studies could reveal additional facets of consciousness functioning.