Lingering questions about which part of the brain produces the feeling of being ‘awake’ have been answered thanks to stunningly detailed new brain images.
The new high-resolution brain scans allowed researchers to see brain connections at a granular “submillimeter” level – that is, down to 3/100th of an inch.
The images were then used to map a neural network of previously invisible pathways in the brain, called the ‘standard ascending arousal network’ or dAAN, which they now theorize is the core area that helps people maintain awake consciousness .
In recent years, neuroscientists who study consciousness have divided this curious mystery of how the human brain is self-aware into two subcategories: “arousal” (wakefulness) and “consciousness” (the subjective experience of life).
The researchers hope that their work exploring this dAAN pathway will help develop new treatments for patients with comas or other conditions that rely on wakefulness.
The new high-resolution brain scans (above) allowed researchers to see brain connections at a granular ‘submillimeter’ level – that is, down to 3/100th of an inch
The areas they mapped were centered around the base of the brain, where it connects to the spinal column: including the brainstem, thalamus, hypothalamus, basal forebrain and cerebral cortex.
“Our goal was to map a human brain network that is crucial for consciousness,” said lead author Dr. Brian Edlow, ‘to provide physicians with better tools to detect, predict, and promote recovery of consciousness in patients with severe brain injury.’
Dr. Edlow’s colleague and senior author of the new study, Dr. Hannah Kinney, specified that “a wide range of neurological disorders” associated with altered states of consciousness could also benefit from the new research.
Dr. Kinney, professor emeritus at Harvard Medical School and Boston Children’s Hospital, noted that the new neural maps could also one day help patients cope with seizures and sudden infant death syndrome, and in patients recovering from comas.
Dr. Nicholas Schiff, professor of neurology and neuroscience at Weill Cornell Medicine – who was not involved in the new study – said Living Science that the team’s neural mapping was an impressive new achievement.
“It’s a wonderful study,” said Dr. Schiff. ‘It’s a map of everything.’
Above is an MRI scan of the key nodes of the human brain, which the authors of the new study say are essential for keeping people awake. The nodes are color-coded for their neural mapping
The study’s authors hope that their work, which examines the ‘wakefulness’ pathways of the conscious brain, will help develop new treatments for coma patients, as well as those experiencing epileptic seizures.
Using a technique called ex vivo magnetic resonance imaging (MRI), a slower form of MRI scanning performed on dead or surgically removed tissue, the researchers were able to create detailed images of the dAAN pathways associated with consciousness.
The areas they mapped were all tightly centered around the center or base of the brain, near where it connects to the spinal column: including the brainstem, thalamus, hypothalamus, basal forebrain and cerebral cortex.
Dr. Kinney, Dr. Edlow and their team then checked this work against so-called resting-state “in vivo 7-tesla functional MRI” data, which had been safely collected from living patients who had volunteered for the Human Connectome Project. .
Based on their mapping work, as they wrote in their new publication in the journal Scientific translational medicinethe researchers believe that the ventral tegmental area, or VTA, in the midbrain will be a key area for treatments to help with wakefulness.
The VTA is known to be the origin of a number of nerve fibers that produce dopamine, the hormone involved in brain ‘reward’ and happiness.
“Our connectivity results suggest that stimulation of the dopaminergic pathways in the ventral tegmental area has the potential to help patients recover from coma,” said Dr. Edlow said in a statement.
“This hub node is connected to many areas of the brain that are crucial for consciousness,” he pointed out.
Dr. Edlow, associate director of the Center for Neurotechnology and Neurorecovery (CNTR) at Boston’s Mass General and associate professor of Neurology at Harvard Medical School, said he hopes to continue providing more detailed neural maps in an effort to help patients who suffered from loss of consciousness.
“We envision that these connectivity maps will allow us to piece together, one individual at a time, the combination of connections necessary and sufficient to restore consciousness,” he said.