Harvard may Have Found the Source of Human Consciousness

Despite the spectacular advances across the scientific spectrum, especially in neuroscience, the human consciousness is still shrouded in mystery. Now Harvard researchers think they have finally localized the physical source of consciousness.

To Find out More About Consciousness, Study the Unconscious

Consciousness has two main components:

• awareness, and
• arousal.

In psychotherapy, awareness is the self-consciousness related to physical and emotional experiences. In neurology, the state of arousal, controlled by the brainstem, is responsible for the sleep-wake cycle, respiratory and cardiac timing.

However, the exact location of awareness had remained unclear. That’s what a team of neurologists at Harvard Medical School and Beth Israel Deaconess Medical Center tried to figure out in their award-winning study, which was published in the journal Neurology.

The team focused on patients with brain injuries, some of whom were in a coma.

Consciousness Relies on the Brainstem and two Cortical Regions

Researchers pinpointed the specific region of the brain stem related to arousal, but also two regions of the cortex, which seem to work together to produce consciousness.

The team of researchers studied 36 patients with brain stem lesions. Of the patients, 12 were in a coma state (unconscious) while 24 were conscious. They then mapped the injuries to see if there was a correlation between the area of injury and conscious state.

It turns out that a small area of the brainstem called the rostral dorsolateral pontine tegmentum was associated with coma symptoms. 10 of 12 unconscious patients had lesions in this area, while only one conscious patient had the same injury location. This suggests that this small region of the brainstem is crucial for consciousness.

To understand how other parts of the brain are connected to this region, researchers used a cerebral diagram of a healthy brain based on the large shared data set called Human Connectome. They identified two areas in the cortex linked to the coma-specific region pontine tegmentum: the anterior insula and the pregenual anterior cingulate cortex.

Michael Fox, HMS assistant professor of neurology at Beth Israel Deaconess, said, “For the first time, we have found a connection between the brainstem region involved in arousal and regions involved in awareness, two prerequisites for consciousness.”

Independent teams will have to confirm their results before it can be asserted that these three regions are the physical source of consciousness in the human brain. Yet, the final determination could unlock an entire field of psychological experimentation.