A research team led by the University of Iowa is reporting that self-awareness is a product of a patchwork of pathways in the brain.
The research challenges an accepted theory that three regions in the brain are critical in self-awareness: the insular cortex, the anterior cingulate cortex, and the medial prefrontal cortex, the neuroscientists note.
The conclusions came from a rare opportunity to study a person with extensive brain damage to those three regions of the brain.
Researchers report the person, a 57-year-old, college-educated man known as “Patient R,” passed all standard tests of self-awareness. He also displayed repeated self-recognition, both when looking in the mirror and when identifying himself in unaltered photographs taken during all periods of his life.
“What this research clearly shows is that self-awareness corresponds to a brain process that cannot be localized to a single region of the brain,” said David Rudrauf, Ph.D., co-corresponding author of the paper, published online in the journal PLOS ONE.
“In all likelihood, self-awareness emerges from much more distributed interactions among networks of brain regions.”
The researchers, who also hypothesize that the brainstem, thalamus, and posteromedial cortices play roles in self-awareness, said they observed that Patient R’s behaviors and communication often reflected depth and self-insight.
Senior author Carissa Philippi, Ph.D., who earned her doctorate in neuroscience at the university in 2011, conducted a detailed interview with Patient R and said he had a deep capacity for introspection, one of humans’ most evolved features of self-awareness.
“During the interview, I asked him how he would describe himself to somebody,” said Philippi, now a postdoctoral research scholar at the University of Wisconsin-Madison. “He said, ‘I am just a normal person with a bad memory.’”
He also demonstrated self-agency, which is the ability to perceive that an action is the consequence of one’s own intention.
When rating himself on personality measures collected over the course of a year, Patient R showed a stable ability to think about and perceive himself.
However, his brain damage also affected his temporal lobes, causing severe amnesia that disrupts his ability to update new memories into his “autobiographical self.” Beyond this disruption, all other features of Patient R’s self-awareness remained fundamentally intact, according to the researchers.
Rudrauf notes that most people who meet Patient R have no idea there is anything wrong with him. “They see a normal-looking middle-aged man who walks, talks, listens, and acts no differently than the average person,” he said.
“According to previous research, this man should be a zombie, but as we have shown, he is certainly not one. Once you’ve had the chance to meet him, you immediately recognize that he is self-aware.”
“Here, we have a patient who is missing all the areas in the brain that are typically thought to be needed for self-awareness yet he remains self-aware,” added co-corresponding author Justin Feinstein, Ph.D.
“Clearly, neuroscience is only beginning to understand how the human brain can generate a phenomenon as complex as self-awareness.”
Source: University of Iowa