> Re a sense of having a self.... Edgar > > > Self-awareness in humans is more complex, diffuse than previously thought > > August 22nd, 2012 in Neuroscience > Researchers at the University of Iowa studied the brain of a patient with > rare, severe damage to three regions long considered integral to > self-awareness in humans (from left to right: the insular cortex, anterior > cingulate cortex, and the medial prefrontal cortex). Based on the scans, the > UI team believes self-awareness is a product of a diffuse patchwork of > pathways in the brain rather than confined to specific areas. Credit: > Department of Neurology, University of Iowa > > Ancient Greek philosophers considered the ability to "know thyself" as the > pinnacle of humanity. Now, thousands of years later, neuroscientists are > trying to decipher precisely how the human brain constructs our sense of self. > > Self-awareness is defined as being aware of oneself, including one's traits, > feelings, and behaviors. Neuroscientists have believed that three brain > regions are critical for self-awareness: the insular cortex, the anterior > cingulate cortex, and the medial prefrontal cortex. However, a research team > led by the University of Iowa has challenged this theory by showing that > self-awareness is more a product of a diffuse patchwork of pathways in the > brain – including other regions – rather than confined to specific areas. > > The conclusions came from a rare opportunity to study a person with extensive > brain damage to the three regions believed critical for self-awareness. 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, co-corresponding author of the paper, published online Aug. 22 > in the journal PLOS ONE. "In all likelihood, self-awareness emerges from much > more distributed interactions among networks of brain regions." The authors > believe the brainstem, thalamus, and posteromedial cortices play roles in > self-awareness, as has been theorized. > > The researchers observed that Patient R's behaviors and communication often > reflected depth and self-insight. First author Carissa Philippi, who earned > her doctorate in neuroscience at the UI in 2011, conducted a detailed > self-awareness 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.'" > > Patient R also demonstrated self-agency, meaning 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 has disrupted > his ability to update new memories into his "autobiographical self." Beyond > this disruption, all other features of R's self-awareness remained > fundamentally intact. > > "Most people who meet R for the first time have no idea that anything is > wrong with him," noted Rudrauf, a former assistant professor of neurology at > the UI and now a research scientist at the INSERM Laboratory of Functional > Imaging in France. "They see a normal-looking middle-aged man who walks, > talks, listens, and acts no differently than the average person." > > "According to previous research, this man should be a zombie," he added. "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." > > Patient R is a member of the UI's world-renowned Iowa Neurological Patient > Registry, which was established in 1982 and has more than 500 active members > with various forms of damage to one or more regions in the brain. > > The researchers had begun questioning the insular cortex's role in > self-awareness in a 2009 study that showed that Patient R was able to feel > his own heartbeat, a process termed "interoceptive awareness." > > The UI researchers estimate that Patient R has ten percent of tissue > remaining in his insula and one percent of tissue remaining in his anterior > cingulate cortex. Some had seized upon the presence of tissue to question > whether those regions were in fact being used for self-awareness. But > neuroimaging results presented in the current study reveal that Patient R's > remaining tissue is highly abnormal and largely disconnected from the rest of > the brain. > > "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, who earned his doctorate at > the UI in February. "Clearly, neuroscience is only beginning to understand > how the human brain can generate a phenomenon as complex as self-awareness." > > Provided by University of Iowa > > > "Self-awareness in humans is more complex, diffuse than previously thought." > August 22nd, 2012. > http://medicalxpress.com/news/2012-08-self-awareness-humans-complex-diffuse-previously.html >
