Innovation

'Patient R' makes scientists revise theory of how brain works

A man with damage in the three brain regions scientists considered crucial for self-awareness passed all tests of self-awareness, changing notions of how the brain works.

Written by Laura Shin, Contributor Sept. 3, 2012 at 8:00 p.m. PT

There's so much we don't know about the brain.

We use techniques like functional neuroimaging to find out which brain regions light up while a subject performs an activity, but whether or not that really means that area is responsible for that function can remain a mystery.

And that's why Patient R, a man who had damage in the three areas of the brain, has proved so useful to researchers: His case has disproved that the three areas of the brain previously thought critical for self-awareness actually are responsible for it.

Even more importantly, his case could upend traditional notions that specific brain regions have specific duties. The brain might actually be more flexible, with certain areas taking on new functions depending on other events in the brain.

Patient R

Self-awareness is a pretty high-level cognitive function.

It's a step (or several steps?) beyond consciousness (as described by Scientific American), because consciousness is just having thoughts, while self-awareness is recognizing that you have thoughts, plus then thinking about your thoughts. Self-aware beings also know their traits, feelings and behaviors. (That's why scientists have asserted that a number of animals are conscious, but none besides humans are said to have self-awareness.)

Neuroimaging studies suggested that self-awareness comes from three areas of the brain: the insular cortex, the anterior cingulate cortex, and the medial prefrontal cortex.

So when David Rudrauf at the University of Iowa in Iowa City heard that Patient R, also known as Roger, suffered extensive brain damage in exactly these areas, he thought Patient R would be a good way to corroborate the neuroimaging studies on self-awareness. Only ten percent of Roger's insula remained, as did only one percent of the anterior cingulate cortex.

And yet, in the experiments, Roger still exhibited a sense of self that allowed him to recognize himself in the mirror and in photographs. He also passed the "tickle test," which is based on the idea that you can't tickle yourself. He could always distinguish between when he was being tickled by others or by himself, and was always more "tickled" by others.

He could even make jokes that showed he had a sense of self. When a researcher asked Roger for permission to tickle, he, jokingly referring to his sweaty armpits, responded, "Got a towel?"

Significance

The authors, who published their study in PLOS One, concluded that the three areas of the brain previously considered critical for self-awareness aren't.

Additionally, they suggest that self-awareness is a diffuse cognitive process that uses many parts of the brain, including those not located in the cerebral cortex.

Rudrauf also told New Scientist that self-awareness and other high-level cognitive functions "involve layers of abstraction and mechanisms that cannot be explained by standard functional-neuroanatomy. ... We would all like simple answers to complicated questions, and we tend to oversimplify our conceptions about the brain and the mind."