The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human

In more general terms, our sense of being an integrated, embodied self seems to depend crucially on back-and-forth, echo-like “reverberation” between the brain and the rest of the body—and indeed, thanks to empathy, between the self and others. Indiscriminate scramblings of the connections between high-level sensory areas and the amygdala, and the resulting distortions to one’s salience landscape, could as part of the same process cause a disturbing loss of this sense of embodiment—of being a distinct, autonomous self anchored in a body and embedded in a society. Perhaps somatic self-stimulation is some children’s attempt to regain their embodiment by reviving and enhancing body-brain interactions while at the same time damping spuriously amplified autonomic signals. A subtle balance of such interactions may be crucial for the normal development of an integrated self, something we ordinarily take for granted as the axiomatic foundation of being a person. No wonder, then, that this very sense of being a person is profoundly disturbed in autism.

We have so far considered two candidate theories for explaining the bizarre symptoms of autism: the mirror-neuron dysfunction hypothesis and the idea of a distorted salience landscape. The rationale for proposing these theories is to provide unitary mechanisms for the bewildering array of seemingly unrelated symptoms that characterize the disorder. Of course, the two hypotheses are not necessarily mutually exclusive. Indeed, there are known connections between the mirror-neuron system and the limbic system. It is possible that distortions in limbic-sensory connections are what lead ultimately to a deranged mirror-neuron system. Clearly, we need more experiments to resolve these issues. Whatever the underlying mechanisms turn out to be, our results strongly suggest that children with autism have a dysfunctional mirror-neuron system that may help explain many features of the syndrome. Whether this dysfunction is caused by genes concerned with brain development or by genes that predispose to certain viruses (that in turn might predispose to seizures), or is due to something else entirely remains to be seen. Meanwhile, it might provide a useful jumping off point for future research into autism, so that someday we may find a way to “bring Steven back.”

Autism reminds us that the uniquely human sense of self is not an “airy nothing” without “habitation and a name.” Despite its vehement tendency to assert its privacy and independence, the self actually emerges from a reciprocity of interactions with others and with the body it is embedded in. When it withdraws from society and retreats from its own body it barely exists; at least not in the sense of a mature self that defines our existence as human beings. Indeed, autism could be regarded fundamentally as a disorder of self-consciousness, and if so, research on this disorder may help us understand the nature of consciousness itself.

CHAPTER 6

  The Power of Babble: The Evolution of Language

…Thoughtful men, once escaped from the blinding influences of traditional prejudice, will find in the lowly stock whence Man has sprung, the best evidence of the splendor of his capacities; and will discern in his long progress through the past, a reasonable ground of faith in his attainment of a nobler future.

—THOMAS HENRY HUXLEY

ON THE LONG FOURTH OF JULY WEEKEND OF 1999, I RECEIVED A phone call from John Hamdi, who had been a colleague of mine at Trinity College, Cambridge, nearly fifteen years earlier. We hadn’t been in contact and it was a pleasant surprise to hear his voice after such a long time. As we exchanged greetings, I smiled to myself, reminded of the many adventures we had shared during our student days. He was now a professor of orthopedic surgery in Bristol, he said. He had noticed a book I’d recently published.

“I know you are mainly involved in research these days,” he said, “but my father, who lives in La Jolla, has had a head injury from a skiing accident followed by a stroke. His right side is paralyzed, and I’d be grateful if you could take a look at him. I want to make sure he’s getting the best treatment available. I heard there’s a new rehab procedure which employs mirrors to help patients recover the use of a paralyzed arm. Do you know anything about this?”