Neuroscience: Brain Power

Originally published in the Globe and Mail. Read the full text here.

Two books delve into the wild world of mental matters

Wilder Penfield was among the most important explorers of the 20th century. A former Princeton class president and varsity athlete, Penfield traded in his all-American credentials to establish an unorthodox medical practice in Montreal in the late twenties. He specialized in neurosurgery, and according to author Sam Kean, "probably did more than any other scientist to explain how the brain works in real time." Penfield kept his patients awake, a common practice, given that the upper brain isn't receptive to physical pain. By administering low-level electric shocks to different parts of the cerebral cortex, he conjured dramatic sights, sounds, or sensations in his subjects' minds. His experiments took medical knowledge past the familiar and into the neurobiological badlands. Prior to his interventions, Kean writes, "whole continents of the neural hemispheres remained as sketchy as early-1500s maps of the Americas."

Penfield is one of the many eccentric visionaries who populate Kean's engrossing, cleverly narrated book The Tale of the Dueling Neurosurgeons: The History of the Human Brain as Revealed by True Stories of Trauma, Madness, and Recovery. Kean draws on bizarre anecdotes (many could be described as tall tales if they weren't actually true) that reveal surprising insights about human cognition. He considers phantom limbs, the complex mechanisms behind facial recognition (and misrecognition), neuroplasticity, synethesia and other discoveries that elevated neuroscience to the forefront of both medical practice and popular culture.

Any history of neuroscience is at least a partial history of psychiatry too, since neurobiology is such a prevailing force within psychiatric thought.The old argument about whether mental illnesses are biologically determined or the product of childhood experiences has had many iterations over the decades since psychoanalysis came to prominence. You can easily see why neurobiological theories became so important. Consider Penfield's experiments: with a simple electrode, he triggered sensory experiences – hissing or thumping sounds, visions of shadows or crosses – that had no basis in external reality. In doing so, he showed delusions for what they are: errant electrical impulses in the human brain. It's hard to imagine a more straightforwardly anatomical illustration of how disordered thinking happens.

Neurobiological breakthroughs pushed the hokier psychoanalytic clichés to the margins of clinical theory. Kean discusses Capgras syndrome (arguably one of the most unsettling conditions out there), in which you become convinced that the people you love have been hollowed out and replaced by robots or clones. The man who discovered the disorder roughly a century ago, French psychiatrist Joseph Capgras, had a stock explanation: repressed incestual urges. Experimental data, however, points to problems with the brain's limbic system, which, among other things, produces a warm feeling of recognition in the presence of somebody you love. Take away that feeling, and even the most familiar face can seem eerily vacuous. Clinicians can assess limbic recognition – or its absence – by monitoring sweat levels on a person's skin. Clearly, Capgras syndrome is a biological disorder with measurable bodily effects. "In light of brain discord," Kean writes, "many delusions seem, if not rational, at least comprehensible. They're simply the failings of a fragile brain."

We can make arguments like this because, at last, we're beginning to feel our way around that complex, ridged and grooved organ beneath our skulls. This is, in many respects, a positive development – one that has enabled effective new drug treatments – but have we gone too far in our efforts to medicalize psychiatry? Today, many specialists, including experts in psychosis and delusion, are trying to shift our attention back toward social and cultural theories of mental illness. If we're going to better understand psychiatric disorders, they insist, neurobiology has to share space with social studies.

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