Brain science leaps forward

Jay Kuten PHOTO/FILE

During my medical training, I was fortunate to have an externship with Dr Paul Yakovlev, professor of neurology and neuro-anatomy, Harvard Medical school.

It was the opportunity to study human neuro-anatomy intensively with such an incredibly thoughtful scientist that attracted me. The added benefit was his laboratory's location within the Warren Anatomical Museum, a treasure trove of historic medical specimens.

I was allowed to open one of the large vertical glass cases that held an iron bar and a human skull with a distinct hole in its roof or frontal bone. I had the privilege of holding in my hand the skull of Phineas P. Gage.

On September 13, 1848, Gage, a railroad construction foreman, was tamping down an explosive charge with the metre-long pointed tamping bar when a spark set off an explosion and drove the rod completely through his head, behind his eye and through his frontal lobe. Gage, with medical help, not only survived the accident but lived another 12 years. His importance to neuroscience rests in the extent of his injuries survivable and the impetus it gave to the 19th and early 20th work on localisation of function within the brain.

Because he exhibited significant dysfunction just after the accident, allegedly becoming profane and abusive, those scientists eager to find the locus of behaviour ascribed the conduct to loss of the frontal lobe with its seat of reflective impulse governing functions.

Others took issue in that Gage later worked as a stage coach driver in Peru where he not only had to plan and carry out complex tasks within an environment where his language skills were barely adequate. His later life gave support to a rehabilitative view of brain damage that is, even now, current. It holds that adding structure to tasks makes for a fuller rehabilitation and return of social skills.

Because direct observation of Gage's behaviour over time was not at hand, theorists of localisation of brain function and opponents could cite him as proof of their positions.

We've come a long way since 1848 in terms of knowledge of brain function, what with electron microscopes, MRIs, CAT and PET scans. We more or less know where things are located in the brain all the way down to the micro level. But how much do we really know? We know a lot about the brainstem's Locus Coeruleus, its connections to many systems, its function as principal brain synthesizer of norepinephrine (adrenalin) and its special function as centre of sleep and wakefulness.

The brain stem contains a set of neurons which regulate our breathing in response to our blood levels of CO2. Too little CO2 causes breathing to stop temporarily, too much can stop the breathing and ourselves permanently. A magnificent balancing act that we only barely understand.

Now we are moving towards an exquisite new method of understanding brain tissue, beyond even electron microscopy. This week, researchers Rudolph Tanzi and Doo Yeon Kim of Harvard announced success not only in growing human brain cells in a petri dish, but by genetic alterations they induced characteristic plaques of amyloid and could also create the axonal fibrillary tangles of tau protein characteristic of Alzheimer's disease. The scientific implications are beyond measure.

While neuroscience has gone beyond localisation of function, I must acknowledge my debt to Dr Yakovlev, beyond the neuro-anatomy he taught. In his breadth of skill and humanity, he exemplified the ideal scientist.

One day, we travelled to a disabled children's hospital where he was consultant. He forewarned that their deformities, serious and severe, rendered their appearance akin to monstrosities. "You must never forget." he said, "that their difference from ourselves is purely quantitative. Never qualitative." Later, I realised his words contained all I needed to know about psychiatry. The rest - the textbooks, the lectures, even the clinical experience - is elaborative commentary.