Brain Power (Page 2)

THE BEST THAT THERE IS

	Cognitive neuroscientist Dr. Tomas Páus

Neuropsychologist Tomás Paus was a high school student in Prague when he came upon Penfield's famous homunculus, or "little man." This refers to a figure drawn crudely from the brain's representation of sensory or motor functions. The proportions of the "body" are determined by the density of touch receptors in the body part, so that sensitive index fingers and lips, for example, are disproportionately large.

After graduating from medical school in 1986, Paus began a PhD in human physiology, studying the frontal lobe. While attending a conference in Amsterdam, he met Brenda Milner, PhD'52, DSc'91, head of the MNI's Cognitive Neuroscience Unit.

"She represents the best that there is in frontal lobe research," Paus remembers thinking upon meeting the famed neuropsychologist. Milner eventually invited him to Montreal as one of her postdoctoral students in cognitive neuroscience. That was in 1990 and he's been here ever since, doing a variety of studies focussed, as ever, on the frontal lobe.

Paus himself has become well known in the neurological community for research in transcranial magnetic stimulation. TMS involves placing magnetic coils over a subject's head. The rapid electric impulses created by the coils are directed to specific sites in the cortex to pinpoint areas of function and assist the researcher in mapping the brain. "TMS measures not just brain behaviour, but how brain activity changes," says Paus. Once it's better understood, TMS may have applications in restoring neural pathways following brain injury or in treating mental illness.

While Paus had other research opportunities in North America, "clearly, my preferred option was to come to the MNI," he says. The strength of its cognitive neuroscience team -- as well as the esprit de corps of the MNI community -- helped him decide.

WILDER PENFIELD'S LEGACY

Indeed, whenever someone gives reasons for choosing the MNI, the same terms seem to crop up: cooperation, idea exchange, collaboration, community. Looking back on the historical roots of the institute, it is hard to determine whether form followed function, or the reverse. Did Penfield's "disease-oriented research team" give rise to an air of cooperation that persists to this day, or did the vitality of that immensely gifted physician, scientist and humanist just naturally lead to such organizational design? No matter: it has been a winning combination -- the attention to detail and the ability to see the whole picture in space and time, the mark of a true visionary.

With an eye to ensuring superior patient care as well as top-notch research facilities, Penfield had a hand in every aspect of the facility's design -- from the placement of windows in the hospital wards to the striking Art Deco lobby where anatomical elements are incorporated in floor and ceiling tiles. The pervading spirit of the operating theatres, clinics and laboratories, however, is the most enduring legacy of a far-sighted surgeon and researcher.

Penfield is best remembered for his work with epilepsy. It paved the way for his investigation of functional neuroanatomy, the study of how various activities, from thinking to performing a multitude of tasks, can be traced to specific sites on and in the brain. This historic work involved the dramatic presentation of the opened cranium of a live patient. As Penfield delicately stimulated this or that part of the cerebral cortex with an electrode, the fully conscious patient reported the sensations which resulted, from strange odours to flashbacks. With Penfield's vanguard work, scientists could begin to map the brain, the source of all our thoughts, feelings and actions. And his epilepsy research symbolized his profound belief that no scientific study of the brain was complete without a close relationship with neurosurgery. His hospital is today the world's largest centre for the surgical treatment of epilepsy.

MILNER AND MEMORY

	Dr. Brenda Milner, founder of the MNI's Cognitive Neuroscience Unit.

One of Penfield's most famous students, known in and outside the McGill environment, is neuropsychologist Brenda Milner. After studying at Cambridge, she came to Canada and began work on her PhD in 1950 with Donald Hebb, chair of McGill's Department of Psychology. Hebb had been a research fellow at the MNI under Penfield, and Milner's interest in the neural basis of memory took her there as well. Once her doctorate was finished, Penfield convinced her to stay on at the Neuro where she became a pioneer.

"It's only a slight exaggeration to say that neuropsychology in North America was born here with Brenda's work," says Baxter, referring to the Cognitive Neuroscience Unit she founded with former student -- and present staff member -- Michael Petrides. Milner's specialty is the study of how information is processed and represented in the brain as memory, perception and thought, among other functions. She has trained most of the top neuropsychologists in North America and has collected dozens of honorary degrees and awards, among them the prestigious Prix du Québec -- named for Wilder Penfield.

A steady stream of students from all over the globe also attests to Milner's high standing as both researcher and teacher. She is perhaps best known for her work with "H.M.," an amnesiac who suffered irreversible damage to his hippocampus during an operation. The tiny subcortical structure is essential for most kinds of memory storage. However, while H.M. cannot remember someone he met an hour earlier, he can learn simple tasks, such as solving visual puzzles. Milner proved that a crucial distinction exists between different kinds of memory and the mechanisms underlying them. Studies of memory are fundamental to neuropsychology, because so many other functions depend on the ability to store and retrieve information. It is also a part of who we are and how we relate to the world.

Now in her eighties, Milner credits her continued active engagement in neuropsychology to an abiding sense of curiosity, something that began when she was very young. A love of "all natural phenomena" led her into psychology, then neuropsychology. "I'm not somebody with brilliant theoretical ideas," she said recently. "I get my ideas and inspiration from what I see. I think I'm a good observer.... I'm extremely curious and nosy about things. I'm very interested in how people and animals and so on behave. And that's what, I suppose, gets me interested in psychology."