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|Photo: Owen Egan|
As the old chestnut goes, there's nothing to fear except fear itself -- except, one might add, for the occasional burst of intrinsic emotional stimuli.
Jorge Armony holds the Canada Research Chair in Affective Neuroscience, and has been a professor in McGill's Department of Psychiatry since last year. His current research focuses on how the brain detects, analyzes and responds to environmental events signalling danger -- and how these activities interact with cognitive processes such as memory, attention and consciousness. In scientific terms, Armony studies the neural basis of emotion. In pop terms, you might say he's into fear factors.
The Canadian Mental Health Association estimates 12 percent of Canadians are affected by anxiety orders, and there is also believed to be a sizable fear component to schizophrenia, depression and post-traumatic stress disorder (PTSD). Armony hopes that the study of how "healthy brains respond to stimuli in a dynamic way" will lead to a greater understanding of, if not a cure for, such medical mysteries.
His study employs the Functional Magnetic Resonance Imaging (fMRI) technology at the Montreal Neurological Institute. A volunteer lies on a bed-like platform, which is inserted into the fMRI. Once inside the scanner's "tunnel," a magnetic field takes pictures of the volunteer's brain as he or she responds to various audio/visual stimuli.
The experiments take two basic approaches. The first is to show the volunteer's "intrinsic emotional stimuli," which usually takes the form of a series of photos depicting various human facial expressions: neutral, fearful, sad, angry, etc. "We tend to detect, and respond to, fearful faces very strongly," Armony notes. "Even if the photos themselves aren't necessarily fear stimuli, they are fear-related stimuli and as such have a particular intrinsic effected value: we respond more strongly to them, our attention is driven toward them."
The other approach is what Armony calls "classical fear conditioning," in which stimulus without emotional meaning (e.g. a picture of a blue circle) is paired with an aversive stimulus (e.g., a sudden loud noise). "It's very similar to Pavlov's experiments with the dogs, the bell and the food," he says, "but it's the negative version. You tend to develop responses to the so-called conditioned stimulus. Although the stimulus was neutral at the beginning, after being paired with something aversive, they themselves require this value.
"It depends on many factors, but this can occur after as little as one pairing. It's still slightly controversial, but some people claim PTSD, or even phobias, are simply one bad association -- one really strong, traumatic association between, say, a car and a car accident. That's an extreme case. In a laboratory setting, it usually takes a few pairings, -- five, ten, twenty."
Armony is careful to note that he's not releasing once-healthy volunteers with a new-found fear of, say, blue circles. "It's also important to point out," he adds, "that what we call 'fear responses' -- essentially brain and physiological responses, like changes in heart rates -- don't necessarily mean that you're going to jump when you see the stimuli. It's more of a defensive, autonomic response to the stimuli."
Another focus to Armony's study is examining the brain's extinction mechanism, which allows for aversive conditioning (e.g., a red square paired with a loud noise) to be extinguished by repeated neutral conditioning (e.g., a red square without the loud noise).
"In fact, one of the theories related to phobias and PTSD is that individuals have a deficit in this extinction process," he says. "So even if they're exposed to reminders of the traumatic event without any consequences, they cannot extinguish their responses."
To date, Armony's work has been with healthy volunteers, but he's beginning to incorporate volunteers with PTSD.
"On a basic science level," he says, "we're trying to understand how the brain deals with emotional stimuli. But from a more applied clinical perspective, we want to understand PTSD and psychiatric conditions such as phobias, in order to eventually prevent them and to help with recovery.
"So, hopefully, to understand how the normal brain deals with emotion will help us understand how the abnormal brain works."