Commanding Attention; February 1995; Scientific American Magazine; by Beardsley; 1 Page(s)

Studying consciousness is a tricky task, so researchers tease apart aspects of mental processing in the hope that the parts may yet illuminate the whole. One of those lines of inquiry recently produced attention-grabbing results--literally. At the annual meeting of the Society for Neuroscience last November, researchers presented new findings on how animals pay attention to visual cues, a process that is being studied as a surrogate for consciousness. It appears that remembered properties of objects can influence which neurons in the visual pathway show sustained activity. The outcome determines which objects¿ representations are relayed to higher brain centers.

The findings come from work in macaque monkeys. Robert Desimone and his associates at the National Institute of Mental Health studied the activity of neurons in the brains of these creatures. In one set of experiments the animals had been trained to respond to a symbol when it was flashed on a screen; an irrelevant, distracting symbol was displayed simultaneously. The scientists found that in at least two higher regions of the visual pathway, neurons that started to respond to the distracting symbol were quickly inhibited by their neighbors. When responding to the target, in contrast, neurons were not inhibited.