There is now proof that, to the brain, a concept and the word for it are two different things, one of the world's leading neurosurgeons told a large Lowell Lecture Hall audience last night.

In the Graduate School of Education's annual William H. Burton lecture, Wilder Penfield, professor at the Montreal Neurological Institute, described years of experiments which imply that concepts and words are stored in different parts of the brain.

Penfield said that in the course of operations to remove small, malfunctioning parts of the brain from epileptics, he had electrically stimulated areas of the brain and determined their function. The operations were done under local anesthetic, so that the patients were conscious.

He blocked the part of the brain which controls speech and then flashed pictures in front of the patients. They said later that they had recognized the objects perfectly but had struggled unsuccessfully to find the correct word for it.

One recognized a butterfly, couldn't remember or say that word and tried consciously to remember "moth," but failed there, too, and finally snapped his fingers in frustration.

Penfield also argued that children control the growth of their own brains. "By selecting to what he will attend, the child conditions his own cortex," he said. "As the years pass, the child, with the help of mothers and teachers, may be said to create his own brain mechanisms."