Do muscles have a mind of their own? A report in the Jan. 10 Nature suggests that they do.

Psychologists studying a 35-year-old woman who had suffered brain damage after carbon-monoxide poisoning found a puzzling anomaly in her abilities. The woman had trouble identifying ordinary objects by color or shape; and when given a card with a line drawn on it and asked to rotate it until it lined up with a slot in front of her, she was unable to do so. Nor could she tell a square from an elongated rectangle, or perceive any difference in their width.

Yet when she was told to reach out and "mail" the card, her hand easily, repeatedly guided it through the slot. And when asked to pick up the squares and other types of rectangles, her fingers automatically assumed the correct width for each.

The experiments indicate that there may be completely different networks of nerves for thinking about objects and for manipulating them. That is, the authors write, "at some level in normal brains" there may be "separate processing systems" which are not related to the kinds of things we perceive, but to "the different uses to which vision can be put."