Functional brain imaging studies of cortical mechanisms for memory.

Recent functional brain imaging studies in humans indicate that learning and memory involve many of the same regions of the cortex that process sensory information and control motor output. The forms of perceptual and motor learning that can occur without conscious recollection are mediated in part by contractions and expansions of representations in the sensory and motor cortex. The same regions are also engaged during the conscious storage and retrieval of facts and events, but these types of memory also bring into play structures involved in the active maintenance of memories "on line" and in the establishment of associative links between the information stored in different sensory areas. Although the picture of memory that is emerging from functional imaging studies is consistent with current physiological accounts, there are puzzles and surprises that will be solved only through a combination of human and animal studies.