The face of cognitive neuroscience has changed drastically since the mid-twentieth century. In the past, lesions were the only basis for inference regarding the functional neuroanatomy of normal cognition. Today the tools of cognitive neuroscience include various methods of neuroimaging, both structural and functional, in normal subjects.

Classifications of Memory Systems

The structure of knowledge representation in the brain is elucidated by the studies of specific dissociations of knowledge loss in brain disease. The question whether there is one memory store or several is of the foremost interest. Studies of amnesias are particularly illuminating in this respect. In most amnesic syndromes, skills are better preserved than facts. Within the declarative domain, context-free information is usually better preserved than context-dependent information. Generic information is better preserved than singular information. Generally, the patient's ability to give a conscious account of...