ABSTRACT
Following certain insults to the brain, an individual may lose knowledge of some categories while retaining knowledge of others. Over the past 25 years, many clinical cases have been reported that demonstrate various patterns of category-specific deficits. Most commonly, patients lose knowledge of living things; in particular, animals. Less commonly, patients lose knowledge of nonliving things, such as manipulable artefacts. In some cases, patients lose a single category, such as living things. In others, they lose multiple categories, such as living things and musical instruments.1
