Editing Semantic memory (section)

=== Category-specific semantic impairments ===
Category-specific semantic impairments are a neuropsychological occurrence in which an individual ability to identify certain categories of objects is selectively impaired while other categories remain undamaged.<ref name=":0">{{Cite journal|last=Capitani, Laiacona, Mahon, Caramazza|date=May 2003|title=What are the Facts of Semantic Category-Specific Deficits? Article Review of the Clinical Evidence|journal=Cognitive Neuropsychology|volume=20|issue=3|pages=213–261|doi=10.1080/02643290244000266|pmid=20957571|s2cid=6464286}}</ref> This condition can result in brain damage that is widespread, patchy, or localized. Research suggests that the temporal lobe, more specifically the structural description system, might be responsible for category specific impairments of semantic memory disorders.<ref name=":0" />

Theories on category-specific semantic deficits tend to fall into two different groups based on their underlying principles. Theories based on the correlated structure principle, which states that conceptual knowledge organization in the brain is a reflection of how often an object's properties occur, assume that the brain reflects the statistical relation of object properties and how they relate to each other. Theories based on the neural structure principle, which states that the conceptual knowledge organization in the brain is controlled by representational limits imposed by the brain itself, assume that organization is internal. These theories assume that natural selective pressures have caused neural circuits specific to certain domains to be formed, and that these are dedicated to problem-solving and survival. Animals, plants, and tools are all examples of specific circuits that would be formed based on this theory.<ref name=":0" />

==== Impairment categories ====
Category-specific semantic deficits tend to fall into two different categories, each of which can be spared or emphasized depending on the individual's specific deficit. The first category consists of animate objects, with animals being the most common deficit. The second category consists of inanimate objects with two subcategories: fruits and vegetables (biological inanimate objects), and artifacts being the most common deficits. The type of deficit does not indicate a lack of conceptual knowledge associated with that category, as the visual system used to identify and describe the structure of objects functions independently of an individual's conceptual knowledge base.<ref name=":0" />

Most of the time, these two categories are consistent with case-study data. However, there are a few exceptions to the rule. Categories like food, body parts, and musical instruments have been shown to defy the animate/inanimate or biological/non-biological categorical division. In some cases, it has been shown that musical instruments tend to be impaired in patients with damage to the living things category despite the fact that musical instruments fall in the non-biological/inanimate category. However, there are also cases of biological impairment where musical instrument performance is at a normal level. Similarly, food has been shown to be impaired in those with biological category impairments. The category of food specifically can present some irregularities though because it can be natural, but it can also be highly processed, such as in a case study of an individual who had impairments for vegetables and animals, while their category for food remained intact.<ref name=":0" />