University of Pennsylvania, Philadelphia, USA.
Cogn Neuropsychol. 2003 May 1;20(3):401-8. doi: 10.1080/02643290244000293.
The organisation of semantic memory into separately lesionable or imageable components must be determined by some combination of genetic and environmental factors. Little is known about the relative contributions of these two factors in establishing the functional architecture of semantic memory. By assessing the semantic memory impairment of an individual who sustained brain damage as a newborn, it is possible to place an upper bound on the contribution of post-natal experience. The present case study demonstrates a profound and enduring impairment in knowledge of "living things" following posterior cerebral artery infarctions at approximately 1 day of age. The design of the two experiments reported here allows us to characterise the subject's semantic memory impairment in terms of its scope and selectivity. The impairment affects both the naming of pictures of living things and the retrieval of verbal information about living things. It cannot be accounted for by differences in the difficulty of retrieving knowledge of living and nonliving things, as the living and nonliving items were equated for difficulty in each experiment. When visual and nonvisual information were queried separately for living and nonliving things, the impairment was manifest for both kinds of information about living things, but for neither kind of information about nonliving things. Because this impairment resulted from brain damage sustained too early for experience to have contributed to the organisation of semantic memory, this case study supports a genetic basis for the living-nonliving distinction in semantic memory.
语义记忆组织成可分别受损或可成像的成分，必须由遗传和环境因素的某种组合决定。关于这两个因素在建立语义记忆的功能结构方面的相对贡献，人们知之甚少。通过评估一个在新生儿时期就遭受脑损伤的个体的语义记忆损伤，可以确定后天经验的贡献上限。本案例研究表明，在大约 1 天大时，由于大脑后动脉梗死，个体对“生物”的知识出现了严重而持久的损伤。这里报告的两项实验的设计使我们能够根据其范围和选择性来描述该主体的语义记忆损伤。损伤影响了生物类图片的命名和关于生物类事物的口头信息的检索。这不能用检索生物和非生物知识的难度差异来解释，因为在每个实验中，生物和非生物项目的难度都是相等的。当分别为生物和非生物项目查询视觉和非视觉信息时，生物类的两种信息都表现出了损伤，但非生物类的两种信息都没有表现出损伤。由于这种损伤是由于大脑损伤发生得太早，以至于经验无法促进语义记忆的组织，因此本案例研究支持语义记忆中生物-非生物区分的遗传基础。
