Neural substrates of semantic memory

Abstract

Semantic memory is described as the storage of knowledge, concepts, and information that is common and relatively consistent across individuals (e.g., memory of what is a cup). These memories are stored in multiple sensorimotor modalities and cognitive systems throughout the brain (e.g., how a cup is held and manipulated, the texture of a cup's surface, its shape, its function, that is related to beverages such as coffee, and so on). Our ability to engage in purposeful interactions with our environment is dependent on the ability to understand the meaning and significance of the objects and actions around us that are stored in semantic memory. Theories of the neural basis of the semantic memory of objects have produced sophisticated models that have incorporated to varying degrees the results of cognitive and neural investigations. The models are grouped into those that are (1) cognitive models, where the neural data are used to reveal dissociations in semantic memory after a brain lesion occurs; (2) models that incorporate both cognitive and neuroanatomical information; and (3) models that use cognitive, neuroanatomic, and neurophysiological data. This review highlights the advances and issues that have emerged from these models and points to future directions that provide opportunities to extend these models. The models of object memory generally describe how category and/or feature representations encode for object memory, and the semantic operations engaged in object processing. The incorporation of data derived from multiple modalities of investigation can lead to detailed neural specifications of semantic memory organization. The addition of neurophysiological data can potentially provide further elaboration of models to include semantic neural mechanisms. Future directions should incorporate available and newly developed techniques to better inform the neural underpinning of semantic memory models.

Category-specific naming and recognition deficits in temporal lobe epilepsy surgical patients

“…We should point out that multiple models of semantic memory exist, and our findings could also be consistent with some of these other models (recent reviews of semantic memory models include: Gainotti, 2006;Hart et al, 2007;. Several of the existing models do not make specific neuroanatomical predictions regarding semantic memory, but rather focus more on the cognitive processes or perceptual features that might give rise to categories in the brain.…”

An integrated neural model of semantic memory, lexical retrieval and category formation, based on a distributed feature representation

“…This aspect shares some ideas with the ''Neural Hybrid Model of semantic Object Memory'' by Hart et al (2007), Kraut et al (2003Kraut et al ( , 2004.…”

“…In the following, some conceptual models based on these ideas will be described briefly: the interested reader can find more details in an excellent recent review paper (Hart et al 2007).…”

The Representation of Objects in the Brain, and Its Link with Semantic Memory and Language: a Conceptual Theory with the Support of a Neurocomputational Model

“…ii) Each object is described by means of a different number of features, which spread over different cortical areas. This is quite a common idea in conceptual models of semantic memory (Caramazza et al 1990;Gainotti 2006;Hart et al 2007). iii) Features are topographically organized.…”

“…Many conceptual theories of semantic memory have been proposed in past decades, based on two fundamental pieces of information: the behavior of patients with neurological lesions in specific brain areas, who exhibit deficits in word recognition, and results of more recent neuroimaging studies, putting in evidence which different brain areas participate to semantic tasks. The interested reader can find several excellent review papers on the subject (Martin & Chao 2001;Hart et al 2007). Just the main fundamental issues, essential for the comprehension of the present chapter, are summarized below.…”