Coherent concepts are computed in the anterior temporal lobes

Abstract

In his Philosophical Investigations, Wittgenstein famously noted that the formation of semantic representations requires more than a simple combination of verbal and nonverbal features to generate conceptually based similarities and differences. Classical and contemporary neuroscience has tended to focus upon how different neocortical regions contribute to conceptualization through the summation of modality-specific information. The additional yet critical step of computing coherent concepts has received little attention. Some computational models of semantic memory are able to generate such concepts by the addition of modality-invariant information coded in a multidimensional semantic space. By studying patients with semantic dementia, we demonstrate that this aspect of semantic memory becomes compromised following atrophy of the anterior temporal lobes and, as a result, the patients become increasingly influenced by superficial rather than conceptual similarities.conceptual knowledge | semantic dementia | semantic memory

White Matter Changes and Confrontation Naming in Retired Aging National Football League Athletes

“…Visual object recognition is associated with neural activity in the temporo-occipital ''what pathway''; a polysynaptic projection system involving the striate, prestriate and inferior temporal cortices. 4,5 Semantic processing is associated with neural activity in the left inferior parietal-posterior superior temporal lobe, 6,7 anterior temporal pole, 8,9 lateral temporal cortex, 8 and fusiform gyrus. Semantic to phonological transfer relies on the left posterior inferior temporal lobe, 10 whereas access to the output phonological lexicon is subserved in part by the left inferior parietal lobule 11 and left frontal operculum.…”

A specific cognitive deficit within semantic cognition across a multi-generational family

“…According to 'hub-and-spoke' theory of semantic cognition ( [12,14,20]; also convergence zones in [10]), stored concepts are generated by mapping distributed knowledge of objects, facts and statements, from across different modalities of input. In neurological patients with SD, disruption to this mapping results in the progressive degradation of stored concepts over time [6,7,12,14]. One interpretation of the deficit was that the affected JR family members have a diminished ability to generate mappings across distributed knowledge of words, objects and facts.…”

“…Within these models, the ATL has been conceptualized as a semantic 'hub' that binds modality-specific inputs from across a distributed network of perception, action and language-specific brain regions [12][13][14]. The neuro-anatomical distribution of brain damage in SD has been measured using structural and functional magnetic resonance imaging (MRI) [15][16][17] and positron emission tomography [18,19].…”

“…The neuro-anatomical distribution of brain damage in SD has been measured using structural and functional magnetic resonance imaging (MRI) [15][16][17] and positron emission tomography [18,19]. The semantic deficit in SD is linked to the deterioration of the inferolateral aspects of the ATL [12,14], and is usually bilateral, across the temporal pole and the rostral-inferior surface. This role for the ATL in the processing of conceptual knowledge is supported by evidence from a range of methods, including functional MRI in healthy adults and Transcranial Magnetic Stimulation (TMS) [13,17,20].…”

Cued Memory Reactivation During SWS Abolishes the Beneficial Effect of Sleep on Abstraction

“…Extracting statistical regularities from our environment, integrating them across different modalities and generalising to new exemplars or situations are fundamental processes in the formation of knowledge 1,2 . Accumulating evidence suggests that these processes of statistical learning and integrative processing are facilitated by sleep [3][4][5][6][7][8][9][10] .…”