Anatomical correlates for category-specific naming of living and non-living things

IntroductionSelective naming categories impairments for living and non-living things are widely reported in brain damaged patients. Electrostimulation mapping was used to study the possible anatomical segregation of living/non-living categories in a prospective series of patients operated on for tumor removal.Materials and methodsFifty brain mappings (patients with no language impairment; range: 14–80 years; mean: 48 years; 26 males; 5 left handed) were performed in 46 left and 4 right hemispheres using two linguistically controlled tasks (naming for living and non-living things) during an awake surgery procedure. Fifteen regions and four macro cortical areas were designed to analyze the distribution of the interference sites.ResultsOver 761 sites stimulated in the lateral hemispheres, 130 naming interferences sites were detected in small cortical areas (< 1 cm2). High individual variability was observed for living/non-living word retrieval localization and organization with a majority (62%) of shared living/non-living interferences. Specific living (12%) or non-living (26%) interferences were found too. In group analysis, no statistical significant anatomical localization was observed for living items in left lateral hemispheric cortex. A statistical significant representation of interference sites for non-living objects was found (Generalized Estimating Equation methodology, z-test = 2.28, p = 0.027) in the left posterolateral temporoparietal cortex. No influence of histopathology, gender and age on anatomical localization of naming categories was detected.ConclusionThe existence of dedicated neural structures for naming non-living things in the left posterolateral temporoparietal cortex is supported by this study although high individual differences exist in the organization of word categories retrieval.

Research highlights
► High individual variability was observed for word retrieval localization.
► Specific living and non-living cortical naming interference sites were found.
► Non-living things naming sites significantly localize in left temporoparietal cortex.