Portrayal of Higher Order Semantics in Subcortical Lesion

Abstract

Higher order semantics pertains to a person’s ability to develop an advanced vocabulary, understand word relationships, paraphrasing, reasoning, and developing the ability to look at things from another individual’s perspective. It has been proposed for some time that subcortical structures, including basal ganglia, thalamus, caudate nucleus, play an important role in the higher order semantic functions. Our study aimed at analyzing how higher order semantics are influenced by subcortical lesion. For this purpose, five semantic domains namely polar questions, semantic anomaly, syntagmatic relation, homonymy and figurative language were selected and assessed using a newly developed evaluation tool. This tool was administered on 30 participants with subcortical lesion without any aphasic component. Our results revealed that individual’s with subcortical lesion performed subpar in all the domains suggesting that pathologies of subcortex can inhibit the activation of semantic skills. Further, within the higher order semantic skills, we identified that homonym and figurative language was significantly impaired followed by syntagmatic relation, semantic anomaly and polar questions. From this we can substantiate that along with cortical structures subcortex also have an inevitable role in semantic processing.