【言語】単語の意味の脳内マップ

A detailed atlas that maps how the meaning of narrative language is represented in the human brain is reported in Nature this week. The research could provide insights into the neurobiological basis of language.

It has been proposed that semantic information (information about the meaning of language) is represented in a group of brain regions that are collectively known as the semantic system. However, the finer details and extent of this network have remained unknown.

Jack Gallant and colleagues analysed brain responses elicited by spoken narrative stories that contained diverse semantic domains - groups of closely related concepts, such as ‘food’, 'tools' or ‘living things’. Seven human participants listened to over two hours of stories from The Moth Radio Hour while the authors collected and modelled functional MRI (fMRI) data to map functional representations of semantic meaning in the human brain. The authors then used an algorithm that analyses the common features of individual maps to generate a semantic atlas.

They find that the semantic system is distributed broadly in more than 100 distinct areas across both hemispheres of the cortex and in intricate patterns that are consistent across individuals. Moreover, specific semantic domains also seem to be represented in specific areas within the semantic system. The authors note, however, that the common life experiences of the participants, all of whom were raised and educated in Western industrial societies may also have contributed to the observed organisational consistency.