Posted by Annapaola Prestia Laboratory of Epidemiology Neuroimaging and Telemedicine, IRCCS Centro San Giovanni di Dio FBF, The National Centre for Research and Care of Alzheimer’s and Mental Diseases, Brescia, Italy

Idiomatic phrases by definition are composed of a sequence of words whose meaning is different from their literal interpretation and their processing may involve further steps, such as realizing that the meaning of the phrases is not literal and associating the component words with their figurative meanings. This fMRI study investigated the differences in brain response in comprehending literal and idiomatic sentences and examined the effect of gender on brain activation during these tasks. Thirty-six adult volunteers (19 females, 17 males) were asked to view idiomatic and literal sentences in a block design format in the fMRI scanner and then to answer comprehension questions. Women showed greater and more widespread activation than men when reading and responding to both idiomatic and literal sentences, in particular in areas not typically associated with language processing (postcentral, precuneus, and superior occipital areas). In particular, during literal sentence comprehension, women showed more significant activation than men in the right postcentral, left middle frontal and left superior frontal gyri. Women also showed increased activation in the right postcentral and left middle frontal gyri, in the right superior occipital lobe, and in the bilateral precuneus during the comprehension task of idiomatic sentences.
Men showed higher functional connectivity than women particularly in both idiom and literal conditions, especially between Broca's and Wernicke's areas, and between left superior temporal and occipital gyri. In brief, while women activated distributed areas without much integration, men showed greater integration between language areas, and between language and visual areas. These results suggest that while men and women are equally accurate in identifying literal and idiom sentences, women perhaps process language more globally or associatively than men. One possibility is that women had parallel thought processes occurring simultaneously as they were performing the language task, while men were perhaps more focused on the single task at hand. A second possible explanation is that women were interpreting the sentences in a more associative manner than men, by making evaluative judgments or reflecting on personal experiences that were triggered when processing the sentences. Given the greater activation in frontal language regions in women compared to men, women's interpretation of these sentences may be at a more globally coherent level.