Neural mechanisms of discourse comprehension: a human lesion study

Abstract

Discourse comprehension is a hallmark of human social behaviour and refers to the act of interpreting a written or spoken message by constructing mental representations that integrate incoming language with prior knowledge and experience. Here, we report a human lesion study (n = 145) that investigates the neural mechanisms underlying discourse comprehension (measured by the Discourse Comprehension Test) and systematically examine its relation to a broad range of psychological factors, including psychometric intelligence (measured by the Wechsler Adult Intelligence Scale), emotional intelligence (measured by the Mayer, Salovey, Caruso Emotional Intelligence Test), and personality traits (measured by the Neuroticism-Extraversion-Openness Personality Inventory). Scores obtained from these factors were submitted to voxel-based lesion-symptom mapping to elucidate their neural substrates. Stepwise regression analyses revealed that working memory and extraversion reliably predict individual differences in discourse comprehension: higher working memory scores and lower extraversion levels predict better discourse comprehension performance. Lesion mapping results indicated that these convergent variables depend on a shared network of frontal and parietal regions, including white matter association tracts that bind these areas into a coordinated system. The observed findings motivate an integrative framework for understanding the neural foundations of discourse comprehension, suggesting that core elements of discourse processing emerge from a distributed network of brain regions that support specific competencies for executive and social function.

Keywords: discourse comprehension; emotional intelligence; personality traits; psychometric intelligence; voxel-based lesion-symptom mapping.

Figure 1

Voxel-based lesion-symptom mapping of discourse comprehension (n = 145). The illustrated results are thresholded at q < 0.01 (using a false discovery rate correction for multiple comparisons). In each axial slice, the right hemisphere is to the left.

Figure 2

Voxel-based lesion-symptom mapping of working memory (n = 145). The illustrated results are thresholded at q < 0.01 (using a false discovery rate correction for multiple comparisons). In each axial slice, the right hemisphere is to the left.

Figure 3

Voxel-based lesion-symptom mapping of discourse comprehension and discourse comprehension (residual) (n = 145). Lesion overlap map illustrating common and distinctive brain regions for discourse comprehension (blue) and discourse comprehension residual (yellow) (n = 145; q < 0.01). Overlap between these factors is illustrated in green. In each axial slice, the right hemisphere is to the left.