Attention to Distinct Goal-relevant Features Differentially Guides Semantic Knowledge Retrieval

Group classification maps for property-specific classifications of (A) concrete properties (i.e., color vs. shape), (B) abstract properties (i.e., theme vs. function), and (C) higher-order property category (i.e., concrete vs. abstract). Both A and C have been corrected for multiple comparisons using a voxel-wise correction based on the distribution of the max statistic across permutations; for B, a more liberal, cluster-based threshold (cluster-forming threshold, F = 2.3) was used. Maps represent classification accuracy for multivariate data with mean activity for each sample removed, ensuring that the classification does not include any effects of univariate activation.

Abstract: A critical aspect of conceptual knowledge is the selective activation of goal-relevant aspects of meaning. Although the contributions of ventrolateral prefrontal and posterior temporal areas to semantic cognition are well established, the precise role of posterior parietal cortex in semantic control remains unknown. Here, we examined whether this region modulates attention to goal-relevant features within semantic memory according to the same principles that determine the salience of task-relevant object properties during visual attention. Using multivoxel pattern analysis, we decoded attentional referents during a semantic judgment task, in which participants matched an object cue to a target according to concrete (i.e., color, shape) or abstract (i.e., function, thematic context) semantic features. The goal-relevant semantic feature participants attended to (e.g., color or shape, function or theme) could be decoded from task-associated cortical activity with abovechance accuracy, a pattern that held for both concrete and abstract semantic features. A Bayesian confusion matrix analysis further identified differential contributions to representing attentional demands toward specific object properties across lateral prefrontal, posterior temporal, and inferior parietal regions, with the dorsolateral pFC supporting distinctions between higher-order properties and the left intraparietal sulcus being the only region supporting distinctions across all semantic features. These results are the first to demonstrate that patterns of neural activity in the parietal cortex are sensitive to which features of a concept are attended to, thus supporting the contributions of posterior parietal cortex to semantic control.

https://www.ncbi.nlm.nih.gov/pubmed/28294713