Semantic memory: distinct neural representations for abstractness and valence

Abstract

The hypothesis that abstract words are grounded in emotion has been supported by behavioral research and corpus studies of English words. A recent neuroimaging study reported that a single brain region, the rostral anterior cingulate cortex (rACC), is responsive to abstract words, and is furthermore modulated by the emotional valence. This finding is surprising because the rACC is not commonly associated with semantic processing. It is possible that the effects observed were driven not by abstractness, but rather by valence, since the abstract words used in that study were significantly more emotional than the concrete words. We tested this hypothesis by presenting participants with words that were abstract/concrete, as well as emotionally valenced/neutral in a 2×2 factorial design. Activations to emotional words overlapped with both abstract and concrete activations throughout the brain. An ROI analysis revealed that the rACC was responsive to valence, not abstractness, when concreteness and valence unconfounded.

Keywords: Abstract concept; Anterior cingulate; Concreteness; Emotion; Semantic memory.

Figure 1

Schematic illustration of a single block during the MRI scan. All three words were either abstract or concrete, as well as being either emotionally valenced or neutral. On the final screen, the participant reads and responds to a question pertaining to the three words in the block. Only the time during the word reading and fixation were included when modeling the hemodynamic response.

Figure 2

(a) Map of regions activated in the abstract vs. nonword contrast (red-yellow) and the concrete vs. nonword contrast (blue). Overlapping activations are shown in green. (b) Map of the regions activated in the valenced vs. nonword contrast. (c) Region of interest using the peak coordinate from Vigliocco, Kousta, Della Rosa, Vinson, Tettamanti, Devlin & Cappa, 2013, and the mean parameter estimates extracted from this ROI across subjects. This graph shows that there were relatively higher activations to valenced words and concrete words.