We study how concepts are acquired and organized in memory. We use imaging and behavioral methods to test the hypothesis that concrete word meaning is an emergent property of the simultaneous re-activation of both single and multiple conjoint features of the objects referred to by the words.
Or work has shown that sensory features that define some aspects of the meaning of concrete words (such as the prototypical size, shape, sound of objects ...) are represented separately in sensory-specific cortical regions (Borghesani et al., 2016). Moreover, we shown that during word reading these representations are active very early in time (by 200 ms) and are recovered in parallel (Borghesani et al., 2018).
A second type of representation that characterizes semantics is one that integrates different features in a single conjunctive multidimensional space. Our work has shown that those conjunctive multidimensional representations emerge in the temporal, frontal, and parietal lobe, and are encoded through a variety of neuronal codes that, intriguingly, also support spatial navigation: a grid-like, distance-dependent, and direction-specific codes (Viganò et al., 2021a, 2021b).
References:
Borghesani V, Buiatti M, Eger E, Piazza M,
Journal of Cognitive Neuroscience, doi:10.1162/jocn_a_01328 (2018).
Borghesani V, Pedregosa F, Buiatti M, Amadon A, Eger E, Piazza M,
Word meaning in the ventral visual path: a perceptual to conceptual gradient of semantic coding
NeuroImage 143, 128-140 (2016)
Viganò S, Rubino V, Di Soccio A, Buiatti M, Piazza M,
Grid-like and distance codes for representing word meaning in the human brain.
NeuroImage, 117876 (2021).
Viganò S, Rubino V, Buiatti M, Piazza M,
The neural representation of absolute direction during mental navigation in conceptual spaces.
Communications Biology 4, 1294 (2021).