AIP Sperimentale 2024, 30° Congresso annuale

Representational organization of grasping actions across motor execution and imagery

Sep 24, 2024, 12:30 PM

2h

Cortile

Poster Lunch & poster 2

Speaker

Laura Marras (MoMiLab, IMT School for Advanced Studies Lucca)

Description

While a robust body of studies suggests that motor performance and imagery share similar cortical networks, it remains unclear whether they also share the same representational organization. A previous study investigated the representational structure of three hand-action types during execution or imagery in motor-related areas. The results showed distinguishable response patterns but a consistent representational geometry of the different action types across the two conditions. Here, we investigated the representation of a larger set of grasping actions. Two groups of participants performed (N=9) or imagined (N=9) grasping 20 common objects during fMRI scanning. Representational dissimilarity matrices (RDMs) for each cortical area (Glasser-HCP Atlas, 360 parcels) and condition were derived, based on the GLM t-scores of each grasp. To identify areas with a similar representational geometry across conditions, we computed the correlation between execution and imagery RDMs. We found significant correlations ($p<0.05$, Mantel test, FDR correction) in 41 areas, with the highest correlation coefficients in bilateral visual areas and left Intraparietal Complex. Finally, to determine whether this common representational structure was driven by a synergistic coding, we compared the RDMs from the significant areas with an RDM derived from a kinematic synergy model. While we found significant correlations ($p<0.05$, FDR correction) in six and two brain areas for the execution and imagery conditions, respectively, no area showed significant correlation in both conditions, suggesting that the common representational structure across motor conditions may not be solely driven by synergistic coding.