Same Action, Different Meaning: Neural substrates of Semantic Goal Representation

Abstract

Accurate control over everyday goal-directed actions is mediated by sensory-motor predictions of intended consequences and their comparison with actual outcomes. Such online comparisons of the expected and re-afferent, immediate, sensory feedback are conceptualized as internal forward models. Current predictive coding theories describing such models typically address the processing of immediate sensory-motor goals, yet voluntary actions are also oriented towards long-term conceptual goals and intentions, for which the sensory consequence is sometimes absent or cannot be fully predicted. Thus, the neural mechanisms underlying actions with distal conceptual goals is far from being clear. Specifically, it is still unknown whether sensory-motor circuits also encode information regarding the global meaning of the action, detached from the immediate, movement-related goal. Therefore, using fMRI and behavioral measures, we examined identical actions (either right or left-hand button presses) performed for two different semantic intentions ('yes'/'no' response to questions regarding visual stimuli). Importantly, actions were devoid of differences in the immediate sensory outcome. Our findings revealed voxel patterns differentiating the two semantic goals in the frontoparietal cortex and visual pathways including the Lateral-occipital complex, in both hemispheres. Behavioral results suggest that the results cannot be explained by kinetic differences such as force. To the best of our knowledge, this is the first evidence showing that semantic meaning is embedded in the neural representation of actions independent of immediate sensory outcome and kinetic differences.

Re-evaluating frontopolar and temporoparietal contributions to detection and discrimination confidence

“…Outside these regions, whole-brain analysis ( p< 0.05, corrected for family-wise error at the cluster level) revealed that activations in bilateral premotor cortex were sensitive to task identity. This is consistent with the successful encoding of semantic meaning of motor actions from associative motor cortex (Aberbach et al, 2021).…”

Proactive inhibition is marked by differences in the pattern of motor cortex activity during movement preparation and execution

“…The ability to shift the distribution of CSE between neuronal inputs may allow for qualitatively equivalent movements to be performed in a variety of ways depending on task-specific goals ( 36 ). In fact, a recent study by Baudry and Duchateau ( 37 ) has shown that CSE rise time before EMG onset occurs 100 ms earlier for smooth ramp than ballistic contractions of tibialis anterior (akin to the response-locked analysis in the present study).…”