Action Intention Modulates the Temporal Dynamics of Object Feature Representation: An Electrophysiological Approach

Action intention has been shown to influence the computation of visual features in a task-relevant manner. Ideomotor theories would suggest that the intention to act on an object is sufficient to integrate its task-relevant visual features, however, support for these theories draw from paradigms that arbitrarily combine task features and affordances, thus requiring working memory representations. However, integration might still be necessary for an overlearned task like grasping given the nonlinearity of motor control computations which require multiple features to be incorporated concurrently. Further, little is known about the time course of these visual feature computations. Thus, the objective of this dissertation was to investigate the temporal dynamics of visual feature representation and how they are modified by action intention, as well as to provide more clarity on the assumption of visual feature integration. To this end, I conducted three electroencephalography (EEG) studies where participants viewed real 3D objects in an action planning phase and either grasped or touched the objects with their knuckle (“knuckling). I then applied time-resolved multivariate analyses to the EEG data to infer the time course of the representation of objects’ visual features. I found that although shape representations during action planning were similar between grasping and knuckling, only for grasping was there a reactivation of shape such that early representations reactivated later ones. Material/weight representations in contrast were only grasp-specific during movement execution, after object contact. However, in a follow-up study I found that when weight information was relayed through arbitrary colours, colour/weight information showed patterns of reactivation during grasp planning, a pattern which was mirrored in beta band, possibly to facilitate the maintenance of weight information in working memory. At this point, I had not found any evidence of integrated representations between shape and weight cues. Yet, in a final study I demonstrated how two visual features which are most relevant during action planning, namely shape and object orientation, integrated in a grasp-specific manner. Collectively, these findings provide a framework for thinking about the representation of visual features such that features are represented and integrated in a phase-specific and task-relevant manner. Taken together, these results contribute novel insights into the computational processes of motor control.

Department dc:contributor.department

Psychology

Year dc:date.issued

2025

Author dc:creator

• Lee, Nina Ho-Yan

Advisor dc:contributor.advisor

• Niemeier, Matthias

• action intention
• EEG
• feature integration
• grasping
• motor control
• visuomotor

Statement dc:rights

• Attribution-NonCommercial-NoDerivatives 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nc-nd/4.0/

Handle dc:identifier.uri

https://hdl.handle.net/1807/150185

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/150185