String-Pulling by the Common Marmoset

From peeling fruit to climbing trees, primates, including humans, routinely perform complex motor tasks with their hands. This thesis develops a string-pulling task to investigate skilled motor control in the common marmoset (Callithrix jacchus). In the first study, we analyzed 15 marmosets of varying ages in their home cages using single-camera markerless motion tracking. In the second study, we analyzed 6 chair-restrained adults using multi-camera 3D tracking. Across both settings, marmosets spontaneously engaged in cyclical string-pulling with distinct reach and withdrawal phases. Movements featured upward gazes during reaches, in-phase horizontal and anti-phase vertical hand trajectories, and greater consistency and speed with their right hand. We also found that withdrawals were faster than reaches and that peak speed scaled with hand distance from the string. Age-related changes in coordination and lateralization were evident but modest. Overall, we show that the string-pulling task offers a robust, ecologically valid framework for studying primate motor control and the neural mechanisms supporting complex, bimanual behaviors.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Neuroscience

Grantor dc:publisher

The University of Western Ontario

Year dc:date.issued

2025

Author dc:creator

• Karkuszewski, Michael

Advisor dc:contributor.advisor

• Pruszynski, Andrew

• Bimanual Coordination
• Kinematics
• Motor Control
• String-Pulling
• Reach-to-Grasp Behaviour.

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/38788

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/38788