Ventral-Dorsal Stream Interactions Supporting Functional Object Grasps

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Emefa Akwayena¹ (eakwayen@andrew.cmu.edu), Emily Gomez, Cheryl Wang, Marty Armstrong, Steven Tang, Tijana Slepcev, Bradford Mahon^1,2; ¹Carnegie Mellon University, ²University of Rochester

Visual cues drive inferences necessary for everyday object-directed actions. For instance, when grasping a hammer to pound a nail, one grasps its handle off of its center of mass, rather than at its midpoint. How are visual cues integrated with a representation of the goal of an object-directed action in order to constrain where and how to grasp the object? This study tested the role of interactions between the ventral and dorsal visual pathways in translating visual cues into functionally appropriate object-directed actions. In Study 1, participants were shown a pair of 3D novel objects on every trial during fMRI scanning; the pair was either the same or different in surface texture (rough/smooth), shape (same shape or isomer), or material property (made of metal, wood or stone). Consistent with prior findings, we found strong preferences for shape processing in the lateral occipitotemporal areas and of surface texture and material properties in ventral occipitotemporal areas. In Study 2, we created real 3D objects such that their weight distribution was systematically related to surface color. Participants were scanned before and after two sessions of behavioral training in a real-world grasping task to learn the color-weight mappings. We found a robust behavioral learning effect that was tightly related to the emergence of neural responses, with training, in the collateral sulcus and anterior intraparietal sulcus. These studies show that interactions between the collateral sulcus and aIPS support the integration of surface visual cues of objects into functionally appropriate object directed grasps.

Topic Area: PERCEPTION & ACTION: Vision