Three-Dimensional Representations of Objects in Dorsal Cortex are Dissociable from Those in Ventral Cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• The ventral visual stream is traditionally linked to object perception, while the dorsal stream handles spatial processing and action.
• Recent findings suggest dorsal regions also contribute to object shape representation, even without motor demands.
• The functional independence and role of these dorsal object representations remain debated.

Purpose of the Study:

• To investigate the dissociability and functional contribution of dorsal object representations.
• To examine neural and behavioral profiles of patients with ventral cortex damage affecting object recognition.

Main Methods:

• Functional magnetic resonance imaging (fMRI) to compare blood oxygen level-dependent (BOLD) responses in ventral and dorsal cortices between patients and controls.
• Psychophysics experiments to assess object perception and sensitivity to structural information in patients.

Main Results:

• Patients with ventral cortex damage showed reduced ventral BOLD sensitivity to 3D object structure compared to controls.
• Patients exhibited object perception deficits but retained residual sensitivity to object-based structural information.
• Dorsal cortex engagement in object shape processing was observed, independent of ventral cortex function.

Conclusions:

• Object representations in the dorsal cortex can be computed independently from the ventral cortex.
• While dorsal representations alone do not support normal object perception, they contribute to a coarse structural description.
• These findings challenge strict functional segregation models of the visual cortex.