Work

Thalamocortical pathways underlying unconscious action-related visual information- evidence from the neural representations of binocularly suppressed tool images

Year: 2024

Type: article

Abstract: In exploring the integral role of human subcortical structures, including the thalamus, brainstem, and basal ganglia, our study delves into their contribution to unconscious high-level perceptual processing, notably focusing on visual categorization. While extensive behavioral and fMRI studies have suggested the significance of subcortical pathways for residual vision within blindsight, the specific involvement of the thalamus, superior colliculus, and basal ganglia in unconscious high-level perceptual processing remains elusive in healthy humans. Here, we employed functional magnetic resonance imaging (fMRI) to investigate the representation of toolness (tools vs. non-tools) and shape (elongated vs. stubby) within subcortical structures while images were made invisible using continuous flash suppression (CFS). Both univariate analysis and multivoxel pattern analysis (MVPA) based on blood-oxygenation level-dependent (BOLD) signals revealed a significant toolness representation in the left thalamus, with the left ventral anterior thalamus (VA, motor-related) as the most important thalamic subregion contributing to the toolness representation under CFS. In the basal ganglia, the left striatum (STR) exhibited robust toolness representation in both univariate analysis and MVPA. Among cortical regions, only area 9a and anterior 10p (part of the dorsolateral prefrontal cortex, DLPFC) demonstrated significant toolness representation. Functional connectivity results indicated that elongated tools increased the connectivity between the bilateral VA in the thalamus and left 9a (DLPFC) and between the right VA and left STR in the basal ganglia, compared to elongated non-tools in CFS. Notably, dynamic causal modeling (DCM) results unveiled a thalamocortical pathway from the left VA in the thalamus to the left 9a (DLPFC) contributing to toolness representation when tool images are rendered invisible by CFS. These findings shed light on the role of the subcortical structures, particularly the thalamus and basal ganglia, and highlight a thalamocortical pathway in healthy humans engaged in unconscious high-level perceptual processing, especially unconscious visual categorization.

Source: Journal of Vision

DOI: 10.1167/jov.24.10.1423

Authors: Zhiqing Deng, Fuying Zhu, Jie Gao, Zhiqiang Chen, Peng Zhang, Juan Chen