Sub-bundle based analysis reveals the role of human optic radiation in visual working memory
Poster No:
2537
Submission Type:
Abstract Submission
Authors:
Yanming Wang1, Huan wang1, Sheng Hu1, Benedictor Alexander Nguchu1, Du Zhang1, Shishuo Chen1, Xiaoxiao Wang1, Bensheng Qiu1
Institutions:
1University of Science and Technology of China, Hefei, Anhui
First Author:
Co-Author(s):
Introduction:
White matter (WM) carries information between gray matter (GM) and is crucial for brain function. Studying the WM functional activities could help people understand the information processing mechanisms of the brain. BOLD fMRI has been widely used to evaluate the GM, but the WM BOLD signals have been rarely explored. Optic radiation (OR) is responsible for the transmission of visual information and is one of the most important WM tracts in the visual system. This study evaluated the population receptive field (pRF) characteristics of OR sub-bundles at the individual level to explore whether BOLD signals of individual OR sub-bundles can encode high-fidelity visual information. In addition, previous studies have reported that the human primary visual cortex (V1) is not only activated by incoming visual information but is also engaged by top-down cognitive processes, such as visual working memory (Lawrence et al., 2018), and that central vision has stronger top-down feedback (Zhaoping, 2021). OR is the most important WM tract connecting V1. This study thus also explored whether OR is involved in the transmission of feedback signals and evaluated the information transmission preferences in the foveal and peripheral sub-bundles.
Methods:
The HCP 7T retinotopy dataset was used to reconstruct the OR. Then, OR was subdivided into sub-bundles based on the anatomical position of termination in V1. To suppress the influence of GM signals, WM masks set to different degrees of restraint were used. The OR sub-bundles were confined within the spaces of these masks, which were ranked as standard and strict sub-bundles. The pRF model was then applied to evaluate the retinotopic properties of these sub-bundles. Moreover, the consistency of the pRF properties of standard sub-bundles with those of V1 subfields at the endpoint of the sub-bundles was evaluated. Correlation analysis was performed to evaluate the relationships of the pRF parameters of the strict and standard sub-bundles. In addition, we applied the HCP working memory dataset to evaluate the activation of the foveal and peripheral OR sub-bundles (fOR, pOR) and LGN and V1 sub-fields (fLGN, pLGN, fV1, pV1) under 0bk and 2bk task and activation differences between 0bk and 2bk. Moreover, the 2bk-0bk contrast differences of foveal and peripheral sub-bundles or subfields were evaluated. Furthermore, we investigated the relationship between the 2bk-0bk contrast and the 2bk task d-prime.
Results:
The OR was well reconstructed and the distribution of the sub-bundles was consistent with previous study (Kammen et al., 2016). For the standard sub-bundles, polar angles exhibited the characteristics of the contralateral visual field and were biased towards the horizontal meridian, Fig. 1A-C. Moreover, eccentricity was significantly positively correlated with pRF size, Fig. 1D. The findings showed that pRF parameters of standard sub-bundles were consistent with the standard retinotopic properties of OR (Wandell et al., 2007 , Wang et al., 2023). Interestingly, there existed similar pRF properties in sub-bundles and corresponding V1 subfields. In addition, the pRF properties of strict sub-bundles also exhibited the standard retinotopic properties and significantly correlated with those of standard sub-bundles, indicating that OR sub-bundle evaluation was GM-free. Notably, the activation under the 2bk task was significantly stronger than that under the 0bk task in fOR, pOR, fLGN, pLGN, fV1 and pV1, Fig. 2A. The 2bk-0bk contrast of fV1 was significantly greater than that of pV1, Fig. 2B. More importantly, 2bk-0bk contrast only in fOR and pOR was significantly positively correlated with 2bk task d-prime, Fig. 2C.
·Figure1. Distribution of pRF properties of standard sub-bundles.
·Figure 2. Activation analysis of OR sub-bundles and LGN and V1 sub-fields.
Conclusions:
The findings demonstrated that the BOLD signals of OR sub-bundles can encode high-fidelity visual information, indicating the feasibility of assessing WM functional activity at the tract sub-bundle level. Moreover, OR not only transmits visual information from bottom to up, but also engages visual working memory.
Learning and Memory:
Working Memory
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI) 2
Diffusion MRI Modeling and Analysis
Segmentation and Parcellation
Perception, Attention and Motor Behavior:
Perception: Visual 1
Keywords:
Cognition
Computational Neuroscience
FUNCTIONAL MRI
HIGH FIELD MR
Tractography
Vision
White Matter
WHITE MATTER IMAGING - DTI, HARDI, DSI, ETC
Other - Working memory; population receptive field (pRF); optic radiation (OR);
1|2Indicates the priority used for review
Provide references using author date format
LAWRENCE S J D, VAN MOURIK T, KOK P, et al. 2018. Laminar Organization of Working Memory Signals in Human Visual Cortex. Current Biology [J], 28: 3435-3440.
WANDELL B A, DUMOULIN S O, BREWER A A 2007. Visual field maps in human cortex. Neuron [J], 56: 366-383.
WANG H, WANG X, WANG Y, et al. 2023. White matter BOLD signals at 7 Tesla reveal visual field maps in optic radiation and vertical occipital fasciculus. Neuroimage [J], 269: 119916.
ZHAOPING L 2021. Contrast-reversed binocular dot-pairs in random-dot stereograms for depth perception in central visual field: Probing the dynamics of feedforward-feedback processes in visual inference. Vision Research [J], 186: 124-139.