Project 1. The mediation of sensory prediction through dual-stream cortical feedbacks

Publication

Chu, Q*., Ma, O*., Hang, Y., & Tian, X. (2022). Dual-stream cortical feedbacks mediate sensory prediction. bioRxiv.
https://doi.org/10.1101/2022.07.12.499695

Research Background

Predictions are constantly generated from diverse sources to optimize cognitive functions in the ever-changing environment. However, the neural origin and generation process of top-down induced prediction remain elusive. We hypothesized that motor-based and memory-based predictions are mediated by distinct feedback networks from motor and memory systems to the sensory cortices. Using fMRI and a dual imagery paradigm, we showed that motor and memory upstream systems excited the auditory cortex in a content-specific manner. Moreover, the inferior and posterior parts of the parietal lobe differentially relayed predictive signals in motor-to-sensory and memory-to-sensory networks. Our results reveal the functionally distinct neural networks that mediate top-down sensory prediction and ground the neurocomputational basis of predictive processing.

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Figure 1.1 The Dual-Stream Prediction Model (DSPM)

My Contribution: Data Analysis & Manuscript Writing

1. Read review articles to understand machine learning techniques in cognitive neuroscience: multi-voxel pattern analysis (MVPA) and multivariate cross-classification (MVCC)
2. Investigated the general structure, analysis stream, and a typical searchlight decoding of The Decoding Toolbox (TDT) for MVPA
3. Wrote MATLAB codes to perform a leave-one-run-out cross-validated searchlight MVPA, including extraction of parameter estimates (“betas”) from a sphere of voxels with a certain center; partitioning of the data for training and test; classification using support vector machine (SVM); accuracy calculation of classifying test data in sphere
4. Wrote MVPA methods part of scientific manuscript

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Figure 1.2 The Decoding Toolbox (TDT). Adapted from Hebart et al., 2015.

My Relevant Skills

1. Cognitive neuroscience methods: brain decoding (MVPA & MVCC)
2. Cognitive neuroscience concepts: sensorimotor integration & episodic memory & mental imagery
3. Machine learning, MATLAB programming, academic writing

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Results (MVPA)

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Significant decoding of videos was found in the left PMC in IS (Imagery of Speech). This decoding of imagery contents in the frontal motor region without participants' overt movement suggests a motor representation space in the motor upstream network.

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For IN (Imagery of Non-speech), decoding accuracy was significantly above chance in bilateral PPC but not in vlPFC nor in the cingulo-opercular network.

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Two-sided paired t-tests showed that the decoding accuracy in parts of PPC (left intraparietal sulcus and right superior parietal lobule) was significantly higher in IN than that in IS reliably across searchlight radii, suggesting memory representations in PPC.