Evidence for enhanced backward connectivity in the third visual pathway following cortico-cortical paired associative stimulation

IF 5.3 2区医学 Q1 NEUROIMAGING

NeuroImage Pub Date : 2026-02-15 Epub Date: 2026-01-27 DOI:10.1016/j.neuroimage.2026.121759

Gabriele Pirazzini , Antonio Cataneo , Silvana Pelle , Alice Marra , Giorgio Arcara , Simone Battaglia , Mauro Ursino , Alessio Avenanti

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引用次数: 0

Abstract

The posterior superior temporal sulcus (pSTS) and early visual cortex (V1/V2) form part of a lateral occipito-temporal network - proposed as a “third” visual pathway - supporting the processing of socially and emotionally relevant information. Prior studies using cortico-cortical paired associative stimulation (ccPAS) applied from pSTS to V1/V2 have shown enhanced recognition of facial emotional expressions, interpreted as reflecting strengthened temporo-occipital backward connectivity. However, direct evidence that ccPAS can modulate pSTS-to-V1/V2 connectivity has been lacking. Here, we applied ccPAS consisting of repeated paired TMS pulses, with the first pulse delivered over pSTS and the second pulse over V1/V2 (ccPAS_STS-V1). A reverse-order protocol (ccPAS_V1-STS) served as a control. Resting-state EEG was recorded before, immediately after, and 30 min post-stimulation to assess functional connectivity. Multivariate spectral Granger Causality analysis characterized the directionality and frequency-dependent dynamics of connectivity. Outdegree metrics revealed that ccPAS_STS-V1 enhanced backward functional connectivity immediately after stimulation, with effects persisting after 30 min, possibly consistent with Hebbian-like associative plasticity in top-down pathways. In addition, an increase in forward connectivity was observed 30 min after ccPAS_V1-STS, and more weakly after ccPAS_STS-V1, possibly reflecting broader compensatory mechanisms. These findings demonstrate that ccPAS can transiently and selectively modulate directional connectivity within the “third” visual pathway, providing insights into the physiological basis of ccPAS and suggesting that previously observed improvements in emotion recognition following ccPAS_STS-V1 may arise from plastic changes in backward pSTS-to-V1/V2 connectivity. More broadly, they underscore the potential of ccPAS to probe and modulate the dynamics of higher-order visual circuits.

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皮质-皮质配对联合刺激后第三视觉通路后向连接增强的证据。

后颞上沟（pSTS）和早期视觉皮层（V1/V2）构成外侧枕颞网络的一部分，被认为是“第三”视觉通路，支持社会和情感相关信息的处理。先前使用皮质-皮质配对联想刺激（ccPAS）从pSTS到V1/V2的研究表明，面部情绪表情的识别增强，这被解释为反映了颞枕向后连接的增强。然而，ccPAS可以调节psts到v1 /V2连接的直接证据一直缺乏。在这里，我们应用了由重复配对的TMS脉冲组成的ccPAS，第一个脉冲通过pSTS传递，第二个脉冲通过V1/V2传递（ccPASSTS-V1）。反序协议（ccPASV1-STS）作为对照。在刺激前、刺激后和刺激后30分钟分别记录静息状态脑电图，以评估功能连通性。多元频谱格兰杰因果分析表征了连通性的方向性和频率依赖性动态。外度指标显示，ccPASSTS-V1在刺激后立即增强了向后功能连接，其效果持续30分钟后，可能与自上而下通路中的hebbian样联想可塑性一致。此外，ccPASV1-STS后30分钟前向连通性增加，ccPASSTS-V1后更弱，可能反映了更广泛的补偿机制。这些研究结果表明，ccPAS可以短暂和选择性地调节第三视觉通路内的定向连接，为ccPAS的生理基础提供了新的见解，并表明先前观察到的ccPASSTS-V1后情绪识别的改善可能源于向后psts - v1 /V2连接的可塑性变化。更广泛地说，他们强调了ccPAS探测和调节高阶视觉电路动态的潜力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

NeuroImage 医学-核医学

CiteScore

11.30

自引率

10.50%

发文量

809

审稿时长

63 days

期刊介绍： NeuroImage, a Journal of Brain Function provides a vehicle for communicating important advances in acquiring, analyzing, and modelling neuroimaging data and in applying these techniques to the study of structure-function and brain-behavior relationships. Though the emphasis is on the macroscopic level of human brain organization, meso-and microscopic neuroimaging across all species will be considered if informative for understanding the aforementioned relationships.