视觉-前庭自我运动加工过程中VIP区的冲突依赖性增益控制

文献信息

中文摘要

视觉和前庭信号被持续整合以估计自我运动，但在自然条件下这些感觉线索常常不一致。皮层回路如何在线索冲突下调节多感觉相互作用，同时保持稳定的朝向表征，仍知之甚少。在此，我们在被动运动刺激期间记录了雄性猕猴腹侧顶内区（VIP）的神经元，同时系统性地改变视觉-前庭朝向偏移。VIP神经元表现出强烈的冲突敏感性增益调制：一致的线索增强神经元反应，而增加的线索偏移则逐渐抑制反应增益。这种效应不仅见于多感觉神经元，也见于被归类为主要视觉或前庭的神经元，表明跨模态相互作用在整个群体中广泛存在。相比之下，偏好朝向的偏移仍然较小，提示线索冲突主要调节反应增益，而非改变朝向调谐。尽管在大线索偏移下单个神经元水平出现显著抑制，群体Fisher信息基本得以保留，表明朝向辨别能力稳健。进一步分析揭示了VIP中灵活的感觉加权，随着线索冲突增加，视觉和前庭的贡献发生转移。最后，一个前馈门控归一化模型通过允许线索冲突动态调节有效归一化池，显著改善了对VIP反应的刻画，从而捕捉到小视觉-前庭朝向偏移下的多感觉增强和大线索冲突下的抑制。总之，这些发现表明VIP表现出冲突依赖性的多感觉增益调节，在感觉冲突下保持稳健的自我运动表征。意义声明：在自然环境中，视觉和前庭线索常常不对齐，这对准确的自我运动感知构成挑战。我们证明，猕猴腹侧顶内区（VIP）的神经元根据视觉-前庭冲突的程度动态调整多感觉增益。随着视觉-前庭朝向偏移增加，神经元反应逐渐增强或抑制，而朝向方向的群体编码基本得以保留。一个冲突敏感性归一化模型解释了这些反应动态，并优于传统的多感觉整合模型，提示VIP实施适应性增益控制计算来调节视觉和前庭信号之间的相互作用。这些结果确定了一种将感觉冲突检测与稳健知觉编码联系起来的皮层机制，推进了我们对大脑多感觉加工的理解。

英文摘要

Visual and vestibular signals are continuously integrated to estimate self-motion, yet these sensory cues are often inconsistent under natural conditions. How cortical circuits regulate multisensory interactions under cue conflict while preserving stable heading representations remains poorly understood. Here, we recorded neurons in male macaque ventral intraparietal area (VIP) during passive movement stimulation while systematically varying visual-vestibular heading offsets. VIP neurons exhibited strong conflict-sensitive gain modulation: congruent cues enhanced neuronal responses, whereas increasing cue offsets progressively suppressed response gain. This effect was observed not only in multisensory neurons but also in neurons classified as predominantly visual or vestibular, indicating widespread cross-modal interactions across the population. In contrast, preferred-heading shifts remain modest, suggesting that cue conflict primarily modulated response gain rather than altering heading tuning. Despite substantial suppression at the single-neuron level under large cue offsets, population Fisher information was largely preserved, indicating robust heading discriminability. Further analyses revealed flexible sensory weighting in VIP, with visual and vestibular contributions shifting as cue conflict increased. Finally, a feedforward-gated normalization model substantially improved the characterization of VIP responses by allowing cue conflict to dynamically regulate the effective normalization pool, thereby capturing both multisensory enhancement at small visual-vestibular heading offset and suppression under large cue conflict. Together, these findings show that VIP exhibits conflict-dependent regulation of multisensory gain, preserving robust self-motion representations under sensory conflict.Significance statement Visual and vestibular cues are often misaligned in natural environments, creating a challenge for accurate self-motion perception. We demonstrate that neurons in the macaque ventral intraparietal area (VIP) dynamically adjust multisensory gain according to the degree of visual-vestibular conflict. As the visual-vestibular heading offset increases, neuronal responses are progressively enhanced or suppressed, while population coding of heading direction remains largely preserved. A conflict-sensitive normalization model accounts for these response dynamics and outperforms traditional multisensory integration models, suggesting that VIP implements adaptive gain-control computations to regulate interactions between visual and vestibular signals. These results identify a cortical mechanism that links sensory conflict detection to robust perceptual coding, advancing our understanding of multisensory processing in the brain.