Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
Cereb Cortex. 2023 Sep 9;33(18):9937-9953. doi: 10.1093/cercor/bhad256.
The neural integration of closely timed auditory and visual stimuli can offer several behavioral advantages; however, an overly broad window of temporal integration-a phenomenon observed in various neurodevelopmental disorders-could have far-reaching perceptual consequences. Non-invasive studies in humans have suggested that the level of GABAergic inhibition in the multisensory cortex influences the temporal window over which auditory and visual stimuli are bound into a unified percept. Although this suggestion aligns with the theory that an imbalance of cortical excitation and inhibition alters multisensory processing, no prior studies have performed experimental manipulations to determine the causal effects of a reduction of GABAergic inhibition on audiovisual temporal perception. To that end, we used a combination of in vivo electrophysiology, neuropharmacology, and translational behavioral testing in rats to provide the first mechanistic evidence that a reduction of GABAergic inhibition in the audiovisual cortex is sufficient to disrupt unisensory and multisensory processing across the cortical layers, and ultimately impair the temporal acuity of audiovisual perception and its rapid adaptation to recent sensory experience. Looking forward, our findings provide support for using rat models to further investigate the neural mechanisms underlying the audiovisual perceptual alterations observed in neurodevelopmental disorders, such as autism, schizophrenia, and dyslexia.
密切时间同步的听觉和视觉刺激的神经整合可以提供若干行为优势；然而，时间整合的过宽窗口——在各种神经发育障碍中观察到的现象——可能会产生深远的感知后果。人类的非侵入性研究表明，多感觉皮层中的 GABA 能抑制水平影响听觉和视觉刺激绑定为统一感知的时间窗口。尽管这一观点与皮质兴奋和抑制失衡改变多感觉处理的理论一致，但以前的研究没有进行实验操作来确定 GABA 能抑制减少对视听时间感知的因果影响。为此，我们使用了体内电生理学、神经药理学和大鼠的转化行为测试相结合的方法，提供了第一个机制证据，证明视听皮层中 GABA 能抑制的减少足以破坏单一感觉和多感觉处理跨越皮层层，并最终损害视听感知的时间锐度及其对最近感觉经验的快速适应。展望未来，我们的发现为使用大鼠模型进一步研究神经发育障碍中观察到的视听感知改变的神经机制提供了支持，例如自闭症、精神分裂症和阅读障碍。
