Zhu Jiating, Zikopoulos Basilis, Yazdanbakhsh Arash
Program in Brain, Behavior & Cognition, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States.
Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States.
bioRxiv. 2023 Apr 28:2023.04.24.538166. doi: 10.1101/2023.04.24.538166.
The strength of certain visual illusions is weakened in individuals with schizophrenia. Such phenomena have been interpreted as the impaired integration of inhibitory and excitatory neural responses, and impaired top-down feedback mechanisms. To investigate whether and how these factors influence the perceived illusions in individuals with schizophrenia, we propose a two-layer network that can model visual receptive fields (RFs), their inhibitory and excitatory subfields, and the top-down feedback. Our neural model suggests that illusion perception changes in individuals with schizophrenia can be influenced by altered top-down mechanisms and the organization of the on-center off-surround receptive fields. Alteration of the RF inhibitory surround and/or the excitatory center can replicate the difference of illusion precepts between individuals with schizophrenia and normal controls. The results show that the simulated top-down feedback modulation enlarges the difference of the model illusion representations, replicating the difference between the two groups. We propose that the heterogeneity of visual and in general sensory processing in schizophrenia can be largely explained by the degree of top-down feedback reduction, emphasizing the critical role of top-down feedback in illusion perception, and to a lesser extent on the imbalance of excitation/inhibition. Our neural model provides a mechanistic explanation for the modulated visual percepts in schizophrenia with findings that can explain a broad range of visual perceptual observations in previous studies. The two-layer motif of the current model provides a general framework that can be tailored to investigate subcortico-cortical (such as thalamocortical) and cortico-cortical networks, bridging neurobiological changes in schizophrenia and perceptual processing.
某些视觉错觉的强度在精神分裂症患者中会减弱。这种现象被解释为抑制性和兴奋性神经反应的整合受损，以及自上而下的反馈机制受损。为了研究这些因素是否以及如何影响精神分裂症患者的错觉感知，我们提出了一个两层网络，该网络可以模拟视觉感受野（RFs）、它们的抑制性和兴奋性子区域以及自上而下的反馈。我们的神经模型表明，精神分裂症患者错觉感知的变化可能受到自上而下机制改变和中心-周边感受野组织的影响。RF抑制性周边和/或兴奋性中心的改变可以复制精神分裂症患者与正常对照组之间错觉感知的差异。结果表明，模拟的自上而下反馈调制扩大了模型错觉表征的差异，复制了两组之间的差异。我们提出，精神分裂症患者视觉及一般感觉处理的异质性在很大程度上可以由自上而下反馈减少的程度来解释，强调了自上而下反馈在错觉感知中的关键作用，而在较小程度上是由兴奋/抑制的不平衡所致。我们的神经模型为精神分裂症中调制的视觉感知提供了一种机制解释，其发现可以解释先前研究中广泛的视觉感知观察结果。当前模型的两层结构提供了一个通用框架，可用于研究皮质下-皮质（如丘脑-皮质）和皮质-皮质网络，弥合精神分裂症中的神经生物学变化与感知处理之间的差距。
