【作者】 刘翔；

【导师】 陈载清；

【作者基本信息】 云南师范大学 ， 光学工程， 2025， 硕士

【摘要】 双目颜色融合与竞争作为立体视觉中的两种特殊感知现象,是探究大脑神经活动和认知功能的有效范式。目前,关于这两种感知现象在前额叶皮层(Prefrontal Cortex,PFC)中的动态响应特征及其涉及到的认知功能调控机制尚未得到系统性解析。随着人口老龄化加剧,认知功能障碍早期筛查与认知功能精准评估的需求日益迫切,而传统行为学方法受限于主观性强、灵敏度不足等问题,亟需开发融合神经活动特征的客观化评估工具。基于此,论文以功能性近红外光谱(functional Near-Infrared Spectroscopy,fNIRS)技术为核心手段,结合双目颜色融合与竞争任务范式,系统探究认知功能正常与障碍群体执行双目颜色融合与竞争感知任务时PFC的响应特征,旨在为认知功能评估提供神经科学依据与创新方法。具体的内容包括:(1)设计了双目颜色融合与竞争的PFC平均功能连接强度实验,通过脑网络分析(基于皮尔逊相关系数计算PFC平均功能连接强度)来解析双目颜色融合、双目颜色竞争及中灰场条件下的认知功能网络。12名认知功能正常参与者与12名认知功能障碍参与者的实验结果表明,认知功能正常群体在双目颜色融合任务中呈现显著增强的PFC功能连接,且平均功能连接强度(r)有着稳定的“双目颜色融合>双目颜色竞争>中灰场”层级结构。认知功能障碍群体的平均功能连接强度没有任务间差异,提示其PFC认知功能失常。(2)设计了双目颜色融合与竞争的PFC激活强度及行为实验,通过广义线性模型进行激活分析,以及对行为学数据进行整合处理得到衡量认知执行功能的指标——任务执行指数(Executive Index,EI),进而揭示双目颜色融合与竞争任务带来的激活强度(β)与行为表现。12名认知功能正常参与者与12名认知功能障碍参与者的实验结果表明,认知功能正常群体在双目颜色融合任务中额叶眼动区(Frontal eye field,FEF)、背外侧前额叶皮层(Dorsolateral Prefrontal Cortex,DLPFC)有着任务间的特异性激活差异,且EI显著高于认知功能障碍群体,凸显其PFC资源动态分配与高阶整合能力。进一步分析发现,认知功能正常群体的行为精准性依赖于PFC亚区功能分化。认知功能障碍群体的PFC激活响应模糊化,且伴随反应延迟与准确率降低,提示其PFC认知功能衰退。(3)基于认知功能正常与障碍群体的PFC响应特征,论文创新性提出以PFC层级响应模式(r双目颜色融合>双目颜色竞争>r中灰场)、特异性激活差异(β双目颜色融合>β双目颜色竞争)及认知功能正常参与者的EI范围(EI正常参与者≥0.2471)为核心的三维评估体系,将认知功能状态划分为正常、障碍及潜在轻度障碍三类,实现了从神经机制到临床表型的量化映射。论文使用了“理论-实验-应用”的研究框架,理论上,首次阐明双目颜色视觉信息处理中PFC的响应特征,并发现认知功能障碍群体存在认知功能网络异常;实验上,设计了基于立体显示平台的双目颜色融合与竞争范式,通过高级视觉任务有效探索了 PFC的神经活动与认知能力;应用上,所提出的评估方法通过融合神经活动与行为动力学数据,突破了传统评估的主观局限,为阿尔茨海默症等认知功能障碍疾病的早期筛查及干预效果量化提供了新思路。更多还原

【Abstract】 Binocular color fusion and rivalry,as two distinct perceptual phenomena in stereoscopic vision,serve as effective paradigms for investigating neural activity and cognitive functions.However,the dynamic response characteristics and cognitive regulatory mechanisms associated with these phenomena in the prefrontal cortex(PFC)remain largely unexplored.With the growing challenge of population aging,there is an urgent need for early screening and precise assessment of cognitive impairment.Traditional behavioral assessments are limited by subjectivity and low sensitivity,highlighting the necessity for objective tools incorporating neural activity features.To address this,the present study employs functional near-infrared spectroscopy(fNIRS)combined with binocular color fusion and rivalry tasks to systematically examine PFC responses in cognitively normal and impaired populations,aiming to provide neuroscientific evidence and innovative approaches for cognitive function assessment.Specifically,this research includes:(1)Designing an experiment on the mean functional connectivity strength in the PFC during binocular color fusion and rivalry.By employing brain network analysis based on Pearson correlation coefficients,this study elucidated cognitive functional networks under binocular color fusion,binocular color rivalry,and mid-gray field conditions.Experimental results from 12 cognitively normal participants and 12 cognitively impaired participants indicated significantly enhanced PFC functional connectivity during binocular color fusion tasks in cognitively normal individuals,exhibiting a consistent hierarchical structure(binocular color fusion>binocular color rivalry>mid-gray field)for mean functional connectivity strength(r).In contrast,cognitively impaired participants showed no task-related differences,suggesting abnormal PFC cognitive functions.(2)Designing behavioral and neural activation experiments involving binocular color fusion and rivalry tasks.General linear model activation analyses and integrated behavioral data yielded an Executive Index(EI),reflecting cognitive executive function,thus revealing activation strength(β)and behavioral performance differences induced by the tasks.The results indicated task-specific activation differences in the frontal eye field(FEF)and dorsolateral prefrontal cortex(DLPFC)during binocular color fusion among cognitively normal individuals,alongside significantly higher EI values compared to the cognitively impaired group,highlighting their dynamic resource allocation and higher-order integration capacity.Further analysis revealed that behavioral accuracy in cognitively normal individuals depended on PFC functional specialization.Conversely,cognitively impaired individuals exhibited blurred PFC activation responses,accompanied by delayed responses and reduced accuracy,indicating diminished PFC regulatory functionality.(3)Based on distinct PFC response characteristics in cognitively normal and impaired populations,the study innovatively proposes a three-dimensional cognitive assessment system.This system encompasses hierarchical PFC response patterns(rBinocular color fusion>rBinocular color rivalry>rMid-gray field),specific activation differences(βBinocular color fusion>βBinocular color rivalry),and EI thresholds established from cognitively normal participants(EINormal participants≥0.2471).Cognitive states are classified into three categories:normal,impaired,and potentially mildly impaired,enabling quantitative mapping from neural mechanisms to clinical phenotypes.This dissertation adopts a "theory-experiment-application" research framework.Theoretically,it elucidates the response characteristics of the PFC in binocular color visual processing and identifies cognitive network abnormalities in cognitively impaired individuals.Experimentally,a stereoscopic display platform was used to design binocular color fusion and rivalry paradigms,effectively exploring the neural activity and cognitive functions of the PFC through advanced visual tasks.Practically,the proposed assessment methods,integrating neural activity and behavioral dynamics,overcome subjective limitations inherent in traditional assessments,providing novel perspectives for early screening and intervention quantification for cognitive impairments such as Alzheimer’s disease.更多还原