arXiv:2601.19723cs.CLcs.AI2026-01被引 3

通过模块化扰动模拟失语症,让大模型像人一样因脑损伤而语言退化。

Component-Level Lesioning of Language Models Reveals Clinically Aligned Aphasia Phenotypes

  • 按临床亚型选择性干扰模型组件,模拟布罗卡与韦尼克失语。
  • 渐进式扰动使语言能力下降,与真实患者失语量表得分一致。
  • 模块化模型更易定位功能组件,适合神经语言研究与康复测试。

大型语言模型(LLMs)展现出类人语言行为和内部表征,可作为语言认知的计算模拟器。本文提出一种基于临床的组件级扰动框架,通过选择性破坏模型功能组件来模拟局灶性脑损伤导致的失语症。该方法在混合专家(MoE)模型与密集变压器模型上统一实施,流程包括:(i) 识别与布罗卡与韦尼克失语相关的组件;(ii) 通过语言探针任务解释这些组件;(iii) 逐步扰动前k个亚型相关组件,使用西方失语症评估量表(WAB)子项综合为失语商(AQ)进行评估。跨架构与扰动策略下,针对亚型的扰动比等规模随机扰动产生更系统、类失语的退化表现;且MoE结构支持更局部化、可解释的表型-组件映射。结果表明,结合临床引导的组件扰动,模块化大模型是模拟失语语言产出并研究语言功能在靶向干扰下退化的理想平台。

原文摘要 · Abstract (English)

Large language models (LLMs) increasingly exhibit human-like linguistic behaviors and internal representations that they could serve as computational simulators of language cognition. We ask whether LLMs can be systematically manipulated to reproduce language-production impairments characteristic of aphasia following focal brain lesions. Such models could provide scalable proxies for testing rehabilitation hypotheses, and offer a controlled framework for probing the functional organization of language. We introduce a clinically grounded, component-level framework that simulates aphasia by selectively perturbing functional components in LLMs, and apply it to both modular Mixture-of-Experts models and dense Transformers using a unified intervention interface. Our pipeline (i) identifies subtype-linked components for Broca's and Wernicke's aphasia, (ii) interprets these components with linguistic probing tasks, and (iii) induces graded impairments by progressively perturbing the top-k subtype-linked components, evaluating outcomes with Western Aphasia Battery (WAB) subtests summarized by Aphasia Quotient (AQ). Across architectures and lesioning strategies, subtype-targeted perturbations yield more systematic, aphasia-like regressions than size-matched random perturbations, and MoE modularity supports more localized and interpretable phenotype-to-component mappings. These findings suggest that modular LLMs, combined with clinically informed component perturbations, provide a promising platform for simulating aphasic language production and studying how distinct language functions degrade under targeted disruptions.

失语症模拟大模型语言神经机制模块化

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