Medical Department, Brookhaven National Laboratory, Upton, NY 11973, United States.
Neuropsychologia. 2011 Jun;49(7):1660-9. doi: 10.1016/j.neuropsychologia.2011.02.037. Epub 2011 Mar 15.
The ability to adapt behavior in a changing environment is necessary for humans to achieve their goals and can be measured in the lab with tests of rule-based switching. Disease models, such as cocaine addiction, have revealed that alterations in dopamine interfere with adaptive set switching, culminating in perseveration. We explore perseverative behavior in individuals with cocaine use disorders (CUD) and healthy controls (CON) during performance of the Wisconsin Card Sorting Test (WCST) (N=107 in each group). By examining perseverative errors within each of the 6 blocks of the WCST, we uniquely test two forms of set switching that are differentiated by either the presence (extradimensional set shifting (EDS) - first 3 blocks) or absence (task-set switching - last 3 blocks) of new contingency learning. We also explore relationships between perseveration and select cognitive and drug use factors including verbal learning and memory, trait inhibitory control, motivational state, and urine status for cocaine (in CUD). Results indicate greater impairment for CUD than CON on the WCST, even in higher performing CUD who completed all 6 blocks of the WCST. Block by block analysis conducted on completers' scores indicate a tendency for greater perseveration in CUD than CON but only during the first task-set switch; no such deficits were observed during EDS. This task-set switching impairment was modestly associated with two indices of immediate recall (r=-.32, -.29) and urine status for cocaine [t (134)=2.3, p<.03]. By distinguishing these two forms of switching on the WCST, the current study reveals a neurocognitive context (i.e. initial stage of task-set switching) implicit in the WCST that possibly relies upon intact dopaminergic function, but that is impaired in CUD, as associated with worse recall and possibly withdrawal from cocaine. Future studies should investigate whether dopaminergically innervated pathways alone, or in combination with other monoamines, underlie this implicit neurocognitive processes in the WCST.
在不断变化的环境中适应行为的能力对人类实现目标是必要的，可以通过基于规则的切换测试在实验室中进行测量。疾病模型，如可卡因成瘾，已经揭示了多巴胺的改变干扰了适应性集切换，最终导致固着。我们在执行威斯康星卡片分类测试 (WCST) 时探索了可卡因使用障碍 (CUD) 个体和健康对照组 (CON) 的固着行为（每组 107 人）。通过检查 WCST 的每个 6 个块内的固着错误，我们独特地测试了两种形式的集切换，这两种形式的集切换通过新的条件学习的存在（外维度集转移 (EDS) - 前 3 个块）或不存在（任务集切换 - 最后 3 个块）来区分。我们还探索了固着与选择认知和药物使用因素之间的关系，包括言语学习和记忆、特质抑制控制、动机状态和可卡因尿液状态（在 CUD 中）。结果表明，CUD 比 CON 在 WCST 上的表现更差，即使是完成 WCST 所有 6 个块的表现较高的 CUD 也是如此。对完成者分数的逐块分析表明，CUD 比 CON 更倾向于固着，但仅在第一个任务集切换期间；在 EDS 期间没有观察到这种缺陷。这种任务集切换损伤与即时回忆的两个指标（r=-.32，-.29）和可卡因尿液状态适度相关 [t (134)=2.3，p<.03]。通过在 WCST 上区分这两种形式的切换，本研究揭示了 WCST 中隐含的神经认知背景（即任务集切换的初始阶段），该背景可能依赖于完整的多巴胺能功能，但在 CUD 中受损，与较差的回忆有关，并且可能与可卡因戒断有关。未来的研究应该调查多巴胺能神经支配的途径是否单独或与其他单胺类物质一起，为 WCST 中的这种隐含神经认知过程提供基础。
