认知与发展心理学研究室知识库

目的:抑制控制在老年阶段的随龄衰退会导致工作记忆能力和液态智力的下降，进而影响老年人的日常认知功能，因此抑制控制在老年阶段的可塑性近年来受到关注。虽然己经有一些干预研究采用抑制任务作为训练任务，但系统探究老年抑制控制能力可塑性并关注远迁移效应的研究很少。此外，采用多模态脑成像全面探究老年阶段抑制控制能力可塑性神经机制的研究非常缺乏。本研究采用认知抑制能力训练，考察老年阶段抑制控制认知和神经可塑性及其迁移效应。

方法:采用单盲实验设计，4_5名老年被试(平均年龄67.0岁)随机进入认知抑制训练组(22人)和有接触对照组(23人)。训练组被试在一个月内每周四次完成自适应训练(4项认知抑制任务);对照组被试每周一次参加团体心理辅导或讲座。前后测包括近迁移任务，远迁移(工作记忆、液态智力、加工速度、视觉空间和情节记忆)任务，结构像MRI、静息态和任务态fMRI实验。任务态fMRI采用延迟匹配范式，包括基线条件、有干扰条件和高负荷条件(3个目标)。

结果：（1）认知抑制能力在老年阶段仍存在可塑性，后测中训练组被试近迁移任务成绩提高，训练效应在三个月后得到较好的保持。（2）在工作记忆能力上发现远迁移效应，后测中训练组被试工作记忆任务成绩提高，迁移效应在三个月后得到一定程度的保持。（3）在液态智力、加工速度、视觉空间能力和情节记忆能力上均未出现远迁移效应。（4）认知抑制训练改变工作记忆任务中大脑的功能激活：有干扰条件下训练后颞叶和梭状回功能激活减少，且改变量与有干扰条件正确率的改变显著负相关，提示被试能够更少地受无关信息的干扰；延迟阶段，高负荷条件下舌回（与前测负荷相关存储区域相邻）功能激活增加，提示被试能够投入更多认知资源参与工作记忆存储。（5）认知抑制训练改变大脑灰质体积：训练后被试中央前回和中央后回灰质体积增加。（6）认知抑制训练改变静息态功能连接：训练后被试左侧颞叶、梭状回（tROI 7、tROI 13）与楔前叶等背侧注意网络区域、楔叶等视觉网络区域功能连接减弱，而与尾状核功能连接增强。

结论：老年阶段，认知抑制能力仍然存在认知和神经可塑性，训练效应能够迁移到工作记忆能力上。训练和迁移效应在三个月后得到保持。

Objectives: The decline of inhibition efficiency in old age could lead to the impairment of working memory and fluid intelligence and subsequently, influence other cognitive abilities. Therefore, attention has been paid to the plasticity in inhibitory control in recent years. But although there have been some studies using inhibition tasks as training tasks, no systemic research on the plasticity in inhibitory control and related transfer effects in old age has been conducted. Moreover, study that uses multi-model MRI techniques to investigate the neural basis of plasticity in inhibitory control is very rare. The current study adopted cognitive inhibition training, to investigate behavioral and neural plasticity in inhibitory control and related transfer effects in old age.

Methods: A single blind experimental design is adopted, and 45 healthy older adults (mean age 67.0) are randomly divided into a cognitive training group (n=22 and an active control group (n=23). Participants in the training group took sessions of adaptive training on cognitive inhibition (4 tasks per session 4 sessions per week, last for 1 month), and participants in the control group participated in 4 sessions of group counseling or lecture (1 session per week, last for 1 month). Pretests and posttests include near transfer tasks that correspond to the training tasks, far transfer tasks (on working memory, fluid intelligence, processing speed, visual spatial ability, and episodic memory) and structural MRI, resting-state fMRI and task-based fMRI scans. In the task-based fMRI experiment, a delayed-match-to-sample task is adopted, containing a baseline condition (1 target), a distraction condition (1 target and 2 distractors), and a high-load condition (3 targets).

Results: (1) Cognitive inhibition has plasticity even in old age. In posttest, performance of participants in the training group on near transfer tasks improved, and this training effect maintained in the follow up three months later. (2) Training effect transferred to working memory capacity. In posttest, performance of participants in the training group on working memory tasks improved, and this transfer effect maintained at some degree in the follow up three months later. (3) No transfer effect to fluid intelligence, processing speed, visual spatial ability, and episodic memory was found. (4) Training on cognitive inhibition altered cortical activation during working memory tasks. In the distraction condition, activation in an ROI in temporal cortex, and fusiform gyrus of participants in the training group decreased significantly.Within the training group, relative signal change in this area was negatively correlated with change of response accuracy in the distraction condition. This result indicated that participants can more effectively ignore irrelevant information. In the high-load condition, activation in an ROI in lingual gyrus (adjacent to regions showing load-dependent delay-period activity in the pretest) of the training group increased significantly, indicating that participants can devote more resource storing working memory contents. (5) Training on cognitive inhibition influenced volume of cortical grey matter. In the posttest, volume of grey matter in an ROI in precentral gyrus and postcentral gyrus of participants in the training group increased. (6) Training on cognitive inhibition influenced resting一state functional connectivity. In the posttest among participants in the training group, ROIs in left temporal cortex and fusiform gyrus (tROI 7, tROI 13) showed decreased connectivity with precuneus (in the dorsal attention network) and cuneus (in the visual network), and increased connectivity with caudate.