Department of Psychology, Temple University, Philadelphia, PA, USA; Center for Cognitive Neuroscience, University of Pennsylvania, Philadelphia, PA, USA.
Neurosci Lett. 2010 Aug 2;479(3):312-6. doi: 10.1016/j.neulet.2010.05.087. Epub 2010 Jun 4.
The role of the posterior parietal cortex in working memory (WM) is poorly understood. We previously found that patients with parietal lobe damage exhibited a selective WM impairment on recognition but not recall tasks. We hypothesized that this dissociation reflected strategic differences in the utilization of attention. One concern was that these findings, and our subsequent interpretation, would not generalize to normal populations because of the patients' older age, progressive disease processes, and/or possible brain reorganization following injury. To test whether our findings extended to a normal population we applied transcranial direct current stimulation (tDCS) to right inferior parietal cortex. tDCS is a technique by which low electric current applied to the scalp modulates the resting potentials of underlying neural populations and can be used to test structure-function relationships. Eleven normal young adults received cathodal, anodal, or sham stimulation over right inferior posterior parietal cortex and then performed separate blocks of an object WM task probed by recall or recognition. The results showed that cathodal stimulation selectively impaired WM on recognition trials. These data replicate and extend our previous findings of preserved WM recall and impaired WM recognition in patients with parietal lobe lesions.
后顶叶皮层在工作记忆（WM）中的作用还不太清楚。我们之前发现，顶叶损伤的患者在识别任务上表现出选择性的 WM 损伤，但在回忆任务上则没有。我们假设这种分离反映了注意力利用的策略性差异。一个担忧是，由于患者年龄较大、疾病进程进展以及/或受伤后的可能的大脑重组，这些发现以及我们随后的解释不会推广到正常人群中。为了测试我们的发现是否适用于正常人群，我们对右顶下叶皮层施加了经颅直流电刺激（tDCS）。tDCS 是一种通过将低电流施加到头皮来调节下伏神经群的静息电位的技术，可用于测试结构-功能关系。11 名正常年轻成年人接受了右顶下后叶皮层的阴极、阳极或假刺激，然后分别进行了回忆或识别探测的物体 WM 任务的单独块。结果表明，阴极刺激选择性地损害了识别试验中的 WM。这些数据复制并扩展了我们之前在顶叶损伤患者中发现的 WM 回忆保存和 WM 识别受损的发现。
