Department of Cognitive Science, Budapest University of Technology and Economics, Budapest, Hungary.
Department of Cognitive Science, Budapest University of Technology and Economics, Budapest, Hungary; Institute of Cognitive Neuroscience and Psychology, Hungarian Academy of Sciences, Budapest, Hungary.
Cortex. 2018 Nov;108:80-91. doi: 10.1016/j.cortex.2018.07.012. Epub 2018 Jul 31.
Repeated encounter with encoded memories is often a fundamental component of long-term learning processes, however, the role of repeated access to encoded memories in long-term consolidation is yet to be clarified. Here we investigated whether the long-term retention of newly acquired associative memories is affected if one of the central areas of the attentional control network is stimulated before or after repeated access to acquired information. Non-clinical participants (undergraduate students, N = 118) were exposed to an associative verbal learning task. Following the initial learning of word pairs, memories for the word pairs were reencountered either by re-presenting the stimuli to the participants for restudying or by cued recall. The reencounter phase was either preceded by (Experiment 1) or followed by (Experiment 2) anodal transcranial Direct Current Stimulation of the right dorsolateral prefrontal cortex. Memory retention was assessed seven days after the reencounter phase. When we measured successful access to learned paired-associates in the reencounter phase, there was no difference between the anodal and sham stimulation condition in either Experiment 1 or 2. However, and importantly, anodal stimulation had a detrimental impact on long-term memory but only when stimulation preceded the reencountering of memories (in Experiment 1). Our results suggest that stimulation of the so-called control network during repeated access to acquired information disrupts the long-term retention of these memories. These findings are in line with earlier results showing that repeated access to learned information systematically decreases the involvement of control processes in retrieval and presumably promotes learning through the automatization of cue-target association. At a neural level, a possible substrate of repeated memory reencountering is a shift in frontohippocampal connectivity.
反复接触已编码的记忆通常是长期学习过程的基本组成部分，然而，反复接触已编码记忆在长期巩固中的作用仍有待阐明。在这里，我们研究了如果在反复接触已获取信息之前或之后刺激注意力控制网络的中心区域之一，新获得的联想记忆的长期保留是否会受到影响。非临床参与者（本科生，N=118）接受了联想性言语学习任务。在最初学习单词对之后，通过重新呈现刺激物供参与者重新学习或通过线索回忆来重新遇到单词对的记忆。再遇到阶段要么在（实验 1）之前，要么在（实验 2）之后，右侧背外侧前额叶皮层进行阳极经颅直流电刺激。在再遇到阶段后七天评估记忆保留情况。当我们在再遇到阶段测量成功访问已学习的成对联想时，在实验 1 或实验 2 中，阳极刺激和假刺激条件之间没有差异。然而，重要的是，阳极刺激对长期记忆有不利影响，但仅在刺激先于记忆再遇到时（在实验 1 中）。我们的结果表明，在反复接触已获取信息期间刺激所谓的控制网络会破坏这些记忆的长期保留。这些发现与早期结果一致，即反复接触已学习的信息会系统地降低控制过程在检索中的参与度，并通过线索-目标关联的自动化促进学习。在神经水平上，反复记忆再遇到的一个可能的基质是额-海马连接的转变。
