Juras Luka, Martinčević Marina, Konstantinović Uroš, Filipović Saša R, Vranić Andrea, Bjekić Jovana
Department of Psychology, Faculty of Humanities and Social Sciences, University of Zagreb, Zagreb, Croatia.
Human Neuroscience Group and Centre for Neuroscience and Neuromodulation, Institute for Medical Research, University of Belgrade, Belgrade, Serbia.
PLoS One. 2025 Jan 30;20(1):e0318593. doi: 10.1371/journal.pone.0318593. eCollection 2025.
Associative memory (AM) plays a crucial role in our ability to link disparate elements of our experiences, yet it is especially vulnerable to age-related decline and pathological conditions. Non-invasive brain stimulation (NIBS), particularly transcranial direct current stimulation (tDCS), has been investigated as a potential intervention to enhance cognitive functions, including AM. Previous tDCS studies yielded inconsistent results, often due to variations in stimulation sites and protocols. Nonetheless, enough evidence suggests that tDCS over the posterior parietal cortex (PPC) can improve AM performance. This study aimed to investigate the cumulative effects of multiple anodal tDCS over the PPC on AM performance alongside item memory and verbal fluency. In a randomized sham-controlled trial, 59 healthy young adults were assigned to either anodal or sham stimulation group, receiving tDCS (1.5 mA, for 20 minutes, at P3) over three consecutive days. Memory performance was assessed at four timepoints: pretest, immediately after the first session, posttest (Day 5), and follow-up (Day 9). Although tDCS was well tolerated, the anticipated enhancement of memory performance was not observed. We interpret these findings in the light of methodological considerations and propose potential explanations for the observed results emphasizing the large between-participants variability in memory performance as a significant factor that may have hindered the detection of tDCS effects.
联想记忆（AM）在我们将不同的经验元素联系起来的能力中起着关键作用，但它特别容易受到与年龄相关的衰退和病理状况的影响。非侵入性脑刺激（NIBS），尤其是经颅直流电刺激（tDCS），已被研究作为一种潜在的干预措施来增强认知功能，包括联想记忆。以往的tDCS研究结果并不一致，这通常是由于刺激部位和方案的差异。尽管如此，有足够的证据表明，对顶叶后皮质（PPC）进行tDCS可以改善联想记忆表现。本研究旨在探讨对PPC进行多次阳极tDCS对联想记忆表现以及项目记忆和言语流畅性的累积效应。在一项随机假刺激对照试验中，59名健康的年轻成年人被分配到阳极刺激组或假刺激组，连续三天接受tDCS（1.5毫安，持续20分钟，在P3部位）。在四个时间点评估记忆表现：预测试、第一次治疗后立即测试、后测试（第5天）和随访（第9天）。虽然tDCS耐受性良好，但未观察到预期的记忆表现增强。我们根据方法学考虑对这些发现进行了解释，并对观察到的结果提出了潜在的解释，强调记忆表现中参与者之间的巨大变异性是一个可能阻碍检测tDCS效应的重要因素。
