San Diego Department of Psychiatry, University of California, San Diego, CA, USA; VA San Diego Healthcare System, San Diego, CA, USA; San Diego State University, San Diego, CA, USA.
San Diego Department of Psychiatry, University of California, San Diego, CA, USA; VA San Diego Healthcare System, San Diego, CA, USA.
Neuromodulation. 2022 Apr;25(3):424-432. doi: 10.1111/ner.13313.
While preliminary evidence suggests that noninvasive vagal nerve stimulation (nVNS) may enhance cognition, to our knowledge, no study has directly assessed the effects of nVNS on brain function and cognitive performance in healthy individuals. The aim of this study was therefore to assess whether nVNS enhances complex visuospatial problem solving in a normative sample. Functional magnetic resonance imaging (fMRI) was used to examine underlying neural substrates.
Participants received transcutaneous cervical nVNS (N = 15) or sham (N = 15) stimulation during a 3 T fMRI scan. Stimulation lasted for 2 min at 24 V for nVNS and at 4.5 V for sham. Subjects completed a matrix reasoning (MR) task in the scanner and a forced-choice recognition task outside the scanner. An analysis of variance (ANOVA) was used to assess group differences in cognitive performance. And linear mixed effects (LMEs) regression analysis was used to assess main and interaction effects of experimental groups, level of MR task difficulty, and recall accuracy on changes in blood oxygen level-dependent (BOLD) signal.
Subjects who received nVNS showed higher accuracy for both easy (p = 0.017) and hard (p = 0.013) items of the MR task, slower reaction times for hard items (p = 0.014), and fewer false negative errors during the forced-choice recognition task (p = 0.047). MR task difficulty related to increased activation in frontoparietal regions (p < 0.001). No difference between nVNS and sham stimulation was found on BOLD response during performance of the MR task.
We hypothesize that nVNS increased attention compared to sham, and that this effect led to enhanced executive functions, and consequently to better performance on visuospatial reasoning and recognition tasks. Results provide initial support that nVNS may be a low-risk, low-cost treatment for cognitive disorders.
虽然初步证据表明非侵入性迷走神经刺激（nVNS）可能增强认知，但据我们所知，尚无研究直接评估 nVNS 对健康个体大脑功能和认知表现的影响。因此，本研究旨在评估 nVNS 是否能增强正常样本的复杂视觉空间问题解决能力。功能性磁共振成像（fMRI）用于检查潜在的神经基质。
参与者在 3T fMRI 扫描期间接受经皮颈部 nVNS（n=15）或假刺激（n=15）。nVNS 刺激持续 2 分钟，电压为 24V；假刺激电压为 4.5V。受试者在扫描仪中完成矩阵推理（MR）任务，并在扫描仪外完成强制选择识别任务。方差分析（ANOVA）用于评估认知表现的组间差异。线性混合效应（LME）回归分析用于评估实验组、MR 任务难度水平和回忆准确性对血氧水平依赖（BOLD）信号变化的主要和交互效应。
接受 nVNS 的受试者在 MR 任务的简单（p=0.017）和困难（p=0.013）项目上表现出更高的准确性，在困难项目上的反应时间更慢（p=0.014），在强制选择识别任务中的假阴性错误更少（p=0.047）。MR 任务难度与额顶叶区域的激活增加有关（p<0.001）。在执行 MR 任务期间，nVNS 和假刺激之间的 BOLD 反应没有差异。
我们假设 nVNS 与假刺激相比增加了注意力，并且这种效应导致了执行功能的增强，从而导致在视觉空间推理和识别任务上的表现更好。结果初步支持 nVNS 可能是一种低风险、低成本的认知障碍治疗方法。
