Chen Chi-Ming A, Stanford Arielle D, Mao Xiangling, Abi-Dargham Anissa, Shungu Dikoma C, Lisanby Sarah H, Schroeder Charles E, Kegeles Lawrence S
Department of Psychology, University of Connecticut, 406 Babbidge Road, Storrs, CT 06269, USA.
Department of Psychiatry, Institute for the Neurosciences, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.
Neuroimage Clin. 2014 Mar 20;4:531-9. doi: 10.1016/j.nicl.2014.03.007. eCollection 2014.
A relationship between working memory impairment, disordered neuronal oscillations, and abnormal prefrontal GABA function has been hypothesized in schizophrenia; however, in vivo GABA measurements and gamma band neural synchrony have not yet been compared in schizophrenia. This case-control pilot study (N = 24) compared baseline and working memory task-induced neuronal oscillations acquired with high-density electroencephalograms (EEGs) to GABA levels measured in vivo with magnetic resonance spectroscopy. Working memory performance, baseline GABA level in the left dorsolateral prefrontal cortex (DLPFC), and measures of gamma oscillations from EEGs at baseline and during a working memory task were obtained. A major limitation of this study is a relatively small sample size for several analyses due to the integration of diverse methodologies and participant compliance. Working memory performance was significantly lower for patients than for controls. During the working memory task, patients (n = 7) had significantly lower amplitudes in gamma oscillations than controls (n = 9). However, both at rest and across working memory stages, there were significant correlations between gamma oscillation amplitude and left DLPFC GABA level. Peak gamma frequency during the encoding stage of the working memory task (n = 16) significantly correlated with GABA level and working memory performance. Despite gamma band amplitude deficits in patients across working memory stages, both baseline and working memory-induced gamma oscillations showed strong dependence on baseline GABA levels in patients and controls. These findings suggest a critical role for GABA function in gamma band oscillations, even under conditions of system and cognitive impairments as seen in schizophrenia.
精神分裂症中已推测工作记忆损害、神经元振荡紊乱与前额叶GABA功能异常之间存在关联；然而，尚未在精神分裂症患者中比较体内GABA测量值与γ波段神经同步性。这项病例对照试点研究（N = 24）将通过高密度脑电图（EEG）获取的基线和工作记忆任务诱发的神经元振荡与通过磁共振波谱在体内测量的GABA水平进行了比较。获得了工作记忆表现、左侧背外侧前额叶皮质（DLPFC）的基线GABA水平以及基线和工作记忆任务期间EEG的γ振荡测量值。由于整合了多种方法和参与者的依从性，本研究的一个主要局限性是用于多项分析的样本量相对较小。患者的工作记忆表现显著低于对照组。在工作记忆任务期间，患者（n = 7）的γ振荡幅度显著低于对照组（n = 9）。然而，在静息状态和整个工作记忆阶段，γ振荡幅度与左侧DLPFC GABA水平之间均存在显著相关性。工作记忆任务编码阶段（n = 16）的γ峰值频率与GABA水平和工作记忆表现显著相关。尽管患者在整个工作记忆阶段存在γ波段幅度缺陷，但基线和工作记忆诱发的γ振荡在患者和对照组中均显示出对基线GABA水平的强烈依赖性。这些发现表明，即使在精神分裂症患者出现的系统和认知障碍情况下，GABA功能在γ波段振荡中也起着关键作用。
