Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium; Department of Health Sciences and Research, Medical University of South Carolina, Charleston, SC, USA.
Prog Neurobiol. 2022 May;212:102247. doi: 10.1016/j.pneurobio.2022.102247. Epub 2022 Feb 8.
Understanding the neurophysiological mechanisms that drive human behavior has been a long-standing focus of cognitive neuroscience. One well-known neuro-metabolite involved in the creation of optimal behavioral repertoires is GABA, the main inhibitory neurochemical in the human brain. Converging evidence from both animal and human studies indicates that individual variations in GABAergic function are associated with behavioral performance. In humans, one increasingly used in vivo approach to measuring GABA levels is through Magnetic Resonance Spectroscopy (MRS). However, the implications of MRS measures of GABA for behavior remain poorly understood. In this respect, it is yet to be determined how GABA levels within distinct task-related brain regions of interest account for differences in behavioral performance. This review summarizes findings from cross-sectional studies that determined baseline MRS-assessed GABA levels and examined their associations with performance on various behaviors representing the perceptual, motor and cognitive domains, with a particular focus on healthy participants across the lifespan. Overall, the results indicate that MRS-assessed GABA levels play a pivotal role in various domains of behavior. Even though some converging patterns emerge, it is challenging to draw comprehensive conclusions due to differences in behavioral task paradigms, targeted brain regions of interest, implemented MRS techniques and reference compounds used. Across all studies, the effects of GABA levels on behavioral performance point to generic and partially independent functions that refer to distinctiveness, interference suppression and cognitive flexibility. On one hand, higher baseline GABA levels may support the distinctiveness of neural representations during task performance and better coping with interference and suppression of preferred response tendencies. On the other hand, lower baseline GABA levels may support a reduction of inhibition, leading to higher cognitive flexibility. These effects are task-dependent and appear to be mediated by age. Nonetheless, additional studies using emerging advanced methods are required to further clarify the role of MRS-assessed GABA in behavioral performance.
理解驱动人类行为的神经生理机制一直是认知神经科学的长期关注点。一种与创建最佳行为模式相关的众所周知的神经代谢物是 GABA，它是人类大脑中的主要抑制性神经化学物质。来自动物和人类研究的综合证据表明，GABA 能功能的个体差异与行为表现有关。在人类中，一种越来越多地用于测量 GABA 水平的体内方法是通过磁共振波谱（MRS）。然而，MRS 测量 GABA 对行为的影响仍知之甚少。在这方面，尚不确定与行为表现差异相关的特定任务相关脑区的 GABA 水平如何解释。
这篇综述总结了横断面研究的结果，这些研究确定了基线 MRS 评估的 GABA 水平，并研究了它们与各种行为表现的关联，这些行为代表了感知、运动和认知领域，特别关注整个生命周期的健康参与者。总的来说，结果表明 MRS 评估的 GABA 水平在各种行为领域中起着关键作用。尽管出现了一些趋同模式，但由于行为任务范式、目标脑区、实施的 MRS 技术和使用的参考化合物的差异，很难得出全面的结论。
在所有研究中，GABA 水平对行为表现的影响表明其具有一般性和部分独立性的功能，涉及独特性、干扰抑制和认知灵活性。一方面，较高的基线 GABA 水平可能支持任务表现期间神经表现的独特性，以及更好地应对干扰和抑制首选反应倾向。另一方面，较低的基线 GABA 水平可能支持抑制的减少，从而提高认知灵活性。这些影响是任务依赖性的，并且似乎由年龄介导。尽管如此，仍需要使用新兴的先进方法进行更多研究，以进一步阐明 MRS 评估的 GABA 在行为表现中的作用。
