Emotion and Development Branch, National Institute of Mental Health, Bethesda, 20892, MD.
Department of Human Development and Quantitative Methodology, University of Maryland, College Park, MD 20742.
J Neurosci. 2023 Dec 13;43(50):8723-8732. doi: 10.1523/JNEUROSCI.0462-23.2023.
Adolescence is an important developmental period, during which substantial changes occur in brain function and behavior. Several aspects of executive function, including response inhibition, improve during this period. Correspondingly, structural imaging studies have documented consistent decreases in cortical and subcortical gray matter volume, and postmortem histologic studies have found substantial (∼40%) decreases in excitatory synapses in prefrontal cortex. Recent computational modeling work suggests that the change in synaptic density underlie improvements in task performance. These models also predict changes in neural dynamics related to the depth of attractor basins, where deeper basins can underlie better task performance. In this study, we analyzed task-related neural dynamics in a large cohort of longitudinally followed subjects (male and female) spanning early to late adolescence. We found that age correlated positively with behavioral performance in the Eriksen Flanker task. Older subjects were also characterized by deeper attractor basins around task related evoked EEG potentials during specific cognitive operations. Thus, consistent with computational models examining the effects of excitatory synaptic pruning, older adolescents showed stronger attractor dynamics during task performance. There are well-documented changes in brain and behavior during adolescent development. However, there are few mechanistic theories that link changes in the brain to changes in behavior. Here, we tested a hypothesis, put forward on the basis of computational modeling, that pruning of excitatory synapses in cortex during adolescence changes neural dynamics. We found, consistent with the hypothesis, that variability around event-related potentials shows faster decay dynamics in older adolescent subjects. The faster decay dynamics are consistent with the hypothesis that synaptic pruning during adolescent development leads to stronger attractor basins in task-related neural activity.
青春期是一个重要的发育阶段，在此期间大脑功能和行为会发生实质性的变化。执行功能的几个方面，包括反应抑制，在此期间会得到改善。相应地，结构影像学研究记录了皮质和皮质下灰质体积的持续减少，而死后组织学研究发现前额叶皮质中的兴奋性突触大量减少（约 40%）。最近的计算建模工作表明，突触密度的变化是任务表现改善的基础。这些模型还预测了与吸引子盆地深度相关的神经动力学变化，其中更深的盆地可以支持更好的任务表现。在这项研究中，我们分析了跨越青少年早期到晚期的大量纵向随访受试者（男性和女性）的与任务相关的神经动力学。我们发现，年龄与 Eriksen Flanker 任务中的行为表现呈正相关。在特定认知操作期间，与任务相关的诱发电位周围，年龄较大的受试者的吸引子盆地也更深。因此，与检查兴奋性突触修剪影响的计算模型一致，青少年后期的受试者在任务表现期间表现出更强的吸引子动力学。在青少年发育过程中，大脑和行为都发生了有案可稽的变化。然而，很少有机制理论将大脑的变化与行为的变化联系起来。在这里，我们检验了一个假设，即基于计算模型提出的假设，即在青春期皮质中修剪兴奋性突触会改变神经动力学。我们发现，与假设一致，事件相关电位周围的变异性在年龄较大的青少年受试者中表现出更快的衰减动力学。更快的衰减动力学与假设一致，即青少年发育过程中的突触修剪导致与任务相关的神经活动中的吸引子盆地更强。
