Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho Braga, Portugal ; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal ; Clinical Academic Center Braga, Portugal.
Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho Braga, Portugal ; Neuropsychophysiology Lab, CIPsi, School of Psychology, University of Minho Braga, Portugal.
Front Hum Neurosci. 2013 Dec 27;7:919. doi: 10.3389/fnhum.2013.00919. eCollection 2013.
Chronic stress has been widely reported to have deleterious impact in multiple biological systems. Specifically, structural and functional remodeling of several brain regions following prolonged stress exposure have been described; importantly, some of these changes are eventually reversible. Recently, we showed the impact of stress on resting state networks (RSNs), but nothing is known about the plasticity of RSNs after recovery from stress. Herein, we examined the "plasticity" of RSNs, both at functional and structural levels, by comparing the same individuals before and after recovery from the exposure to chronic stress; results were also contrasted with a control group. Here we show that the stressed individuals after recovery displayed a decreased resting functional connectivity in the default mode network (DMN), ventral attention network (VAN), and sensorimotor network (SMN) when compared to themselves immediately after stress; however, this functional plastic recovery was only partial as when compared with the control group, as there were still areas of increased connectivity in dorsal attention network (DAN), SMN and primary visual network (VN) in participants recovered from stress. Data also shows that participants after recovery from stress displayed increased deactivations in DMN, SMN, and auditory network (AN), to levels similar to those of controls, showing a normalization of the deactivation pattern in RSNs after recovery from stress. In contrast, structural changes (volumetry) of the brain areas involving these networks are absent after the recovery period. These results reveal plastic phenomena in specific RSNs and a functional remodeling of the activation-deactivation pattern following recovery from chronic-stress, which is not accompanied by significant structural plasticity.
慢性应激已被广泛报道对多个生物系统具有有害影响。具体来说，长期应激暴露后，几个大脑区域的结构和功能重塑已经被描述；重要的是，其中一些变化最终是可逆的。最近，我们研究了应激对静息态网络（RSNs）的影响，但对于应激恢复后 RSNs 的可塑性还一无所知。在此，我们通过比较同一批个体在应激暴露前后的功能和结构水平，来研究 RSNs 的“可塑性”；结果还与对照组进行了对比。在这里，我们发现与应激后即刻的自身相比，应激恢复后的个体在默认模式网络（DMN）、腹侧注意网络（VAN）和感觉运动网络（SMN）中的静息功能连接性降低；然而，与对照组相比，这种功能上的恢复只是部分的，因为在应激恢复后的参与者中，背侧注意网络（DAN）、SMN 和初级视觉网络（VN）中仍然存在连接性增加的区域。数据还显示，与对照组相比，应激恢复后的参与者的 DMN、SMN 和听觉网络（AN）的去激活程度增加，达到与对照组相似的水平，表明应激恢复后 RSNs 的去激活模式得到了正常化。相比之下，在恢复期间，涉及这些网络的大脑区域的结构变化（体积）并不存在。这些结果揭示了特定 RSNs 中的可塑性现象以及应激恢复后激活-去激活模式的功能重塑，这与显著的结构可塑性无关。
