Department of Psychology, Temple University, United States.
Department of Psychology, Temple University, United States; Department of Neuroscience Program, Temple University, United States.
Brain Res. 2022 Feb 15;1777:147755. doi: 10.1016/j.brainres.2021.147755. Epub 2021 Dec 18.
Post-weaning social isolation stress has been shown to increase addiction-like behavior in adulthood. These long-term behavioral alterations may be due to long lasting isolation-induced structural changes to neurons in brain regions involved in reward processing. Previous studies have shown that various stressors alter dendritic spine density in the prefrontal cortex (PFC) and the nucleus accumbens, though many of these studies examine the short-term effects of stress, and are primarily conducted in males. There is mounting evidence that males and females exhibit differences in their stress responses, with some studies showing sex differences in stress-induced plasticity. To determine the long-lasting, sex-specific alterations in spine density following post-weaning social isolation, male and female mice were either isolated or group housed at weaning and spine density was measured once they reached adulthood. Post-weaning isolation increased spine density in the PFC of both the males and females, although the effects in the infralimbic cortex were more pronounced in the females. In the nucleus accumbens, adolescent isolation increased spine density in males only in the core and shell. Females also had higher baseline spine density than males in the nucleus accumbens core. Together these data suggest that adolescent social isolation causes long-term, sex-specific alterations to the prefrontal cortex and the nucleus accumbens.
断奶后社交隔离应激已被证明会增加成年后的类似成瘾行为。这些长期的行为改变可能是由于长期的隔离诱导的与奖励处理相关的大脑区域神经元的结构变化。先前的研究表明，各种应激源会改变前额叶皮层（PFC）和伏隔核中的树突棘密度，尽管许多这些研究都考察了应激的短期影响，并且主要在雄性中进行。越来越多的证据表明，男性和女性在应激反应方面存在差异，一些研究表明应激诱导的可塑性存在性别差异。为了确定断奶后社交隔离后长期的、性别特异性的棘密度变化，雄性和雌性小鼠在断奶时被单独或分组饲养，并且在成年后测量一次棘密度。断奶后隔离增加了雄性和雌性 PFC 的棘密度，尽管在女性的下边缘皮层中影响更为明显。在伏隔核中，青少年隔离仅增加了核心和壳中的雄性棘密度。雌性的伏核核心中的基线棘密度也高于雄性。这些数据表明，青少年社交隔离会导致前额叶皮层和伏隔核的长期、性别特异性改变。
