Nikolaienko Oksana, Klymenko Mariia, Isaeva Elena
Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.
Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.
Neurol Res. 2023 Dec;45(12):1152-1160. doi: 10.1080/01616412.2023.2257444. Epub 2023 Sep 12.
Social interaction at a young age plays a critical role in the normal maturation of the brain and neuroendocrine system. Deprivation of social contacts has been associated with numerous cognitive and emotional abnormalities. However, neurobiological mechanisms that may underlie these effects remain poorly understood. In the present study, we examined the effect of 4-6-week social isolation during the adolescent period on rat spatial memory and emotional responses and investigated synaptic plasticity in the dorsal (DH) and ventral hippocampus (VH), which are known to be differently involved in these behaviors.
Male Wistar rats were housed individually or in groups of four for 4-6 weeks immediately after weaning. At the end of the isolation period, rats were subjected to behavioral testing or electrophysiological studies. Behavioral tests included behavioral excitability, sucrose preference, open field (OF), elevated plus maze (EPM), Morris water maze (MWM), and Y-maze test. For plasticity experiments, long-term potentiation (LTP) in Schaffer collateral/СA1 synapses was induced using high-frequency stimulation (HFS) on transverse hippocampal slices.
Social isolation induced hyperexcitability, increased anxiety- and anhedonia-like behaviors, while no significant changes were observed in cognitive tasks. Electrophysiological recordings revealed enhanced short-term potentiation (STP) in the VH and suppressed LTP in the DH of isolated animals compared to group-housed controls.
Our findings suggest that adolescent social isolation has distinct effects on synaptic plasticity in the VH and DH and leads to emotional dysregulation rather than impairments in cognitive performance.
幼年时期的社交互动在大脑和神经内分泌系统的正常成熟过程中起着关键作用。社交接触的剥夺与众多认知和情绪异常有关。然而，这些影响背后的神经生物学机制仍知之甚少。在本研究中，我们研究了青春期4 - 6周的社会隔离对大鼠空间记忆和情绪反应的影响，并研究了背侧海马（DH）和腹侧海马（VH）的突触可塑性，已知这两个区域在这些行为中发挥不同作用。
雄性Wistar大鼠在断奶后立即单独饲养或每4只为一组饲养4 - 6周。在隔离期结束时，对大鼠进行行为测试或电生理研究。行为测试包括行为兴奋性、蔗糖偏好、旷场试验（OF）、高架十字迷宫试验（EPM）、莫里斯水迷宫试验（MWM）和Y迷宫试验。对于可塑性实验，在横向海马切片上使用高频刺激（HFS）诱导Schaffer侧支/CA1突触的长时程增强（LTP）。
社会隔离导致兴奋性增强、焦虑样和快感缺失样行为增加，而在认知任务中未观察到显著变化。电生理记录显示，与群居对照相比，隔离动物的VH中短期增强（STP）增强，DH中LTP受到抑制。
我们的研究结果表明，青春期社会隔离对VH和DH中的突触可塑性有不同影响，并导致情绪失调而非认知能力受损。
