Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands.
Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA.
Neurobiol Learn Mem. 2019 Apr;160:83-90. doi: 10.1016/j.nlm.2018.03.018. Epub 2018 Mar 24.
Sleep and sleep loss have a profound impact on hippocampal function, leading to memory impairments. Modifications in the strength of synaptic connections directly influences neuronal communication, which is vital for normal brain function, as well as the processing and storage of information. In a recently published study, we found that as little as five hours of sleep deprivation impaired hippocampus-dependent memory consolidation, which was accompanied by a reduction in dendritic spine numbers in hippocampal area CA1. Surprisingly, loss of sleep did not alter the spine density of CA3 neurons. Although sleep deprivation has been reported to affect the function of the dentate gyrus, it is unclear whether a brief period of sleep deprivation impacts spine density in this region. Here, we investigated the impact of a brief period of sleep deprivation on dendritic structure in the dentate gyrus of the dorsal hippocampus. We found that five hours of sleep loss reduces spine density in the dentate gyrus with a prominent effect on branched spines. Interestingly, the inferior blade of the dentate gyrus seems to be more vulnerable in terms of spine loss than the superior blade. This decrease in spine density predominantly in the inferior blade of the dentate gyrus may contribute to the memory deficits observed after sleep loss, as structural reorganization of synaptic networks in this subregion is fundamental for cognitive processes.
睡眠和睡眠不足对海马体功能有深远影响，导致记忆障碍。突触连接强度的改变直接影响神经元通讯，这对大脑的正常功能以及信息的处理和存储至关重要。在最近发表的一项研究中，我们发现，即使只有五个小时的睡眠剥夺也会损害海马体依赖的记忆巩固，同时伴随着海马体 CA1 区树突棘数量的减少。令人惊讶的是，睡眠剥夺并没有改变 CA3 神经元的棘突密度。虽然睡眠剥夺已被报道会影响齿状回的功能，但目前尚不清楚短暂的睡眠剥夺是否会影响该区域的棘突密度。在这里，我们研究了短暂的睡眠剥夺对背侧海马齿状回树突结构的影响。我们发现，五个小时的睡眠剥夺会降低齿状回的棘突密度，对分支棘突的影响尤为明显。有趣的是，从棘突丢失的角度来看，齿状回的下叶似乎比上叶更脆弱。这种主要发生在齿状回下叶的棘突密度下降，可能导致睡眠剥夺后观察到的记忆缺陷，因为该亚区的突触网络结构重组对于认知过程至关重要。
