Klein Alexandra S, Donoso José R, Kempter Richard, Schmitz Dietmar, Beed Prateep
Neuroscience Research Center, Charité University Berlin, Germany.
Department of Biology, Institute for Theoretical Biology, Humboldt UniversityBerlin, Germany; Bernstein Center for Computational NeuroscienceBerlin, Germany.
Front Syst Neurosci. 2016 Oct 26;10:83. doi: 10.3389/fnsys.2016.00083. eCollection 2016.
The entorhinal cortices in the temporal lobe of the brain are key structures relaying memory related information between the neocortex and the hippocampus. The medial entorhinal cortex (MEC) routes spatial information, whereas the lateral entorhinal cortex (LEC) routes predominantly olfactory information to the hippocampus. Gamma oscillations are known to coordinate information transfer between brain regions by precisely timing population activity of neuronal ensembles. Here, we studied the organization of gamma oscillations in the MEC and LEC of the transgenic (tg) amyloid precursor protein (APP)-presenilin 1 (PS1) mouse model of Alzheimer's Disease (AD) at 4-5 months of age. gamma oscillations using the kainate model peaked between 30-50 Hz and therefore we analyzed the oscillatory properties in the 20-60 Hz range. Our results indicate that the LEC shows clear alterations in frequency and power of gamma oscillations at an early stage of AD as compared to the MEC. The gamma-frequency oscillation slows down in the LEC and also the gamma power in dorsal LEC is decreased as early as 4-5 months in the tg APP-PS1 mice. The results of this study suggest that the timing of olfactory inputs from LEC to the hippocampus might be affected at an early stage of AD, resulting in a possible erroneous integration of the information carried by the two input pathways to the hippocampal subfields.
大脑颞叶中的内嗅皮质是在新皮质和海马体之间传递记忆相关信息的关键结构。内侧内嗅皮质（MEC）传递空间信息，而外侧内嗅皮质（LEC）主要将嗅觉信息传递至海马体。已知伽马振荡通过精确计时神经元群的群体活动来协调大脑区域之间的信息传递。在此，我们研究了4至5月龄的阿尔茨海默病（AD）转基因（tg）淀粉样前体蛋白（APP）-早老素1（PS1）小鼠模型的MEC和LEC中伽马振荡的组织情况。使用红藻氨酸模型的伽马振荡在30至50赫兹之间达到峰值，因此我们分析了20至60赫兹范围内的振荡特性。我们的结果表明，与MEC相比，LEC在AD早期阶段伽马振荡的频率和功率出现明显改变。在tg APP-PS1小鼠中，早在4至5个月时，LEC中的伽马频率振荡就会减慢，并且背侧LEC中的伽马功率也会降低。这项研究的结果表明，在AD早期阶段，从LEC到海马体的嗅觉输入时间可能会受到影响，从而可能导致两条输入通路传递至海马体亚区的信息错误整合。
