Mankin Emily A, Diehl Geoffrey W, Sparks Fraser T, Leutgeb Stefan, Leutgeb Jill K
Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada.
Neuron. 2015 Jan 7;85(1):190-201. doi: 10.1016/j.neuron.2014.12.001.
The hippocampal CA2 subregion has a different anatomical connectivity pattern within the entorhino-hippocampal circuit than either the CA1 or CA3 subregion. Yet major differences in the neuronal activity patterns of CA2 compared with the other CA subregions have not been reported. We show that standard spatial and temporal firing patterns of individual hippocampal principal neurons in behaving rats, such as place fields, theta modulation, and phase precession, are also present in CA2, but that the CA2 subregion differs substantially from the other CA subregions in its population coding. CA2 ensembles do not show a persistent code for space or for differences in context. Rather, CA2 activity patterns become progressively dissimilar over time periods of hours to days. The weak coding for a particular context is consistent with recent behavioral evidence that CA2 circuits preferentially support social, emotional, and temporal rather than spatial aspects of memory.
海马体CA2亚区在内嗅-海马回路中具有与CA1或CA3亚区不同的解剖学连接模式。然而，与其他CA亚区相比，CA2神经元活动模式的主要差异尚未见报道。我们发现，行为大鼠单个海马体主神经元的标准空间和时间放电模式，如位置野、θ调制和相位进动，在CA2中也存在，但CA2亚区在群体编码方面与其他CA亚区有很大不同。CA2神经元集群并未显示出对空间或情境差异的持续编码。相反，CA2活动模式在数小时至数天的时间段内会逐渐变得不同。对特定情境的弱编码与最近的行为证据一致，即CA2回路优先支持记忆的社交、情感和时间方面而非空间方面。
