Hernández-Pérez J Jesús, Gutiérrez-Guzmán Blanca E, Olvera-Cortés María E
Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Morelia, Michoacán, Mexico; Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico.
Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Morelia, Michoacán, Mexico; Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico.
Neuroscience. 2016 Nov 19;337:224-241. doi: 10.1016/j.neuroscience.2016.09.003. Epub 2016 Sep 8.
The theta rhythm is necessary for hippocampal-dependent spatial learning. It has been proposed that each hippocampal stratum can generate a current theta dipole. Therefore, considering that each hippocampal circuit (CA1, CA3, and Dentate Gyrus (DG)) contributes differently to distinct aspects of a spatial memory, the theta oscillations on each stratum and their couplings may exhibit oscillatory dynamics associated with different stages of learning. To test this hypothesis, the theta oscillations from five hippocampal strata were recorded in the rat during different stages of learning in a Morris maze. The peak power, the relative power (RP) and the coherence between hippocampal strata were analyzed. The early acquisition stage of the Morris task was characterized by the predominance of slow frequency theta activity and high coupling between specific hippocampal strata at slow frequencies. However, on the last training day, the theta oscillations were faster in all hippocampal strata, with tighter coupling at fast frequencies between the CA3 pyramidal stratum and other strata. Our results suggest that modifications to the theta frequency and its coupling can be a means by which the hippocampus differentially operates during acquisition and retrieval states.
θ节律对于依赖海马体的空间学习是必要的。有人提出,海马体的每个层都可以产生一个当前的θ偶极子。因此,考虑到每个海马体回路(CA1、CA3和齿状回(DG))对空间记忆的不同方面有不同贡献,每个层上的θ振荡及其耦合可能表现出与学习不同阶段相关的振荡动力学。为了验证这一假设,在大鼠于莫里斯迷宫中学习的不同阶段记录了五个海马体层的θ振荡。分析了峰值功率、相对功率(RP)以及海马体各层之间的相干性。莫里斯任务的早期习得阶段的特征是低频θ活动占主导,且特定海马体层在低频时耦合度高。然而,在最后一个训练日,所有海马体层的θ振荡都更快,CA3锥体层与其他层在高频时耦合更紧密。我们的结果表明,θ频率及其耦合的改变可能是海马体在习得和检索状态下进行差异化运作的一种方式。