Bullock T H, Buzsáki G, McClune M C
Neurobiology Unit, School of Medicine, University of California, San Diego, La Jolla 92093.
Neuroscience. 1990;38(3):609-19. doi: 10.1016/0306-4522(90)90055-9.
The ongoing micro-electroencephalogram was recorded with a chronically implanted comb-like array of 16 tungsten semi-microelectrodes 0.2 or 0.25 mm apart, spanning CA1 strata oriens, pyramidale and radiatum and into subiculum, in four behavioral states: walking, standing still, paradoxical and slow wave sleep and under scopolamine. Power, phase and coherence spectra were computed, the latter two for each of the 120 pairs, in frequency bands from 1 to 64 Hz. (1) Coherence is high for all frequencies within the same subfield, e.g. stratum radiatum, but falls with distance. Theta frequency (8 Hz), when prominent and widespread (during "theta states" walking and paradoxical sleep), shows the most widespread synchrony: coherence falls slowly, from 1.0 at 0.2 mm to 0.7 at c. 2 mm longitudinally within stratum radiatum; all other frequencies fall two or three times faster. (2) An abrupt drop in coherence occurs across field borders (CA1-subiculum) and between stratum oriens and radiatum, across a line just under stratum pyramidale, between high coherence regions on each side of the coherence discontinuity. A less extreme drop occurs in stratum radiatum 0.4 mm from the subiculum border, without obvious histological correlate. The discontinuities in coherence are stable through all four behavioral states as well as under scopolamine. (3) Phase profiles diagonally across CA1 and into subiculum show abrupt, local shifts of phase (up to 125) at these same levels. No gradual shift reaching 180 (phase reversal) occurs in the span of loci examined. (4) The theta power peak in theta states is not necessarily due to additional energy in that band; in some conditions it is mainly due to reduced power in other frequencies. Root mean square voltage is generally less in the high theta ("synchronized") than in the non-theta states. Only the theta peak correlates with a peak in coherence. (5) Significant microstructure in the dynamics of neuronal cooperativity distinguishes behavioral states and regions of the hippocampal cortex.
使用一个长期植入的梳状阵列记录连续的脑电图，该阵列由16个钨半微电极组成，电极间距为0.2或0.25毫米，跨越CA1区的原层、锥体层和辐射层并进入下托，记录了四种行为状态下的脑电图：行走、静止站立、异相睡眠和慢波睡眠以及在东莨菪碱作用下的脑电图。计算了功率、相位和相干谱，后两者针对120对电极中的每一对，计算频段为1至64赫兹。（1）在同一子区域内，例如辐射层，所有频率的相干性都很高，但会随着距离下降。θ频率（8赫兹），当显著且广泛存在时（在“θ状态”行走和异相睡眠期间），显示出最广泛的同步性：相干性下降缓慢，在辐射层内纵向从0.2毫米处的1.0下降到约2毫米处的0.7；所有其他频率下降速度快两到三倍。（2）在区域边界（CA1 - 下托）以及原层和辐射层之间，在锥体层下方的一条线上，相干性会突然下降，在相干性不连续两侧的高相干区域之间。在距下托边界0.4毫米处的辐射层中出现较小幅度的下降，没有明显的组织学关联。相干性的不连续在所有四种行为状态以及东莨菪碱作用下都是稳定的。（3）对角穿过CA1并进入下托的相位剖面图显示，在这些相同水平上相位会突然发生局部偏移（高达125）。在所检查的位点范围内，没有出现逐渐偏移达到180（相位反转）的情况。（4）θ状态下的θ功率峰值不一定是由于该频段的额外能量；在某些情况下，它主要是由于其他频率的功率降低。高θ（“同步”）状态下的均方根电压通常比非θ状态下的低。只有θ峰值与相干性峰值相关。（5）神经元协同作用动力学中的显著微观结构区分了行为状态和海马皮层区域。
