Collins D R, Lang E J, Paré D
Département de Physiologie, Faculté de Médecine, Université Laval, Québec, Canada.
Neuroscience. 1999;89(4):1025-39. doi: 10.1016/s0306-4522(98)00396-0.
The perirhinal cortex lies at the interface between the neocortex and allocortex. Whether the perirhinal cortex expresses spontaneous electroencephalographic rhythms that are characteristic of the allocortex and/or of the neocortex is unknown. Thus, the present investigation was undertaken to characterize the activity of the perirhinal cortex with respect to various electroencephalographic rhythms that are displayed by neocortical areas or the entorhino-hippocampal system during different behavioral states of vigilance in chronically-implanted cats. Although perirhinal and neocortical electroencephalograms underwent similar state-dependent changes in amplitude, the ubiquitous neocortical sleep spindles were absent from the perirhinal cortex. In addition, while the slow sleep oscillation (0.5-1 Hz), which is pervasive in the neocortex, was present in the perirhinal cortex, its temporal relation to the neocortical oscillation was highly variable. In contrast, a high degree of correlation was found between perirhinal and entorhinal electroencephalographic activities in all behavioral states. In particular, during waking and paradoxical sleep, multiple simultaneously recorded entorhinal and perirhinal sites displayed an oscillation in the theta range which was highly correlated. To rule out the possibility that the perirhinal theta oscillation reflected volume conduction from neighboring structures, single-unit recordings were performed. Spike-triggered averages and peri-event histograms revealed that perirhinal cells displayed a statistically significant theta-related modulation of their spontaneous activity, albeit weaker than that observed in the entorhinal cortex. Thus, from the standpoint of spontaneous electroencephalographic rhythms, the perirhinal cortex is more closely related to the entorhino-hippocampal system than to the neocortex.
嗅周皮质位于新皮质和旧皮质之间的界面处。嗅周皮质是否表达具有旧皮质和/或新皮质特征的自发脑电图节律尚不清楚。因此，本研究旨在描述嗅周皮质在慢性植入猫的不同警觉行为状态下，相对于新皮质区域或内嗅-海马系统所显示的各种脑电图节律的活动情况。尽管嗅周皮质和新皮质脑电图在幅度上经历了类似的状态依赖性变化，但嗅周皮质中没有普遍存在的新皮质睡眠纺锤波。此外，虽然在新皮质中普遍存在的慢睡眠振荡（0.5-1赫兹）在嗅周皮质中也存在，但其与新皮质振荡的时间关系高度可变。相比之下，在所有行为状态下，嗅周皮质和内嗅皮质的脑电图活动之间都发现了高度相关性。特别是在清醒和异相睡眠期间，多个同时记录的内嗅皮质和嗅周皮质部位显示出在θ范围内的振荡，且高度相关。为了排除嗅周皮质θ振荡反映来自相邻结构的容积传导的可能性，进行了单单位记录。触发尖峰平均和事件周围直方图显示，嗅周皮质细胞的自发活动显示出与θ相关的统计学显著调制，尽管比在内嗅皮质中观察到的要弱。因此，从自发脑电图节律的角度来看，嗅周皮质与内嗅-海马系统的关系比与新皮质的关系更为密切。
