Burns L L, Marczynski T J
Brain Res. 1982 Mar 4;235(1):51-64. doi: 10.1016/0006-8993(82)90195-0.
In unrestrained cats, temporal patterns of single neuronal firing in the centrum medianum-parafascicular complex (CM-Pf) of thalamus were studied during a state of motionless quiet wakefulness. The spike trains from each neuron were electronically divided into episodes that occurred during desynchronized EEG and those that occurred during bursts of 6-14 Hz EEG spindles or alpha-like activity over the parieto-occipital cortex and in the CM-Pf. Contrary to expectations based on the theory of inhibitory phasing of neuronal activity, the episodes of synchronized quiet wakefulness (S-QW) were associated with independent and random distribution of spike intervals, although they tended to occur in clusters. During episodes of desynchronized quiet wakefulness (D-QW), significant temporal patterns were emitted by most neurons studied. The results suggest that: (a) during D-QW and increased levels of vigilance, temporal patterns are generated by cognitive processes and enhanced specific connectivities between CM-Pf neurons and other systems; (b) if connectivity is defined as increased certainty of synaptic transmission and iterative activation of the same pathways, then the assumption that the gross EEG thalamo-cortical synchronization represents increased connectivities between the CM-Pf neurons and other systems, may be erroneous; and (c) since temporal patterns of single neuronal discharges are determined by specific spatio-temporal distribution of synaptic drive, therefore during EEG spindles, most EPSP-IPSP sequences impinging upon CM-Pf neurons are conveyed by randomly varying polysynaptic pathways and have random spatio-temporal distribution on the soma and dendrites. In light of other observations, such a process is equivalent to an active introduction of uncertainty or 'entropy' into the information processing system, a state which may be important in preserving plasticity of operational modes of CM-Pf neurons and those with which they directly and/or indirectly interact.
在未受约束的猫中，研究了丘脑中央中核-束旁复合体（CM-Pf）在静止安静觉醒状态下单个神经元放电的时间模式。每个神经元的脉冲序列通过电子方式分为在脑电图去同步化期间出现的发作期，以及在顶枕叶皮层和CM-Pf中出现6-14赫兹脑电图纺锤波或类α活动爆发期间出现的发作期。与基于神经元活动抑制相位理论的预期相反，同步安静觉醒（S-QW）发作期与脉冲间隔的独立随机分布相关，尽管它们倾向于成簇出现。在去同步安静觉醒（D-QW）发作期，大多数被研究的神经元发出了显著的时间模式。结果表明：（a）在D-QW和警觉水平提高期间，时间模式由认知过程以及CM-Pf神经元与其他系统之间增强的特定连接性产生；（b）如果连接性被定义为突触传递确定性的增加和相同通路的反复激活，那么认为脑电图丘脑-皮层同步化总体代表CM-Pf神经元与其他系统之间连接性增加的假设可能是错误的；（c）由于单个神经元放电的时间模式由突触驱动的特定时空分布决定，因此在脑电图纺锤波期间，大多数作用于CM-Pf神经元的兴奋性突触后电位-抑制性突触后电位序列通过随机变化的多突触通路传递，并且在胞体和树突上具有随机的时空分布。根据其他观察结果，这样一个过程相当于在信息处理系统中主动引入不确定性或“熵”，这种状态对于保持CM-Pf神经元及其直接和/或间接相互作用的神经元的操作模式的可塑性可能很重要。
