Alonso A, Khateb A, Fort P, Jones B E, Mühlethaler M
Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada.
Eur J Neurosci. 1996 Jan;8(1):169-82. doi: 10.1111/j.1460-9568.1996.tb01178.x.
Evidence has suggested that the nucleus basalis magnocellularis has the potential to influence the functional state of the cerebral cortex through topographically organized, widespread projections of the cholinergic cells in that nucleus. It has also been shown that, in addition to the cholinergic neurons, other non-cholinergic magnocellular basal forebrain neurons, some of which have been identified as gamma-aminobutyric acid-ergic, project into the cerebral cortex and thus may also participate in the modulation of its activity. We have performed a comparative study of the intrinsic rhythmic properties of immunohistochemically and morphologically characterized choline acetyltransferase (ChAT)-positive and ChAT-negative cells of the nucleus basalis by means of intracellular recordings in guinea pig brain slices. Our results demonstrate that relatively large, multipolar cholinergic and non-cholinergic neurons each display differential voltage-dependent properties that allow them to discharge rhythmically in spike bursts and spike clusters, respectively, at low frequencies (< 10 Hz). Cholinergic cells display bursts of 2-4 action potentials (at approximately 200 Hz) riding on low-threshold spikes recurring at a low frequency (< 5 Hz) when depolarized from a membrane potential more negative than -55 mV and display low-frequency (< 10-15 Hz) tonic firing when depolarized from a more positive level. In contrast, non-cholinergic cells fire in a unique mode, displaying non-adapting clusters of spikes interspersed with rhythmic subthreshold membrane-potential oscillations when depolarized from levels less negative than -55 mV. The spike clusters repeat rhythmically at relatively low frequencies (2-10 Hz). The intracluster spiking frequency is relatively high and coincides approximately with that of the intervening membrane-potential oscillations (approximately 20-70 Hz). The cluster frequency of the non-cholinergic cells corresponds, in the same manner as the burst frequency of the cholinergic cells, to a delta (1-4 Hz) or theta (4-10 Hz) range of activity, whereas the intra-cluster and tonic spike frequencies of the non-cholinergic cells correspond to high beta to gamma ranges of electroencephalographic activity (19-30 Hz and 30-60 Hz, respectively). We propose that the different modes of oscillatory firing by the cholinergic and non-cholinergic basal forebrain cell populations could collectively contribute to the rhythmic modulation of slow and fast rhythms within the cerebral cortex.
有证据表明，大细胞基底核有潜力通过该核中胆碱能细胞的拓扑组织化广泛投射来影响大脑皮层的功能状态。研究还表明，除了胆碱能神经元外，其他非胆碱能大细胞基底前脑神经元（其中一些已被确定为γ-氨基丁酸能神经元）也投射到大脑皮层，因此也可能参与其活动的调节。我们通过在豚鼠脑片上进行细胞内记录，对基底核中免疫组织化学和形态学特征化的胆碱乙酰转移酶（ChAT）阳性和ChAT阴性细胞的内在节律特性进行了比较研究。我们的结果表明，相对较大的多极胆碱能和非胆碱能神经元各自表现出不同的电压依赖性特性，使它们分别在低频（<10 Hz）下以尖峰爆发和尖峰簇的形式有节奏地放电。当从比 -55 mV更负的膜电位去极化时，胆碱能细胞会在低频（<5 Hz）重复出现的低阈值尖峰上出现2 - 4个动作电位的爆发（约200 Hz），而当从更正的水平去极化时，会出现低频（<10 - 15 Hz）的强直放电。相比之下，非胆碱能细胞以独特的模式放电，当从比 -55 mV更负的水平去极化时，会显示出不适应的尖峰簇，其间穿插有节律性的阈下膜电位振荡。尖峰簇以相对较低的频率（2 - 10 Hz）有节奏地重复。簇内尖峰频率相对较高，大约与其间的膜电位振荡频率（约20 - 70 Hz）一致。非胆碱能细胞的簇频率与胆碱能细胞的爆发频率一样，对应于δ（1 - 4 Hz）或θ（4 - 10 Hz）活动范围，而非胆碱能细胞的簇内和强直尖峰频率分别对应于脑电图活动的高β到γ范围（分别为19 - 30 Hz和30 - 60 Hz）。我们提出，胆碱能和非胆碱能基底前脑细胞群的不同振荡放电模式可能共同有助于大脑皮层内慢节律和快节律的节律性调节。
