Kang Y, Endo K, Araki T, Mitani A
Exp Brain Res. 1986;62(2):281-92. doi: 10.1007/BF00238847.
The cortico-cortical projection from area 5 to area 4 gamma was studied in anesthetized cats. Intracortical microstimulation of area 5 produced EPSPs in pyramidal tract (PT) cells in area 4 gamma. Such EPSPs were analysed in a total of 54 fast PT cells. The rising phase of these EPSPs was often composed of fast and slow components. Fast-rising EPSPs (fast component) were produced predominantly by stimulation within layer III of area 5 while slow-rising EPSPs (slow component) were evoked predominantly by stimulation within layer V of area 5. The amplitudes of the fast and slow components of EPSPs produced during repetitive stimulation within layers III and V of area 5 decreased and increased, respectively, with an increase in the stimulus frequency without any appreciable changes in their latency and time-to-peak. The slow component was much less influenced by membrane hyperpolarization than the fast component. Retrogradely labeled neurons were found not only in layer III but also in layer V of area 5 following HRP injection centered on superficial layers (I-III) of area 4 gamma. It is suggested that there are two groups of cortico-cortical neurons in layers III and V of area 5, which may make monosynaptic contact with the proximal and distal sites of fast PT cells in area 4 gamma, respectively.
在麻醉猫中研究了从5区到4γ区的皮质-皮质投射。对5区进行皮质内微刺激可在4γ区的锥体束（PT）细胞中产生兴奋性突触后电位（EPSP）。在总共54个快速PT细胞中对这种EPSP进行了分析。这些EPSP的上升相通常由快速和慢速成分组成。快速上升的EPSP（快速成分）主要由5区III层内的刺激产生，而慢速上升的EPSP（慢速成分）主要由5区V层内的刺激诱发。在5区III层和V层内重复刺激期间产生的EPSP的快速和慢速成分的幅度分别随着刺激频率的增加而降低和增加，而其潜伏期和峰值时间没有任何明显变化。慢速成分比快速成分受膜超极化的影响小得多。在以4γ区浅层（I-III）为中心注射辣根过氧化物酶（HRP）后，不仅在5区III层而且在5区V层发现了逆行标记的神经元。提示5区III层和V层存在两组皮质-皮质神经元，它们可能分别与4γ区快速PT细胞的近端和远端位点形成单突触联系。
