Ito K, McCarley R W
Brain Res. 1987 Apr 14;409(1):97-110. doi: 10.1016/0006-8993(87)90745-1.
The connectivity between medial pontine reticular formation (mPRF) and bulbar reticular formation (BRF) was studied by intracellular recordings of mPRF neuronal responses to microstimulation of BRF in unanesthetized, undrugged cats. There was a very high percentage (75-90%) of monosynaptic latency postsynaptic potentials (PSPs) in mPRF neurons in response to microstimulation of 3 BRF areas: the magnocellular tegmental field (FTM), the bulbar gigantocellular tegmental field (BFTG), and bulbar lateral tegmental field (BFTL). The type of initial orthodromic response produced in mPRF neurons by BRF stimulation was predominantly (75-95%) a monosynaptic excitatory PSP (EPSP) which was characterized by a rapid rise time, a nearly constant latency, and often led to spike potential generation. In contrast, the percentage of initial monosynaptic inhibitory PSPs (IPSPs) was much lower for FTM (12.3%), for BFTG (12.5%) and was zero for BFTL. While microstimulation techniques alone cannot differentiate between excitation of fibers of passage and neuronal somata, the very high percentage of initial EPSPs in our data and the anatomical evidence for dense BRF to mPRF neuronal projections as compared with less dense projections from fibers passing through BRF to mPRF suggest that excitatory BRF-mPRF connections are predominant. The high degree of connectivity between BRF and mPRF may furnish an important substrate for functional interaction. Comparison of the mPRF neuronal population that was not antidromically activated by FTM microstimulation vs the mPRF neuronal population that was antidromically activated from FTM and also studied for orthodromic responsiveness showed no statistically significant differences between these populations on the parameters of percentage of monosynaptic input, monosynaptic initial EPSPs, monosynaptic initial IPSPs and presence of a PSP with a latency of less than 5 ms. For BRF connectivity this suggests an identity of mPRF input and output neurons with respect to synaptic response properties.
通过在未麻醉、未用药的猫身上对脑桥内侧网状结构（mPRF）神经元对延髓网状结构（BRF）微刺激的反应进行细胞内记录，研究了mPRF与BRF之间的连接性。在mPRF神经元中，对BRF的3个区域进行微刺激时，即大细胞被盖区（FTM）、延髓巨细胞被盖区（BFTG）和延髓外侧被盖区（BFTL），有非常高比例（75 - 90%）的单突触潜伏期突触后电位（PSP）。BRF刺激在mPRF神经元中产生的初始顺向反应类型主要（75 - 95%）是单突触兴奋性PSP（EPSP），其特征为上升时间快、潜伏期几乎恒定，且常导致动作电位产生。相比之下，FTM的初始单突触抑制性PSP（IPSP）百分比要低得多（12.3%），BFTG为（12.5%），而BFTL则为零。虽然仅靠微刺激技术无法区分过路纤维的兴奋和神经元胞体的兴奋，但我们数据中初始EPSP的高比例以及BRF到mPRF神经元的密集投射的解剖学证据，与从BRF穿过到mPRF的纤维的较稀疏投射相比，表明兴奋性BRF - mPRF连接占主导。BRF与mPRF之间的高度连接性可能为功能相互作用提供重要基础。比较未被FTM微刺激逆向激活的mPRF神经元群体与被FTM逆向激活并同时研究顺向反应性的mPRF神经元群体，在单突触输入百分比、单突触初始EPSP、单突触初始IPSP以及潜伏期小于5毫秒的PSP存在情况等参数上，这些群体之间没有统计学上的显著差异。对于BRF连接性而言，这表明mPRF的输入和输出神经元在突触反应特性方面具有一致性。
