Neuronal mechanisms controlling the spatial attention and gaze movements

中脑臂旁区、脚-桥被盖核（PPTN）和背侧被盖核（LDTN）是胆碱能投射的主要来源。它们被定向到几个脑区，包括丘脑的外侧膝状体核（LGN）、上级丘（SC）、黑质的多巴胺神经元和脑桥延髓网状结构。最近的研究表明，PPTN胆碱能神经元有助于控制门控运动和注意行为。为了进一步阐明脑干胆碱能系统的功能，我们分析了PPTN神经元的单单位活动在三个清醒的日本猴子，而他们正在执行视觉引导GAP/NO-GAP扫视任务。约64%（45/70）的测试神经元表现出阶段性的变化，在他们的扫视到目标：26个细胞的活动增加（爆发型细胞），和19个减少（暂停型细胞）。除了它们的前行为外，差距期间，爆发神经元倾向于显示活动增加，而暂停细胞减少（即。例如，在注视点的偏移和扫视目标的开始之间的200-ms空白期）。这些结果表明，PPTN神经元参与了扫视目标的准备。此外，7个神经元表现出紧张性的增加，他们的活动，从intertrial间隔（奖励之间的时间在前一次试验和发作的注视点在随后的试验），直到结束的扫视。此外，29个神经元有一个紧张，和5个阶段，增加活动时，固定点第一次出现。后一种行为与即将到来的扫视目标的成功完成密切相关，从而表明这些神经元有助于控制动物的警惕性。

A substantial number of cholinergic projections originate from the parabrachial region in the midbrain the pedunculo-pontine tegmental nucleus(PPTN), and the latero-dorsal tegmental nucleus(LDTN). They are directed to several brain regions, icluding the lateral geniculate nusleus(LGN) of the thalamus, the superior colliculus(SC), dopamine neurons in substantia nigra, and the ponto-medullary reticular formation. Recent studies have suggested that the PPTN cholinergic neurons help control gating movements and attentive behaviors. To further clarify the function of the brainstem cholinergic system, we analyzed the single-unit activity of PPTN neurons in three awake Japanese monkeys while they were performing visually guided GAP/NO-GAP saccade tasks. About 64% (45/70) of the tested neurons exhibited a phasic change in their activity, which preceded their saccade-to-target : 26 cells had an increase in activity (burst-type cells), and 19 a decrease (pause-type cells). In addition to their presaccadic behavior, the burst neurons tended to show an increase in activity, and the pause cells a decrease, during the GAP period(i. e., the 200-ms blank period between the offset of the fixation point and onset of the saccade target). These results suggested that PPTN neurons are involved in the preparation for a saccade-to-target. Additionally, 7 neurons exhibited a tonic increase in their activity from the intertrial interval (the time between the reward in the preceding trial and onset of the fixation point in the succeeding trial) until the end of the saccade. Furthermore, 29 neurons had a tonic, and 5 a phasic, increase in activity when the fixation point first appeared. This latter behavior was closely correlated with the successful completion of the upcoming saccade-to-target, thereby suggesting that such neurons contribute to control of the animals' vigilance.