Department of Health Sciences, and Program in Neuroscience, Boston University and School of Medicine, Boston, Massachusetts 02215, USA.
J Neurosci. 2010 Dec 1;30(48):16068-81. doi: 10.1523/JNEUROSCI.1773-10.2010.
Dorsolateral prefrontal areas 46 and 10 are involved in distinct aspects of cognition. Area 46 has a key role in working memory tasks, and frontopolar area 10 is recruited in complex multitask operations. Both areas are innervated by the anterior cingulate cortex (ACC), a region associated with emotions and memory but is also important for attentional control through unknown synaptic mechanisms. Here, we found that in rhesus monkeys (Macaca mulatta) most axon terminals labeled from tracers injected into ACC area 32 innervated spines of presumed excitatory neurons, but ∼20-30% formed mostly large synapses with dendritic shafts of presumed inhibitory neurons in the upper layers (I-IIIa) of dorsolateral areas 10, 46, and 9. Moreover, area 32 terminals targeted preferentially calbindin and, to a lesser extent, calretinin neurons, which are thought to be inhibitory neurons that modulate the gain of task-relevant activity during working memory tasks. Area 46 was distinguished as a recipient of more (by ∼40%) area 32 synapses on putative inhibitory neurons. Area 10 stood apart as recipient of significantly larger (by ∼40% in volume) area 32 terminals on spines of putative excitatory neurons. These synaptic specializations suggest that area 32 has complementary roles, potentially enhancing inhibition in area 46 and strengthening excitation in area 10, which may help direct attention to new tasks while temporarily holding in memory another task.
背外侧前额叶区域 46 和 10 参与了认知的不同方面。区域 46 在工作记忆任务中起着关键作用，而额极区域 10 则在复杂的多任务操作中被招募。这两个区域都由前扣带皮层（ACC）支配，ACC 与情绪和记忆有关，但它也通过未知的突触机制对注意力控制很重要。在这里，我们发现，在猕猴（Macaca mulatta）中，大多数从前扣带皮层区域 32 注射示踪剂标记的轴突末梢支配假定兴奋性神经元的棘突，但约 20-30%形成与背外侧区域 10、46 和 9 的上层（I-IIIa）中假定抑制性神经元的树突干形成主要是大的突触。此外，区域 32 的末梢优先靶向 calbindin，并且在较小程度上靶向 calretinin 神经元，这些神经元被认为是在工作记忆任务期间调节与任务相关的活动增益的抑制性神经元。区域 46 被区分出来，作为区域 32 对假定抑制性神经元的突触的接受者（增加约 40%）。区域 10 作为区域 32 对假定兴奋性神经元的棘突的突触接受者的差异明显更大（体积增加约 40%）。这些突触特化表明，区域 32 具有互补的作用，可能增强区域 46 的抑制作用，增强区域 10 的兴奋作用，这可能有助于在暂时记住另一项任务的同时，将注意力引导到新的任务上。
