García-Cabezas Miguel Á, Barbas Helen
Brain Struct Funct. 2014 Sep;219(5):1735-54. doi: 10.1007/s00429-013-0598-3.
Behavioral and functional studies in humans suggest that attention plays a key role in activating the primary olfactory cortex through an unknown circuit mechanism. We report that a novel pathway from the anterior cingulate cortex, an area which has a key role in attention, projects directly to the primary olfactory cortex in rhesus monkeys, innervating mostly the anterior olfactory nucleus. Axons from the anterior cingulate cortex formed synapses mostly with spines of putative excitatory pyramidal neurons and with a small proportion of a neurochemical class of inhibitory neurons that are thought to have disinhibitory effect on excitatory neurons. This novel pathway from the anterior cingulate is poised to exert a powerful excitatory effect on the anterior olfactory nucleus, which is a critical hub for odorant processing via extensive bilateral connections with primary olfactory cortices and the olfactory bulb. Acting on the anterior olfactory nucleus, the anterior cingulate may activate the entire primary olfactory cortex to mediate the process of rapid attention to olfactory stimuli.
人类的行为和功能研究表明，注意力通过一种未知的神经回路机制在激活初级嗅觉皮层中起关键作用。我们报告称，来自前扣带回皮层（在注意力方面起关键作用的一个区域）的一条新通路直接投射到恒河猴的初级嗅觉皮层，主要支配前嗅核。来自前扣带回皮层的轴突主要与假定的兴奋性锥体神经元的棘突以及一小部分被认为对兴奋性神经元具有去抑制作用的神经化学类抑制性神经元形成突触。这条从前扣带回发出的新通路有望对前嗅核产生强大的兴奋性作用，前嗅核是通过与初级嗅觉皮层和嗅球广泛的双侧连接进行气味处理的关键枢纽。作用于前嗅核，前扣带回可能激活整个初级嗅觉皮层，以介导对嗅觉刺激的快速注意力过程。
