Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida 33431, USA.
J Comp Neurol. 2011 Dec 15;519(18):3766-801. doi: 10.1002/cne.22733.
The medial orbital (MO) and ventral orbital (VO) cortices are prominent divisions of the orbitomedial prefrontal cortex. To our knowledge, no previous report in the rat has comprehensively described the projections of MO and VO. By using the anterograde tracer Phaseolus vulgaris leucoagglutinin and the retrograde tracer Fluoro-Gold, we examined the efferent projections of MO and VO in the rat. Although MO and VO projections overlap, MO distributes more widely throughout the brain, particularly to limbic structures, than does VO. The main cortical targets of MO were the orbital, ventral medial prefrontal (mPFC), agranular insular, piriform, retrosplenial, and parahippocampal cortices. The main subcortical targets of MO were the medial striatum, olfactory tubercle, claustrum, nucleus accumbens, septum, substantia innominata, lateral preoptic area, and diagonal band nuclei of the basal forebrain; central, medial, cortical, and basal nuclei of amygdala; paratenial, mediodorsal, and reuniens nuclei of the thalamus; posterior, supramammillary, and lateral nuclei of the hypothalamus; and periaqueductal gray, ventral tegmental area, substantia nigra, dorsal and median raphe, laterodorsal tegmental, and incertus nuclei of the brainstem. By comparison, VO distributes to some of these same sites, notably to the striatum, but lacks projections to parts of limbic cortex, to nucleus accumbens, and to the amygdala. VO distributes much more strongly, however, than MO to the medial (frontal) agranular, anterior cingulate, sensorimotor, posterior parietal, lateral agranular retrosplenial, and temporal association cortices. The patterns of MO projections are similar to those of the mPFC, whereas the projections of VO overlap with those of the ventrolateral orbital cortex (VLO). This suggests that MO serves functions comparable to those of the mPFC, such as goal-directed behavior, and VO performs functions similar to VLO such as directed attention. MO/VO may also serve as a link between lateral orbital and medial prefrontal cortices.
眶内侧（MO）和眶腹侧（VO）皮质是眶额前皮质的显著分支。据我们所知，以前在大鼠中没有全面描述 MO 和 VO 的投射。通过使用顺行示踪剂 Phaseolus vulgaris leucoagglutinin 和逆行示踪剂 Fluoro-Gold，我们检查了大鼠 MO 和 VO 的传出投射。尽管 MO 和 VO 的投射有重叠，但 MO 的分布比 VO 更广泛，特别是在边缘结构中。MO 的主要皮质靶区为眶额、腹侧前扣带回皮质、颗粒下岛叶、梨状皮质、后隔区和海马旁回皮质。MO 的主要皮质下靶区为内侧纹状体、嗅结节、屏状核、伏隔核、隔核、无名质、外侧视前区和基底前脑的斜角带核；杏仁核的中央核、内侧核、皮质核和基底核；丘脑的背内侧核、中背侧核和 reunien 核；下丘脑的后核、乳突核和外侧核；以及中脑导水管周围灰质、腹侧被盖区、黑质、中缝背核、外侧背核和脑桥的未定核。相比之下，VO 分布于一些相同的部位，特别是纹状体，但缺乏对边缘皮质的某些部分、伏隔核和杏仁核的投射。然而，VO 比 MO 更强烈地分布于内侧（额）颗粒下、前扣带回、感觉运动、后顶叶、外侧颗粒下后隔区和颞叶联合皮质。MO 投射的模式与 mPFC 的相似，而 VO 的投射与外侧眶额皮质（VLO）的重叠。这表明 MO 具有类似于 mPFC 的功能，例如目标导向行为，而 VO 具有类似于 VLO 的功能，例如定向注意。MO/VO 也可能作为外侧眶额和内侧前额皮质之间的联系。
