Furtak Sharon C, Wei Shau-Ming, Agster Kara L, Burwell Rebecca D
Department of Psychology, Brown University, Providence, RI 02912, USA.
Hippocampus. 2007;17(9):709-22. doi: 10.1002/hipo.20314.
The parahippocampal region in the rodent brain includes the perirhinal, postrhinal, and entorhinal cortices, the presubiculum, and the parasubiculum. In recent years, the perirhinal and postrhinal cortices have been a focus in memory research because they supply highly processed, polymodal sensory information to the hippocampus, both directly and via the entorhinal cortex. Available evidence indicates that these cortices receive different complements of cortical information, which are then forwarded to the hippocampus via parallel pathways. Here we have summarized the cortical, subcortical, and hippocampal connections of the perirhinal and postrhinal cortices in order to provide further insight into the nature of the information that is processed by these regions prior to arriving in the hippocampus. As has been previously described, the cortical afferents of the rodent postrhinal cortex are dominated by structures known to be involved in the processing of visual and spatial information, whereas the cortical afferents of the perirhinal cortex result in remarkable convergence of polymodal sensory information. The two regions are also differentiated by their cortical efferents. The perirhinal cortex projects more strongly to piriform, frontal, and insular regions, whereas the postrhinal cortex projects preferentially to visual and visuospatial regions. The subcortical connections of the two regions provide further evidence that they have different functions. For example, the perirhinal cortex has strong reciprocal connections with the amygdala, which suggest involvement in processing affective stimuli. Subcortical input to the postrhinal cortex is dominated by projections from dorsal thalamic structures, particularly the lateral posterior nucleus. Although the perirhinal and postrhinal cortices are considered to contribute to the episodic memory system, many questions remain about their particular roles. A detailed description of the anatomical connections of the perirhinal and postrhinal cortices will permit the generation of new, anatomically guided, hypotheses about their role in episodic memory and other cognitive processes.
啮齿动物大脑中的海马旁区域包括嗅周皮质、嗅后皮质、内嗅皮质、前下托和下托旁区。近年来，嗅周皮质和嗅后皮质一直是记忆研究的重点，因为它们直接或通过内嗅皮质向海马体提供经过高度处理的多模式感觉信息。现有证据表明，这些皮质接收不同的皮质信息补充，然后通过平行通路转发到海马体。在这里，我们总结了嗅周皮质和嗅后皮质的皮质、皮质下和海马体连接，以便进一步了解这些区域在到达海马体之前所处理信息的性质。如前所述，啮齿动物嗅后皮质的皮质传入神经主要由已知参与视觉和空间信息处理的结构主导，而嗅周皮质的皮质传入神经则导致多模式感觉信息的显著汇聚。这两个区域在皮质传出神经方面也有所不同。嗅周皮质向梨状皮质、额叶皮质和岛叶皮质投射更强，而嗅后皮质则优先向视觉和视觉空间区域投射。这两个区域的皮质下连接进一步证明它们具有不同的功能。例如，嗅周皮质与杏仁核有很强的相互连接，这表明其参与情感刺激的处理。嗅后皮质的皮质下输入主要由背侧丘脑结构，特别是外侧后核的投射主导。尽管嗅周皮质和嗅后皮质被认为对情景记忆系统有贡献，但关于它们的具体作用仍有许多问题。对嗅周皮质和嗅后皮质解剖连接的详细描述将有助于产生关于它们在情景记忆和其他认知过程中作用的新的、基于解剖学的假设。
