![hippocampus stereology hippocampus stereology](https://www.frontiersin.org/files/Articles/158767/fnagi-07-00196-HTML/image_m/fnagi-07-00196-g005.jpg)
On the venous side, vascularization begins with the intrahippocampal veins that drain into the superficial hippocampal veins.
![hippocampus stereology hippocampus stereology](https://i1.rgstatic.net/publication/7603880_Application_of_the_physical_disector_to_the_central_nervous_system_Estimation_of_the_total_number_of_neurons_in_subdivisions_of_the_rat_hippocampus/links/5a775747a6fdccbb3c098582/largepreview.png)
Some evidence suggests the stratum pyramidale (pyramidal cells layer) of the Amun’s horns (CA) regions of hippocampus contain the highest density of the microvessels. Arterial vascularization of the hippocampus emerges from the collateral branches of the posterior cerebral artery and the anterior choroidal artery, forming the network of superficial hippocampal arteries that branch into the deep intrahippocampal arteries with higher levels of vascularization in ventral as opposed to dorsal hippocampus. The vascular development and anatomy of the rat hippocampus show strong similarities to those in humans. Clinical studies and postmortem analysis suggest a significant interaction between Aβ deposition and microvascular pathology in a large majority (∼90%) of patients with confirmed AD. These microvascular changes appear closely associated with neuroinflammation caused by microglia activation and release of pro-inflammatory cytokines in response to the deposition of insoluble amyloid-β (Aβ) protein. Microvasculature disruptions in the brain parenchyma, especially in neocortical and hippocampal subregions, are part of the progressive neurodegeneration in brains of patients with Alzheimer’s disease (AD).