Direct visualization of the perforant pathway in the human brain with ex vivo diffusion tensor imaging Citation

Citation Augustinack Jean C., et al. "Direct visualization of the perforant pathway in the human brain with ex vivo diffusion tensor imaging." Front. Hum. Neurosci. 4:42. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. In the AD brain, incoming afferents lose their connections to the hippocampal formation and it is well known that mesocortical areas become disconnected from the hippocampus and the perforant pathway is destroyed in early AD (Hyman et al., 1986; Hyman et al., 1988; Salat et al., 2008). Thus, perforant pathway plays a crucial role in AD. More specific evaluation of structures, such as the perforant pathway, in the medial temporal lobe at high resolution using ex vivo methods could ultimately provide methods to evaluate AD in vivo imaging. Before that is possible, better characterization of perforant pathway in control brain at high resolution is necessary to establish a baseline for non-diseased brains. In a healthy brain, incoming sensory information from visual, auditory, somatic association cortices converges in the mesocortical regions (Jones and Powell, 1970; Van Hoesen et al., 1972) and then sends a massive projection to the dentate gyrus granule cells and hip-pocampal pyramidal neurons via the perforant pathway or tempo-for memory consolidation. Thus, the perforant pathway begins in entorhinal layer II and superficial layer III. It ascends upward through the angular bundle and perforates the presubiculum, subiculum and subsequently hippocampal sulcus throughout the anterior–posterior extent of the entorhinal cortex (EC). This temporoammonic pathway predominantly terminates on the outer two-thirds of the molecular layer of the dentate gyrus. The EC has additional, albeit lesser, effer-ents: the temporoalvear and crossed temporoammonic pathways. In this paper, we begin by outlining a few issues that affect the quality of ex vivo imaging, such as fixation, gadolinium enhancement , iron content, or lack thereof, in tissue. We present high