Claustrum of the short‐tailed fruit bat, Carollia perspicillata: Alignment of cellular orientation and functional connectivity. Issue 6 (1st June 2016)

• Record Type: Journal Article
• Authors: Orman, Rena; Kollmar, Richard; Stewart, Mark
• Is Part Of: Journal of comparative neurology. Volume 525:Issue 6(2017)
• Page Start: 1459
• Page End: 1474
• Publication Date: 2016-06-01
• Subjects: claustrum -- latexin -- excitatory synapse -- RRID AB_2571634 -- RRID AB_177621; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24036
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract : The claustrum is a gray‐matter structure that underlies neocortex and reciprocates connections with cortical and subcortical targets. In lower mammals, the claustrum is directly adjacent to neocortex, making the definition of claustral boundaries challenging. Latexin, an endogenous inhibitor of metallocarboxypeptidases, localizes to claustral cells, enabling a clear delineation of claustrum. Given its proportionately large claustrum, we hypothesized that the short‐tailed fruit bat, Carollia perspicillata, can be a useful model for claustral structure–function relations. We used latexin immunohistochemistry to identify claustral boundaries and intrinsic structure and multielectrode recordings from brain slices to explore intrinsic excitatory connectivity of the claustrum. Carollia's claustrum contains cells whose intrinsic connectivity and alignment permit the generation of spontaneous, synchronous population events and mirror their pattern of spread in disinhibited brain slices over millimeters. Carollia shows cellular alignment and spontaneous population‐activity spread along both horizontal and dorsoventral axes. Carollia claustrum possesses intrinsic excitatory connectivity sufficient to: 1) generate single, spontaneous, synchronized burst discharges, 2) support activity spread along axes where claustral cells are aligned, and 3), because of multiple axes for cell alignment, support activity spread along both rostrocaudal and dorsoventral axes. The smaller event sizes in bat claustrum compared with rat claustrum are consistent with events occurring in population subsets rather than the full claustral cell population. The overall size of claustrum, its pronounced vascularity, and its more complex intrinsic connectivity than rat suggest that the bat is an animal model for claustral structure and function that will permit unique access to claustrum's processing capabilities. J. Comp. Neurol. 525:1459–1474, 2017. © 2016 Wiley Periodicals, Inc. Abstract : We used latexin immunohistochemistry to delineate the claustrum in the brain of a microbat, Carollia perspicillata, as one of the first definitions of claustrum in bat brain. We found a directional organization of latexin‐positive cells in bat claustrum that mirrored the generation and spread of synchronous activity within disinhibited claustrum. The intrinsic organization of bat claustrum appears to support both rostro‐caudal and dorso‐ventral connectivity in different sets of claustral cells.