The entorhinal cortex of the Megachiroptera: A comparative study of Wahlberg's epauletted fruit bat and the straw-coloured fruit bat

Institute of Anatomy, University of Zurich, Zurich, Switzerland.
Brain Structure and Function (Impact Factor: 5.62). 05/2010; 214(4):375-93. DOI: 10.1007/s00429-010-0239-z
Source: PubMed


This study describes the organisation of the entorhinal cortex of the Megachiroptera, Strawcoloured fruit bat and Wahlberg’s epauletted fruit bat. Using Nissl and Timm stains, parvalbumin and SMI-32 immunohistochemistry, we identified 5 fields within the medial(MEA) and lateral (LEA) entorhinal areas. MEA fields ECL and EC are characterised by a poor differentiation between layers II and III, a distinct layer IV and broad, stratified layers V
and VI. LEA fields EI, ER and EL are distinguished by cell clusters in layer II, a clear differentiation between layers II and III, a wide columnar layer III, and a broad sublayer Va. Clustering in LEA layer II was more typical of the Straw-coloured fruit bat. Timm-staining was most intense in layers Ib and II across all fields, and layer III of field ER. Parvalbuminlike staining varied along a medio-lateral gradient with highest immunoreactivity in layers II and III of MEA and more lateral fields of LEA. Sparse SMI-32-like immunoreactivity was seen only in Wahlberg’s epauletted fruit bat. Of the neurons in MEA layer II, ovoid stellate cells account for ~38%, polygonal stellate cells for ~8%, pyramidal cells for ~18%, oblique
pyramidal cells for ~6%, and other neurons of variable morphology for ~29%. Differences between bats and other species in cellular make-up and cytoarchitecture of layer II may relate to their 3-dimensional habitat. Cytoarchitecture of layer V in conjunction with high
encephalisation and structural changes in the hippocampus suggest similarities in efferent hippocampal-entorhinal-cortical interactions between fruit bats and primates.

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    • "Twenty μm horizontal sections were cut and Giemsa-stained (Merck, Darmstadt, Germany) in 67 mmol KH2PO4 solution for 40 min at room temperature, differentiated in KH2PO4 for 90 s, dehydrated and cover-slipped. Mossy fiber terminals were Timm-stained following the procedure described before (Gatome et al., 2010). "
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