| Summary: | This thesis presents a new three-dimensional atlas for analyzing the neuroanatomical structures of the avian brain. Using magnetic resonance imaging (MRI) and X-ray computed tomography (CT), the brain of an Anna’s Hummingbird (Calypte anna) was scanned. These datasets were co-registered using three-dimensional visualisation software and overlaid with thionin stained slices in the sagittal and coronal view. Results show that previously developed techniques for creating three-dimensional atlases in other birds can be successfully used for representing the anatomical structures of hummingbirds (Güntürkün et al., 2013; Poirier et al., 2008; Vellema et al., 2011). There is no previous atlas, neither two nor three-dimensional, available for hummingbirds or any other wild-caught bird. Studies requiring avian neural recordings have not included hummingbirds, but this combination of imaging protocols along with descriptions from the literature provides the necessary and sufficient information for outlining many of the major functional structures in the Anna’s hummingbird brain. The co-registered datasets are also sufficient for constructing histological data into a three-dimensional representation that is functional in guiding classical tract tracing and electrophysiology experiments. By creating brain area delineations in three dimensions and anchoring these data to a skull, researchers will now be able to reach target structures from outside of the brain. For two regions of the brain, the lentiformis mesencephali and nucleus of the basal optic route, suggested stereotaxic coordinates and angles are provided. Through expanding the collection of atlases to include hummingbirds we introduce a new animal that will be especially useful for future studies of avian motor control.
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