Quantification and Structure of Mitochondria in Spiking Neurons of the Simplex Skate Retina
Danica Damaso
Department of Biology
Faculty Supervisor: Ivan A. Anastassov
The benthic cartilaginous fish Leucoraja erinacea (Little Skate) has a unique “simplex” retina consisting of rod photoreceptor cells that can function under both photopic and scotopic conditions. This differs from usual vertebrate species, which have duplex retinas consisting of rod and cone photoreceptors that adapt to scotopic and photopic light, respectively. Skate photoreceptors are found mainly within the retina’s outer layer, where they respond to stimuli with graded potentials, while spiking neurons are found in the inner retina, where they synthesize photoreceptor information in the form of spike coding. The focus of this study is the quantification of organelles in ganglion cells, one of only two spiking cells in the retina, using segmentation of serial section electron microscopy data. 3D reconstructions of mitochondria in ganglion cells were generated using PyReconstruct software. Quantifications, like mitochondrial surface area and volume, allow for comparisons among mitochondrial populations using measures like complexity indices. Here, we aim to understand the anatomical diversity of organelle structure between cells types, and determine if mitochondrial complexity reveals aspects of functional diversity in spiking neurons. We aim to catalog existing structure-function connections, and if they explain functionality under the full range of environmental lighting conditions in skate.