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School of Biological and Behavioural Sciences

Eva Sheardown

PhD student



Project title: Imaging the neurobiology of numerosity- the evolution of counting

Summary: The project focuses on the characterization of the ontogeny of numerosity discrimination in wild type and mutant zebrafish. The goal is to identify the neural circuits and cell biology underlying the ability of zebrafish to assess number (numerosity) and in so doing, test the hypothesis that numerosity is evolutionarily conserved. We are using zebrafish as our model system as fish, though evolutionarily distant, have been shown to be able to assess numerosity, and the transparent nature of larval zebrafish makes them ideally suited for imaging studies. Behavioral analysis of wildtype zebrafish and zebrafish carrying mutations in genes predicted from human studies to affect numerosity will be used to identify lines of fish with differential abilities for use in imaging studies and to test the hypothesis that cognition of numerosity is evolutionarily conserved. Light sheet based imaging of larval and juvenile zebrafish will be used to identify the cells and neural circuits involved. Identification of ‘number neurons’ and the neural circuitry underlying numerosity in distantly related vertebrates such as zebrafish, and analysis of the impact of the disruption of homologues of genes associated with human numerical skills could provide a breakthrough in our understanding of the evolution of numerosity and provide insight into numerosity, maths and its disturbances in our own species. 



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