Plasticity In The Cns Of Blind Fish After Eye Regeneration

SummaryNeuronal reorganization is a critical step in the recovery of function, whether after injury or as in responseto disease. In our research training program, we will use a new animal model to address neuralreorganization in the visual circuit. The fish Astyanax mexicanus provides a particularly novel window intonetwork remodeling because it is extant in two readily available forms: a visual river-dwelling (surface fish)form and a cave-dwelling form (cavefish). It is closely related to zebrafish, and all techniques use in thiszebrafish can be used in Astyanax. Adult cavefish lack eyes and the corresponding visual neuralstructures are severely reduced. Eye development is nevertheless initiated during embryogenesis, butlater arrests with the lens undergoing programmed cell death and the rest of the eye degenerating andsinking into the orbit. However, it is possible to rescue the eye, and the corresponding visual circuits, bytransplanting an embryonic surface fish lens into a degenerating cavefish eye. We will use neuroanatomy,behavior and calcium imaging to measure the changes that occur in the brains of blind cavefishes afterdevelopmental manipulation. Our central hypothesis is that the developing optic tectum circuitry in thecavefish is robust and receptive to coherent visual information, so that homeostatic mechanisms will allowfor the emergence of visual codes. Our specific objective is to test the malleability of the optic tectumcircuitry in response to visual input during development. To accomplish this, we will train twoundergraduate students, one master's student and a PhD student as well as high school volunteers from acharter school in Newark, NJ.