Postdoc Spotlight: Shedding Light on Cavefish Behavior

Growing up Robert Andrew Kozol, Ph.D., spent his childhood catching frogs and snakes in the ponds and lakes of Michigan.

"I was always one of those kids that loved going to the aquarium, more-so than the zoo," Kozol said.

That curiosity for nature never left him, and now he's leading a research study on Mexican cavefish as a postdoctoral fellow in the Harriet L. Wilkes Honors College, to uncover how these unique creatures can shed light on human health, such as sensory motor issues or autism spectrum disorder (ASD).

"At an early age I realized I would likely pursue science," Kozol said. "Research experiences have provided me with the feeling of childlike curiosity that I am passing down to my kids. My daughter is now developing a passion for fish."

As an undergraduate at the University of Rhode Island, Kozol thought he wanted to be a deep-sea fish biologist. "It was interesting learning about the deep-sea fish, specifically in the Mariana Trench, and what it takes for them to live in that environment," said Kozol, adding that later became engrossed in behavioral neuroscience when he worked as a research associate in Miami, creating ASD gene models from examining zebrafish. Kozol decided to continue his work on zebrafish and earned a doctorate degree in behavioral neuroscience at the University of Miami, studying how gene variants related to ASD cause difficulty with sensory processing.

In 2018, he began his current position at FAU as a postdoctoral fellow, where he pitched a project on the investigation of the evolution of phototaxis, the behavior of being drawn to light, in cavefish. "I was looking to use an animal model that can probe questions regarding the evolution of complex behaviors," Kozol said. "Fortunately, FAU has a cavefish research hub with an evolutionary focus on how the environment influences genes to modify sensorimotor circuits and behaviors."

Kozol is interested in studying cavefish and surface fish because they are the same species of fish each having their own unique genetic variation. Both cavefish and surface fish can restructure its own sensorimotor systems in response to its environment. Kozol analyzes the differences in the fish's genetics to investigate how its variations impact its sensorimotor systems. "As a neuroscientist, I am interested in the role that genetics plays in sensorimotor development and function," Kozol said. "Many developmental disorders [in humans] coincide with sensorimotor deficits that impair quality of life, but our understanding of the development and function of sensory systems remains poorly understood." By understanding how cavefish genes helps sensorimotor systems, this research can help humans who have developmental disabilities.

Even though cavefish and surface fish are the same species of fish, they have entirely different living circumstances. The key difference is that cavefish have no eyesight, due to living in pitch black waters, and sleep, fight and stress less than surface fish. "The cavefish brain is quite small, so we test them when they are about a week old, to image their brain to look at 100,000 to 150,000 neurons, which is less complicated to study than a mammalian model like mice." Kozol explains that the process of studying the brain starts with staining the brain's proteins with an antibody so he can observe changes in the neurons. "The goal is to map the brain-wide activity [in cavefish], a few minutes after a stimulus."

Through such brain scans, Kozol said, he was able to see the subtle differences in neurons between the two relatives of fish and can pin-point the parts of the brain that control the behavior of the fish being drawn to light sources. This helps him to better understand the development of the fish's sensory systems in its genes and how they are similar to humans.

"It is that natural genetic variation that explains difference in brain function and behavior, which makes this model so powerful in investigating how genes impact sensorimotor system development and function," Kozol said.