Circuit Mechansims of Color Preference

University Of Miami, Coral Gables FL

Investigators

Abstract

Understanding human preference for colors remains an enduring challenge in psychophysics since the 1800’s. While some general principles have been proposed, underlying biology of color preference remains elusive due largely to the many confounding factors that affect human color preference and the technical challenges associated in addressing them. Using the simple fruit fly which has been used for over 100 years to address basic neurobiological questions, the PI has recently established a new paradigm to investigate fly response to color light. The results upended several prior dogma in the field and revealed for the first time that color light preference changes rhythmically with the time of day. This time-dependence highlights a previously unknown regulatory principle and suggests that a thorough understanding of color choice in animals must account for the daily variations. The proposal will take advantage of the powerful genetic tools available in the fruit fly to describe and characterize a neural circuit that controls these rhythmic changes in color preference. The hypothesized circuit combines light information with external temperature and output of the built-in clock network in the fly brain. Each of these systems---visual, thermosensory and endogenous clock---has considerable neurobiological overlap between flies and humans. Therefore, results from the project are anticipated to provide major conceptual advances towards understanding biological control of color preference in humans. Undergraduate and graduate trainees will be engaged in carrying out proposed experiments, in disseminating results through publications and scientific talks, and in helping the PI with educational activities involving local middle-school students. This project will leverage a novel multi-color paradigm to describe a circuit that integrates light, temperature and time inputs to adjust innate color preference in fruit flies. Flies given a choice of color-light illuminated areas, prefer green and dim in a time-of-day dependent manner. The preference relies on the eyes, the antenna, thermosensory channels and modulated by the brain’s circadian clock. These findings hypothesize a circuit that incorporates photic and circadian signals from photoreceptors with temperature signal from peripheral and internal thermometers. The combined signal flows through dorsolateral clock neurons before impinging on downstream circuits. Specifically, the project will utilize the Gal4/UAS system to separately identify a thermosensory circuit and a minimal subset of clock neurons needed for normal control of color preference. Studies will also leverage known neuropeptide signaling network to identify cells that function as a site for multisensory integration in color preference downstream of lateral neurons. Fast-acting neurotransmitters, like octopamine and serotonin, are known to mediate sensory inputs into the fly nervous system and this project will define neurotransmitter receptors that are critical for temperature and photic inputs into color preference. Through these studies, the project will lay the foundation for a circuit-level understanding of innate color preference. Scientific results from the project will be integrated into outreach activities that will promote STEM education among middle-school students. All activities will involve the PI with graduate and undergraduate trainees, who will together disseminate the findings through peer-reviewed publications and presentations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.