Karen P. Maruska - US grants

DESCRIPTION (provided by applicant): Neural plasticity enables the nervous system to adapt to environmental change. The objective of the proposed experiments is to understand the cellular and molecular control of neuronal plasticity using the gonadotropin releasing-hormone (GnRH1)-containing neurons in the hypothalamus as a model system. Knowledge of the mechanisms that regulate changes in individual neuron morphology and synapse formation is critically important for understanding normal function and plasticity in the adult vertebrate brain. However, little is known about the genetic regulation of structural neuronal changes and their functional consequences for neuron activity. To test hypotheses about how and how quickly the plasticity of GnRH1 neurons is regulated, the well-described teleost fish model Astatotilapia burtoni will be used. A. burtoni GnRH1 neurons are plastic over short time scales in adults, enlarging eight-fold and dramatically increasing their dendritic arbors when males switch from a subordinate (non-reproductive) to a dominant (reproductive) state. Two specific aims are proposed: 1) To measure the temporal sequence of structural gene activation responsible for environmentally-induced reversible GnRH1 neuronal plasticity. Laser capture of individual GnRH1 neurons followed by complementary microarray and candidate gene approaches will identify structural genes that regulate adaptive changes in GnRH1 neuron morphology. This set of experiments will reveal the molecular players implicated in neuronal plasticity and their time couse of activation. 2) To test the functional role(s) of a candidate molecule, target of rapamycin (TOR), in controlling plasticity and function of GnRH1 neurons. I will inhibit TOR protein function during times of maximal plastic change in GnRH1 neurons, and measure GnRH1 neuron functional output. These experiments will show whether TOR is required for GnRH1 plasticity in animals that are naturally induced to become reproductively competent, and whether specific structural changes are necessary for proper GnRH1 neuron function. These data will provide an understanding of the causal relationships between GnRH1 neuron morphology, structural gene activation, and functional output. Results will identify how neuronal plasticity is regulated and how it controls reproductive competence in vertebrates. Using the gene expression data, I will be able to develop an hypothesis of how structural genes interact to further our understanding of the inherent flexibility in individual neurons. PUBLIC HEALTH RELEVANCE: Understanding how neuronal plasticity is affected by the social environment, and what genes are involved in proper GnRH1 neuron morphology and function in vertebrates, will be valuable for developing therapies for neuroendocrine disorders, leading to overall improved public health.

This award supports a conference symposium entitled ?Sending and Receiving Signals: Endocrine Modulation of Social Communication? scheduled to occur in Washington D.C. at the annual meeting of the Society for Integrative and Comparative Biology (SICB). Animal communication is vital to survival, reproduction, and species persistence, but little is known about how an individual?s sensory and signaling abilities may change based on their internal hormonal state. This symposium brings together diverse experts working at the frontiers of research on this topic in various animals and sensory systems to disseminate cutting-edge research via presentations, promote discussion, and develop novel future research directions. The symposium will assess the current and future state of the field and explore the potential for evolutionary pressures to influence how animals communicate with each other in different behavioral contexts. Outcomes of these conference presentations will be disseminated broadly via publications, social media, and will represent seminal educational resources for students. The award will broaden participation by supporting and providing opportunities for underrepresented minorities and early career researchers to present their science and help direct the future of the research field. The collective outcomes also bear broad societal implications relevant to biodiversity and species? responses to global climate change, as well as professional development opportunities for the next generation of scientists.

This conference symposium will explore how sending and receiving sensory information in social contexts can be profoundly influenced by an individual?s reproductive and hormonal state. While this is particularly relevant in species that cycle in and out of breeding condition, many studies on animal communication at different biological levels do not consider potential modulatory influences on behaviors. This conference symposium will address this major knowledge gap through the integration of approaches from neuroscience, endocrinology, animal behavior, biomechanics, sensory ecology, and evolution. Such integration is not only critical to making substantive advances in this area, it is also timely. By making researchers in diverse fields aware of this modulatory influence on communication across different animal taxa, various sensory channels, and distinct social contexts, it will inspire new research directions and formulation of novel scientific questions and approaches to advance the field. Considering modulation in communication is critical to accurate interpretations of study conclusions, making this topic crucial for advancement of knowledge and development of future hypothesis testing. Insights gained from these presentations and discussions on sensory plasticity have the potential to fundamentally change current thinking about sensory function and animal communication and will allow researchers to address more focused comparative and evolutionary questions related to sexual selection, speciation, signaling systems, co-evolution, and physiological mechanisms in the future.

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.