Abstract
A major goal in neuroscience is to understand how nervous systems generate and coordinate behaviors. Consider walking; even though walking may look similar from individual to individual, the connections between the cells in the nervous systems of those individuals will be different. These differences produce what we call “variability,” for example, in gait and or rhythm of walking. The sources of variability are primarily due to genetic factors between individuals (i.e., two individuals having different genetic makeups) or differences in gene expression within individuals (e.g., channel densities within a class of neurons in the brain.) Although variability has been shown to contribute to behaviors, the role that variability plays in the production of behaviors has not been determined, owing to the complexity of the nervous system. My project objective is to produce a grant proposal that will address this issue. I will use the medicinal leech, Hirudo sp., to explore variability in the properties of neurons. The medicinal leech is ideal for this study because behaviors can be studied from sensory input to motor output, and the cells are large, have distinct electrical properties, and occupy stereotyped locations within the nervous system so that they can be identified between individuals and within individuals. I will catalogue variability in intrinsic properties and then characterize this variability as being "within animals" and "between animals." I expect that between animal variability will be greater than within animal variability. I plan to submit this grant to the National Institute of Health (NIH) Small Research Grant Program. I have conducted a thorough literature review in vertebrates and invertebrates. I have matched this information with some preliminary data that I collected. The literature review is nearly complete and now my main focus will be analyzing my preliminary data. For this project, I have generated a measure of the standard input to two cells that contribute to the production of several behaviors in the leech. I identified several parameters for this standard input and measured variability for these parameters between and within animals. I will then use a repeated measures ANOVAs to assess the amount of within animal variability and coefficient of variation to assess variability between animals. This will serve as preliminary data for the grant proposal.