1. The Effects of Choline Supplementation and Brain-Derived Neurotrophic Factor (BDNF) on Hippocampal Volume Changes as a Measurement of Depression Leigh P. Mathieu 1 & Melissa J. Glenn 2 1 Department of Biology; 2 Department of Psychology Colby College, Waterville, Maine 04901 Introduction Research Questions ReferencesAcknowledgments Experimental DesignResults Hypotheses Genetic Manipulation BDNF +/- vs. Wildtype Prenatal Diet Choline supplemented vs. Standard- fed BirthControl Diet Adult behavioral testing Sacrifice Current Direction Brain slicing Mounting and staining Micro- scope analysis Hippocampus Dentate gyrus I would like to thank Amanda Kimball, the research technician of Glenn Behavioral Neuroscience Lab and funding from Maine INBRE. 1) Are there changes in hippocampus volume that result from BDNF knockdown? [1] Glenn, M.J., Abrams, R.S., & Mcclurg, L. (2012). Supplementary choline during development exerts antidepressent-like effects in adult female rats. Brain Research. 1443, 52-63. [2] Laurent, R.S., Helm, S.R. & Glenn, M.J. (2013). Reduced cocaine=seeking behavior in heterozygous BDNF knockout rats. Neuroscience Letters, 544, 94-99. [3] L. Lu, J. Dempsey, S.Y. Liu, J.M. Bossert, Y. Shaham, A single infusion of brain-derived neurotrophic factor into the ventral tegmental area induces long lasting potentiation of cocaine seeking after withdrawl, J. Neurosci. 24(2004) 1604-1611. 2) Does choline supplementation compensate for BDNF knockdown in hippocampus volume? Depression is the leading cause of disability in the United States  Affects one in six individuals in span of lifetime  Characteristic symptoms include lowered mood state, social withdrawal, cognitive defects, and feelings of worthlessness or guilt  Associated with decreased hippocampal volume  Develops from combination of environmental and biological factors  Depression linked with failure of adult hippocampal neurogenesis and neuroplasticity Brain-derived neurotrophic factor (BDNF) plays crucial role in formation and plasticity of neuronal networks, including neurogenesis, responsible in aspects of mood regulation and antidepressant- like effect  Low levels of BDNF can lead to depression  Genetic variants and mutations in neurotrophic genes affect how dopaminergic synapses in the reward pathway function Efforts to boost BDNF and neurogenesis found in food  Supplementation of essential nutrient Choline found to increase adult hippocampal neurogenesis and BDNF levels  We predict that BDNF knockout rats will have lower hippocampal volumes compared to wildtype rats  We predict that choline supplementation will increase BDNF levels in BDNF knockouts and increase hippocampal volume Animals: Wildtype females mated with heterozygous males missing one copy of BDNF gene to produce HET rats, compared with wildtype (WT) rats with two BDNF genes. Half of each group treated with standard diet, and half treated with choline diet Brain slicing: Every 4 th 60µm section of brains from all groups (WT/STD, WT/SUP, HET/STD, HET/SUP) sliced with vibratome sectioning coronal cuts Mounting: Sections mounted on gelatin-coated slides Staining: Cell bodies stained using cresyl violet, cover-slipped Microscope Analysis: Hippocampal volume will be assessed at 40x magnification  Area of hippocampus appraised in preliminary analysis Bb BBBBb BBBBb Genetic Manipulation BDNF Expected Results: smaller hippocampal area in standard HET rats; normal hippocampal area in supplemented HET rats Preliminary Analysis with one rat per group: hippocampus larger in supplemented HET rats We are currently examining and comparing hippocampal areas of rats belonging to the four groups. Given the finding that choline supplementation can restore neurogenesis and plasticity, we are hoping to find evidence that it will restore hippocampal size in BDNF knockout rats.