Adult-generated cells are found in the dentate gyrus (DG) of the hippocampus and the subventricular zone (SVZ) of the rostral lateral ventricle in mammalian brains. Scientists have focused on these two brain areas to characterize the factors mediating adult neurogenesis, determine the phenotypes of the new cells, and reveal their potential functional significance. While new cells are also found in several other brain areas, little is known about the morphological characteristics, neurochemical phenotypes, and functions of these new cells. In this proposal, we focus on the amygdala - a brain area which is important for sensory processing, information integration, and the modulation of a variety of physiological and behavioral functions, and which contains adult-generated cells but has received little attention in the neurogenesis field. We will use the socially monogamous female prairie voles (Microtus ochrogaster) as our model system as the vole's amygdala contained adult-generated cells, their rates of proliferation were facilitated by social interactions and diminished by social isolation, and treatment of an antimitotic drug reduced new neurons in the amygdala and inhibited social attachment formation. Our working hypothesis is that social/chemosensory stimuli from a conspecific affect amygdala neurogenesis in a stimulus-, time- and area-specific manner, adult-generated amygdala neurons integrate into the existing neural circuitry, express certain neurochemical phenotypes, and play a functional role in mediating social behavior. To test this hypothesis, we will focus on the amygdala to (1) examine the role of chemosensory stimuli in cell proliferation, (2) reveal the critical period for such social/chemosensory experience to enhance cell survival, (3) determine the neuromorphological and neurochemical characteristics of these new cells, (4) and examine the role of new amygdala cells in social behavior. Data from this study will shed light into amygdala adult neurogenesis and provide a starting point for the investigation of the amygdala neurogenic potential to be used as treatment for neurodegenerative-related amygdala deficits.
Project Narrative Newly-generated cells in the adult mammalian brains (adult neurogenesis) have the potential to be used as treatment for neurodegenerative diseases. Here we propose to examine adult neurogenesis in the amygdala in the socially monogamous prairie voles to test the hypothesis that social environment affects adult neurogenesis in the amygdala, and newly-generated amygdaloid cells integrate into the neural circuitry and play a functional role in the regulation of social behaviors.
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