Neuronal Plasticity in the Olfactory Bulb of Mothers

.....................................................................................................................................7 Introduction .............................................................................................................................10 Preface: Plasticity in the Mammalian Brain .................................................................................10 The Transition into Motherhood – An Example of Naturally Occurring Plasticity ................................11 Organization and Connectivity of the Olfactory System ..................................................................13 The OB: Cell Types and Synapses ..............................................................................................14 1: GCs as a Junction of Inputs ...................................................................................................17 2: GCs Continuously Undergo Neurogenesis throughout Adulthood .................................................17 Objectives .................................................................................................................................21 Materials and Methods ...........................................................................................................23 Animals .................................................................................................................................23 Lentiviral Vectors ...................................................................................................................23 Stereotaxic Injection of Lentivirus into the Stem Cell Niche .............................................................24 Chronic Window Implantation over Both OBs ..............................................................................24 Tissue Processing and Histology ................................................................................................25 Two-Photon Imaging ...............................................................................................................25 Confocal Microscopy ...............................................................................................................27 Intrinsic-Signal Imaging ...........................................................................................................27 Loose patch recordings of GCs ..................................................................................................28 Processing and Concatenation of Imaged Slices ............................................................................29 Data Analyses ........................................................................................................................30 Statistics ...............................................................................................................................33 Results .....................................................................................................................................35 Chapter I: Granule Cell Activity is modified in Lactating Mothers Following Parturition .....................35 Chapter II: Faster Maturation and Enhanced Synaptic Integration of Adult-Born Neurons in the Olfactory Bulb of Lactating Mothers ...........................................................................................47 Chapter III: Three-Dimensional Distribution Patterns of Adult-Born Neurons in the Mouse Olfactory Bulb ........................................................................................................................59 Discussion ...............................................................................................................................66 The Temporal Activity of GCs is Modified in Mothers during both Spontaneous Conditions and Odor Presentation .................................................................................................................66 Possible Factors that Can Induce the Modified Activity of GCs in Mothers .........................................67 Odor Representations in the OB Might Change in Mothers Following Parturition ...............................68 Enhanced Integration of abGCs Can Result in an Increase in MC Inhibition in Mothers .......................70 Factors that Can Regulate the Enhanced Integration of Adult-Born Neurons in Mothers .......................72 Studying the Spatial Distribution of abGCs in Mothers ...................................................................73 References ...............................................................................................................................76 Hebrew Abstract ......................................................................................................................89