In Vivo Imaging of Experience-Dependent Plasticity in the Retrosplenial Cortex Following Unilateral Hippocampal Lesions

Thumbnail Image
Torry, Megan E.
University of Lethbridge. Faculty of Arts and Science
Journal Title
Journal ISSN
Volume Title
Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience
Mechanisms of learning and memory influence brain connectivity. Hippocampal outflow targets the ipsilateral retrosplenial cortex (RSC) and thus influences plasticity in the neocortex. Evidence from fixed tissue suggests that hippocampal lesions prevent the increase in dendritic spines due to an enrichment environment; however, may prevent observation of a larger effect on synaptic turnover across time. Longitudinal two-photon microscopy was used to compare specific ipsilateral and contralateral RSC locations in vivo, before and after enrichment. Consolidation theory predicts that in the absence of one hippocampus the ipsilateral RSC will undergo asymmetry in plasticity following enrichment exposure. In both hemispheres, synaptic turnover persists during home-cage housing with a slight transient increase following transfer to enrichment. There was greater axon growth and a lasting ~7% increase in spine density in the RSC ipsilateral to the lesion. Irregularities in transgenic mouse genetics, and particulars regarding the functionality between pre and post-synaptic elements remain enigmatic.
environmental enrichment , Axon boutons , Dendritic spines , In vivo imaging , Two photon microscopy