The nature and role of structural changes underlying experience-dependent plasticity in visual cortex. (360G-Wellcome-078436_Z_05_Z)

The rewiring of synaptic connections is considered to be one fundamental way by which the mammalian neocortex stores information and recovers from injury. The likely substrates of cortical plasticity are dendritic spines, since they bear the majority of excitatory synapses and are influenced by synaptic plasticity in vitro. How experience influences the dynamics of spines remains largely unexplored in the living animal. By combining long-term, intrinsic signal imaging and two-photon microscopy in mouse visual cortex, I will correlate the structural dynamics of dendritic spines to functional changes accompanying monocular deprivation (MD). In mice, the shift in ocular dominance (OD) after MD is based on different physiological mechanisms in juvenile and adult animals, is fully reversible, and can be substantially enhanced in adults by MD experience earlier in life. This experimental model therefore provides an excellent context in which to determine how experience-enabled changes in the number, turnover and geometry of spines are affected by age or prior experience. Since LTD and LTP are selectively associated with OD plasticity in juvenile and adult animals, respectively, I will investigate whether the induction of these forms of synaptic plasticity in visual cortex slices induces spine changes similar to those in vivo after MD.