Developmental plasticity of immature glutamatergic synapses in the mouse matosensory (barrel) cortex

• Applicants: Professor Dr. Dirk Feldmeyer; Professor Dr. Kurt Gottmann
• Subject Area: Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2007 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 40137203

During the postnatal development of the mammalian neocortex, a complex network of synaptically connected neurons is formed involving activity-dependent cellular mechanisms. Although glutamatergic synapses with immature functional properties, so-called “silent” synapses, have been described in the early postnatal hippocampus, our knowledge about immature glutamatergic synapses in the developing neocortex is rather limited. As a general hypothesis, immature synapses are thought to be transformed to mature synapses by developmental plasticity processes. Both pre- and postsynaptic maturation appear to be involved in this functional plasticity. Here, we will focus on the investigation of presynaptically immature glutamatergic synapses on layer 5B pyramidal neurons in the mouse somatosensory (barrel) cortex. Patch-clamp recordings and paired-pulse stimulation in acute cortex slices will be used to identify presynaptically immature synapses. These immature synapses will be characterized electrophysiologically with respect to both presynaptic release properties and postsynaptic AMPA and NMDA receptor function. In particular, we will analyse the coupling of pre- and postsynaptic maturation at identified synapses using paired recordings. Moreover, we will study the activity-dependent conversion of presynaptically immature synapses to fully functional synapses and the involvement of NMDA receptor activation.

• DFG Programme: Research Grants