"Positive and negative regulators of structural plasticity in the mouse hippocampus"
The functions of neural circuits in the adult brain are determined by the architecture of axons and dendrites and of the synapses connecting them. Changes in synaptic connectivity - structural plasticity - have been correlated to functional cheanges at synapses - functional plasticity - and are thought to underlie learning and memory processes. Yet, long-term in vivo imaging in the adult brain reveals that the neuronal network is remarkably stable providing a substrate for long term memory storage. These observations seggest the need for a set of molecules regulating the balance between stability and plasticity of mature neuronal networks, ensuring the spatiall and temporal specificity of plastic changes, thus preventing interferance between different memory events. Here we combine electrophysiological and time lapse imaging methods in living neurons of organotypic hippocampal cultures to analyze a role of NogoA signaling in restricting activity dependent functional and structural synaptic plasticity in the mature murine hippocampus. Moreover, we show that the brain derived neurotrophic factor (BDNF) signaling via its receptor TrkB is crucial in maintaining the mature architecture and function (via calcium imaging) of specific hippocampal neuron types both in vitro and in vivo.