Synaptic Reorganization in Scaled Networks of Controlled Size

@article{citeulike:2140476, abstract = {Neurons in plastic regions of the brain undergo fundamental changes in the number of cells connecting to them as a result of development, plasticity and disease. Across these same time periods, functional changes in cellular and synaptic physiology are known to occur and are often characterized as developmental features of these periods. However, it remains possible that many such changes are direct consequences of the modified degree of partnering, and that neurons intrinsically scale their physiological parameters with network size. To systematically vary a recurrent network's number of neurons while measuring its synaptic properties, we used microfabricated extracellular matrix adhesive islands created with soft lithography to culture neuronal clusters of precise sizes, and assessed their intrinsic connectivity using intracellular recordings and confocal microscopy. Both large and small clusters supported constant densities of excitatory and inhibitory neurons. However, neurons that were provided with more potential partners (larger clusters) formed more connections per cell via an expanded dendritic surface than cocultured smaller clusters. Electrophysiologically, firing rate was preserved across clusters even as size and synapse number increased, due in part to synapses in larger networks having reduced unitary strengths, and sparser paired connectivity. Larger networks also featured a particular increase in the number of excitatory connections onto inhibitory dendrites. We suggest that these specific homeostatic mechanisms, which match the number, strength, and architecture of connections to the number of total available cellular partners in the network, could account for several known phenomena implicated in the formation, organization and degeneration of neuronal circuits. 10.1523/JNEUROSCI.3863-07.2007}, author = {Wilson, Nathan R. and Ty, Michael T. and Ingber, Donald E. and Sur, Mriganka and Liu, Guosong }, citeulike-article-id = {2140476}, doi = {http://dx.doi.org/10.1523/JNEUROSCI.3863-07.2007}, journal = {J. Neurosci.}, keywords = {071218, homeostatic\_plasticity, synaptic\_plasticity}, month = {December}, number = {50}, pages = {13581--13589}, posted-at = {2007-12-18 11:08:37}, priority = {2}, title = {Synaptic Reorganization in Scaled Networks of Controlled Size}, url = {http://dx.doi.org/10.1523/JNEUROSCI.3863-07.2007}, volume = {27}, year = {2007} }

TY - JOUR ID - citeulike:2140476 L3 - citeulike-article-id:2140476 TI - Synaptic Reorganization in Scaled Networks of Controlled Size JF - J. Neurosci. VL - 27 IS - 50 SP - 13581 EP - 13589 N2 - Neurons in plastic regions of the brain undergo fundamental changes in the number of cells connecting to them as a result of development, plasticity and disease. Across these same time periods, functional changes in cellular and synaptic physiology are known to occur and are often characterized as developmental features of these periods. However, it remains possible that many such changes are direct consequences of the modified degree of partnering, and that neurons intrinsically scale their physiological parameters with network size. To systematically vary a recurrent network's number of neurons while measuring its synaptic properties, we used microfabricated extracellular matrix adhesive islands created with soft lithography to culture neuronal clusters of precise sizes, and assessed their intrinsic connectivity using intracellular recordings and confocal microscopy. Both large and small clusters supported constant densities of excitatory and inhibitory neurons. However, neurons that were provided with more potential partners (larger clusters) formed more connections per cell via an expanded dendritic surface than cocultured smaller clusters. Electrophysiologically, firing rate was preserved across clusters even as size and synapse number increased, due in part to synapses in larger networks having reduced unitary strengths, and sparser paired connectivity. Larger networks also featured a particular increase in the number of excitatory connections onto inhibitory dendrites. We suggest that these specific homeostatic mechanisms, which match the number, strength, and architecture of connections to the number of total available cellular partners in the network, could account for several known phenomena implicated in the formation, organization and degeneration of neuronal circuits. 10.1523/JNEUROSCI.3863-07.2007 KW - 071218 KW - homeostatic_plasticity KW - synaptic_plasticity AU - Wilson, Nathan AU - Ty, Michael AU - Ingber, Donald AU - Sur, Mriganka AU - Liu, Guosong PY - 2007/12/12/ UR - http://dx.doi.org/10.1523/JNEUROSCI.3863-07.2007 ER -