How are the Molecular Components of Central Neuron synapses assembled during development, and how is the molecular composition and thus functional responsiveness of individual synapses regulated in response to synaptic activity? We study these questions of Synaptogenesis and Synaptic Plasticity mainly from the point of view of the cellular and molecular biology of the postsynaptic neuron. Using a dissociated hippocampal cell culture system, we are determining the sequence of assembly of molecular components of the two major synapse types in the mammalian brain: excitatory glutamatergic synapses and inhibitory gabaergic synapses. We are currently focusing on the molecular mechanisms underlying Subcellular Targeting of Glutamate Receptors, including the independent targeting of nmda versus ampa receptors, the activity dependence of ndma receptor targeting, and cis-acting signals in metabotropic receptors that mediate targeting.