Synapse-organizing proteins not only allow neurons to connect but also impact neuronal networks once they are formed. This is underlined by a wealth of studies including from our group that synaptic adhesion proteins can modulate synaptic plasticity and impact memory processes. We address how synapse-organizing proteins contribute to the remodeling of neuronal connections. On the one hand, we investigate hippocampus-dependent memory processes. On the other, we use the paradigm of visual system plasticity to determine roles of trans-synaptic interactions in the experience-dependent maturation of cortical networks. This approach is based on in vivo electrophysiological recordings. Our work has translational potential as synaptic aberrations are a hallmark of autism-spectrum disorders and schizophrenia.