Dendritic signal integration.

Recent studies have identified various forms of active dendritic signals that may contribute to neuronal integration. One of the most remarkable findings is the demonstration of highly localized Ca2+ transients that are limited to small dendritic segments and even to single dendritic spines. In addition, through use of the powerful two-photon excitation imaging technique, it has been possible to reveal the existence of dendritic Ca2+ signals under in vivo conditions. Finally, active backpropagation of action potentials into dendrites has been shown to boost dendritic Ca2+ signals supralinearly and, thus, to contribute to the induction of long-term potentiation.