Dendrites are the predominant entry site for excitatory
synaptic potentials in most types of central neurons.
There is increasing evidence that dendrites are not just
passive transmitting devices but play active roles in
synaptic integration through linear and non-linear mechanisms.
Frequently, excitatory synapses are formed on
dendritic spines. In addition to relaying incoming electrical
signals, spines can play important roles in modifying
these signals through complex biochemical
processes and, thereby, determine learning and memory
formation. Here, we review recent advances in our understanding
of the function of spines and dendrites in
central mammalian neurons in vivo by focusing particularly
on insights obtained from Ca2+ imaging studies.