Although individual neurons can be intrinsically oscillatory and can b
e network pacemakers, motor patterns are often generated in a more dis
tributed manner. Synaptic connections with other neurons are important
because they either modify the rhythm of the pacemaker cell or are es
sential for pattern generation in the first place. Computational studi
es of half-center oscillators have made much progress in describing ho
w neurons make transitions between active and inactive phases in these
simple networks. In addition to characterizing phase transitions, rec
ent studies have described the synaptic mechanisms that are important
for the initiation and maintenance of activity in half-center oscillat
ors.