The analysis of patterns of pitch and duration over time in natural segmented sounds is fundamentally relevant to the analysis of speech, environmental sounds and music. The neural basis for differences between the processing of pitch and duration sequences is not established. We carried out a PET activation study on nine right-handed musically naive subjects, in order to examine the basis for early pitch- and duration-sequence analysis. The input stimuli and output task were closely controlled. We demonstrated a strikingly similar bilateral neural network for both types of analysis. The network is right lateralised and includes the cerebellum, posterior superior temporal cortices, and inferior frontal cortices. These data are consistent with a common initial mechanism for the analysis of pitch and duration patterns within sequences.