Another important distinction and source of confusion is the difference between temporal coding and temporal processing (Figure 2). We refer to temporal processing as the decoding of temporal information or the generation of timed motor responses. In its simplest form, temporal processing may consist of neurons that respond selectively to the interval between two events. By definition, to process temporal information, one must start with spike patterns in which information is encoded in the temporal domain. In the sensory domain we focus on cases in which the temporally encoded information arises directly from external stimuli (e.g., duration discrimination, Morse code, rhythm perception, etc.). In addition to these external temporal codes, theoretical and experimental data suggest that temporal codes may also be internally generated.