Paced auditory stimuli with distinct characteristics affect differently the clock-like neural process?

In millisecond timing research, two forms of timing are distinguished: event-based and emergent timing (Spencer and Ivry, Brain Cogn, 2005, 58, 84-93). The essential difference between the two timing modes is considered to be consisting in the involvement or noninvolment of a clock-like neural process, i.e., an abstract effector-independent representation of the time intervals to be produced (Wing and Kristofferson, Percept Psycholphys, 1973, 14: 5-12). The character of movements in a rhythmic motor task is considered a key factor for eliciting a specific mode of timing. The class of discrete movements, defined as having a clear-cut beginning and end, shown to engage the involvement of clock-like neural process (Huys et al., 2008, PLoS Comput Biol, 4: e1000061.10.1371). Discrete movements are not the only ones favoring exploitation of the event-based timing. Recent studies have demonstrated that salient auditory markers, such as streams of clicks (Torre and Delignières, 2008, Biol Cyb, 99: 159-170) and tactile feedback (Studenka et al., 2012, Q J Exp Psychol 65, 1086-1100.10.1080), are also able to elicit the event-based timing. Here, we investigated whether simple and complex paced auditory stimuli, as streams of clicks and excerpts of music, influence differently the processes for temporal regulation. Particularly, we wanted to study if music, when compared with clicks, has a different power in encouraging the event-based timing. Also, since Zelaznik and Rosembaum (2010, J Exp Psychol H Percept Perfor, 36: 1565-1575) provided evidence that external auditory event representation of movement favors event-based timing, we decided to explore whether the recall of an auditory stimulus, where auditory imagery is involved and is simulating an internal auditory representation, might influence timing control processes. In order to answer to these questions, subjects have participated in a session in which sets of repeated isochronous wrist's flexion-extensions were performed under various auditory conditions and during their recall. Kinematics was recorded and temporal parameters were extracted and analyzed. Results indicate that streams of clicks and music do affect differently the timing processes, with music having only a minor role in provoking event-based timing, especially evident at high ranges of tempi. In addition, the auditory experience, constructed of components drawn from memory in the absence of direct sensory instigation of experience, favors the involvement of event-based timing.