Cerebellar response to alternating tone sequences

This paper describes a preliminary investigation into the contributions of the cerebellum in forming complex auditory perceptions. It is hypothesized that the cerebellum plays an important role in the interpretation of timing cues in auditory signals. A series of six tones forming either one or two perceptual streams/groups are used to investigate the response of the cerebellum. The tone sequence is presented in both fast and slow durations. Evoked potential/EEG measurements were taken using a 9-electrode montage in the cerebellum region, outside of the typical 10-20 electrode arrangement. The stimuli consist of similar frequencies and intensities, but evoke very different perceptual interpretations depending on the overall rate of the tone sequence duration. For the faster repetition rate, the cerebellum response was observed to be oscillatory in nature, with amplitude variations appearing to be both linear and non-linear functions of stimulus frequency. For the slower repetition rate, the oscillatory response was suppressed.