Abstract:

The perceptual experience of a rhythm depends on its metrical interpretation. Prior work using magnetoencephalography has shown that brain activity reflects a listener's metrical interpretation of simple ambiguous rhythms: neural response to a note c oinciding with the listener's internal sense of the beat is enhanced in the beta frequency range (20–30 Hz). An unanswered question raised by this result is where in the brain the transient periodic enhancement of evoked response to the beat might arise. Ongoing research on brain responses to syncopated rhythmic patterns is presented. In these syncopated patterns, some beats are never marked by physical tones. It is asked if the increase in transient beta activity observed in prior experiments can also indicate internal beat placement even in the predictable absence of a physical input. If so, it may reveal the nature of the internal modulation of cortical responses to sound and enable localization of its source. The presentation will conclude with a discussion of what brain architectures may be able to support beat perception and synchronization, with reference to nonhuman animals. [Work supported by Neurosciences Research Foundation.]