Rhythmic interactions: Musical tempo, electroencephalographic activity and autonomic responses. Pilot studies

Human behavior is shaped by complex motivations, and music-through its intensity, tempo, rhythm, and accentuation-modulates emotion and physiological state; it can promote relaxation and enhance motor performance. Two pilot studies were conducted: Study 1 (Group 1, n = 4) explored electroencephalographic cortical activity, and Study 2 (Group 2, n = 8) explored autonomic activity, both in response to rhythmic auditory stimuli. Furthermore, Study 2 included a comparison of results among musicians and non-musicians. All participants underwent electroencephalogram (EEG) recording in the temporal areas, electrocardiogram (ECG), respiratory movements, eye movements, and electromyogram. Only periods of alert wakefulness were processed. In Group 1, the relative power in the delta, theta, and alpha bands of the recorded temporal sites was analyzed; in Group 2, heart rate (HR), heart rate variability (HRV), and respiratory rate (RR) were calculated. All three EEG bands changed with music versus silence. Theta showed the most consistent and tempo-sensitive modulation. Alpha power decreased indicating an expected sensory blockade yet also participated in detecting tempo transitions. Delta varied least, consistent with wakeful recordings. RR amplitude and regularity increased with rhythmic stimulation, more markedly in non-musicians. Non-musicians exhibited sustained HR increases and higher HRV with music, whereas musicians showed an initial HR rise followed by reduction below control and lower HRV. These preliminary results would further contribute to the understanding that rhythmic auditory sensory input modulates brain activity at many levels, from basic autonomic controls to cortical activity, and that this new incoming information impacts differently depending on the previous information stored in the brain.