Dysregulation of the autonomic nervous system (ANS) and the hypothalamic–pituitary–adrenal (HPA) axis has been implicated in psychiatric disorders. Music therapy (MT) has been shown to modulate heart-rate variability (HRV) and salivary stress markers, physiological markers of the ANS and HPA axes, respectively. Given the prominent role of arousal and stress physiology in many psychiatric disorders, MT has the potential to provide therapeutic benefits in psychiatry. Active MT requires patients to engage rhythmically with music; in contrast, passive MT requires patients to listen to music, eliminating the rhythmic movement seen in active MT. Yet, it remains unknown whether active or passive MT differentially modulates arousal and stress physiology. We contrasted the effects of active and passive MT experiences to examine the differential impact of rhythmic movement on the ANS and HPA axes in healthy participants. Individuals (N = 16) participated in a crossover study of 40 min of an active MT and a passive MT intervention. HRV recordings and saliva samples were collected both before and after each intervention. The high-frequency component (HF) and the ratio of low-frequency to high-frequency components (LF/HF) were calculated as cardiac markers of parasympathetic and sympathetic ANS activation, respectively. Saliva samples were analyzed for alpha-amylase and cortisol, markers of the sympathetic ANS and HPA axes, respectively. Active MT and passive MT interventions differentially modulated LF/HF, where active MT decreased LF/HF and passive MT increased LF/HF. These results indicate that MT affects the ANS and suggests that differences in engagement between active MT and passive MT lead to a differential modulation of the sympathetic ANS.

Rhythmic entrainment—defined as a stable temporal relationship between external periodic signals and endogenous rhythmic processes—allows individuals to coordinate with environmental rhythms. However, the impact of inter-individual differences on entrainment processes as a function of the tempo of external periodic signals remain poorly understood. To better understand the effects of endogenous differences and varying tempos on rhythmic entrainment, 20 young healthy adults participated in a spontaneous motor tempo (SMT) task and synchronization-continuation tasks at three experimental tempos (50, 70, and 128 bpm; 1200, 857, and 469 ms inter onset interval (IOI)). We hypothesized that SMT task performance and tempo would influence externally paced synchronization-continuation task behavior. Indeed, intrinsic rhythmicity assessed through the SMT task predicted performance in the externally paced task, allowing us to characterize differences in entrainment behavior between participants with low and high endogenous rhythmicity. High rhythmicity individuals, defined by better SMT performance, deviated from externally paced pulses sooner than individuals with low rhythmicity, who were able to maintain externally paced pulses for longer. The magnitude of these behavioral differences depended on the experimental tempo of the synchronization-continuation task. Our results indicate that differences in intrinsic rhythmicity vary between individuals and relate to tempo-dependent entrainment performance.

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21The neuroactive metabolites of the steroid hormones progesterone (P4) and testosterone 22 (T) are GABAergic modulators that influence cognitive control, yet the specific effect of P4 and T 23 on brain network activity remains poorly understood. Here, we investigated if a fundamental 24 oscillatory network activity pattern related to cognitive control, frontal midline theta (FMT) 25 oscillations, are modulated by steroids hormones, P4 and T. We measured the concentration P4 26 and T using salivary enzyme immunoassay and FMT oscillations using high-density 27 electroencephalography (EEG) during the eyes-open resting state in fifty-five healthy female and 28 male participants. Electrical brain activity was analyzed using Morlet wavelet convolution, 29 beamformer source localization, background noise spectral fitting, and phase amplitude coupling 30 analysis. Steroid hormone concentrations and biological sex were used as predictors for scalp 31 and source-estimated theta oscillations and for top-down theta-gamma phase amplitude 32 coupling. Elevated concentrations of P4 predicted increased FMT oscillatory amplitude across 33 both sexes, and no relationship was found with T. The positive correlation with P4 was specific 34 to the frontal-midline electrodes and survived correction for the background noise of the brain. 35Using source localization, FMT oscillations were localized to the frontal-parietal network. 36Additionally, theta amplitude within the frontal-parietal network, but not the default mode 37 network, positively correlated with P4 concentration. Finally, P4 concentration correlated with 38 increased coupling between FMT phase and posterior gamma amplitude. Our results suggest that 39 P4 concentration modulates brain activity via upregulation of theta oscillations in the frontal-40 parietal network and increased top-down control over posterior cortical sites. 41 42 Significance Statement 43The neuroactive metabolites of the steroid hormones progesterone (P4) and testosterone 44 (T) are GABAergic modulators that influence cognitive control, yet the specific effect of P4 and T 45 on brain network activity remains poorly understood. Here, we investigated if a fundamental 46 oscillatory network activity pattern related to cognitive control, frontal midline theta (FMT) 47 oscillations, are modulated by steroids hormones, P4 and T. Our results suggest that P4 48 concentration modulates brain activity via upregulation of theta oscillations in the frontal-49 parietal network and increased top-down control over posterior cortical sites. 50 51

The neuroactive metabolites of the steroid hormones progesterone (P4) and testosterone (T) are GABAergic modulators that influence cognition, yet, the specific effect of P4 and T on brain network activity remains poorly understood. Here, we investigated if a fundamental oscillatory network activity pattern, often related to cognitive control, frontal midline theta (FMT) oscillations, are modulated by steroids hormones, P4 and T. We measured the concentration of P4 and T using salivary enzyme immunoassay and FMT oscillations using high‐density electroencephalography (EEG) during eyes‐open resting‐state in 55 healthy women and men. Electrical brain activity was analyzed using Fourier analysis, aperiodic signal fitting, and beamformer source localization. Steroid hormone concentrations and biological sex were used as predictors for scalp and source‐estimated amplitude of theta oscillations. Elevated concentrations of P4 predicted increased amplitude of FMT oscillations across both sexes, and no relationship was found with T. The positive correlation with P4 was specific to the frontal midline electrodes and survived correction for the background aperiodic signal of the brain. Using source localization, FMT oscillations were localized to the frontal‐parietal network (FPN). Additionally, theta amplitude within the FPN, but not the default mode network, positively correlated with P4 concentration. Our results suggest that P4 concentration modulates brain activity via upregulation of theta oscillations in the FPN.