Giorgio Lazzari

The pleasurable urge to move to music (“groove”) has been shown to be greatest for moderately complex musical rhythms. This is thought to occur because temporal predictions from the motor system reinforce our perception of the beat when there is a balance between expectation and surprise. The supplementary motor area (SMA) has been identified as the potential origin of these temporal predictions. Thus, to causally test the role of the SMA in the experience of groove, we used continuous theta burst stimulation (cTBS) to disrupt activity in this region or an active control site (V1). Nonmusicians listened to and rated musical clips that varied in rhythmic complexity and groove before and after stimulation. Following inhibitory stimulation over the left SMA, participants preferred moving to music with higher rhythmic complexity while after V1 stimulation, they preferred moving to music with lower rhythmic complexity. Pleasure ratings, however, were unaffected. These results suggest that the SMA weighs the precision of beat‐based predictions generated by the dorsal auditory stream. Therefore, stimulating the SMA may have disinhibited the dorsal striatum or other nodes generating the beat‐based predictions. In summary, these findings provide causal evidence that the SMA and V1 play critical roles in embodied rhythm processing.

The pleasurable urge to move to music (“groove”) has been shown to be greatest for moderately complex musical rhythms. This is thought to occur because temporal predictions from the motor system reinforce our perception of the beat when there is a balance between expectation and surprise. The supplementary motor area (SMA) has been identified as the potential origin of these temporal predictions. Thus, to causally test the role of the SMA in the experience of groove, we used continuous theta burst stimulation (cTBS) to disrupt activity in this region or an active control site (V1). Non-musicians listened to and rated musical clips that varied in rhythmic complexity and groove before and after stimulation. Following inhibitory stimulation over left SMA, participants preferred moving to music with higher rhythmic complexity while after V1 stimulation, they preferred moving to music with lower rhythmic complexity. Pleasure ratings, however, were unaffected. These results suggest that the SMA weighs the precision of beat-based predictions generated by the dorsal auditory stream. Therefore, stimulating the SMA may have disinhibited the dorsal striatum or other nodes generating the beat-based predictions. In summary, these findings provide causal evidence that the SMA and V1 play critical roles in embodied rhythm processing.

Humans can flexibly extract a regular beat from complex rhythmic auditory patterns, as often occurs in music. Contemporary models of beat perception suggest that the premotor cortex (PMC) and the supplementary motor area (SMA) are integral to this process. However, how these motor planning regions actively contribute to beat perception, along with any potential hemispheric specialization, remains open questions. Therefore, following the validation of stimuli in a behavioral experiment (Experiment I, N = 29, 12 males, mean age = 23.8 ± 0.7 years), we employed transcranial magnetic stimulation (TMS) to test the causal contribution of these regions to beat perception. In Experiment II (N = 40, 16 males, mean age = 23.2 ± 2.37 years), we applied online repetitive TMS (rTMS) over a defined grid encompassing the right rostral and caudal dPMC, SMA, and pre‐SMA, and a sham control location. Results showed that stimulation of the caudal portion of right dPMC selectively affected beat perception compared to all other regions. In Experiment III (preregistered, N = 42, 17 males, mean age = 23.5 ± 2.61 years), we tested the lateralization of this contribution by applying rTMS over right and left caudal dPMC. Our results showed that only stimulation over right, but not left, dPMC modulated beat perception. Finally, across all three experiments, individual differences in musical reward predicted beat perception sensitivity. Together, these results support the causal role of the right dPMC in generating internal action predictions and perceptual expectations regarding ongoing sequential events, in line with recent models emphasizing the role of the dorsal auditory stream in beat‐based temporal perception. These findings offer valuable insights into the functional organization of the premotor cortex, contributing to a deeper understanding of the neural mechanisms involved in human rhythm perception.

Differences in sensorimotor integration mechanisms have been observed between people who stutter (PWS) and controls who do not. Delayed auditory feedback (DAF) introduces timing discrepancies between perception and action, disrupting sequence production in verbal and non-verbal domains. While DAF consistently enhances speech fluency in PWS, its impact on non-verbal sensorimotor synchronization abilities remains unexplored. A total of 11 PWS and 13 matched controls completed five tasks: (1) unpaced tapping; (2) synchronization-continuation task (SCT) without auditory feedback; (3) SCT with DAF, with instruction either to align the sound in time with the metronome; or (4) to ignore the sound and align their physical tap to the metronome. Additionally, we measured participants’ sensitivity to detecting delayed feedback using a (5) delay discrimination task. Results showed that DAF significantly affected performance in controls as a function of delay duration, despite being irrelevant to the task. Conversely, PWS performance remained stable across delays. When auditory feedback was absent, no differences were found between PWS and controls. Moreover, PWS were less able to detect delays in speech and tapping tasks. These findings show subtle differences in non-verbal sensorimotor performance between PWS and controls, specifically when action–perception loops are disrupted by delays, contributing to models of sensorimotor integration in stuttering.

Psychophysical observations indicate that the spatial profile of visuospatial attention includes a central enhancement around the attentional focus, encircled by a narrow zone of reduced excitability in the immediate surround. This inhibitory ring optimally amplifies relevant target information, likely stemming from top-down frontoparietal recurrent activity modulating early visual cortex activations. However, the mechanisms through which neural suppression gives rise to the surrounding attenuation and any potential hemispheric specialization remain unclear. We used transcranial magnetic stimulation to evaluate the role of two regions of the dorsal attention network in the center-surround profile: the frontal eye field and the intraparietal sulcus. Participants performed a psychophysical task that mapped the entire spatial attentional profile, while transcranial magnetic stimulation was delivered either to intraparietal sulcus or frontal eye field on the right (Experiment 1) and left (Experiment 2) hemisphere. Results showed that stimulation of right frontal eye field and right intraparietal sulcus significantly changed the center-surround profile, by widening the inhibitory ring around the attentional focus. The stimulation on the left frontal eye field, but not left intraparietal sulcus, induced a general decrease in performance but did not alter the center-surround profile. Results point to a pivotal role of the right dorsal attention network in orchestrating inhibitory spatial mechanisms required to limit interference by surrounding distractors.