Switching perception of musical meters by listening to different acoustic cues of biphasic sound stimulus.

Meter is one of the core features of music perception. It is the cognitive grouping of regular sound sequences, typically for every 2, 3, or 4 beats. Previous studies have suggested that one can not only passively perceive the meter from acoustic cues such as loudness, pitch, and duration of sound elements, but also actively perceive it by paying attention to isochronous sound events without any acoustic cues. Studying the interaction of top-down and bottom-up processing in meter perception leads to understanding the cognitive system's ability to perceive the entire structure of music. The present study aimed to demonstrate that meter perception requires the top-down process (which maintains and switches attention between cues) as well as the bottom-up process for discriminating acoustic cues. We created a "biphasic" sound stimulus, which consists of successive tone sequences designed to provide cues for both the triple and quadruple meters in different sound attributes, frequency, and duration. Participants were asked to focus on either frequency or duration of the stimulus, and to answer how they perceived meters on a five-point scale (ranged from "strongly triple" to "strongly quadruple"). As a result, we found that participants perceived different meters by switching their attention to specific cues. This result adds evidence to the idea that meter perception involves the interaction between top-down and bottom-up processes.

Transitioning between preparatory and precisely sequenced neuronal activity in production of a skilled behavior.

Precise neural sequences are associated with the production of well-learned skilled behaviors. Yet, how neural sequences arise in the brain remains unclear. In songbirds, premotor projection neurons in the cortical song nucleus HVC are necessary for producing learned song and exhibit precise sequential activity during singing. Using cell-type specific calcium imaging we identify populations of HVC premotor neurons associated with the beginning and ending of singing-related neural sequences. We characterize neurons that bookend singing-related sequences and neuronal populations that transition from sparse preparatory activity prior to song to precise neural sequences during singing. Recordings from downstream premotor neurons or the respiratory system suggest that pre-song activity may be involved in motor preparation to sing. These findings reveal population mechanisms associated with moving from non-vocal to vocal behavioral states and suggest that precise neural sequences begin and end as part of orchestrated activity across functionally diverse populations of cortical premotor neurons.

Novel approach for understanding the neural mechanisms of auditory-motor control: pitch regulation by finger force.

Music performance and speech production require neural circuits to integrate auditory information and motor commands to achieve rapid and accurate control of sound properties. This article proposes a novel approach for investigating neural substrates related to audiomotor integration. An experiment examined the brain activities involved in sensorimotor integration in a simplified audiomotor task: pitch regulation using finger-pinching force. The brain activities of the participants were measured using functional magnetic resonance imaging (fMRI) while they were performing the task. Two additional tasks were performed: an auditory-only task in which subjects listened to sound stimuli without any motor action and a motor-only task where they applied their finger force to the sensor in the absence of auditory feedback. The fMRI results showed the brain activities related to the online pitch regulation in the dorsal premotor cortex (dPMC), planum temporale (PT), primary auditory cortex, and part of the midbrain. The involvement of dPMC and PT was consistent with findings in previous studies on other audiomotor systems, implying that these regions appeared to be important for connecting the auditory feedback to motor actions.