Biology subjects

Tachibana, R. O.

Publications and source records attributed to Tachibana, R. O..

10 recordsLinked to original sources

bioRxiv2025

Why early birds sing early: rebound singing from nighttime suppression can explain dawn chorus

Many birds sing vigorously at dawn, a phenomenon widely known as the "dawn chorus." While its adaptive functions have been extensively studied, the proximate mechanisms underlying this widespread phenomenon have remained largely unexplored. Here, we demonstrate that intense morning singing resembling the dawn chorus is evoked as a rebound from singing suppression prior to dawn in captive zebra finches. Our findings indicate that when birds become hormonally aroused in darkness well before dawn, the suppression of spontaneous singing by darkness enhances their intrinsic motivation to sing. This elevated motivation subsequently triggers a rebound of intense singing immediately upon an increase in ambient light. These results reveal mechanisms by which intense morning singing arises from the interaction between the birds arousal state and ambient light, providing a plausible mechanistic explanation for the dawn chorus. Additionally, we found that rebound morning singing accelerates morning changes in song structure, supporting the existing hypothesis that the dawn chorus functions as a vocal warm-up to rapidly optimize song performance following nighttime silence. Together, our findings provide both mechanistic and functional insights into the dawn chorus and other diel vocal patterns in songbirds.

animal behavior and cognition↗

bioRxiv2025

Neural entrainment predicts the anticipatory P300 component during musical meter perception: An EEG study using dual-meter sound stimuli

Meter, the organization of beats into regular groupings, is a core element of music perception that arises from the interplay between the bottom-up processing of acoustic features and top-down attentional mechanisms. To disentangle this interplay, we previously developed dual-meter stimuli consisting of band-limited noise bursts that varied in center frequency and duration, with one feature following a triple-meter pattern and the other a quadruple-meter pattern. The perceived meter thus switches between the two by shifting attention from one acoustic feature to another, even when the physical stimulus remains identical. Using these stimuli, we investigated whether directing attention to specific acoustic features is associated with neural entrainment and anticipatory processing of the perceived metrical structure, and whether the former predicts the latter, by recording electroencephalogram (EEG) signals while isolating the effects of acoustic differences. We found that EEG spectral profiles shifted toward the metrical structure of the attended feature, and that the P300 component, an index of anticipatory processing, tended to be larger when the metrical structure was disrupted than when it remained intact, although both measures varied considerably across individuals. Critically, linear regression analysis revealed that participants whose neural entrainment more closely tracked the attended metrical structure exhibited significantly larger P300 responses to metrical violations. These findings suggest that attending to specific acoustic features links neural entrainment with anticipatory processing, which may underlie meter perception.

neuroscience↗

bioRxiv2024

Beyond dichotomy: diversity of rat's ultrasonic vocalizations

Rats emit ultrasonic vocalizations (USVs) in diverse contexts, and these USVs are thought to serve many biological functions, such as socio-coordinating and alarming functions. In particular, rat USVs have been established as a good model for studying emotional expressions. Since the discovery of USVs in rats, it has gradually been revealed that two families of juvenile and adult rat USVs with distinct acoustic features are closely linked to different affective states: 50-kHz (high-short) calls are associated with positive affective states, whereas 22-kHz (low-long) calls are associated with negative affective states. Although various subtypes within high-short and low-long calls have been proposed and used, most studies adopt the dichotomous framework of first dividing USVs into high-short or low-long calls. The diversity of rat USVs may have been overlooked due to this high-short / low-long dichotomous framework, as such labeling could discourage reporting of actual measured acoustic properties. Considering that several recent studies claim to have found new USV categories outside this framework, we conducted a systematic survey of descriptions of rat USVs in the literature. We identified 15 articles reporting USVs that are outside the dichotomous framework. Our results support the existence of diverse USVs beyond the dichotomy, highlighting the importance of research on a broader range of vocalizations that might reflect complex affective states beyond the simple distinction between positive and negative.

animal behavior and cognition↗

bioRxiv2023

Spectral consistency in sound sequence affects perceptual accuracy in discriminating subdivided rhythmic patterns

Musical compositions are distinguished by their unique rhythmic patterns, determined by subtle differences in how regular beats are subdivided. Precise perception of these subdivisions is essential for discerning nuances in rhythmic patterns. While musical rhythm typically comprises sound elements with a variety of timbres or spectral cues, the impact of such spectral variations on the perception of rhythmic patterns remains unclear. Here, we show that consistency in spectral cues affects perceptual accuracy in discriminating subdivided rhythmic patterns. We conducted online experiments using rhythmic sound sequences consisting of band-passed noise bursts to measure discrimination accuracy. Participants were asked to discriminate between a swing-like rhythm sequence, characterized by a 2:1 interval ratio, and its more or less exaggerated version. This task was also performed under two additional rhythm conditions: inversed-swing rhythm (1:2 ratio) and regular subdivision (1:1 ratio). The center frequency of the band noises was either held constant or alternated between two values. Our results revealed a significant decrease in discrimination accuracy when the center frequency was alternated, irrespective of the rhythm ratio condition. This suggests that rhythm perception is not only shaped by temporal structure but also affected by spectral properties.

neuroscience↗

bioRxiv2020

Spontaneous variability predicts adaptive motor response in vocal pitch control

Our motor system uses sensory feedback to keep behavioral performance in desired status. From this view, motor fluctuation is not simply noise inevitably caused in the nervous system, but should provide a role in generating variations to explore better outcomes via their sensory feedback. Vocal control system offers a good model to investigate such adaptive sensory-motor interactions. The pitch, or fundamental frequency (FF), of voice is adaptively regulated by hearing its auditory feedback to compensate FF deviations. Animal studies, particularly for songbirds, have demonstrated that the variability in vocal features contributes to the adaptive control, although the same issue in human vocalizations has remained unclear. Here, we tested whether and how the motor variability contributes to adaptive control of vocal FF in humans. We measured the amount of compensatory vocal responses against FF shifts in the auditory feedback, and quantified the motor variability as amplitudes of spontaneous FF fluctuations during no shift vocalizations. The result showed a positive correlation between the ratio of compensation and the spontaneous vocal variability. Further analysis indicated that this correlation was due to slowly fluctuating components (<5 Hz) of the variability, but not fast fluctuations (6-30 Hz), which is likely to reflect controllability from the central nervous system. Moreover, the compensatory responses consisted of the same frequency range with the slow component in the spontaneous variability. These findings consistently demonstrated that the spontaneous motor variability predicts the adaptive control in vocal FF, supporting the motor exploration hypothesis. Significance statementWe regulate our own vocalization by hearing own voice. This fact is typically observed as canceling-out (compensatory) responses in vocalized pitch when artificial pitch shifts were induced in the auditory feedback of own voice. Interestingly, the amount of such compensation widely ranges among talkers from perfect cancellation to almost nothing. Here we demonstrated that participants who spontaneously exhibited larger fluctuations showed greater amounts of the compensation against feedbacked pitch shifts. Our in-depth analyses showed that slowly fluctuating components in spontaneous pitch variability are specifically correlated with the compensation ratios, and was shared in the compensatory response as a dominant component. These findings support the idea that such variability contributes to generating motor explorations to find better outcomes in motor controls.

neuroscience↗

bioRxiv2020

Measuring Long Context Dependency in Birdsong Using an Artificial Neural Network with a Long-Lasting Working Memory

Context dependency is a key feature in sequential structures of human language, which requires reference between words far apart in the produced sequence. Assessing how long the past context has an effect on the current status provides crucial information to understand the mechanism for complex sequential behaviors. Birdsongs serve as a representative model for studying the context dependency in sequential signals produced by non-human animals, while previous reports were upper-bounded by methodological limitations. Here, we newly estimated the context dependency in birdsongs in a more scalable way using a modern neural-network-based language model whose accessible context length is sufficiently long. The detected context dependency was beyond the order of traditional Markovian models of birdsong, but was consistent with previous experimental investigations. We also studied the relation between the assumed/auto-detected vocabulary size of birdsong (i.e., fine-vs. coarse-grained syllable classifications) and the context dependency. It turned out that the larger vocabulary (or the more fine-grained classification) is assumed, the shorter context dependency is detected.

animal behavior and cognition↗

bioRxiv2019

Paternal aging affects the developmental patterns of ultrasonic vocalization induced by maternal separation in neonatal mice individually

Infant crying is an innate communicative behavior that is frequently impaired in certain neurodevelopmental disorders (NDDs). Since advanced paternal age is a reported risk factor for NDDs in offspring, we evaluated the impact of a fathers age on early vocal development in C57BL/6J mice. We recorded and applied a unique combination of computational analyses to ultrasonic vocalizations (USVs) emitted by mouse pups sired by young and aged fathers. Our data showed that advanced paternal age reduced the number and duration of USVs, and altered the syllable composition in pups. Moreover, pups born to young fathers showed convergent vocal characteristics with a rich repertoire during postnatal development, while those born to aged fathers exhibited more divergent vocal patterns with limited repertoire. Principal component analysis in conjunction with clustering analysis demonstrated that pups from aged fathers deviated from typical trajectories of vocal development, which were considered as atypical individuals. Thus, our study indicates that advanced paternal age has a significant effect on offsprings early vocal development. It is suggested that the trajectories of vocal development could be a useful marker of the NDD-like phenotype associated with the advanced paternal age. In addition, our comprehensive computational analysis described here is an effective approach to characterize the altered individual diversity relevant to neurodevelopmental disorders. One Sentence SummaryAdvanced paternal age affects vocal development in early postnatal mice, with more pups showing atypical developmental trajectories.

neuroscience↗

bioRxiv2019

USVSEG: A robust segmentation of rodents’ ultrasonic vocalization

Rodents ultrasonic vocalization (USV) provides useful information to assess their social behaviors. Despite of previous efforts for classifying subcategories of time-frequency patterns of USV syllables to associate with their functional relevances, detection of vocal elements from continuously recorded data have remained to be not well-optimized. We here propose a novel procedure for detecting USV segments in continuous sound data with background noises which were inevitably contaminated during observation of the social behavior. The proposed procedure utilizes a stable version of spectrogram and additional signal processing for better separation of vocal signals by reducing variation of the background noise. Our procedure also provides a precise time tracking of spectral peaks within each syllable. We showed that this procedure can be applied to a variety of USVs obtained from several rodent species. A performance test with an appropriate parameter set showed performance for detecting USV syllables than conventional methods.

animal behavior and cognition↗

bioRxiv2018

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 discovered 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.

neuroscience↗

bioRxiv2017

Welfare of zebra finches used in research

Over the past 50 years, songbirds have become a valuable model organism for scientists studying vocal communication from its behavioral, hormonal, neuronal, and genetic perspectives. Many advances in our understanding of vocal learning result from research using the zebra finch, a close-ended vocal learner. We review some of the manipulations used in zebra finch research, such as isolate housing, transient/irreversible impairment of hearing/vocal organs, implantation of small devices for chronic electrophysiology, head fixation for imaging, aversive song conditioning using sound playback, and mounting of miniature backpacks for behavioral monitoring. We highlight the use of these manipulations in scientific research, and estimate their impact on animal welfare, based on the literature and on data from our past and ongoing work. The assessment of harm-benefits tradeoffs is a legal prerequisite for animal research in Switzerland. We conclude that a diverse set of known stressors reliably lead to suppressed singing rate, and that by contraposition, increased singing rate may be a useful indicator of welfare. We hope that our study can contribute to answering some of the most burning questions about zebra finch welfare in research on vocal behaviors.

animal behavior and cognition↗