Temporal Features Of Song Research Articles

Inheritance of temporal song features in Java sparrows

Inheritance of temporal song features in Java sparrows

Differential Song Deficits after Lentivirus-Mediated Knockdown of FoxP1, FoxP2, or FoxP4 in Area X of Juvenile Zebra Finches.

Mutations in the transcription factors FOXP1 and FOXP2 are associated with speech impairments. FOXP1 is additionally linked to cognitive deficits, as is FOXP4. These FoxP proteins are highly conserved in vertebrates and expressed in comparable brain regions, including the striatum. In male zebra finches, experimental manipulation of FoxP2 in Area X, a striatal song nucleus essential for vocal production learning, affects song development, adult song production, dendritic spine density, and dopamine-regulated synaptic transmission of striatal neurons. We previously showed that, in the majority of Area X neurons FoxP1, FoxP2, and FoxP4 are coexpressed, can dimerize and multimerize with each other and differentially regulate the expression of target genes. These findings raise the possibility that FoxP1, FoxP2, and FoxP4 (FoxP1/2/4) affect neural function differently and in turn vocal learning. To address this directly, we downregulated FoxP1 or FoxP4 in Area X of juvenile zebra finches and compared the resulting song phenotypes with the previously described inaccurate and incomplete song learning after FoxP2 knockdown. We found that experimental downregulation of FoxP1 and FoxP4 led to impaired song learning with partly similar features as those reported for FoxP2 knockdowns. However, there were also specific differences between the groups, leading us to suggest that specific features of the song are differentially impacted by developmental manipulations of FoxP1/2/4 expression in Area X.SIGNIFICANCE STATEMENT We compared the effects of experimentally reduced expression of the transcription factors FoxP1, FoxP2, and FoxP4 in a striatal song nucleus, Area X, on vocal production learning in juvenile male zebra finches. We show, for the first time, that these temporally and spatially precise manipulations of the three FoxPs affect spectral and temporal song features differentially. This is important because it raises the possibility that the different FoxPs control different aspects of vocal learning through combinatorial gene expression or by acting in different microcircuits within Area X. These results are consistent with the deleterious effects of human FOXP1 and FOXP2 mutations on speech and language and add FOXP4 as a possible candidate gene for vocal disorders.

Developmental modulation and predictability of age-dependent vocal plasticity in adult zebra finches

Predicting the nature of behavioral plasticity can provide insight into mechanisms of behavioral expression and control. Songbirds like the zebra finch rely on vocal signals for communication, and the performance of these signals demonstrate considerable plasticity over development. Traditionally, these signals were thought to be fixed in adulthood, but recent studies have revealed significant age-dependent changes to spectral and temporal features of song in adult songbirds. A number of age-dependent changes to song resemble acute changes to adult song performance across social contexts (e.g., when an adult male sings to a female relative to when he sings in isolation). The ability of variation in social context-dependent changes to predict variation in age-dependent plasticity would suggest shared mechanisms, but little is known about this predictability. In addition, although developmental experiences can shape adult plasticity, little is known about the extent to which social interactions during development affect age-dependent change to adult song. To this end, we systematically analyzed age- and context-dependent changes to adult zebra finch song, and then examined the degree to which age-dependent changes varied across birds that were social or non-socially tutored birds and to which social context-dependent changes predicted age-dependent changes. Non-socially tutored birds showed more dramatic changes to the broad structure of their motif over time than socially tutored birds, but non-socially and socially tutored birds did not differ in the extent of changes to various spectral and temporal features of song. Overall, we found that adult zebra finches produced longer and more spectrally stereotyped songs when they were older than when they were younger. Moreover, regardless of developmental tutoring, individual variation in age-dependent changes to song bout duration and syllable repetition were predicted by variation in social context-dependent changes to these features. These data indicate that social experiences during development can shape some aspects of adult plasticity and that acute context-dependent and long-term age-dependent changes to some song features could be mediated by modifications within similar neural substrates.

Distinctive but functionally convergent song phenotypes characterize two new allopatric species of the Chrysoperla carnea-group in Asia, Chrysoperla shahrudensis sp. nov. and Chrysoperla bolti sp. nov. (Neuroptera: Chrysopidae)

Chrysoperla shahrudensis sp. nov. is discovered in northern Iran, co-occurring with at least five other cryptic species of the Chrysoperla carnea-group. It is distinguished by the volley period and tonality of its courtship duetting song. Another Asian species from alpine meadows of northern Kyrgyzstan, previously C. ‘adamsi-K’ but here named Chrysoperla bolti sp. nov., has a song distinct from but convergent with both C. shahrudensis and North American Chrysoperla adamsi. Coordinated duets can be established in the laboratory between individuals of C. shahrudensis and recorded songs of either C. bolti or C. adamsi. Such functional song equivalence in distinct allopatric species suggests that repeated episodes of parallel speciation can drive the origin of cryptic species diversity in lacewings. Morphology, life history, and ecology of larvae and adults of C. shahrudensis and C. bolti are then formally described. Adding C. shahrudensis to a large mitochondrial DNA data set for ≈ 21 species shows it to be similar to neither C. adamsi nor C. bolti, further supporting independent, convergent evolution of song rather than song similarity due to relationship. Although C. bolti and C. shahrudensis are both from Asia and share some basic temporal song features, the two taxa are distinct, allopatric biological species.www.zoobank.org/urn:lsid:zoobank.org:pub:D9B7BDC9-6C09-468B-A6B-D378628EC557

Imaging auditory representations of song and syllables in populations of sensorimotor neurons essential to vocal communication.

Vocal communication depends on the coordinated activity of sensorimotor neurons important to vocal perception and production. How vocalizations are represented by spatiotemporal activity patterns in these neuronal populations remains poorly understood. Here we combined intracellular recordings and two-photon calcium imaging in anesthetized adult zebra finches (Taeniopygia guttata) to examine how learned birdsong and its component syllables are represented in identified projection neurons (PNs) within HVC, a sensorimotor region important for song perception and production. These experiments show that neighboring HVC PNs can respond at markedly different times to song playback and that different syllables activate spatially intermingled PNs within a local (~100 μm) region of HVC. Moreover, noise correlations were stronger between PNs that responded most strongly to the same syllable and were spatially graded within and between classes of PNs. These findings support a model in which syllabic and temporal features of song are represented by spatially intermingled PNs functionally organized into cell- and syllable-type networks within local spatial scales in HVC.

Vocal motor changes beyond the sensitive period for song plasticity.

Behavior is critically shaped during sensitive periods in development. Birdsong is a learned vocal behavior that undergoes dramatic plasticity during a sensitive period of sensorimotor learning. During this period, juvenile songbirds engage in vocal practice to shape their vocalizations into relatively stereotyped songs. By the time songbirds reach adulthood, their songs are relatively stable and thought to be "crystallized." Recent studies, however, highlight the potential for adult song plasticity and suggest that adult song could naturally change over time. As such, we investigated the degree to which temporal and spectral features of song changed over time in adult Bengalese finches. We observed that the sequencing and timing of song syllables became more stereotyped over time. Increases in the stereotypy of syllable sequencing were due to the pruning of infrequently produced transitions and, to a lesser extent, increases in the prevalence of frequently produced transitions. Changes in song tempo were driven by decreases in the duration and variability of intersyllable gaps. In contrast to significant changes to temporal song features, we found little evidence that the spectral structure of adult song syllables changed over time. These data highlight differences in the degree to which temporal and spectral features of adult song change over time and support evidence for distinct mechanisms underlying the control of syllable sequencing, timing, and structure. Furthermore, the observed changes to temporal song features are consistent with a Hebbian framework of behavioral plasticity and support the notion that adult song should be considered a form of vocal practice.

Syringeal Specialization of Frequency Control during Song Production in the Bengalese Finch (Lonchura striata domestica)

BackgroundSinging in songbirds is a complex, learned behavior which shares many parallels with human speech. The avian vocal organ (syrinx) has two potential sound sources, and each sound generator is under unilateral, ipsilateral neural control. Different songbird species vary in their use of bilateral or unilateral phonation (lateralized sound production) and rapid switching between left and right sound generation (interhemispheric switching of motor control). Bengalese finches (Lonchura striata domestica) have received considerable attention, because they rapidly modify their song in response to manipulations of auditory feedback. However, how the left and right sides of the syrinx contribute to acoustic control of song has not been studied.MethodologyThree manipulations of lateralized syringeal control of sound production were conducted. First, unilateral syringeal muscular control was eliminated by resection of the left or right tracheosyringeal portion of the hypoglossal nerve, which provides neuromuscular innervation of the syrinx. Spectral and temporal features of song were compared before and after lateralized nerve injury. In a second experiment, either the left or right sound source was devoiced to confirm the role of each sound generator in the control of acoustic phonology. Third, air pressure was recorded before and after unilateral denervation to enable quantification of acoustic change within individual syllables following lateralized nerve resection.SignificanceThese experiments demonstrate that the left sound source produces louder, higher frequency, lower entropy sounds, and the right sound generator produces lower amplitude, lower frequency, higher entropy sounds. The bilateral division of labor is complex and the frequency specialization is the opposite pattern observed in most songbirds. Further, there is evidence for rapid interhemispheric switching during song production. Lateralized control of song production in Bengalese finches may enhance acoustic complexity of song and facilitate the rapid modification of sound production following manipulations of auditory feedback.

Regulation of learned vocal behavior by an auditory motor cortical nucleus in juvenile zebra finches

In the process of song learning, songbirds such as the zebra finch shape their initial soft and poorly formed vocalizations (subsong) first into variable plastic songs with a discernable recurring motif and then into highly stereotyped adult songs. A premotor brain area critically involved in plastic and adult song production is the cortical nucleus HVC. One of HVC's primary afferents, the nucleus interface of the nidopallium (NIf), provides a significant source of auditory input to HVC. However, the premotor involvement of NIf has not been extensively studied yet. Here we report that brief and reversible pharmacological inactivation of NIf in juvenile birds leads to transient degradation of plastic song toward subsong, as revealed by spectral and temporal song features. No such song degradation is seen following NIf inactivation in adults. However, in both juveniles and adults NIf inactivation leads to a transient decrease in song stereotypy. Our findings reveal a contribution of NIf to song production in juveniles that agrees with its known role in adults in mediating thalamic drive to downstream vocal motor areas during sleep.

Evaluating the importance of different temporal features of calling songs in cricket phonotaxis

Event Abstract Back to Event Evaluating the importance of different temporal features of calling songs in cricket phonotaxis Gundula Meckenhäuser1, 2*, Matthias R. Hennig3 and Martin P. Nawrot1, 2 1 Freie Universität Berlin, Institute of Biology, Germany 2 Bernstein Center for Computational Neuroscience Berlin, Germany 3 Humboldt-Universität zu Berlin, Department of Biology, Germany Acoustic signals are used by Gryllus bimaculatus to communicate and they play a key role in mate choice. Males produce calling songs to attract females, females in turn use these songs to discriminate conspecific songs from the signals of other species. If they are willing to pair females approach the singing male - a behavior referred to as phonotaxis. So far, extensive behavioral experiments in which phonotactic responses of female crickets were tested by varying song features, revealed that song patterns are processed in the time rather than in the spectral domain [1]. Here, we explored the relevant cues for song pattern discrimination on several time scales. We present feed-forward artificial neural networks (ANNs) that quantitatively predict the phonotactic value for untested calling songs that are described by temporal features such as duration, pause, period and duty cycle for both pulses and chirps. We employ ANNs with the following architecture: Input neurons representing temporal song features project to nonlinear neurons in the hidden layer which project to the output neuron that relates the phonotactic value. For training and testing the networks we used 218 artificial songs for which the phonotactic values had already been determined in experiments. Our complete ANNs that use eight temporal song features show a mean squared error (MSE) of MSE = 0.034. By a greedy backward elimination of features, we came up with minimal ANNs using just pulse period, chirp duration and chirp duty cycle as features. The dimensionality reduction of the feature space also improved the performance: The mean squared error for minimal networks is MSE = 0.019. Thus, our findings suggest that among all tested temporal features, pulse period on the short time scale and chirp duration and chirp duty cycle on the long time scale are the most relevant ones for the evaluation of conspecific signals. Further, the minimal ANNs show high predictive power and can be used to complement experimental testing of female phonotaxis in the laboratory. Acknowledgements This work is funded by the German Research Council (DFG) within the Collaborative Research Center "Theoretical Biology" (SFB 618).

Rapid Interhemispheric Switching during Vocal Production in a Songbird

To generate complex bilateral motor patterns such as those underlying birdsong, neural activity must be highly coordinated across the two cerebral hemispheres. However, it remains largely elusive how this coordination is achieved given that interhemispheric communication between song-control areas in the avian cerebrum is restricted to projections received from bilaterally connecting areas in the mid- and hindbrain. By electrically stimulating cerebral premotor areas in zebra finches, we find that behavioral effectiveness of stimulation rapidly switches between hemispheres. In time intervals in which stimulation in one hemisphere tends to distort songs, stimulation in the other hemisphere is mostly ineffective, revealing an idiosyncratic form of motor dominance that bounces back and forth between hemispheres like a virtual ping-pong ball. The intervals of lateralized effectiveness are broadly distributed and are unrelated to simple spectral and temporal song features. Such interhemispheric switching could be an important dynamical aspect of neural coordination that may have evolved from simpler pattern generator circuits.

Neural representation of spectral and temporal features of song in the auditory forebrain of zebra finches as revealed by functional MRI

Song perception in songbirds, just as music and speech perception in humans, requires processing the spectral and temporal structure found in the succession of song-syllables. Using functional magnetic resonance imaging and synthetic songs that preserved exclusively either the temporal or the spectral structure of natural song, we investigated how vocalizations are processed in the avian forebrain. We found bilateral and equal activation of the primary auditory region, field L. The more ventral regions of field L showed depressed responses to the synthetic songs that lacked spectral structure. These ventral regions included subarea L3, medial-ventral subarea L and potentially the secondary auditory region caudal medial nidopallium. In addition, field L as a whole showed unexpected increased responses to the temporally filtered songs and this increase was the largest in the dorsal regions. These dorsal regions included L1 and the dorsal subareas L and L2b. Therefore, the ventral region of field L appears to be more sensitive to the preservation of both spectral and temporal information in the context of song processing. We did not find any differences in responses to playback of the bird's own song vs other familiar conspecific songs. We also investigated the effect of three commonly used anaesthetics on the blood oxygen level-dependent response: medetomidine, urethane and isoflurane. The extent of the area activated and the stimulus selectivity depended on the type of anaesthetic. We discuss these results in the context of what is known about the locus of action of the anaesthetics, and reports of neural activity measured in electrophysiological experiments.

Influence of Auditory Stimulation on the Development of Syntactical and Temporal Features in European Starling Song

ABsTRAcr.-We investigated how European Starlings (Sturnus vulgaris) were influenced during song learning by acoustic patterns lacking certain syntactical and temporal features of the species-specific song. Hand-reared males were exposed to a sequence of heterospecific song patterns (song types of Common Nightingales, Luscinia megarhynchos) which, in contrast to normal starling song, were not reiterated, were evenly separated by breaks throughout the entire tutor sequence, and did not show an increase in maximum frequency from the beginning to the end of the sequence. The experimental males acquired none or only a few of the song patterns from the training tape and developed songs with aspects of normal syntax (sequential order of low- and high-frequency motif types) and temporal organization (more breaks between motifs at beginning than at end of song). These features are missing in the songs of males reared in complete acoustic isolation (Chaiken et al. 1993). Therefore, we conclude that European Starlings have a predetermined knowledge of some syntactical and temporal song features, but need an acoustic input from the environment to convert such information into a corresponding vocal output. The results show that acoustic patterns effective in stimulating such a development do not need to contain specific features of starling song. Received 14 June 1995, accepted 20 August 1995.

Temporal Relationships in White-Throated Sparrow Song

Bird song has been likened to human music for centuries (e.g., Anonymous 1717, Hartshorne 1973). The analogy between bird song and music is perpetrated to some degree by the use of musical terms to describe avian vocalizations: individual sound elements are called and strings of notes are called songs. In most modern studies of song this analogy has fallen out of favor (e.g., Dobson and Lemon 1977). However, recent studies have shown that fixed relationships between the frequencies of adjacent notes, a defining feature of human music, occur in the songs of several species, and the birds seem to use this feature to recognize their songs (e.g., see Weary et al. 1991). The aim of the present study was to determine if there are other predictable relationships between notes. In particular we investigated whether the duration of song notes sung by White-throated Sparrows (Zonotrichia albicollis) are correlated. When an individual produces a relatively long first note, do the subsequent notes tend to be longer? These temporal relationships between notes are termed rhythm when describing music. The familiar tune is still recognized when it is sped up or slowed down (changes in tempo), because the temporal relationships between the notes (and internote intervals) are maintained. The only formal study of rhythm perception in nonhuman animals was done in the laboratory on European Starlings (Sturnus vulgaris) (Hulse et al. 1984). This study showed that birds can learn to discriminate rhythmic from arrhythmic sound patterns, and can generalize this discrimination over changes in tempo. How important are the temporal relationships among sounds in nature? For birds, there is some evidence that these relationshipsare important. Becker's (1982) review pointed to several temporal features of song that are important in species recognition. For example, the manipulation of the intervals between notes in a song affects recognition in several species, including White-throated Sparrows (Falls 1963). Also, interspecific comparisons have demonstrated that birds which sing longer songs also tend to use greater intervals to separate them (Dobson and Lemon 1975, Weary and Lemon 1988). Thus, certain aspects of timing do seem important in bird song. Other evidence is harder to interpret. For example, Lambrechts and Dhondt (1987) found that during the course ofa song, Great Tits (Parus major) tend to sing with progressively longer intervals between notes. The rhythmic aspect of this behavior is that when Great Tits produce longer inter-note intervals, they also produce longer inter-phrase intervals (phrases consist of groups of notes). The arrhythmic aspect is that there is no corresponding increase in the duration of the notes themselves. Thus, in one respect Great Tits maintain rhythm over a change in tempo, but in another they do not.