A Minicomputer-aided Method for the Detection of Features from Vocalisations of the Cotton-top Tamarin

Lagging behind the methodological standard reached in human speech analysis, spectrograms from animal vocalisations must still be analysed at least partly “by hand”. The method described here uses minicomputer feature detection techniques to extract frequency modulation and amplitude modulation contours and the number of harmonics automatically from cotton-top tamarin vocalisations. This system thus offers a very workable tool for the detailed analysis of animal vocalisations, as demonstrated in an application where the stereotypy of an amplitude modulation pattern of cotton-top tamarin calls is shown.     

Infant-care Behavior of Non-reproductive Helpers in a Communal-care Primate,the Cotton-top Tamarin (Saguinus oedipus)

Infant-care behavior patterns of captive cotton-top tamarins were examined to assess factors defining participation by non-reproductive helpers. The time spent carrying infants and characteristics of infant transfers were examined for 47 helpers in a total of 18 groups. We predicted that age, previous experience, and carrying opportunity would all affect participation of non-reproductive helpers. Our results confirm that carrying by non-reproductive helpers was related to age, with older helpers carrying more often. However, this difference declined with increasing infant age, suggesting that body size of the carrier was not the only factor determining participation in carrying. When observations were classified relative to type of interaction with infants, older juveniles were found to both investigate and harass infants more often than subadults or younger juveniles. There was no effect of gender on carrying. The carrying behavior of subadults was not affected by their previous experience; that is, subadults with no previous exposure to infants carried as often as those with previous experience. Inter-individual variation among helpers was high; within 11 twin litters of helpers, one animal usually carried significantly more than the other.     

Noise-Induced Frequency Modifications of Tamarin Vocalizations: Implications for Noise Compensation in Nonhuman Primates

Previous research suggests that nonhuman primates have limited flexibility in the frequency content of their vocalizations, particularly when compared to human speech. Consistent with this notion, several nonhuman primate species have demonstrated noise-induced changes in call amplitude and duration, with no evidence of changes to spectral content. This experiment used broad- and narrow-band noise playbacks to investigate the vocal control of two call types produced by cotton-top tamarins (Saguinus Oedipus). In ‘combination long calls’ (CLCs), peak fundamental frequency and the distribution of energy between low and high frequency harmonics (spectral tilt) changed in response to increased noise amplitude and bandwidth. In chirps, peak and maximum components of the fundamental frequency increased with increasing noise level, with no changes to spectral tilt. Other modifications included the Lombard effect and increases in chirp duration. These results provide the first evidence for noise-induced frequency changes in nonhuman primate vocalizations and suggest that future investigations of vocal plasticity in primates should include spectral parameters.     

Ultrasonic Vocalizations in Rat Sexual Behavior

Ultrasonic vocalizations are very conspicuous during rat matingactivity. Two types of calls are produced by both sexes. Thefirst, brief complex calls with the main frequency centeredabout 50 kHz, occur primarily in conjunction with solicitationand mounting activity. The second type of call is the long,22 kHz whistle which is emitted mainly by the male during thepostejaculatory refractory period, but also by both male andfemale at other times during the copulatory sequence. The occurrenceof ultrasonic vocalizations is correlated with sexual motivationof rats. Males emit more 50 kHz calls before successful matingtests than before tests in which they fail to ejaculate. Furthermore,more vocalizations are emitted by the pair prior to intromissionsthan prior to mounts without intromission. Just before ejaculationthere is a large increase in the rate of calling and, at times,transition by the male to calling at 22 kHz. This latter eventmay represent physiological dearousal by the male. Followingejaculation, the male characteristically emits 22 kHz vocalizationsand exhibits a sleep-like EEG pattern. The function of the postejaculatoryvocalization may be to enforce separation between the matingpair, while at the same lime maintaining contact between thepartners. Fifty kHz calls, on the other hand, prime and facilitatesexual responsiveness of the female. Tape recorded vocalizationsof mating rats facilitate solicitation behavior of estrous femalesin the presence of castrated males, and such females also showa preference for these sounds in a "Y" maze. Deafening of femalesdoes not affect their normal pacing of copulatory contacts,but it drastically reduces their solicitation behavior. Thestudies summarized in this paper lead us to conclude that ultrasonicvocalizations play a major role in the integration of reproductiveactivity in the Norway rat, Rattus norvegicus.     

Spectrographic Description of Vocalizations in Captive Otolemur garnettii

To advance knowledge of the vocal communication associated with close proximity social interactions in Garnett's greater bush baby (Otolemur garnettii), we measured acoustic and temporal properties of vocalizations from videotaped recordings of captives in two main social contexts: mother-infant interactions and adult male-female pair introductions and reintroductions. We used a real-time sonagraph or software program to display, edit, and analyze vocal waveforms, and to provide wideband and narrowband spectrograms. Vocalization characteristics measured include fundamental frequency (via inspection of harmonics) and spectral features such as formant frequency, intensity, and duration. The vocal repertoire contained 4 major types of vocalizations: 1) barks and complex multiple bark sequences, 2) low frequency flutter/hums and growls, 3) high frequency clicks and spits, and 4) noisy shrieks. We describe several vocalizations for the first time and provide a clear classification of some of them on the basis of call durations (long/short growls). Complex bark sequences, previously described as distant communication calls, were invariant and were not often emitted by individuals when in close proximity. When classified spectrographically, the remaining 3 call types, which occurred when individuals were in close proximity, were less stereotypical, and gradations within call types were apparent. Our results show that although nocturnal and non-gregarious, complex communicatory signals of bush babies constitute a vocal repertoire formerly thought to be characteristic only of diurnal, gregarious primates.     

Use of Social and Ecological Information in Tamarin Foraging Decisions

A major consequence of group living is that foragers may rely on social information in addition to ecological information to locate feeding sites. Although conspecifics can provide cues as to the spatial location of food patches, individual foraging decisions also must include some assessment of the likelihood of obtaining access to a resource other group members seek. This likelihood differs in the 2 models generally proposed to explain intragroup social foraging: the information-sharing model and the producer-scrounger model. We conducted an experimental field study on wild groups of emperor (Saguinus imperator) and saddleback (S. fuscicollis) tamarins to determine the foraging strategies adopted by individual group members and their relationship to social rank, food intake, and the ability to use ecological and social information in making intra-patch foraging decisions. Individual tamarins applied different behavioral strategies compatible with a finder-joiner paradigm to solve foraging problems. About half of the individuals in each study group initiated 74%–90% of all food searches and acted as finders. Most alpha individuals adopted a joiner strategy by monitoring the activities of others' to obtain a reward. The individual arriving first at a reward platform enjoyed a finder's advantage. Despite differences in search effort, both finders and joiners presented similar abilities in learning to associate ecological cues with the presence of food rewards at our experimental feeding stations. We conclude that within a group foraging context, tamarins integrate social and ecological information in decision-making.     

Cues in the Web-Building Process

SYNOPSIS. Sensory events presumably guide the orb-weaver inthe sequence of placing radii. However, at a given stage ofconstruction, several sectors of the web may be equivalent inthe sense that they possess features capable of eliciting radius-building.Observation of the natural progress of construction cannot revealthese characteristics. Some delineation of the problem may beobtained by compelling the spider to identify equivalent sectors.This procedure was followed for Araneus diademntus by selectivelydestroying threads, in effect repeatedly forcing the spiderinto the same web-array. The "candidate" sectors—thoseregions which are placed and replaced by the spider—aresufficiently described by the size of their central angles inearly stages of radius-building, but not in later stages. Anglesof relatively large size are left open in the upper half ofthe web. Sensory guidance in construction of radii may dependupon response to a complex array of forces in the web.     

Vocalizations in wild canids and possible effects of domestication

On the basis of spectrographic evidence it has been possible to identify twelve basic vocal sound types of canid species.Vocalizations may be mixed either by successive emission of two or more sound types, by superimposition of these sounds, or by a combination of these two forms. The same basic sound type may differ among canid species along the dimensions of sound duration, separation time between consecutive sounds, principle frequencies, cyclicity, and context.Developmental data indicate that domestic dogs first begin to mix sounds by successive sound emissions at about 10 days of age and later by superimposition between 2 and 3 weeks of age. The frequency of occurence of the basic sound types in different contexts varied between species but not within species. The possible effects of domestication on canid vocalizations are discussed.     

中国大杜鹃的鸣声

一直以来认为广布欧洲大陆和亚洲大陆的大杜鹃 ,其鸣声在地区之间无差异 ,而分布在亚洲的大杜鹃的鸣声至今未有系统的研究报道。本文以分布在中国北部的大杜鹃指名亚种和新疆亚种的广告鸣叫为主要研究对象 ,将其与在四川和云南省分布的大杜鹃华西亚种以及分布在朝鲜、日本、俄罗斯和英格兰的大杜鹃指名亚种的广告鸣叫进行了初步比较。在中国分布的大杜鹃有五种鸣叫类型。中国所有采集地大杜鹃的广告鸣叫都由两个音节组成 ,并且与英国分布种群的广告鸣叫很相似。各地大杜鹃的领域鸣唱呈现出个体质的高度保守性和数量性状的明显差异     

Cotton-top tamarins (Saguinus (o.) oedipus) in a semi-naturalistic captive colony

To test the prediction that the breeding success of captive cotton-top tamarins (Saguinus (o.) oedipus) could be improved by maintaining them in groups whose size and age-sex composition resembled those of wild groups, data were collated from 6.5 years of records from a breeding colony that otherwise had housing and husbandry procedures similar to those of other successful colonies. Group size and composition in the colony closely resembled those of wild groups, and infant survival was the highest yet reported for the species, with 69% of the 124 infants born reared by their parents to adulthood, and a mean surviving litter size of 1.5 infants. Abortion, stillbirth, and parental neglect of infants were rare. Parity had several effects on reproduction: mean litter size decreased, but percentage infant survival increased; interbirth intervals decreased in length; and seasonality in reproduction was more pronounced for the first four litters born to breeding females than for their subsequent litters, with a birth peak in the spring. Although a spacious and complex physical environment, retention of offspring in their natal families until experience of several sets of infant siblings had been obtained, and non-invasive husbandry and research techniques may all have contributed to the colony's success, it seems possible that the improvement over other colonies is due to the resemblance of group composition to those of wild tamarins.     

Simultaneous binding of Guidance Cues NET1 and RGM blocks extracellular NEO1 signaling

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Targeted Training of Ultrasonic Vocalizations in Aged and Parkinsonian Rats

Voice deficits are a common complication of both Parkinson disease (PD) and aging; they can significantly diminish quality of life by impacting communication abilities. ^{1, 2} Targeted training (speech/voice therapy) can improve specific voice deficits,^{3, 4} although the underlying mechanisms of behavioral interventions are not well understood. Systematic investigation of voice deficits and therapy should consider many factors that are difficult to control in humans, such as age, home environment, age post-onset of disease, severity of disease, and medications. The method presented here uses an animal model of vocalization that allows for systematic study of how underlying sensorimotor mechanisms change with targeted voice training. The ultrasonic recording and analysis procedures outlined in this protocol are applicable to any investigation of rodent ultrasonic vocalizations.The ultrasonic vocalizations of rodents are emerging as a valuable model to investigate the neural substrates of behavior.^5-8 Both rodent and human vocalizations carry semiotic value and are produced by modifying an egressive airflow with a laryngeal constriction.^{9, 10} Thus, rodent vocalizations may be a useful model to study voice deficits in a sensorimotor context. Further, rat models allow us to study the neurobiological underpinnings of recovery from deficits with targeted training.To model PD we use Long-Evans rats (Charles River Laboratories International, Inc.) and induce parkinsonism by a unilateral infusion of 7 μg of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle which causes moderate to severe degeneration of presynaptic striatal neurons (for details see Ciucci, 2010).^{11, 12} For our aging model we use the Fischer 344/Brown Norway F1 (National Institute on Aging).Our primary method for eliciting vocalizations is to expose sexually-experienced male rats to sexually receptive female rats. When the male becomes interested in the female, the female is removed and the male continues to vocalize. By rewarding complex vocalizations with food or water, both the number of complex vocalizations and the rate of vocalizations can be increased (Figure 1).An ultrasonic microphone mounted above the male''s home cage records the vocalizations. Recording begins after the female rat is removed to isolate the male calls. Vocalizations can be viewed in real time for training or recorded and analyzed offline. By recording and acoustically analyzing vocalizations before and after vocal training, the effects of disease and restoration of normal function with training can be assessed. This model also allows us to relate the observed behavioral (vocal) improvements to changes in the brain and neuromuscular system.     

Predation Cues in Solitary bee Nests

Predation at the nesting site can significantly affect solitary bees’ reproductive success. We tested female red mason bees’ (Osmia bicornis L.) acceptance of potential nesting sites, some of which were marked with cues coming from predated conspecifics (crushed bees) or from a predator itself (rodent excreta). In our experiment, females did not avoid nests marked with either of the two predator cues. We suggest that bee females do not recognize these two cues as risky. Alternatively, costs of abandoning natal aggregation might be too high compared with any perceived predation risk of staying. Moreover, the presence of crushed bees can provide positive information about the presence of conspecifics and, possibly, information about a nesting aggregation that may be preferred by bees when choosing a nesting site.     

Gaze in Visual Search Is Guided More Efficiently by Positive Cues than by Negative Cues

Visual search can be accelerated when properties of the target are known. Such knowledge allows the searcher to direct attention to items sharing these properties. Recent work indicates that information about properties of non-targets (i.e., negative cues) can also guide search. In the present study, we examine whether negative cues lead to different search behavior compared to positive cues. We asked observers to search for a target defined by a certain shape singleton (broken line among solid lines). Each line was embedded in a colored disk. In “positive cue” blocks, participants were informed about possible colors of the target item. In “negative cue” blocks, the participants were informed about colors that could not contain the target. Search displays were designed such that with both the positive and negative cues, the same number of items could potentially contain the broken line (“relevant items”). Thus, both cues were equally informative. We measured response times and eye movements. Participants exhibited longer response times when provided with negative cues compared to positive cues. Although negative cues did guide the eyes to relevant items, there were marked differences in eye movements. Negative cues resulted in smaller proportions of fixations on relevant items, longer duration of fixations and in higher rates of fixations per item as compared to positive cues. The effectiveness of both cue types, as measured by fixations on relevant items, increased over the course of each search. In sum, a negative color cue can guide attention to relevant items, but it is less efficient than a positive cue of the same informational value.