02919nas a2200133 4500008004100000245009500041210006900136520244100205100002102646700002202667700002402689700002002713856005202733 2019 eng d00aAre dialects socially learned in marmoset monkeys? Evidence from translocation experiments0 aAre dialects socially learned in marmoset monkeys Evidence from 3 a

The acoustic properties of vocalizations in common marmosets differ between populations. These differences may be the result of social vocal learning, but they can also result from environmental or genetic differences between populations. We performed translocation experiments to separately quantify the influence of a change in the physical environment (experiment 1), and a change in the social environment (experiment 2) on the acoustic properties of calls from individual captive common marmosets. If population differences were due to genetic differences, we expected no change in the vocalizations of the translocated marmosets. If differences were due to environmental factors, we expected vocalizations to permanently change contingent with environmental changes. If social learning was involved, we expected that the vocalizations of animals translocated to a new population with a different dialect would become more similar to the new population. In experiment 1, we translocated marmosets to a different physical environment without changing the social composition of the groups or their neighbours. Immediately after the translocation to the new facility, one out of three call types showed a significant change in call structure, but 5–6 weeks later, the calls were no longer different from before the translocation. Thus, the novel physical environment did not induce long lasting changes in the vocalizations of the marmosets. In experiment 2, we translocated marmosets to a new population with a different dialect. Importantly, our previous work had shown that these two populations differed significantly in vocalization structure. The translocated marmosets were still housed in their original social group, but after translocation they were surrounded by the vocalizations from neighbouring groups of the new population. The vocal distance between the translocated individuals and the new population decreased for two out of three call types over 16 weeks. Thus, even without direct social contact or interaction, the vocalizations of the translocated animals converged towards the new population, indicating that common marmosets can modify their calls due to acoustic input from conspecifics alone, via crowd vocal learning. To our knowledge, this is the first study able to distinguish between different explanations for vocal dialects as well as to show crowd vocal learning in a primate species.

1 aZürcher, Yvonne1 aWillems, Erik, P.1 aBurkart, Judith, M.1 aSakata, Jon, T. uhttp://dx.plos.org/10.1371/journal.pone.022248601645nas a2200145 4500008004100000245005300041210005300094520118300147100002001330700002601350700002001376700002401396700002501420856005401445 2019 eng d00aVocal state change through laryngeal development0 aVocal state change through laryngeal development3 a

Across vertebrates, progressive changes in vocal behavior during postnatal development are typically attributed solely to developing neural circuits. How the changing body influences vocal development remains unknown. Here we show that state changes in the contact vocalizations of infant marmoset monkeys, which transition from noisy, low frequency cries to tonal, higher pitched vocalizations in adults, are caused partially by laryngeal development. Combining analyses of natural vocalizations, motorized excised larynx experiments, tensile material tests and high-speed imaging, we show that vocal state transition occurs via a sound source switch from vocal folds to apical vocal membranes, producing louder vocalizations with higher efficiency. We show with an empirically based model of descending motor control how neural circuits could interact with changing laryngeal dynamics, leading to adaptive vocal development. Our results emphasize the importance of embodied approaches to vocal development, where exploiting biomechanical consequences of changing material properties can simplify motor control, reducing the computational load on the developing brain.

1 aZhang, Yisi, S.1 aTakahashi, Daniel, Y.1 aLiao, Diana, A.1 aGhazanfar, Asif, A.1 aElemans, Coen, P. H. uhttp://www.nature.com/articles/s41467-019-12588-601458nas a2200169 4500008004100000245006800041210006800109260001600177490000700193520091600200100002201116700003001138700002601168700001801194700002201212856005401234 2019 eng d00aCognitive control of complex motor behavior in marmoset monkeys0 aCognitive control of complex motor behavior in marmoset monkeys cJan-12-20190 v103 a

Marmosets have attracted significant interest in the life sciences. Similarities with human brain anatomy and physiology, such as the granular frontal cortex, as well as the development of transgenic lines and potential for transferring rodent neuroscientific techniques to small primates make them a promising neurodegenerative and neuropsychiatric model system. However, whether marmosets can exhibit complex motor tasks in highly controlled experimental designs—one of the prerequisites for investigating higher-order control mechanisms underlying cognitive motor behavior—has not been demonstrated. We show that marmosets can be trained to perform vocal behavior in response to arbitrary visual cues in controlled operant conditioning tasks. Our results emphasize the marmoset as a suitable model to study complex motor behavior and the evolution of cognitive control underlying speech.

1 aPomberger, Thomas1 aRisueno-Segovia, Cristina1 aGultekin, Yasemin, B.1 aDohmen, Deniz1 aHage, Steffen, R. uhttp://www.nature.com/articles/s41467-019-11714-801982nas a2200157 4500008004100000022001400041245010800055210006900163260001600232300001600248490000800264520146300272100002001735700001801755856005101773 2018 eng d a0001-496600aFrom behavior to physiology and back again: The role of auditory cortex in vocal production and control0 aFrom behavior to physiology and back again The role of auditory  cJan-09-2018 a1898 - 18990 v1443 a

Vocal communication plays an important role in the lives of both humans and many animal species. Ensuring accurate communication, however, requires auditory self-monitoring to control vocal production and rapidly compensate for errors in vocal output. Despite the importance of this process, the underlying neural mechanisms are relatively unknown. Previous work has demonstrated that neurons in the auditory cortex are suppressed during vocal production, while simultaneously maintaining their sensitivity to vocal feedback, suggesting a role in auditory self-monitoring. The behavioral role of auditory cortex in vocal control, however, remains unclear. We investigated the function of auditory cortical activity during vocal self-monitoring and feedback-dependant vocal control in marmoset monkeys. Using real-time frequency-shifted feedback during vocalization, we demonstrate that marmosets exhibit rapid compensatory changes in vocal production, a feedback-dependent behavior that is predicted by the activities of neurons in auditory cortex. We further establish the role of auditory cortex in vocal control using electrical microstimulation to evoke rapid changes in produced vocalizations. These findings suggest a causal role for the auditory cortex in vocal self-monitoring and feedback-dependent vocal control, linking mechanisms of production and perception, and have important implications for understanding human speech motor control.

1 aEliades, Steven1 aTsunada, Joji uhttp://asa.scitation.org/doi/10.1121/1.506831702567nas a2200205 4500008004100000022001300041245008200054210006900136260001600205520171200221653002301933653002501956653003501981653001302016653002802029653002702057100002202084700002202106856023302128 2018 eng d a0165027000aSemi-chronic laminar recordings in the brainstem of behaving marmoset monkeys0 aSemichronic laminar recordings in the brainstem of behaving marm cJan-10-20183 a

Background

Chronic recordings with multi-electrode arrays are widely used to study neural networks underlying complex primate behaviors. Most of these systems are designed for studying neural activity in the cortical hemispheres resulting in a lack of devices being capable of simultaneously recording from ensembles of neurons in deep brainstem structures. However, to fully understand complex behavior, it is fundamental to also decipher the intrinsic mechanisms of the underlying motor pattern generating circuits in the brainstem.

New Method

We report a light-weight system that simultaneously measures single-unit activity from a large number of recording sites in the brainstem of marmoset monkeys. It includes a base chamber fixed to the animal’s skull and a removable upper chamber that can be semi-chronically mounted to the base chamber to flexibly position an embedded micro-drive containing a 32-channel laminar probe to record from various positions within the brainstem for several weeks.

Results

The current system is capable of simultaneously recording stable single-unit activity from a large number of recording sites in the brainstem of vocalizing marmoset monkeys.

Comparison with Existing Methods

To the best of our knowledge, chronic systems to record from deep brainstem structures with multi-site laminar probes in awake, behaving monkeys do not yet exist.

Conclusions

The semi-chronic implantation of laminar electrodes into the brainstem of behaving marmoset monkeys opens new research possibilities in fully understanding the neural mechanisms underlying complex behaviors in marmoset monkeys.

10aCallithrix jacchus10aimplanted electrodes10alaminar multi-site microprobes10aprimates10asemi-chronic recordings10asingle-unit recordings1 aPomberger, Thomas1 aHage, Steffen, R. uhttps://linkinghub.elsevier.com/retrieve/pii/S0165027018303406https://api.elsevier.com/content/article/PII:S0165027018303406?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0165027018303406?httpAccept=text/plain01928nas a2200169 4500008004100000022001400041245009100055210006900146260001600215300001400231490000800245520138700253100002301640700002101663700002301684856005101707 2018 eng d a0001-496600aClassification of producer characteristics in primate long calls using neural networks0 aClassification of producer characteristics in primate long calls cJan-07-2018 a344 - 3530 v1443 a

Primate long calls are high-amplitude vocalizations that can be critical in maintaining intragroup contact and intergroup spacing, and can encode abundant information about a call's producer, such as age, sex, and individual identity. Long calls of the wild emperor (Saguinus imperator) and saddleback (Leontocebus weddelli) tamarins were tested for these identity signals using artificial neural networks, machine-learning models that reduce subjectivity in vocalization classification. To assess whether modelling could be streamlined by using only factors which were responsible for the majority of variation within networks, each series of networks was re-trained after implementing two methods of feature selection. First, networks were trained and run using only the subset of variables whose weights accounted for ≥50% of each original network's variation, as identified by the networks themselves. In the second, only variables implemented by decision trees in predicting outcomes were used. Networks predicted dependent variables above chance (≥58.7% for sex, ≥69.2 for age class, and ≥38.8% for seven to eight individuals), but classification accuracy was not markedly improved by feature selection. Findings are discussed with regard to implications for future studies on identity signaling in vocalizations and streamlining of data analysis.

1 aRobakis, Efstathia1 aWatsa, Mrinalini1 aErkenswick, Gideon uhttp://asa.scitation.org/doi/10.1121/1.5046526