Heidelberg University (Ohio)

About: Heidelberg University (Ohio) is a education organization based out in Tiffin, Ohio, United States. It is known for research contribution in the topics: Eutrophication & Tributary. The organization has 101 authors who have published 184 publications receiving 8272 citations. The organization is also known as: Heidelberg College & Heidelburg College.

Personality, Motives, and Political Participation

Abstract: Abstract This chapter reviews and discusses research on personality, motives, and political participation. It introduces the concepts of personality and motives and discusses their role within participation research. In particular, the literature on personality traits (“Big Five”) and civic engagement is summarized showing that openness to experience and extraversion are the most important correlates of political participation. Regarding motives, the focus is on the role of political interest, political knowledge, political efficacy, and partisanship as factors that promote political action. Beyond reviewing the existing literature, the chapter argues that the link between psychological factors, like personality traits and motives, and political participation is likely to be context dependent. Empirical analyses shown in this chapter lend support to this argument.

Industry 4.0: Opinion of a Roboticist on Machine Learning [Student’s Corner]

Abstract: History of Industry 4.0 tracks the advancement in the manufacturing process that changed the way we think about human labor in the industry. In the second half of the XVIII century, we find the birth of the first industrialization process with the development of the first steam engine by James Watt as key factor of the first industrial revolution. It was largely beneficial in terms of manufacturing a number of various goods and providing a better standard of living for a wide part of modern world population. Machines allowed faster and easier production, and they made all kinds of innovations and technologies possible as well. Around 1840 the second industrial revolution picked up. Historians sometimes refer to this as “The Technological Revolution” occurring mainly in Britain, Germany and United States.

Editor's evaluation: Two conserved vocal central pattern generators broadly tuned for fast and slow rates generate species-specific vocalizations in Xenopus clawed frogs

Abstract: Full text Figures and data Side by side Abstract Editor's evaluation Introduction Results Discussion Materials and methods Data availability References Decision letter Author response Article and author information Metrics Abstract Across phyla, males often produce species-specific vocalizations to attract females. Although understanding the neural mechanisms underlying behavior has been challenging in vertebrates, we previously identified two anatomically distinct central pattern generators (CPGs) that drive the fast and slow clicks of male Xenopus laevis, using an ex vivo preparation that produces fictive vocalizations. Here, we extended this approach to four additional species, X. amieti, X. cliivi, X. petersii, and X. tropicalis, by developing ex vivo brain preparation from which fictive vocalizations are elicited in response to a chemical or electrical stimulus. We found that even though the courtship calls are species-specific, the CPGs used to generate clicks are conserved across species. The fast CPGs, which critically rely on reciprocal connections between the parabrachial nucleus and the nucleus ambiguus, are conserved among fast-click species, and slow CPGs are shared among slow-click species. In addition, our results suggest that testosterone plays a role in organizing fast CPGs in fast-click species, but not in slow-click species. Moreover, fast CPGs are not inherited by all species but monopolized by fast-click species. The results suggest that species-specific calls of the genus Xenopus have evolved by utilizing conserved slow and/or fast CPGs inherited by each species. Editor's evaluation This important paper compares the neural basis for different calling songs in five species of clawed Xenopus frogs using neural activity recordings combined with lesions of pathways and stimulation of specific parts of the circuit. The evidence supporting the claims is solid and reveals conservation and variation in the circuits generating fast and slow clicks in courtship calls. The work will be of broad interest to neurophysiologists beyond the vocalization topic. https://doi.org/10.7554/eLife.86299.sa0 Decision letter Reviews on Sciety eLife's review process Introduction Closely related species often exhibit dramatically different courtship behavior despite other similarities. This diversity of courtship behavior is a result of sexual selection, which leads to reproductive isolation and speciation (Boughman, 2002; Ritchie, 2007; Ryan, 2021). The nervous system of animals underlying courtship behavior is made up of both ancestral traits inherited through evolutionary lineage and derived traits selected to serve unique functions for a species. Identification of these traits can provide insights into the evolutionary trajectory underlying speciation. For instance, in crickets, the conserved and derived components of the courtship song neural circuitry are distributed along the abdominal ganglia, while in Drosophila, the conserved components are the command neurons that initiate the courtship song, and the derived components are the downstream thoracic neural networks (Ding et al., 2019). However, the strategies employed by the nervous system to introduce behavioral diversity in vertebrates are not well understood, partly due to the lack of reduced preparation for detailed electrophysiological analyses. The courtship vocalizations of the genus Xenopus offer a rare opportunity to explore the evolution of neural circuitry in vertebrates, as reduced preparations are available. All species of Xenopus produce species- and sex-specific vocalizations consisting of a series of clicks produced by the larynx specialized to generate sound under water (Yager, 1992; Kwong-Brown et al., 2019). Male Xenopus use advertisement calls containing a species-specific rate of clicks (0.6–150 Hz) (Tobias et al., 2011; Evans et al., 2015) to attract females, many of which are monophasic (i.e., clicks are repeated at a monotonous rate), while a few are biphasic (i.e. trains of clicks with two distinct rates are contained in a call). In contrast, female Xenopus produce ‘release calls’ consisting of slow clicks (<20 Hz) to escape from clasping males when not gravid. However, administering testosterone to adult female X. laevis results in the production of male-specific advertisement calls in 1–3 months (Potter et al., 2005). Previously, we developed an ex vivo, isolated brain preparation from which fictive vocalizations can be elicited in male and female African clawed frogs, X. laevis (Rhodes et al., 2007). Vocalizations of X. laevis are generated by central pattern generators (CPGs; Marder and Bucher, 2001; Rhodes et al., 2007), neural networks that autonomously produce rhythmic motor programs in the absence of rhythmic central or sensory input (for reviews, see Marder and Bucher, 2001). The advertisement calls of male X. laevis is biphasic and are made of fast and slow trills containing clicks repeated at 60 and 30 Hz, respectively. The male X. laevis vocal pathways consist of the premotor nuclei in the parabrachial nucleus (PBN, formerly known as dorsal tegmental area of the medulla, DTAM) and the laryngeal motor nuclei, the nucleus ambiguus (NA), with extensive reciprocal connections (Brahic and Kelley, 2003). The advertisement call of male X. laevis consists of fast and slow trills containing clicks repeated at 60 and 30 Hz, respectively. We discovered that the fast and slow trills are generated by a pair of anatomically distinct CPGs contained in left and right hemi-brain in male X. laevis: fast trill CPGs contain neurons in the PBNs and NAs, whereas the slow trill CPGs are contained in the caudal brainstem including NAs (Yamaguchi et al., 2017). The aim of the study was to determine if fast and slow trill CPGs discovered in male X. laevis are unique to this species or conserved across species of Xenopus. To this end, we developed ex vivo preparations in males of three additional species, X. amieti, X. cliivi, and X. tropicalis. Using these preparations, we examined the electrophysiological activity of the vocal neural circuitry during fictive advertisement calling in males of four species, including X. petersii (for which a fictive preparation had been previously developed; Barkan et al., 2018), which produce calls containing clicks repeated at variable rates. We also investigated if female X. laevis acquire fast trill-like CPGs or modify an existing CPG network in response to testosterone. Furthermore, we explored whether fast trill-like CPGs are present but remain latent as an evolutionary vestige in species that only produce slow clicks by examining the synapses that serve the critical function of the fast trill-like CPGs. We found that the two CPGs with conserved function and location are shared among species to generate species-specific courtship fast or slow clicks. Additionally, we found that fast trill-like CPGs are present only in species that produce fast clicks and their presence appears to be regulated by testosterone in these species. Results Isolated male brains of all species generate fictive advertisement calls resembling in vivo calls when exposed to appropriate stimuli In this study, we used five species of Xenopus including X. laevis. Advertisement calls from the males of all five species are shown in Figure 1A as in vivo calls. The click rates and the number of clicks contained in advertisement calls of each species are summarized in Figure 1B and C as in vivo data. Out of the males of five species we studied, two species produced advertisement calls that contained clicks repeated only at rates >50 Hz (i.e. monophasic calls as previously described) – X. amieti (mean ± s.e., 143.0±2.90 Hz), X. cliivi (59.82±6.50 Hz), one species produced advertisement calls containing clicks repeated only at rates <35 Hz – X. tropicalis (31.9+1.18 Hz), and two species produced advertisement calls with both fast (>50 Hz) and slow (<35 Hz) clicks (i.e. biphasic calls as previously described) – X. petersii (69.9+2.02 Hz, 31.3+1.99 Hz), and X. laevis (58.3+2.47 Hz), 38.4+2.98 Hz. Figure 1 with 1 supplement see all Download asset Open asset Phylogeny of five species of Xenopus and their advertisement calls. (A). Chronogram, in vivo vocalizations, and fictive vocalizations recorded from males of each species. Left column: chronogram based on mitochondrial DNA (Modified from Evans et al., 2015) of studied species. Middle column: amplitude envelope (top panel) and sound spectrogram (bottom panel) of in vivo advertisement calls. Right column: fictive advertisement calls recorded ex vivo from the isolated brain. The green and blue background of traces indicate fast (>50 Hz) and slow (<35 Hz) clicks, respectively, and the vertical lines below the fictive vocalizations labeled with ‘stim’ indicate electrical stimuli applied to the rostral-lateral cerebellum (RLCB, D) to elicit fictive calls in some brains. The type of stimulus following the species name indicates what was used to elicit the fictive calls shown, and those in parenthesis are other stimulus types that are also effective in eliciting fictive calls. (B). Comparison of click and compound action potential (CAP) rates of calls recorded in vivo and ex vivo from each species. Each circle with an error bar indicates the mean + s.e. of click or CAP rates (in Hz). For both B and C, asterisks preceding the species name indicate significant differences between the rates of clicks/CAPs produced in vivo and ex vivo. Note that some error bars are hidden behind the data points due to the small size. (C). The number of clicks/CAPS in a call recorded in vivo and ex vivo. Each circle with an error bar indicates the mean + s.e. of click/CAP number. The first and the second sample sizes after species name refers to in vivo and fictive data, respectively. (D). The location of the rostral-lateral cerebellum (RLCB), a site that is effective in eliciting fictive calls when stimulated electrically. Left; a cartoon showing the dorsal view of an isolated brain of Xenopus. The double headed arrow indicates rostral (R) and caudal (C) orientation of the brain. When dextran dye was injected into the nucleus ambiguus (NA), axons of projection neurons in the NA and the parabrachial nucleus (PBN) that project reciprocally to each other are labeled and can be viewed from the dorsal surface of the brain as seen in the photo on the right. The area at the lateral edge of the cerebellum (CB) along the labeled projections is the RLCB (white arrow). Delivering stimulus pulses to this area using a concentric electrode elicits fictive calls in most brains except in the brain of X. tropicalis. CB; cerebellum, CN V; cranial nerve V, NA; nucleus ambiguus, OB; olfactory bulb. OT; optic tectum, PB; parabrachial nucleus, T; telencephalon. Next, we developed a method to obtain fictive vocalizations from isolated brains of the males of all the Xenopus species used in this study. Previous studies had shown that application of serotonin (5HT) to the isolated brains of male X. laevis and X. petersii readily elicited fictive advertisement calls (Rhodes et al., 2007; Barkan and Zornik, 2019). In this study, we found that we could also induce fictive advertisement calls from the isolated brains of three additional species (Figure 1A, right column), but the types of stimuli required varied depending on species. For instance, 5HT alone did not elicit fictive calls from the brains of X. tropicalis (Figure 1—figure supplement 1A, n=7), but a combination of 5HT and N-methylaspartate (NMA, Figure 1A, right column, Figure 1—figure supplement 1A) was effective. In contrast, neither 5HT alone nor 5HT and NMA together induced fictive calls from the isolated brains of X. amieti and X. cliivi (Figure 1—figure supplement 1B, top trace, for example). However, trains of electrical pulses delivered to the rostral-lateral cerebellum (RLCB, Figure 1D) readily evoked fictive advertisement calls (Figure 1A, right column, Figure 1—figure supplement 1B). The RLCB is the region in the brain where the ascending and descending axons of the projection neurons in the parabrachial nucleus (PB) and the nucleus ambiguus (NA) are located close to the surface of the brain. Dextran dye injected into NA that labeled anterograde and retrograde axons allowed us to visualize this location (Figure 1D). Electrically stimulating RLCB likely activates a previously unidentified component of the central vocal pathways that initiates vocalizations. Interestingly, electrical stimulation delivered to the RLCB was effective in evoking fictive advertisement calls from all males tested in this study (Figure 1—figure supplement 1C, for example), except for male X. tropicalis (Figure 1—figure supplement 1A, n=6). The stimulus pulse duration used was 40us with a frequency ranging from 10 to 100 Hz, amplitudes varying from 0.7 to 6mA, and a pulse count ranging from 3 to 30. Effective stimulus parameters varied greatly between preparations, and there was no observable difference in the effective parameters between species. The temporal structure of fictive advertisement calls closely resembled the calls recorded in vivo, as shown by comparing the sound amplitude envelope (top traces for each species) on the left column and the fictive call traces on the right column in Figure 1A. Although the exact rate of compound action potentials (CAPs) is significantly slower (Figure 1B) and the number of CAPs contained in fictive calls differ from the calls recorded in vivo in some species (Figure 1C), the overall temporal structure is well preserved in all species. Parabrachial nuclei activity coincides with fictive advertisement calls that contain compound action potentials repeated at frequency above 50Hz Previously, we found that in male X. laevis, the parabrachial nucleus (PBN) is active during fictive fast trills, but remains inactive or exhibits minimal activity (less than twice the amplitude of the noise) during fictive slow trills. (Yamaguchi et al., 2017; Figure 2Aiv). Here, we investigated whether this observation applies to males of other species including X. amieti, X. cliivi, X. petersii, and X. tropicalis. The results showed that in all these species, the PBN was predominantly active during fictive calls that contain compound action potentials (CAPs) repeated at rates faster than 50 Hz (indicated by traces with a green background in Figure 2A), but not during fictive calls containing CAPs repeated at rates below 35 Hz (indicated by traces with blue background in Figure 2A). In male X. amieti, X. cliivi, and X. petersii a PBN local field potential (LFP) showed phasic activity that correlated with the CAPs during fictive calls containing CAPs faster than 50 Hz, similar to what was observed in male X. laevis during fictive fast trills (indicated by all traces with green background in Figure 2A). The mean power spectral density (PSD) of the PBN LFP waveform (normalized to the maximum power for each animal) showed a clear peak at the frequency corresponding to the CAP repetition rates, as was also observed in male X. laevis (Figure 2C). However, in specie with slow clicks in their advertisement calls (slow trills of male X. petersii and the advertisement calls of male X. tropicalis), the PBN activity was mostly absent during fictive slow clicks (Figure 2A, traces with blue background). In a few brains, some PBN LFP phase-locked to CAPs was observed during slow CAPs (Figure 2A, see LFP during slow trills of male X. petersii and male X. laevis), but the LFP amplitude was significantly lower than that during fictive fast clicks (Figure 2A, see the amplitude of LFP during slow trills of male X. petersii and male X. laevis compared to that during fast trills). Consequently, the mean normalized PSD of the PBN LFP recorded during fictive slow clicks showed no clear peak (Figure 2B). Figure 2 Download asset Open asset The activity of the parabrachial nucleus during fictive advertisement calls. (A). Local field potential (LFP) recordings obtained from the parabrachial nucleus (PBN) during fictive advertisement calling in male X. amieti (i), male X. cliivi (ii), male X. peterii (iii), male X. laevis (iv), and male X. tropicalis (v). Top traces; laryngeal nerve recording, bottom traces: PBN LFP recordings. The green and blue backgrounds indicate fast (>50 Hz) and slow (<35 Hz) compound action potentials (CAPs), respectively. Vertical lines below the traces labeled with ‘stim’ indicate the timing of electrical pulses delivered to the RLCB (Figure 1D) to elicit fictive advertisement calls in some cases. (B). mean power spectral density (PSD) of PBN LFP recordings during fictive slow clicks seen in A. Blue frames show the mean ± std of the CAP rates for slow clicks. (C). Mean PSD of PBN LFP recordings during fictive fast clicks seen in A. Green frames show the mean ± std of the CAP rates for fast clicks. For brevity, we will refer to all clicks and compound action potentials (CAPs) repeated at a rate >50 Hz as ‘fast clicks/CAPs’, and the species that generate them (male X. amieti, X. cliivi, X. petersii, and X. laevis) as ‘fast clicker’ even if their advertisement calls also include slow clicks (i.e. male X. petersii and male X. laevis). Similarly, we refer to all clicks and CAPs repeated at a rate <35 Hz as ‘slow clicks/CAPs’ and the species that produce only slow clicks (i.e. male X. tropicalis) as ‘slow clickers’. It is important to note that the vocal repertoire of Xenopus species includes calls other than advertisement calls. Male X. laevis, for example, produce amplectant clicks (10 Hz) when clasping gravid females (Tobias et al., 2004) and ‘ticking’ when clasped by a male (Tobias et al., 2014). In this study, we discovered that male X. cliivi and X. amieti produce novel calls containing clicks repeated at 6–20 Hz (with single or double clicks as repetition units) in the presence of conspecific males. We named these calls ‘long-slow calls’ (Figure 3A and C). Fortuitously, we recorded these fictive calls containing slower CAP rates generated spontaneously from isolated brains, including long-slow calls from one male X. amieti (Figure 3B) and two male X. cliivi brains (Figure 3D), amplectant clicks from four male X. laevis (Figure 3E left), and ticking from three male X. laevis (Figure 3E middle). When PBN LFP recordings during these slow fictive calls were examined, we found that the PBNs were either silent (Figure 3B and E amplectant call) or showed activity (Figure 3D and E, release calls) significantly lower in amplitude than activity accompanying fictive fast clicks (Figure 3B, D and E right panels). These results suggest that, regardless of the vocal repertoire of the species, the PBN does not play a significant role, if any, in producing fictive slow clicks (<35 Hz) compared to its role in producing fast clicks (>50 Hz). Figure 3 Download asset Open asset Calls produced by fast clickers containing slow (<35 Hz) clicks are not accompanied by salient parabrachial nucleus activity. (A, C), Amplitude envelope (top) and the sound spectrogram (bottom) of a ‘long slow call’ produced by male X. amieti (A) and male X. cliivi (C) in vivo. (B, D), Presumed fictive long slow call(left with blue background) and fictive advertisement call (right with green background) obtained from the same brain of a male X. amieti (B) and male X. cliivi (D). Top; Laryngeal motor nerve recordings, bottom; parabrachial nucleus (PBN) local field potential (LFP) recordings. The same Y scale for the PBN LFP (but with an extended X scale) is used for both fictive calls for ease of amplitude comparison. (E). A fictive amplectant call (left), fictive ticking (middle), and fictive advertisement call (right) recorded from a brain of the same male X. laevis. Top; laryngeal nerve recording, bottom; PBN LFP recording. The Y scale for the PB LFP recordings (but not the X scale) is the same for all three recordings for ease of amplitude comparison. After testosterone-induced vocal masculinization, the parabrachial nucleus of female Xenopus laevis, which was silent during fictive release calls, becomes active Previously, we showed that adult female X. laevis, which normally produce release calls containing clicks trains at a rate of ~6 Hz (Figure 4A), can generate male-like advertisement calls within 1–3 months of testosterone treatment (Figure 4B; Potter et al., 2005). Our objective was to determine whether female X. laevis use slow trill-like central pattern generators (CPGs), like those observed in male X. laevis, to produce release calls. Additionally, we aimed to determine if females acquire fast trill-like CPGs or continue to use the existing slow trill-like CPGs to produce masculinized fast click calls. To this end, we examined the activity of parabrachial nucleus (PBN) during vocal production in control and testosterone-treated female X. laevis. Figure 4 Download asset Open asset The parabrachial nucleus that is silent during release calling in female X. laevis becomes active after testosterone-induced vocal masculinization. (A, B) Amplitude envelope (top) and sound spectrogram (bottom) of a release call (A) and advertisement call (B) recorded in vivo from female X. laevis and testosterone-treated female X. laevis. The blue and green background behind the amplitude envelope indicates slow (<35 Hz) and fast (>50 Hz) clicks, respectively. (C) Click repetition rates and click number per call recorded in vivo and ex vivo from female X. laevis and testosterone-treated female X. laevis. Each triangle with an error bar indicates the mean ± s.e. of click repetition rate (top) and click number per call (bottom). The names of the animal preceded by an asterisk indicate a significant difference between the in vivo and fictive calls. The sample sizes following species name refer to in vivo and fictive data, respectively. (D, E) Fictive release call and advertisement calls recorded from an isolated brain of a female X. laevis and testosterone-treated female X. laevis. Top trace; laryngeal nerve recordings, bottom trace; local field potential (LFP) recordings obtained from the parabrachial nucleus (PBN). The blue and green background behind the amplitude envelope indicates slow (<35 Hz) and fast (>50 Hz) clicks, respectively. The type of stimulus following the species name indicates what was used to elicit the fictive calls shown, and that in parenthesis is another stimulus type that is also effective in eliciting fictive calls. Compare the PBN activity during fast trills to those recorded from the intact female during fictive release calling. (F, G) Mean power spectral density (PSD) of PBN LFP recordings during fictive release calling in female X. laevis (F) and fictive advertisement calling in testosterone-treated female X. laevis (G). Blue and green frames show the mean + std of the CAP rates for fictive release calls, slow trills, and fast trills. The application of serotonin (5HT) elicited fictive release calls and advertisement calls from the isolated brains of control and testosterone-treated female X. laevis, respectively (Figure 4D and E). In testosterone-treated females, electrical stimulation delivered to the rostral-lateral cerebellum (RLCB) also elicited fictive advertisement calls. Although the exact rate and the number of compound action potentials (CAPs) in the fictive calls are significantly different in some cases (Figure 4C), the overall temporal structure resemble those of calls recorded in vivo (Figure 4A, B, D and E). In control females, the PBN remained silent during fictive release calls in all animals tested (n=13, Figure 4D bottom trace). The mean power spectral density (PSD) of the PBN local field potential (LFP) during fictive release calls showed no peak (Figure 4F). In contrast, in testosterone-treated female X. laevis, the PBN showed phasic activity coinciding with CAPs during fast trills, but not during slow trills (Figure 4E), similar to male X. laevis. The mean PSD of the PBN LFP during fast trills had peaks between 50 and 60 Hz (Figure 4G left graph) while no peak is evident during slow trills (Figure 4G right graph), like male X. laevis (Figure 2A and C). Thus, we conclude that testosterone enables the recruitment of female PBNs to generate the phasic activity that accompanies fictive fast trills. Results obtained from males and females Xenopus show that the presence of PBN activity is associated with the CAP repetition rates. During fictive calls with CAP rates greater than 50 Hz, PBN shows activity phase-locked to the CAPs, whereas during fictive calls with CAP rates slower than 35 Hz, the PBN shows almost no activity in all species and sexes examined. Throughout the rest of our analyses, we refer to control and testosterone-treated female X. laevis as slow and fast clickers, respectively. Unilateral transection between the parabrachial nucleus and the nucleus ambiguus desynchronizes left and right laryngeal nerve activity during fast, but not slow clicks in five Xenopus species Previously, we showed that transected left and right hemi-brains of male X. laevis can generate both fast and slow trills, indicating that there are pairs of fast and slow trill central pattern generators (CPGs) in the left and right brainstem (Figure 5A, left schematic; Yamaguchi et al., 2017). When we unilaterally transected the projections between the parabrachial nucleus (PBN) and the nucleus ambiguus (NA) (Figure 5B, left schematic), the brain still produced fictive advertisement calls, but the compound action potentials (CAPs) from the two nerves desynchronize during fast trill only, not during slow trills (Figure 5B and C Yamaguchi et al., 2017). Based on these results, we concluded that the fast trill CPGs span between the PBN and NA (Figure 5A left, green oscillators), whereas the slow trill CPGs are confined to the caudal brainstem (Figure 5A left, blue oscillators). When fast trill CPGs on the transected side become dysfunctional, signals from the functional fast trill CPGs on the intact side are transmitted to the non-functional side during fast trills, causing a delay in the production of the CAPs on the transected side compared to the intact side (Figure 5B and C; Yamaguchi et al., 2017). However, CAPs during slow trills of the transected brain remain unaffected since slow trill CPGs on both sides are functional. Here, we investigated the effect of unilateral transection between the PBN and NA on CAP synchrony in fast and slow clickers to determine if fast trill-like and slow trill-like CPGs are present in the brains of fast and slow clickers. Figure 5 Download asset Open asset A model of fast trill and slow trill central pattern generators (CPGs) in male Xenopus laevis based on a previous study (Yamaguchi et al., 2017). (A). Left and right fast trill CPGs (green) span across the parabrachial nucleus (PBN) and the nucleus ambiguus (NA) whereas the slow trill CPGs (blue) are contained in the NA. The left and right CPGs coordinate their activity via reciprocal projection (shown as double-headed horizontal arrows). During fast and slow trills of a fictive advertisement call, compound action potentials (CAPs) produced by the left (blue) and right (red) laryngeal nerves are synchronous. (B). When a right PBN and right NA are transected (scissors with dotted line), the right fast trill CPGs become dysfunctional while the left fast trill CPGs and both slow trill CPGs remain functional. When a fictive advertisement call is elicited from the transected brain, the CAPs produced by the nerve on the transected side (right) were delayed compared to those produced by the nerve on the intact side (left) during fast trill, but not during slow trills. This delay is likely caused by the fact that the laryngeal motoneurons on the transected side (right) are driven by the fast trill CPGs on the intact (left) side during the fast trill. However, during slow trill, slow trill CPGs on both sides remain functional even after the transection, and therefore, there is no delay between the two nerves. (C). Cross-correlation coefficient as a function of lag time between left and right laryngeal nerve recording. In the control brain, the maximum cross-correlation coefficient is zero, and the activity of the two nerves is synchronous. The lag time of the maximum cross-correlation coefficient becomes positive during fast, but not during slow trills after the transection. First, we confirmed that CAPs recorded from the left and right laryngeal nerves are synchronous during fictive calls (a measure of CAP synchrony, see Methods). When the maximum lag time between the left and right CAPs (a measure of synchrony, see Materials and methods) during both fictive slow and fast clicks were compared, they did not differ significantly from zero (slow clicks: one-sample sign test, p=0.557, n=26 including 11 male X. tropicalis, 4 male X. petersii, 9 female X. laevis, and 2 testosterone-treated female X. laevis Figure 6G control, fast clicks: P>0.790, n=14 including 4 male X. amieti, 3 male X. cliivi, 5 male X. petersii, and 2 testosterone-treated female X. laevis, Figure 7E control), indicating that CAPs recorded from the two nerves are synchronous during both fast and slow clicks in all intact brains. We also verified the completeness of the unilateral transection anatomically (Figure 6A) by depositing fluorescent dextran into the NA post-hoc and checking the absence of the labeled soma and axon terminals in the PBN on the transected side (Figure 6B). Figure 6 Download asset Open asset The unilateral transection between the parabrachial nucleus (PBN) and the nucleus ambiguus (NA) did not change the synchrony of the compound action potentials (C