Ontogeny of Inner Ear Saccular Development in the Plainfin Midshipman (Porichthys notatus)

2021 ◽  
pp. 1-11
Author(s):  
Nicholas R. Lozier ◽  
Joseph A. Sisneros

The auditory system of the plainfin midshipman fish (<i>Porichthys notatus</i>) is an important sensory system used to detect and encode biologically relevant acoustic stimuli important for survival and reproduction including social acoustic signals used for intraspecific communication. Previous work showed that hair cell (HC) density in the midshipman saccule increased seasonally with reproductive state and was concurrent with enhanced auditory saccular sensitivity in both females and type I males. Although reproductive state-dependent changes in HC density have been well characterized in the adult midshipman saccule, less is known about how the saccule changes during ontogeny. Here, we examined the ontogenetic development of the saccule in four relative sizes of midshipman (larvae, small juveniles, large juveniles, and nonreproductive adults) to determine whether the density, total number, and orientation patterns of saccular HCs change during ontogeny. In addition, we also examined whether the total number of HCs in the saccule differ from that of the utricle and lagena in nonreproductive adults. We found that HC density varied across developmental stage. The ontogenetic reduction in HC density was concurrent with an ontogenetic increase in macula area. The orientation pattern of saccular HCs was similar to the standard pattern previously described in other teleost fishes, and this pattern of HC orientation was retained during ontogeny. Lastly, the estimated number of saccular HCs increased with developmental stage from the smallest larvae (2,336 HCs) to the largest nonreproductive adult (145,717 HCs), and in nonreproductive adults estimated HC numbers were highest in the saccule (mean ± SD = 28,479 ± 4,809 HCs), intermediate in the utricle (mean ± SD = 11,008 ± 1,619 HCs) and lowest in the lagena (mean ± SD = 4,560 ± 769 HCs).

2009 ◽  
Vol 102 (2) ◽  
pp. 1121-1131 ◽  
Author(s):  
Joseph A. Sisneros

The plainfin midshipman fish, Porichthys notatus, is a seasonally breeding species of marine teleost fish that generates acoustic signals for intraspecific social and reproductive-related communication. Female midshipman use the inner ear saccule as the main acoustic endorgan for hearing to detect and locate vocalizing males that produce multiharmonic advertisement calls during the breeding season. Previous work showed that the frequency sensitivity of midshipman auditory saccular afferents changed seasonally with female reproductive state such that summer reproductive females became better suited than winter nonreproductive females to encode the dominant higher harmonics of the male advertisement calls. The focus of this study was to test the hypothesis that seasonal reproductive-dependent changes in saccular afferent tuning is paralleled by similar changes in saccular sensitivity at the level of the hair-cell receptor. Here, I examined the evoked response properties of midshipman saccular hair cells from winter nonreproductive and summer reproductive females to determine if reproductive state affects the frequency response and threshold of the saccule to behaviorally relevant single tone stimuli. Saccular potentials were recorded from populations of hair cells in vivo while sound was presented by an underwater speaker. Results indicate that saccular hair cells from reproductive females had thresholds that were ∼8 to 13 dB lower than nonreproductive females across a broad range of frequencies that included the dominant higher harmonic components and the fundamental frequency of the male's advertisement call. These seasonal-reproductive-dependent changes in thresholds varied differentially across the three (rostral, middle, and caudal) regions of the saccule. Such reproductive-dependent changes in saccule sensitivity may represent an adaptive plasticity of the midshipman auditory sense to enhance mate detection, recognition, and localization during the breeding season.


2020 ◽  
Vol 223 (14) ◽  
pp. jeb225177
Author(s):  
Brooke J. Vetter ◽  
Joseph A. Sisneros

ABSTRACTThe plainfin midshipman fish (Porichthys notatus) is an established model for investigating acoustic communication because the reproductive success of this species is dependent on the production and reception of social acoustic signals. Previous work showed that female midshipman have swim bladders with rostral horn-like extensions that project close to the saccule and lagena, while nesting (type I) males lack such rostral swim bladder extensions. The relative close proximity of the swim bladder to the lagena should increase auditory sensitivity to sound pressure and higher frequencies. Here, we test the hypothesis that the swim bladder of female midshipman enhances lagenar sensitivity to sound pressure and higher frequencies. Evoked potentials were recorded from auditory hair cell receptors in the lagena in reproductive females with intact (control condition) and removed (treated condition) swim bladders while pure tone stimuli (85–1005 Hz) were presented by an underwater speaker. Females with intact swim bladders had auditory thresholds 3–6 dB lower than females without swim bladders over a range of frequencies from 85 to 405 Hz. At frequencies from 545 to 1005 Hz, only females with intact swim bladders had measurable auditory thresholds (150–153 dB re. 1 µPa). The higher percentage of evoked lagenar potentials recorded in control females at frequencies >505 Hz indicates that the swim bladder extends the bandwidth of detectable frequencies. These findings reveal that the swim bladders in female midshipman can enhance lagenar sensitivity to sound pressure and higher frequencies, which may be important for the detection of behaviorally relevant social signals.


2020 ◽  
Vol 223 (17) ◽  
pp. jeb226464
Author(s):  
Loranzie S. Rogers ◽  
Joseph A. Sisneros

ABSTRACTThe plainfin midshipman, Porichthys notatus, is a soniferous marine teleost fish that generates acoustic signals for intraspecific social communication. Nocturnally active males and females rely on their auditory sense to detect and locate vocally active conspecifics during social behaviors. Previous work showed that the midshipman inner ear saccule and lagena are highly adapted to detect and encode socially relevant acoustic stimuli, but the auditory sensitivity and function of the midshipman utricle remain largely unknown. Here, we characterized the auditory evoked potentials from hair cells in the utricle of non-reproductive type I males and tested the hypothesis that the midshipman utricle is sensitive to behaviorally relevant acoustic stimuli. Hair cell potentials were recorded from the rostral, medial and caudal regions of the utricle in response to pure tone stimuli presented by an underwater speaker. We show that the utricle is highly sensitive to particle motion stimuli produced by an underwater speaker positioned in the horizontal plane. Utricular potentials were recorded across a broad range of frequencies with lowest particle acceleration (dB re. 1 m s−2) thresholds occurring at 105 Hz (lowest frequency tested; mean threshold −32 dB re. 1 m s−2) and highest thresholds at 605–1005 Hz (mean threshold range −5 to −4 dB re. 1 m s−2). The high gain and broadband frequency sensitivity of the utricle suggest that it likely serves a primary auditory function and is well suited to detect conspecific vocalizations including broadband agonistic signals and the multiharmonic advertisement calls produced by reproductive type I males.


Behaviour ◽  
2014 ◽  
Vol 151 (8) ◽  
pp. 1209-1227 ◽  
Author(s):  
Karen M. Cogliati ◽  
Sigal Balshine ◽  
Bryan D. Neff

There has been much debate about how male alternative reproductive tactics (ARTs) evolve. In particular, researchers question whether ARTs have evolved as a conditional, ‘best of a bad job’ strategy where one tactic has higher fitness than the other, or whether they have evolved as a result of a genetic polymorphism where both tactics have equal fitness. Despite the large number of species known to have ARTs, tests of equal fitness between tactics have only been conducted in a handful of species. We tested the prediction of equal fitness using the plainfin midshipman (Porichthys notatus), a species with two well characterized male ARTs: guarding type I males and cuckolding type II males. We collected data across three years and three sampling locations to determine the proportion of each reproductive tactic, as well as the proportion of offspring sired by each male type using microsatellite markers. Our analysis suggests that males adopting the conventional guarding tactic likely have higher fitness compared to males adopting the cuckolder type II tactic. Also, we show that the guarding male tactic is able to gain paternity through cuckoldry, and that these males, who sometimes guard and sometimes cuckold, are responsible for the majority of paternity lost within nests. Indeed, the classic cuckolding type II males were responsible for only a small fraction of the paternity lost. These results highlight the degree of flexibility in male behaviour even among individuals adopting the same male tactic. Taken together, our results provide the first exploration of the evolution of male ARTs in plainfin midshipman and, given the tractability of midshipman system, a valuable next step will be to look for gene-by-environment interactions on tactic development and expression.


Endocrinology ◽  
2014 ◽  
Vol 155 (12) ◽  
pp. 4868-4880 ◽  
Author(s):  
Masaharu Hasebe ◽  
Shinji Kanda ◽  
Hiroyuki Shimada ◽  
Yasuhisa Akazome ◽  
Hideki Abe ◽  
...  

Kisspeptin (Kiss) neurons show drastic changes in kisspeptin expression in response to the serum sex steroid concentration in various vertebrate species. Thus, according to the reproductive states, kisspeptin neurons are suggested to modulate various neuronal activities, including the regulation of GnRH neurons in mammals. However, despite their reproductive state-dependent regulation, there is no physiological analysis of kisspeptin neurons in seasonal breeders. Here we generated the first kiss1-enhanced green fluorescent protein transgenic line of a seasonal breeder, medaka, for histological and electrophysiological analyses using a whole-brain in vitro preparation in which most synaptic connections are intact. We found histologically that Kiss1 neurons in the nucleus ventralis tuberis (NVT) projected to the preoptic area, hypothalamus, pituitary, and ventral telencephalon. Therefore, NVT Kiss1 neurons may regulate various homeostatic functions and innate behaviors. Electrophysiological analyses revealed that they show various firing patterns, including bursting. Furthermore, we found that their firings are regulated by the resting membrane potential. However, bursting was not induced from the other firing patterns with a current injection, suggesting that it requires some chronic modulations of intrinsic properties such as channel expression. Finally, we found that NVT Kiss1 neurons drastically change their neuronal activities according to the reproductive state and the estradiol levels. Taken together with the previous reports, we here conclude that the breeding condition drastically alters the Kiss1 neuron activities in both gene expression and firing activities, the latter of which is strongly related to Kiss1 release, and the Kiss1 peptides regulate the activities of various neural circuits through their axonal projections.


2015 ◽  
Vol 291 (2) ◽  
pp. 837-847 ◽  
Author(s):  
Yuki Taga ◽  
Masashi Kusubata ◽  
Kiyoko Ogawa-Goto ◽  
Shunji Hattori

2020 ◽  
Vol 32 (1) ◽  
pp. 3
Author(s):  
Saskia Bosch ◽  
Pierre Viviers ◽  
Wayne Derman ◽  
Richard De Villiers

Background: In an acute field-side setting, it is often challenging to differentiate benign sports-related concussion (SRC) from potential, more sinister, intracranial pathology. Moreover, recovery in the ensuing days and weeks is often complex as the resolution of classical signs and symptoms does not always follow a standard pattern. Aim: To highlight the value of a structured and repeated thorough clinical assessment approach toward SRC, particularly as atypical and unexpected sequences in patient recovery patterns may require further specialist referral and intervention. Findings: A football goalkeeper sustained a concussion in which symptoms failed to resolve as expected. Deterioration in his clinical condition led to an eventual diagnosis of Chiari malformation (type I), which required surgical intervention.Implications: Non-typical recovery patterns of concussion may be indicative of increased severity when considered retrospectively. However, clinicians should not discount the possibility of underlying conditions. Keywords: concussion, soccer, sports-related head injury


2021 ◽  
Author(s):  
Jose Manuel Latorre Estivalis ◽  
Ewald Grosse-Wilde ◽  
Gabriel R Fernandes ◽  
Bill S Hansson ◽  
Marcelo Gustavo Lorenzo

Background Triatomine bugs are the blood feeding insect vectors transmitting Chagas disease to humans, a neglected tropical disease that affects over 8 million people, mainly in Latin America. The behavioral responses to host cues and bug signals in Rhodnius prolixus are state dependent, i.e., they vary as a function of post-ecdysis age. At the molecular level, these changes in behavior are probably due to a modulation of peripheral and central processes. In the present study, we report a significant modulation of the expression of a large set of sensory-related genes. Results were generated by means of antennal transcriptomes of 5th instar larvae along the first week (days 0, 2, 4, 6 and 8) after ecdysis sequenced using the Illumina platform. Results Age induced significant changes in transcript abundance were established in more than 6,120 genes (54,7 % of 11,186 genes expressed) in the R. prolixus antenna. This was especially true between the first two days after ecdysis when more than 2,500 genes had their expression significantly altered. In contrast, expression profiles were almost identical between day 6 and 8, with only a few genes showing significant modulation of their expression. A total of 86 sensory receptors, odorant carriers and odorant degrading enzymes were significantly modulated across age points and clustered into three distinct expression profiles. Conclusions The set of sensory genes whose expression increased with age (profile 3) may include candidates underlying the increased responsiveness to host cues shown by R. prolixus during the first days after molting. For the first time, we describe the maturation process undergone at the molecular level by the peripheral sensory system is described in an hemimetabolous insect.


2019 ◽  
Vol 222 (14) ◽  
pp. jeb204552 ◽  
Author(s):  
Orphal Colleye ◽  
Brooke J. Vetter ◽  
Robert A. Mohr ◽  
Lane H. Seeley ◽  
Joseph A. Sisneros

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