scholarly journals Catecholaminergic Fiber Innervation of the Vocal Motor System Is Intrasexually Dimorphic in a Teleost with Alternative Reproductive Tactics

2015 ◽  
Vol 86 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Zachary N. Ghahramani ◽  
Miky Timothy ◽  
Gurpreet Kaur ◽  
Michelle Gorbonosov ◽  
Alena Chernenko ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Motor System ◽  
Advertisement Call ◽  
Motor Nucleus ◽  
Type I ◽  
Type Ii ◽  
Fiber Density ◽  
Reproductive Tactics ◽  
Long Duration ◽  
Behavioral Divergence

Catecholamines, which include the neurotransmitters dopamine and noradrenaline, are known modulators of sensorimotor function, reproduction, and sexually motivated behaviors across vertebrates, including vocal-acoustic communication. Recently, we demonstrated robust catecholaminergic (CA) innervation throughout the vocal motor system in the plainfin midshipman fish Porichthys notatus, a seasonal breeding marine teleost that produces vocal signals for social communication. There are 2 distinct male reproductive morphs in this species: type I males establish nests and court females with a long-duration advertisement call, while type II males sneak spawn to steal fertilizations from type I males. Like females, type II males can only produce brief, agonistic, grunt type vocalizations. Here, we tested the hypothesis that intrasexual differences in the number of CA neurons and their fiber innervation patterns throughout the vocal motor pathway may provide neural substrates underlying divergence in reproductive behavior between morphs. We employed immunofluorescence (-ir) histochemistry to measure tyrosine hydroxylase (TH; a rate-limiting enzyme in catecholamine synthesis) neuron numbers in several forebrain and hindbrain nuclei as well as TH-ir fiber innervation throughout the vocal pathway in type I and type II males collected from nests during the summer reproductive season. After controlling for differences in body size, only one group of CA neurons displayed an unequivocal difference between male morphs: the extraventricular vagal-associated TH-ir neurons, located just lateral to the dimorphic vocal motor nucleus (VMN), were significantly greater in number in type II males. In addition, type II males exhibited greater TH-ir fiber density within the VMN and greater numbers of TH-ir varicosities with putative contacts on vocal motor neurons. This strong inverse relationship between the predominant vocal morphotype and the CA innervation of vocal motor neurons suggests that catecholamines may function to inhibit vocal output in midshipman. These findings support catecholamines as direct modulators of vocal behavior, and differential CA input appears reflective of social and reproductive behavioral divergence between male midshipman morphs.

scholarly journals Antioxidant Gene Expression in Vocal Hindbrain of a Teleost Fish

2018 ◽  
Author(s):  
Clara Liao ◽  
Ni Y. Feng ◽  
Andrew H. Bass
Keyword(s):  
Oxidative Stress ◽  
Breeding Season ◽  
Motor Neurons ◽  
Sound Production ◽  
Cellular Respiration ◽  
Type I ◽  
Type Ii ◽  
Antioxidant Genes ◽  
Long Duration ◽  
Significant Difference

ABSTRACTPlainfin midshipman fish (Porichthys notatus) have a remarkable capacity to generate long duration advertisement calls known as hums, each of which may last for close to two hours and be repeated throughout a night of courtship activity during the breeding season. The midshipman’s striking sound production capabilities provide a unique opportunity to investigate the mechanisms that motor neurons require for withstanding high-endurance activity. The temporal properties of midshipman vocal behaviors are largely controlled by a hindbrain central pattern generator that includes vocal motor neurons (VMN) that directly determine the activity pattern of target sonic muscles and, in turn, a sound’s pulse repetition rate, duration and pattern of amplitude modulation. Of the two adult midshipman male reproductive phenotypes -- types I and II-- only type I males acoustically court females with hums from nests that they build and guard, while type II males do not produce courtship hums but instead sneak or satellite spawn to steal fertilizations from type I males. A prior study using next generation RNA sequencing showed increased expression of a number of cellular respiration and antioxidant genes in the VMN of type I males during the breeding season, suggesting they help to combat potentially high levels of oxidative stress linked to this extreme behavior. This led to the question of whether the expression of these genes in the VMN would vary between actively humming versus non-humming states as well as between male morphs. Here, we tested the hypothesis that to combat oxidative stress, the VMN of reproductively active type I males would exhibit higher mRNA transcript levels for two superoxide dismutases (sod1,sod2) compared to the VMN of type II males and females that do not hum and in general both of which have a more limited vocal repertoire than type I males. The results showed no significant difference insod1transcript expression across reproductive morphs in the VMN and the surrounding hindbrain, and no difference ofsod2across the two male morphs and females in the SH. However, we observed a surprising, significantly lower expression ofsod2transcripts in the VMN of type I males as compared to type II males. We also found no significant difference insod1andsod2expression between actively humming and non-humming type I males in both the VMN and surrounding hindbrain. These findings overall lead us to conclude that increased transcription ofsod1andsod2is not necessary for combatting oxidative stress from the demands of the midshipman high-endurance vocalizations, but warrant future studies to assess protein levels, enzyme activity levels, as well as the expression of other antioxidant genes. These results also eliminate one of the proposed mechanisms that male midshipman use to combat potentially high levels of oxidative stress incurred by motor neurons driving long duration vocalization and provide more insight into how motor neurons are adapted to the performance of extreme behaviors.

Cellular studies of peripheral neurons in siphon skin of Aplysia californica

1979 ◽  
Vol 42 (2) ◽  
pp. 530-557 ◽  
Author(s):  
C. H. Bailey ◽  
V. F. Castellucci ◽  
J. Koester ◽  
E. R. Kandel
Keyword(s):  
Motor Neurons ◽  
Synaptic Input ◽  
Firing Pattern ◽  
White Cell ◽  
Type I ◽  
Type Ii ◽  
Peripheral Neurons ◽  
Peripheral Neuron ◽  
Type I Neuron ◽  
Kinetics Of

1. To account for the similarity in the kinetics of habituation between the central and peripheral components of siphon withdrawal, we have tested the idea (52) that each centrally located mechanoreceptor sensory neuron sends two branches to siphon motor neurons; one to centrally located siphon motor neurons and a collateral branch that remains in the periphery and innervates the peripheral siphon motor neurons. 2. We have found a group of peripheral siphon motor neurons and tested the connection onto these cells by central mechanoreceptors. In addition, we have defined by various electrophysiological and morphological criteria two general classes of peripheral neurons that lie along the course of the siphon nerve. 3. One class (type I) consists of only a single cell in each animal. This peripheral neuron typically has the largest cell body found lying along the siphon nerve and is the only peripheral nerve cell that appears white when viewed under epi-illumination. The type I neuron often has a highly regular firing pattern, which occurs in the absence of spontaneous synaptic input. The three-dimensional morphology of this neuron suggests a paucity of fine processes, most of which do not arborize and may terminate in the connective tissue sheath. Fine structural observations of the peripheral white cell have revealed the presence of large densecore granules. The peripheral type I neuron is similar in most of its electrophysiological and morphological properties to central neurons postulated to be neurosecretory. The peripheral white cell is, at present, the only peripheral neuron we can identify with certainty as a unique individual. 4. The second class (type II) of peripheral neurons are siphon motor neurons for the peripheral component of the siphon-withdrawal reflex. In contrast to the type I neurons, members of the second class of peripheral neurons possess smaller, more spherical cell bodies that have varying amounts of orange pigmentation and which give rise to a relatively well-developed and arborized dendritic tree. Type II neurons feature an irregular spontaneous firing pattern that is occasionally modulated by a rich spontaneous synaptic input. Peripheral siphon motor neurons have restricted motor fields that produce contraction of the mantle floor and the base of the siphon. Most of the type II neurons were found to be electrically coupled to one another. 5. The peripheral siphon motor neurons resemble the central siphon motor neurons in that they receive a collateral synapse from centrally located mechanoreceptor sensory neurons. This peripheral sensory-to-motor synapse exhibits the same kinetics of decrement as its central counterpart, both of which parallel behavioral habituation. 6. The rich mechanoreceptor input onto the relatively isolated dendritic trees of the peripheral siphon motor neurons provide a uniquely restricted neuropil to study the sensory-to-motor synapse. The peripheral motor neurons may, therefore, be a useful simple preparation for the cellular study of behavioral plasticity.

scholarly journals Hierarchical control of locomotion by distinct types of spinal V2a interneurons in zebrafish

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Evdokia Menelaou ◽  
David L. McLean
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Hierarchical Control ◽  
Higher Order ◽  
Type I ◽  
Type Ii ◽  
Timing Control ◽  
Amplitude Control ◽  
Spinal Interneurons ◽  
Larval Zebrafish

Abstract In all vertebrates, excitatory spinal interneurons execute dynamic adjustments in the timing and amplitude of locomotor movements. Currently, it is unclear whether interneurons responsible for timing control are distinct from those involved in amplitude control. Here, we show that in larval zebrafish, molecularly, morphologically and electrophysiologically distinct types of V2a neurons exhibit complementary patterns of connectivity. Stronger higher-order connections from type I neurons to other excitatory V2a and inhibitory V0d interneurons provide timing control, while stronger last-order connections from type II neurons to motor neurons provide amplitude control. Thus, timing and amplitude are coordinated by distinct interneurons distinguished not by their occupation of hierarchically-arranged anatomical layers, but rather by differences in the reliability and probability of higher-order and last-order connections that ultimately form a single anatomical layer. These findings contribute to our understanding of the origins of timing and amplitude control in the spinal cord.

Physiology of Neuronal Subtypes in the Respiratory–Vocal Integration Nucleus Retroamigualis of the Male Zebra Finch

2005 ◽  
Vol 94 (4) ◽  
pp. 2379-2390 ◽  
Author(s):  
M. F. Kubke ◽  
Y. Yazaki-Sugiyama ◽  
R. Mooney ◽  
J. M. Wild
Keyword(s):  
Motor Neurons ◽  
Zebra Finch ◽  
Synaptic Input ◽  
Cell Types ◽  
Inhibitory Input ◽  
Type I ◽  
Type Ii ◽  
Intracellular Recordings ◽  
Electrophysiological Properties ◽  
Premotor Neurons

Learned vocalizations, such as bird song, require intricate coordination of vocal and respiratory muscles. Although the neural basis for this coordination remains poorly understood, it likely includes direct synaptic interactions between respiratory premotor neurons and vocal motor neurons. In birds, as in mammals, the medullary nucleus retroambigualis (RAm) receives synaptic input from higher level respiratory and vocal control centers and projects to a variety of targets. In birds, these include vocal motor neurons in the tracheosyringeal part of the hypoglossal motor nucleus (XIIts), other respiratory premotor neurons, and expiratory motor neurons in the spinal cord. Although various cell types in RAm are distinct in their anatomical projections, their electrophysiological properties remain unknown. Furthermore, although prior studies have shown that RAm provides both excitatory and inhibitory input onto XIIts motor neurons, the identity of the cells in RAm providing either of these inputs remains to be established. To characterize the different RAm neuron types electrophysiologically, we used intracellular recordings in a zebra finch brain stem slice preparation. Based on numerous differences in intrinsic electrophysiological properties and a principal components analysis, we identified two distinct RAm neuron types (types I and II). Antidromic stimulation methods and intracellular staining revealed that type II neurons, but not type I neurons, provide bilateral synaptic input to XIIts. Paired intracellular recordings in RAm and XIIts further indicated that type II neurons with a hyperpolarization-dependent bursting phenotype are a potential source of inhibitory input to XIIts motor neurons. These results indicate that electrically distinct cell types exist in RAm, affording physiological heterogeneity that may play an important role in respiratory–vocal signaling.

scholarly journals GRB Progenitors and Observational Criteria

2011 ◽  
Vol 7 (S279) ◽  
pp. 102-109
Author(s):  
Bing Zhang
Keyword(s):  
Compact Star ◽  
High Redshift ◽  
Compact Stars ◽  
Type I ◽  
Type Ii ◽  
Long Duration ◽  
Multi Wavelength ◽  
Third Dimension ◽  
Low Amplitude ◽  
Short Grbs

AbstractPhenomenologically, two classes of GRBs (long/soft vs. short/hard) are identified based on their γ-ray properties. The boundary between the two classes is vague. Multi-wavelength observations lead to identification of two types of GRB progenitors: one related to massive stars (Type II), and another related to compact stars (Type I). Evidence suggests that the majority of long GRBs belong to Type II, while at least the majority of nearby short GRBs belong to Type I. Nonetheless, counter examples do exist. Both long-duration Type I and short-duration Type II GRBs have been observed. In this talk, I review the complications in GRB classification and efforts in diagnosing GRB progenitors based on multiple observational criteria. In particular, I raise the caution to readily accept that all short/hard GRBs detected by BATSE are due to compact star mergers. Finally, I propose to introduce “amplitude” as the third dimension (besides “duration” and “hardness”) to quantify burst properties, and point out that the “tip-of-the-iceberg” effect may introduce confusion in defining the physical category of GRBs, especially for low-amplitude, high-redshift GRBs.

scholarly journals Distinct Spinal V2a and V0d Microcircuits Distribute Locomotor Control in Larval Zebrafish

2019 ◽  
Author(s):  
Evdokia Menelaou ◽  
Sandeep Kishore ◽  
David L. McLean
Keyword(s):  
Spinal Cord ◽  
Conceptual Framework ◽  
Distributed Control ◽  
Motor Neurons ◽  
Type I ◽  
Type Ii ◽  
Spinal Interneurons ◽  
Larval Zebrafish ◽  
Locomotor Control ◽  
Pattern Control

SUMMARYSpinal interneurons coordinate adjustments in the rhythm and pattern of locomotor movements. Two prevailing models predict that interneurons either share or hierarchically distribute control of these key parameters. Here, we have tested each model in the coordination of swimming in larval zebrafish by circumferential excitatory V2a and commissural inhibitory V0d interneurons. We define two types of V2a neuron based on morphology, electrophysiology and connectivity. Type I V2as primarily propagate and amplify rhythmic signals biased to interneurons, while type II V2as primarily segregate and expedite patterning signals biased to motor neurons. Distributed control arises by differences in the likelihood of connections within types and the relative weights of connections between them, but not by a strict anatomical hierarchy. Heterogeneity among V0d neurons supports a similar functional distinction. Our findings provide a hybrid conceptual framework to better understand the origins of rhythm and pattern control in the spinal cord.

scholarly journals The Physics of Supernovae

1986 ◽  
Vol 89 ◽  
pp. 90-120 ◽  
Author(s):  
S.E. Woosley ◽  
Thomas A. Weaver
Keyword(s):  
White Dwarfs ◽  
Massive Stars ◽  
Type I ◽  
Type Ii ◽  
Physical Processes ◽  
Probable Explanation ◽  
Electron Positron ◽  
Long Duration ◽  
New Form ◽  
Electron Positron Pair

AbstractPresupernova models of massive stars are presented and their explosion by “delayed neutrino transport” examined. A new form of long duration Type II supernova model is also explored based upon repeated encounter with the electron-positron pair instability in stars heavier than about 60 M⊙. Carbon deflagration in white dwarfs is discussed as the probable explanation of Type I supernovae and special attention is paid to the physical processes whereby a nuclear flame propagates through degenerate carbon.

Inward rectification and its effects on the repetitive firing properties of bulbospinal neurons located in the ventral part of the nucleus tractus solitarius

1993 ◽  
Vol 70 (2) ◽  
pp. 590-601 ◽  
Author(s):  
M. S. Dekin
Keyword(s):  
Membrane Potential ◽  
Nucleus Tractus Solitarius ◽  
Reversal Potential ◽  
Repetitive Firing ◽  
Inward Rectification ◽  
Motor Nucleus ◽  
Type I ◽  
Type Ii ◽  
Membrane Hyperpolarization ◽  
Negative Current

1. An in vitro brain stem slice from adult guinea pigs was used to study the effects of membrane hyperpolarization in two classes of bulbospinal neurons, called types I and II, from the ventral parts of the nucleus tractus solitarius (vNTS). These bulbospinal neurons project to the phrenic motor nucleus and make up the dorsal respiratory group, a sensorimotor integrating area for rhythmic breathing movements. 2. Negative current injections (1 s long) were used in the discontinuous current-clamp mode to study the input resistance (Rin) in both classes of bulbospinal vNTS neurons. The mean Rin for type I neurons was 88.7 +/- 13.8 (SD) M omega (n = 19) and for type II neurons was 92.6 +/- 14.0 M omega (n = 16). Both classes of neurons displayed a depolarizing sag and inward rectification during negative current injections to membrane-potential levels less than or equal to -70 mV. The magnitude of the depolarizing sag became larger as the size of the negative current step was increased. On release from hyperpolarization, both cell types also exhibited a large anode break hyperpolarization (ABH). 3. The ABH was abolished in the presence of 5 mM 4-amino-pyridine (4-AP), whereas the depolarizing sag and inward rectification were not affected. In the place of the ABH, a small postinhibitory rebound (PIR) depolarization was observed on release from hyperpolarization. The magnitude of PIR was dependent on the size of the depolarizing sag. In the presence of both 5 mM 4-AP and 5 mM Cs+, the depolarizing sag and PIR were completely blocked, whereas Rin was increased. 4. The ionic currents underlying the ABH and depolarizing sag were directly observed by the use of the discontinuous single-electrode voltage-clamp technique. The ABH was caused by activation of an A-current (IKA). The depolarizing sag was associated with a hyperpolarization-activated inward current (IH), which was activated at membrane-potential levels less than or equal to -70 mV. The peak amplitude of IH in type I neurons was -335 +/- 16 pA (n = 13) and in type II cells was -327 +/- 14 pA (n = 11). 5. IH currents did not display inactivation during the hyperpolarizing voltage step. The IH current became larger when [K+]o was increased from 4 mM (control) to 12 mM and was blocked in the presence of 5 mM Cs+. The estimated reversal potential for the IH current was -41.5 +/- 4.8 mV (n = 8).(ABSTRACT TRUNCATED AT 400 WORDS)

Morphological Characteristics and Central Projections of Two Types of Interneurons in the Visual Pathway of Hermissenda

2002 ◽  
Vol 87 (1) ◽  
pp. 322-332 ◽  
Author(s):  
Terry Crow ◽  
Lian-Ming Tian
Keyword(s):  
Motor Neurons ◽  
Synaptic Input ◽  
Morphological Characteristics ◽  
Excitatory Input ◽  
Higher Order ◽  
Inhibitory Input ◽  
Type I ◽  
Type Ii ◽  
Central Projections ◽  
Inhibitory Synaptic Input

The synaptic interactions between photoreceptors in the eye and second-order neurons in the optic ganglion of the nudibranch mollusk Hermissenda are well characterized. However, the higher-order neural circuitry of the visual system, consisting of cerebropleural interneurons that receive synaptic input from photoreceptors and project to pedal motor neurons that mediate visually guided behaviors, is only partially understood. In this report we have examined the central projections of two identified classes of cerebropleural interneurons that receive excitatory or inhibitory synaptic input from identified photoreceptors. The classification of the interneurons was based on both morphological and electrophysiological criteria. Type I interneurons received monosynaptic excitatory or inhibitory synaptic input from identified photoreceptors and projected to postsynaptic targets within the cerebropleural ganglion. Type II interneurons, characterized here for the first time, received polysynaptic excitatory or inhibitory synaptic input from identified photoreceptors and projected to postsynaptic targets in either the ipsilateral pedal ganglion or the contralateral cerebropleural ganglion. Type I interneurons exhibited unique intraganglionic projections to different regions of the cerebropleural ganglion, depending on whether they received excitatory or inhibitory synaptic input from identified photoreceptors. Type I interneurons that received monosynaptic excitatory input from identified B photoreceptors terminated near the cerebropleural commissure and had multiple regions of varicosities located at branches that projected from the primary axon. Type I interneurons that received monosynaptic inhibitory input from identified B photoreceptors projected to the anterior cerebropleural ganglion and exhibited varicosities localized to the terminal region of the primary axonal process. Type II interneurons that received polysynaptic inhibitory input from identified photoreceptors projected to the contralateral cerebropleural ganglion. Most type II interneurons that projected to the pedal ganglia received polysynaptic excitatory input from identified photoreceptors. These results indicate that there is at least one additional interneuron in the higher-order visual circuit between type I interneurons and pedal motor neurons responsible for the generation of phototactic locomotion in Hermissenda.

scholarly journals Behavioural tactic predicts preoptic-hypothalamic gene expression more strongly than developmental morph in fish with alternative reproductive tactics

2018 ◽  
Vol 285 (1871) ◽  
pp. 20172742 ◽  
Author(s):  
Joel A. Tripp ◽  
Ni Y. Feng ◽  
Andrew H. Bass
Keyword(s):  
Gene Expression ◽  
Social Behaviour ◽  
Hormonal Regulation ◽  
Paternal Care ◽  
Expression Patterns ◽  
Alternative Reproductive Tactics ◽  
Type I ◽  
Type Ii ◽  
Reproductive Tactics ◽  
Territory Defence

Reproductive success relies on the coordination of social behaviours, such as territory defence, courtship and mating. Species with extreme variation in reproductive tactics are useful models for identifying the neural mechanisms underlying social behaviour plasticity. The plainfin midshipman ( Porichthys notatus ) is a teleost fish with two male reproductive morphs that follow widely divergent developmental trajectories and display alternative reproductive tactics (ARTs). Type I males defend territories, court females and provide paternal care, but will resort to cuckoldry if they cannot maintain a territory. Type II males reproduce only through cuckoldry. We sought to disentangle gene expression patterns underlying behavioural tactic, in this case ARTs, from those solely reflective of developmental morph. Using RNA-sequencing, we investigated differential transcript expression in the preoptic area-anterior hypothalamus (POA-AH) of courting type I males, cuckolding type I males and cuckolding type II males. Unexpectedly, POA-AH differential expression was more strongly coupled to behavioural tactic than morph. This included a suite of transcripts implicated in hormonal regulation of vertebrate social behaviour. Our results reveal that divergent expression patterns in a conserved neuroendocrine centre known to regulate social-reproductive behaviours across vertebrate lineages may be uncoupled from developmental history to enable plasticity in the performance of reproductive tactics.

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