scholarly journals Polysensory Interneuronal Projections to Foot Contractile Pedal Neurons in Hermissenda

2009 ◽  
Vol 101 (2) ◽  
pp. 824-833 ◽  
Author(s):  
Terry Crow ◽  
Lian-Ming Tian
Keyword(s):  
Neural Circuit ◽  
Behavioral Responses ◽  
Neural Circuitry ◽  
Type I ◽  
Synaptic Connections ◽  
Pedal Ganglion ◽  
Conditioning Procedure ◽  
Efferent Neurons ◽  
Conditioned Responses ◽  
Ciliary Locomotion

A Pavlovian-conditioning procedure may produce modifications in multiple behavioral responses. As an example, conditioning may result in the elicitation of a specific somatomotor conditioned response (CR) and, in addition, other motor and visceral CRs. In the mollusk Hermissenda conditioning produces two conditioned responses: foot-shortening and decreased locomotion. The neural circuitry supporting ciliary locomotion is well characterized, although the neural circuit underlying foot-shortening is poorly understood. Here we describe efferent neurons in the pedal ganglion that produce contraction or extension of specific regions of the foot in semi-intact preparations. Synaptic connections between polysensory type Ib and type Is interneurons and identified foot contractile efferent neurons were examined. Type Ib and type Is interneurons receive synaptic input from the visual, graviceptive, and somatosensory systems. Depolarization of type Ib interneurons evoked spikes in identified tail and lateral foot contractile efferent neurons. Mechanical displacement of the statocyst evoked complex excitatory postsynaptic potentials (EPSPs) and spikes recorded from type Ib and type Is interneurons and complex EPSPs and spikes in identified foot contractile efferent neurons. Depolarization of type Ib interneurons in semi-intact preparations produced contraction and shortening along the rostrocaudal axis of the foot. Depolarization of Is interneurons in semi-intact preparations produced contraction of the anterior region of the foot. Taken collectively, the results suggest that type Ib and type Is polysensory interneurons may contribute to the neural circuit underlying the foot-shortening CR in Hermissenda.

scholarly journals Sensory Regulation of Network Components Underlying Ciliary Locomotion in Hermissenda

2008 ◽  
Vol 100 (5) ◽  
pp. 2496-2506 ◽  
Author(s):  
Terry Crow ◽  
Lian-Ming Tian
Keyword(s):  
Neural Network ◽  
Spike Activity ◽  
Electrical Coupling ◽  
Rhythmic Activity ◽  
Burst Activity ◽  
Type I ◽  
Sensory Regulation ◽  
The Neural Network ◽  
Efferent Neurons ◽  
Ciliary Locomotion

Ciliary locomotion in the nudibranch mollusk Hermissenda is modulated by the visual and graviceptive systems. Components of the neural network mediating ciliary locomotion have been identified including aggregates of polysensory interneurons that receive monosynaptic input from identified photoreceptors and efferent neurons that activate cilia. Illumination produces an inhibition of type Ii (off-cell) spike activity, excitation of type Ie (on-cell) spike activity, decreased spike activity in type IIIi inhibitory interneurons, and increased spike activity of ciliary efferent neurons. Here we show that pairs of type Ii interneurons and pairs of type Ie interneurons are electrically coupled. Neither electrical coupling or synaptic connections were observed between Ie and Ii interneurons. Coupling is effective in synchronizing dark-adapted spontaneous firing between pairs of Ie and pairs of Ii interneurons. Out-of-phase burst activity, occasionally observed in dark-adapted and light-adapted pairs of Ie and Ii interneurons, suggests that they receive synaptic input from a common presynaptic source or sources. Rhythmic activity is typically not a characteristic of dark-adapted, light-adapted, or light-evoked firing of type I interneurons. However, burst activity in Ie and Ii interneurons may be elicited by electrical stimulation of pedal nerves or generated at the offset of light. Our results indicate that type I interneurons can support the generation of both rhythmic activity and changes in tonic firing depending on sensory input. This suggests that the neural network supporting ciliary locomotion may be multifunctional. However, consistent with the nonmuscular and nonrhythmic characteristics of visually modulated ciliary locomotion, type I interneurons exhibit changes in tonic activity evoked by illumination.

scholarly journals Network interneurons underlying ciliary locomotion in Hermissenda

2013 ◽  
Vol 109 (3) ◽  
pp. 640-648 ◽  
Author(s):  
Terry Crow ◽  
Nan Ge Jin ◽  
Lian-Ming Tian
Keyword(s):  
Spike Activity ◽  
Excitatory Postsynaptic Potential ◽  
Type I ◽  
Type Ii ◽  
Visually Guided ◽  
Monosynaptic Connection ◽  
Postsynaptic Potential ◽  
The Neural Network ◽  
Efferent Neurons ◽  
Ciliary Locomotion

In the nudibranch mollusk Hermissenda, ciliary locomotion contributes to the generation of two tactic behaviors. Light elicits a positive phototaxis, and graviceptive stimulation evokes a negative gravitaxis. Two classes of light-responsive premotor interneurons in the network contributing to ciliary locomotion have been recently identified in the cerebropleural ganglia. Aggregates of type I interneurons receive monosynaptic excitatory (Ie) or inhibitory (Ii) input from identified photoreceptors. Type II interneurons receive polysynaptic excitatory (IIe) or inhibitory (IIi) input from photoreceptors. The ciliary network also includes type III inhibitory (IIIi) interneurons, which form monosynaptic inhibitory connections with ciliary efferent neurons (CENs). Illumination of the eyes evokes a complex inhibitory postsynaptic potential, a decrease of Ii spike activity, a complex excitatory postsynaptic potential, and an increase of Ie spike activity. Here, we characterized the contribution of identified I, II, and IIIi interneurons to the neural network supporting visually guided locomotion. In dark-adapted preparations, light elicited an increase in the tonic spike activity of IIe interneurons and a decrease in the tonic spike activity of IIi interneurons. Fluorescent dye-labeled type II interneurons exhibited diverse projections within the circumesophageal nervous system. However, a subclass of type II interneurons, IIe(cp) and IIi(cp) interneurons, were shown to terminate within the ipsilateral cerebropleural ganglia and indirectly modulate the activity of CENs. Type II interneurons form monosynaptic or polysynaptic connections with previously identified components of the ciliary network. The identification of a monosynaptic connection between Ie and IIIi interneurons shown here suggest that they provide a major role in the light-dependent modulation of CEN spike activity underlying ciliary locomotion.

Statocyst Hair Cell Activation of Identified Interneurons and Foot Contraction Motor Neurons in Hermissenda

2004 ◽  
Vol 91 (6) ◽  
pp. 2874-2883 ◽  
Author(s):  
Terry Crow ◽  
Lian-Ming Tian
Keyword(s):  
Hair Cell ◽  
Motor Neurons ◽  
Hair Cells ◽  
Cell Activation ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Type I ◽  
Phototactic Behavior ◽  
Circuit Components ◽  
Ciliary Locomotion

Pavlovian conditioning of Hermissenda produces both light-elicited inhibition of normal positive phototactic behavior and conditioned stimulus (CS)-elicited foot-shortening. Rotation, the unconditioned stimulus (US) elicits foot-shortening and reduced forward ciliary locomotion. The neural circuit supporting ciliary locomotion and its modulation by light is known in some detail. However, the neural circuits responsible for rotation-elicited foot-shortening and reduced forward ciliary locomotion are not known. Here we describe components of the neural circuit in Hermissenda that produce anterior foot contraction and ciliary activation mediated by statocyst hair cells. We have characterized in semi-intact preparations newly identified pedal ventral contraction motor neurons (VCMNs) and interneurons (Ib). Type Ib interneurons receive polysynaptic input from statocyst hair cells and project directly to VCMNs and cilia-activating motor neurons. Depolarization of VCMNs with extrinsic current in normal artificial seawater (ASW) and high-divalent cation ASW, and under conditions where central synaptic transmission was suppressed with 5 mM Ni2+ ASW, elicited a contraction of the ipsilateral anterior foot measured from videotape recordings. Mechanical displacement of the statocyst or depolarization of identified statocyst hair cells with extrinsic current elicited spikes and complex excitatory postsynaptic potentials (EPSPs) in type Ib interneurons and complex EPSPs and spikes recorded in VCMNs. Type Ib interneurons are electrically coupled and project to VCMNs and VP1 cilia-activating motor neurons located in the contralateral pedal ganglia. The results indicate that statocyst hair-cell-mediated anterior foot contraction and graviceptive ciliary locomotion involve different interneuronal circuit components from the circuit previously identified as supporting light modulated ciliary locomotion.

scholarly journals A hindbrain dopaminergic neural circuit prevents weight gain by reinforcing food satiation

2021 ◽  
Vol 7 (22) ◽  
pp. eabf8719
Author(s):  
Yong Han ◽  
Guobin Xia ◽  
Yanlin He ◽  
Yang He ◽  
Monica Farias ◽  
...  
Keyword(s):  
Weight Gain ◽  
Food Intake ◽  
Neural Circuit ◽  
Neural Circuitry ◽  
Dynamic Regulation ◽  
Satiety Response ◽  
Food Satiation ◽  
Lateral Parabrachial Nucleus ◽  
Genetic Deletion ◽  
Feeding Bout

The neural circuitry mechanism that underlies dopaminergic (DA) control of innate feeding behavior is largely uncharacterized. Here, we identified a subpopulation of DA neurons situated in the caudal ventral tegmental area (cVTA) directly innervating DRD1-expressing neurons within the lateral parabrachial nucleus (LPBN). This neural circuit potently suppresses food intake via enhanced satiation response. Notably, this cohort of DAcVTA neurons is activated immediately before the cessation of each feeding bout. Acute inhibition of these DA neurons before bout termination substantially suppresses satiety and prolongs the consummatory feeding. Activation of postsynaptic DRD1LPBN neurons inhibits feeding, whereas genetic deletion of Drd1 within the LPBN causes robust increase in food intake and subsequent weight gain. Furthermore, the DRD1LPBN signaling manifests the central mechanism in methylphenidate-induced hypophagia. In conclusion, our study illuminates a hindbrain DAergic circuit that controls feeding through dynamic regulation in satiety response and meal structure.

scholarly journals Axodendritic versus axosomatic cochlear efferent termination is determined by afferent type in a hierarchical logic of circuit formation

2021 ◽  
Vol 7 (4) ◽  
pp. eabd8637
Author(s):  
Jemma L. Webber ◽  
John C. Clancy ◽  
Yingjie Zhou ◽  
Natalia Yraola ◽  
Kazuaki Homma ◽  
...  
Keyword(s):  
Hair Cells ◽  
Fiber Type ◽  
Afferent Fiber ◽  
Outer Hair Cells ◽  
Type I ◽  
Type Ii ◽  
Efferent Neurons ◽  
Distinct Pair ◽  
Mechanosensory Hair Cells ◽  
Circuit Formation

Hearing involves a stereotyped neural network communicating cochlea and brain. How this sensorineural circuit assembles is largely unknown. The cochlea houses two types of mechanosensory hair cells differing in function (sound transmission versus amplification) and location (inner versus outer compartments). Inner (IHCs) and outer hair cells (OHCs) are each innervated by a distinct pair of afferent and efferent neurons: IHCs are contacted by type I afferents receiving axodendritic efferent contacts; OHCs are contacted by type II afferents and axosomatically terminating efferents. Using an Insm1 mouse mutant with IHCs in the position of OHCs, we discover a hierarchical sequence of instructions in which first IHCs attract, and OHCs repel, type I afferents; second, type II afferents innervate hair cells not contacted by type I afferents; and last, afferent fiber type determines if and how efferents innervate, whether axodendritically on the afferent, axosomatically on the hair cell, or not at all.

Modulation of Fictive Feeding by Dopamine and Serotonin inAplysia

2000 ◽  
Vol 83 (1) ◽  
pp. 374-392 ◽  
Author(s):  
Evgeni A. Kabotyanski ◽  
Douglas A. Baxter ◽  
Susan J. Cushman ◽  
John H. Byrne
Keyword(s):  
Feeding Activity ◽  
Neural Correlates ◽  
Neural Circuitry ◽  
Pattern Generator ◽  
Synaptic Connections ◽  
Rhythmic Movements ◽  
Motor Programs ◽  
Dopaminergic Cells ◽  
Buccal Ganglia ◽  
Bath Application

The buccal ganglia of Aplysia contain a central pattern generator (CPG) that mediates rhythmic movements of the buccal apparatus during feeding. Activity in this CPG is believed to be regulated, in part, by extrinsic serotonergic inputs and by an intrinsic and extrinsic system of putative dopaminergic cells. The present study investigated the roles of dopamine (DA) and serotonin (5-HT) in regulating feeding movements of the buccal apparatus and properties of the underlying neural circuitry. Perfusing a semi-intact head preparation with DA (50 μM) or the metabolic precursor of catecholamines (l-3–4-dihydroxyphenylalanine, DOPA, 250 μM) induced feeding-like movements of the jaws and radula/odontophore. These DA-induced movements were similar to bites in intact animals. Perfusing with 5-HT (5 μM) also induced feeding-like movements, but the 5-HT-induced movements were similar to swallows. In preparations of isolated buccal ganglia, buccal motor programs (BMPs) that represented at least two different aspects of fictive feeding (i.e., ingestion and rejection) could be recorded. Bath application of DA (50 μM) increased the frequency of BMPs, in part, by increasing the number of ingestion-like BMPs. Bath application of 5-HT (5 μM) did not significantly increase the frequency of BMPs nor did it significantly increase the proportion of ingestion-like BMPs being expressed. Many of the cells and synaptic connections within the CPG appeared to be modulated by DA or 5-HT. For example, bath application of DA decreased the excitability of cells B4/5 and B34, which in turn may have contributed to the DA-induced increase in ingestion-like BMPs. In summary, bite-like movements were induced by DA in the semi-intact preparation, and neural correlates of these DA-induced effects were manifest as an increase in ingestion-like BMPs in the isolated ganglia. Swallow-like movements were induced by 5-HT in the semi-intact preparation. Neural correlates of these 5-HT-induced effects were not evident in isolated buccal ganglia, however.

scholarly journals Muscarinic acetylcholine receptors modulate HCN channel properties in vestibular ganglion neurons

2022 ◽  
Author(s):  
Daniel Bronson ◽  
Radha Kalluri
Keyword(s):  
Signaling Cascades ◽  
Hcn Channels ◽  
Type I ◽  
Hcn Channel ◽  
Firing Patterns ◽  
Vestibular Ganglion ◽  
Muscarinic Acetylcholine ◽  
Efferent Neurons ◽  
Ganglion Neurons ◽  
Channel Properties

Vestibular efferent neurons play an important role in shaping vestibular afferent excitability and accordingly, on the information encoded by their spike patterns. Efferent-modulation is linked to muscarinic signaling cascades that affect ion channel conductances, most notably low-voltage gated potassium channels such as KCNQ. Here we tested and found that muscarinic signaling cascades also modulate hyperpolarization-activated cyclic-nucleotide gated channels (HCN). HCN channels play a key role in controlling spike-timing regularity and a non-chemical form of transmission between type I hair cells and vestibular afferents. The impact of cholinergic efferent input on HCN channels was assessed using voltage-clamp methods, which measure currents in the disassociated cell bodies of vestibular ganglion neurons (VGN). Membrane properties in VGN were characterized before and after administration of the muscarinic acetylcholine receptor (mAChR) agonist Oxotremorine-M (Oxo-M). We found that Oxo-M shifted the voltage-activation range of HCN channels in the positive direction by 4.1 +/- 1.1 mV, which more than doubled the available current when held near rest at -60 mV (a 184 +/- 90.1% increase, n=19). This effect was not blocked by pre-treating the cells with a KCNQ channel blocker, linopirdine, which suggests that this effect is not dependent on KCNQ currents. We also found that HCN channel properties in the baseline condition and sensitivity to mAChR activation depended on cell size and firing patterns. Large-bodied neurons with onset firing patterns had the most depolarized activation range and least sensitivity to mAChR activation. Together, our results highlight the complex and dynamic regulation of HCN channels in VGN.

scholarly journals Neural Circuits Underlying Behavioral Flexibility: Insights From Drosophila

2022 ◽  
Vol 15 ◽  
Author(s):  
Anita V. Devineni ◽  
Kristin M. Scaplen
Keyword(s):  
Drosophila Melanogaster ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Internal State ◽  
Behavioral Responses ◽  
Behavioral Flexibility ◽  
Environmental Context ◽  
Behavioral State ◽  
Insight Into

Behavioral flexibility is critical to survival. Animals must adapt their behavioral responses based on changes in the environmental context, internal state, or experience. Studies in Drosophila melanogaster have provided insight into the neural circuit mechanisms underlying behavioral flexibility. Here we discuss how Drosophila behavior is modulated by internal and behavioral state, environmental context, and learning. We describe general principles of neural circuit organization and modulation that underlie behavioral flexibility, principles that are likely to extend to other species.

scholarly journals Encoding Fear of Heights by Basolateral Amygdala Neurons

2020 ◽  
Author(s):  
Jun Liu ◽  
Longnian Lin ◽  
Dong V Wang
Keyword(s):  
Basolateral Amygdala ◽  
Contextual Information ◽  
Brain Regions ◽  
Neural Representation ◽  
Conditioning Procedure ◽  
Freely Behaving ◽  
Conditioned Responses ◽  
High Place ◽  
Innate Fear ◽  
Fear Of Heights

SUMMARYFear of heights is evolutionarily important for survival, yet it is unclear how and which brain regions encode such height threats. Given the importance of the basolateral amygdala (BLA) in processing both learned and innate fear, we investigated how BLA neurons may respond to high place exposure in freely behaving mice. We found that a discrete set of BLA neurons exhibited robust firing increases when the mouse was either exploring or placed on a high place, accompanied by increased heart rate and freezing. Importantly, these high-place fear neurons were only activated under height threats but not mild anxiogenic conditions. Furthermore, after a fear conditioning procedure, these high-place fear neurons developed conditioned responses to the context, but not the cue, indicating a convergence in encoding of dangerous/risky contextual information. Our results provide insights into the neural representation of the fear of heights and may have implications for treatment of excessive fear disorders.

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