scholarly journals Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Luis A Bezares-Calderón ◽  
Jürgen Berger ◽  
Sanja Jasek ◽  
Csaba Verasztó ◽  
Sara Mendes ◽  
...  
Keyword(s):  
Startle Response ◽  
Predator Avoidance ◽  
Receptor Cell ◽  
Neural Circuitry ◽  
Whole Body ◽  
Wiring Diagram ◽  
Planktonic Larva ◽  
Simultaneous Activation ◽  
Receptor Neurons ◽  
Effector Response

Startle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behaviour. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously raise the parapodia. The response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.

scholarly journals Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance

2018 ◽  
Author(s):  
Luis A. Bezares-Calderón ◽  
Jürgen Berger ◽  
Sanja Jasek ◽  
Csaba Verasztó ◽  
Sara Mendes ◽  
...  
Keyword(s):  
Startle Response ◽  
Predator Avoidance ◽  
The Body ◽  
Whole Body ◽  
Wiring Diagram ◽  
Planktonic Larva ◽  
Effector Cells ◽  
Simultaneous Activation ◽  
Receptor Neurons ◽  
Effector Response

AbstractStartle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behavior. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously contract the body and raise the parapodia. The startle response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.Short SummaryThe neuronal circuitry of the Platynereis startle response links polycystin-dependent hydrodynamic sensors to muscle and ciliary effector cells

scholarly journals Author response: Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance

2018 ◽  
Author(s):  
Luis A Bezares-Calderón ◽  
Jürgen Berger ◽  
Sanja Jasek ◽  
Csaba Verasztó ◽  
Sara Mendes ◽  
...  
Keyword(s):  
Startle Response ◽  
Predator Avoidance ◽  
Neural Circuitry ◽  
Author Response

The vibrational startle response of the desert locust Schistocerca gregaria

1999 ◽  
Vol 202 (16) ◽  
pp. 2151-2159 ◽  
Author(s):  
T. Friedel
Keyword(s):  
Stimulus Intensity ◽  
Startle Response ◽  
Schistocerca Gregaria ◽  
Whole Body ◽  
Desert Locust ◽  
Intracellular Recordings ◽  
Stimulus Amplitude ◽  
Co Activation ◽  
Motor Neurones ◽  
Fast Twitch

Substratum vibrations elicit a fast startle response in unrestrained quiescent desert locusts (Schistocerca gregaria). The response is graded with stimulus intensity and consists of a small, rapid but conspicuous movement of the legs and body, but it does not result in any positional change of the animal. With stimuli just above threshold, it begins with a fast twitch of the hindlegs generated by movements of the coxa-trochanter and femur-tibia joints. With increasing stimulus intensity, a rapid movement of all legs may follow, resulting in an up-down movement of the whole body. The magnitude of both the hindleg movement and electromyographic recordings from hindleg extensor and flexor tibiae muscles increases with stimulus amplitude and reaches a plateau at vibration accelerations above 20 m s(−)(2) (peak-to-peak). Hindleg extensor and flexor tibiae muscles in unrestrained animals are co-activated with a mean latency of 30 ms. Behavioural thresholds are as low as 0. 47 m s(−)(2) (peak-to-peak) at frequencies below 100 Hz but rise steeply above 200 Hz. The response habituates rapidly, and inter-stimulus intervals of 2 min or more are necessary to evoke maximal reactions. Intracellular recordings in fixed (upside-down) locusts also revealed co-activation of both flexor and extensor motor neurones with latencies of approximately 25 ms. This shows that the neuronal network underlying the startle movement is functional in a restrained preparation and can therefore be studied in great detail at the level of identified neurones.

Interaction between acoustic startle and habituated neck postural responses in seated subjects

2007 ◽  
Vol 102 (4) ◽  
pp. 1574-1586 ◽  
Author(s):  
Jean-Sébastien Blouin ◽  
Gunter P. Siegmund ◽  
J. Timothy Inglis
Keyword(s):  
Startle Response ◽  
Acoustic Startle ◽  
Acoustic Startle Response ◽  
Neck Muscles ◽  
Whole Body ◽  
Neck Muscle ◽  
Postural Response ◽  
Root Mean Square Amplitude ◽  
Postural Responses ◽  
Spatial Changes

Postural and startle responses rapidly habituate with repeated exposures to the same stimulus, and the first exposure to a seated forward acceleration elicits a startle response in the neck muscles. Our goal was to examine how the acoustic startle response is integrated with the habituated neck postural response elicited by forward accelerations of seated subjects. In experiment 1, 14 subjects underwent 11 sequential forward accelerations followed by 5 additional sled accelerations combined with a startling tone (124-dB sound pressure level) initiated 18 ms after sled acceleration onset. During the acceleration-only trials, changes consistent with habituation occurred in the root-mean-square amplitude of the neck muscles and in the peak amplitude of five head and torso kinematic variables. The subsequent addition of the startling tone restored the amplitude of the neck muscles and four of the five kinematic variables but shortened onset of muscle activity by 9–12 ms. These shortened onset times were further explored in experiment 2, wherein 16 subjects underwent 11 acceleration-only trials followed by 15 combined acceleration-tone trials with interstimulus delays of 0, 13, 18, 23, and 28 ms. Onset times shortened further for the 0- and 13-ms delays but did not lengthen for the 23- and 28-ms delays. These temporal and spatial changes in EMG can be explained by a summation of the excitatory drive converging at or before the neck muscle motoneurons. The present observations suggest that habituation to repeated sled accelerations involves extinguishing the startle response and tuning the postural response to the whole body disturbance.

scholarly journals Development of a vibrational startle response assay for screening environmental pollutants and drugs impairing predator avoidance

2019 ◽  
Vol 650 ◽  
pp. 87-96 ◽  
Author(s):  
Melissa Faria ◽  
Eva Prats ◽  
Karen Adriana Novoa-Luna ◽  
Juliette Bedrossiantz ◽  
Cristian Gómez-Canela ◽  
...  
Keyword(s):  
Startle Response ◽  
Predator Avoidance ◽  
Environmental Pollutants

Physiological activity of newly differentiated olfactory receptor neurons correlated with morphological recovery from olfactory nerve section in the salamander

1981 ◽  
Vol 45 (3) ◽  
pp. 529-549 ◽  
Author(s):  
P. A. Simmons ◽  
T. V. Getchell
Keyword(s):  
Olfactory Bulb ◽  
Spontaneous Activity ◽  
Histological Examination ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Olfactory Nerve ◽  
Olfactory Receptor Neurons ◽  
Nerve Section ◽  
Receptor Neurons

1. Extracellular unitary recordings were made from the olfactory epithelium of the salamander, Ambystoma tigrinum, at numerous time points following olfactory nerve section. Unitary response properties were correlated with histological examination of the same tissues. 2. At 10 days following nerve section, unitary activity was rarely recorded in all regions of the epithelium. Histological examination indicated that virtually the entire mature olfactory receptor cell population had undergone retrograde degeneration. Transneuronal degeneration was not observed in the olfactory bulb, although the olfactory nerve and glomerular layers were substantially reduced in size. 3. At subsequent times, unitary impulse activity gradually returned, consisting of both spontaneous activity and odor-evoked discharges. Anatomical recovery of the olfactory epithelium preceded that of the olfactory bulb. A positive correlation was found between neuronal differentiation in the olfactory epithelium and the recovery of receptor cell function. 4. Patterns of spontaneous activity, odor specificities, intensity-response functions, and adaptive properties studied in newly differentiated olfactory receptor neurons were indistinguishable from those observed in control units. This indicated that these properties were intrinsic to the receptor neurons. 5. Spontaneously active and responsive units were encountered prior to olfactory nerve connection with the bulb. It is concluded that receptor neurons pass through two phases of functional maturity: the first independent of bulbar contact and the second dependent on presumed synaptic contact with bulbar neurons.

scholarly journals Evolution of neuronal anatomy and circuitry in two highly divergent nematode species

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Ray L Hong ◽  
Metta Riebesell ◽  
Daniel J Bumbarger ◽  
Steven J Cook ◽  
Heather R Carstensen ◽  
...  
Keyword(s):  
Body Position ◽  
Nematode Species ◽  
Detailed Examination ◽  
Wiring Diagram ◽  
C Elegans ◽  
Neuronal Processes ◽  
Patterns Of Behavior ◽  
Receptor Neurons ◽  
Neuronal Number ◽  
Independent Features

The nematodes C. elegans and P. pacificus populate diverse habitats and display distinct patterns of behavior. To understand how their nervous systems have diverged, we undertook a detailed examination of the neuroanatomy of the chemosensory system of P. pacificus. Using independent features such as cell body position, axon projections and lipophilic dye uptake, we have assigned homologies between the amphid neurons, their first-layer interneurons, and several internal receptor neurons of P. pacificus and C. elegans. We found that neuronal number and soma position are highly conserved. However, the morphological elaborations of several amphid cilia are different between them, most notably in the absence of ‘winged’ cilia morphology in P. pacificus. We established a synaptic wiring diagram of amphid sensory neurons and amphid interneurons in P. pacificus and found striking patterns of conservation and divergence in connectivity relative to C. elegans, but very little changes in relative neighborhood of neuronal processes. These findings demonstrate the existence of several constraints in patterning the nervous system and suggest that major substrates for evolutionary novelty lie in the alterations of dendritic structures and synaptic connectivity.

Occurrence and biogeographic significance of Heliaster (Echinodermata: Asteroidea) from the Pliocene of southwest Florida

1988 ◽  
Vol 62 (01) ◽  
pp. 126-132 ◽  
Author(s):  
Douglas S. Jones ◽  
Roger W. Portell
Keyword(s):  
Central American ◽  
Eastern Pacific ◽  
Whole Body ◽  
Marine Fauna ◽  
Western Atlantic ◽  
Southwest Florida ◽  
Extant Species ◽  
Geologic Record ◽  
Central American Isthmus

Whole body asteroid fossils are rare in the geologic record and previously unreported from the Cenozoic of Florida. However, specimens of the extant species,Heliaster microbrachiusXantus, were recently discovered in upper Pliocene deposits. This marks the first reported fossil occurrence of the monogeneric Heliasteridae, a group today confined to the eastern Pacific. This discovery provides further non-molluscan evidence of the close similarities between the Neogene marine fauna of Florida and the modern fauna of the eastern Pacific. The extinction of the heliasters in the western Atlantic is consistent with the pattern of many other marine groups in the region which suffered impoverishment following uplift of the Central American isthmus.

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