Live demonstration: Spiking neural circuit based navigation inspired by C. elegans thermotaxis

Author(s):  
Chirag Shetty ◽  
Sri Nitchith ◽  
Rishabh Rawat ◽  
S. R. Nandakumar ◽  
Pritesh Shah ◽  
...  
2012 ◽  
Vol 15 (12) ◽  
pp. 1675-1682 ◽  
Author(s):  
Arantza Barrios ◽  
Rajarshi Ghosh ◽  
Chunhui Fang ◽  
Scott W Emmons ◽  
Maureen M Barr

2006 ◽  
Vol 20 (21) ◽  
pp. 2955-2960 ◽  
Author(s):  
E. Kodama ◽  
A. Kuhara ◽  
A. Mohri-Shiomi ◽  
K. D. Kimura ◽  
M. Okumura ◽  
...  
Keyword(s):  

2005 ◽  
Vol 17 (3) ◽  
pp. 318-326 ◽  
Author(s):  
Michiyo Suzuki ◽  
◽  
Takeshi Goto ◽  
Toshio Tsuji ◽  
Hisao Ohtake ◽  
...  

The nematode <I>Caenorhabditis elegans (C. elegans)</I>, a relatively simple organism in structure, is one of the most well-studied multicellular organisms. We developed a <I>virtual C. elegans</I> based on the actual organism to analyze motor control. We propose a dynamic body model, including muscles, controlled by a neural circuit model based on the actual nematode. The model uses neural oscillators to generate rhythmic movement. Computer simulation confirmed that the <I>virtual C. elegans</I> realizes motor control similar qualitatively to that of the actual organism. Specified classes of neurons are killed in the neural circuit model corresponding to actual <I>unc</I> mutants, demonstrating that resulting movement of the <I>virtual C. elegans</I> resembles that of actual mutants.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Seika Takayanagi-Kiya ◽  
Keming Zhou ◽  
Yishi Jin

Presynaptic ligand-gated ion channels (LGICs) have long been proposed to affect neurotransmitter release and to tune the neural circuit activity. However, the understanding of their in vivo physiological action remains limited, partly due to the complexity in channel types and scarcity of genetic models. Here we report that C. elegans LGC-46, a member of the Cys-loop acetylcholine (ACh)-gated chloride (ACC) channel family, localizes to presynaptic terminals of cholinergic motor neurons and regulates synaptic vesicle (SV) release kinetics upon evoked release of acetylcholine. Loss of lgc-46 prolongs evoked release, without altering spontaneous activity. Conversely, a gain-of-function mutation of lgc-46 shortens evoked release to reduce synaptic transmission. This inhibition of presynaptic release requires the anion selectivity of LGC-46, and can ameliorate cholinergic over-excitation in a C. elegans model of excitation-inhibition imbalance. These data demonstrate a novel mechanism of presynaptic negative feedback in which an anion-selective LGIC acts as an auto-receptor to inhibit SV release.


2019 ◽  
Author(s):  
Mahekta R. Gujar ◽  
Aubrie M. Stricker ◽  
Erik A. Lundquist

AbstractUNC-6/Netrin is a conserved axon guidance cue that directs growth cone migrations in the dorsal-ventral axis of C. elegans and in the vertebrate spinal cord. UNC-6/Netrin is expressed in ventral cells, and growth cones migrate ventrally toward or dorsally away from UNC-6/Netrin. Recent studies of growth cone behavior during outgrowth in vivo in C. elegans have led to a polarity/protrusion model in directed growth cone migration away from UNC-6/Netrin. In this model, UNC-6/Netrin first polarizes the growth cone via the UNC-5 receptor, leading to dorsally biased protrusion and F-actin accumulation. UNC-6/Netrin then regulates protrusion based on this polarity. The receptor UNC-40/DCC drives protrusion dorsally, away from the UNC-6/Netrin source, and the UNC-5 receptor inhibits protrusion ventrally, near the UNC-6/Netrin source, resulting in dorsal migration. UNC-5 inhibits protrusion in part by excluding microtubules from the growth cone, which are pro-protrusive. Here we report that the RHO-1/RhoA GTPase and its activator GEF RHGF-1 inhibit growth cone protrusion and MT accumulation in growth cones, similar to UNC-5. However, growth cone polarity of protrusion and F-actin were unaffected by RHO-1 and RHGF-1. Thus, RHO-1 signaling acts specifically as a negative regulator of protrusion and MT accumulation, and not polarity. Genetic interactions suggest that RHO-1 and RHGF-1 act with UNC-5, as well as with a parallel pathway, to regulate protrusion. The cytoskeletal interacting molecule UNC-33/CRMP was required for RHO-1 activity to inhibit MT accumulation, suggesting that UNC-33/CRMP might act downstream of RHO-1. In sum, these studies describe a new role of RHO-1 and RHGF-1 in regulation of growth cone protrusion by UNC-6/Netrin.Author SummaryNeural circuits are formed by precise connections between axons. During axon formation, the growth cone leads the axon to its proper target in a process called axon guidance. Growth cone outgrowth involves asymmetric protrusion driven by extracellular cues that stimulate and inhibit protrusion. How guidance cues regulate growth cone protrusion in neural circuit formation is incompletely understood. This work shows that the signaling molecule RHO-1 acts downstream of the UNC-6/Netrin guidance cue to inhibit growth cone protrusion in part by excluding microtubules from the growth cone, which are structural elements that drive protrusion.


2016 ◽  
Author(s):  
Maria A. Lim ◽  
Jyothsna Chitturi ◽  
Valeriya Laskova ◽  
Jun Meng ◽  
Daniel Findeis ◽  
...  

AbstractNeuromodulators shape neural circuit dynamics. Combining electron microscopy, genetics, transcriptome profiling, calcium imaging, and optogenetics, we discovered a peptidergic neuron that modulates C. elegans motor circuit dynamics. The Six/SO-family homeobox transcription factor UNC-39 governs lineage-specific neurogenesis to give rise to a neuron RID. RID bears the anatomic hallmarks of a specialized endocrine neuron: it harbors near-exclusive dense core vesicles that cluster periodically along the axon, and expresses multiple neuropeptides, including the FMRF-amide-related FLP-14. RID activity increases during forward movement. Ablating RID reduces the sustainability of forward movement, a phenotype partially recapitulated by removing FLP-14. Optogenetic depolarization of RID prolongs forward movement, an effect reduced in the absence of FLP-14. Together, these results establish the role of a neuroendocrine cell RID in sustaining a specific behavioral state in C. elegans.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Patrick Laurent ◽  
Zoltan Soltesz ◽  
Geoffrey M Nelson ◽  
Changchun Chen ◽  
Fausto Arellano-Carbajal ◽  
...  

Brains organize behavior and physiology to optimize the response to threats or opportunities. We dissect how 21% O2, an indicator of surface exposure, reprograms C. elegans' global state, inducing sustained locomotory arousal and altering expression of neuropeptides, metabolic enzymes, and other non-neural genes. The URX O2-sensing neurons drive arousal at 21% O2 by tonically activating the RMG interneurons. Stimulating RMG is sufficient to switch behavioral state. Ablating the ASH, ADL, or ASK sensory neurons connected to RMG by gap junctions does not disrupt arousal. However, disrupting cation currents in these neurons curtails RMG neurosecretion and arousal. RMG signals high O2 by peptidergic secretion. Neuropeptide reporters reveal neural circuit state, as neurosecretion stimulates neuropeptide expression. Neural imaging in unrestrained animals shows that URX and RMG encode O2 concentration rather than behavior, while the activity of downstream interneurons such as AVB and AIY reflect both O2 levels and the behavior being executed.


2015 ◽  
Author(s):  
Patrick Laurent ◽  
Zoltan Soltesz ◽  
Geoffrey M Nelson ◽  
Changchun Chen ◽  
Fausto Arellano-Carbajal ◽  
...  

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