A Cholinergic Sensory-Motor Circuit Controls the Male Copulation Behavior in C. elegans

The nervous system coordinates a sequence of muscle movements to give rise to animal behaviors. In complex invertebrates or lab-studied vertebrates, due to the large number of cells in their nervous systems and the complexities of their behaviors, it is difficult to address how circuits process information to direct each motor output of the behavior. In this dissertation, I used the Caenorhabditis elegans male copulation behavior as a model to address how a compact circuit coordinates different behavioral programs. Insertion of a male copulatory organ into a suitable mate is a conserved and necessary behavioral step for most terrestrial mating. However, the detailed molecular and cellular mechanisms for this distinct social interaction have not been elucidated in any animal. During mating, the C. elegans male cloaca is positioned over the hermaphrodite’s vulva as he attempts to insert his copulatory spicules repetitively. Rhythmic spicule thrusts cease when insertion is sensed. Circuit components consisting of sensory/motor neurons and sex muscles for these steps have been previously identified, but it was unclear how their outputs are integrated to generate a coordinated behavior pattern. Here, I show that contraction of the male oblique muscles is required to sustain genital contact between the sexes. These muscles are innervated by the postcloacal sensilla (p.c.s.) sensory/motor neurons, which secret ACh to activate the levamisole-sensitive AChR and the ACR-16-containing ionotropic AChR on the oblique muscles. For spicules to rhythmically thrust during genital contact, activity of the oblique muscles and the gubernacular muscles is transmitted to the spicule protractor muscles instantaneously via gap junctions between these muscles and causes shallow protractor contractions. The rhythmic protractor contractions eventually switch to sustained contraction, as the SPC sensory-motor neurons integrate information of spicule position at the vulva with inputs from the hook and cloacal sensilla. The ERG-like K+ channel, UNC-103, which decreases the spicule circuit excitability, is likely to set a threshold requirement for integration of these inputs, so that sustained spicule muscle contraction is not stimulated by fewer inputs. In addition, I demonstrate that a cholinergic signaling pathway mediated by a muscarinic acetylcholine receptor, GAR-3, is used to enhance the ionotropic AChRs-mediated fast synaptic transmission in the copulation circuit. GAR-3 is expressed in multiple cells of the copulation circuit, but mainly in the cholinergic p.c.s. neurons and SPC neurons. Activation of GAR-3 is coupled to Gαq to trigger downstream signal transduction events that modulate neurotransmitter release from these neurons. Males with a loss-of-function allele of the gar-3 gene are defective in inserting their spicules into the hermaphrodite’s vulva efficiently. Since the p.c.s. neurons regulate the male’s contact with the hermaphrodite’s vulva, and the SPC neurons are required for spicule insertion during mating, GAR-3 probably facilitates male mating behavior via enhancing synaptic transmission from these neurons to their postsynaptic partners

Fermionic zero modes in self-dual vortex background

We study fermionic zero modes in the background of self-dual vortex on a two-dimensional non-compact extra space in 5+1 dimensions. In the Abelian Higgs model, we present an unified description of the topological and non-topological self-dual vortex on the extra two dimensions. Based on it, we study localization of bulk fermions on a brane with inclusion of Yang-Mills and gravity backgrounds in six dimensions. Through two simple cases, it is shown that the vortex background contributes a phase shift to the fermionic zero mode, this phase is actually origin from the Aharonov-Bohm effect.Comment: 11 pages, no figures, to appear in MPL

Fermionic zero modes in gauge and gravity backgrounds On T2T^2

In this note we study fermionic zero modes in gauge and gravity backgrounds taking a two dimensional compact manifold $T^2$ as extra dimensions. The result is that there exist massless Dirac fermions which have normalizable zero modes under quite general assumptions about these backgrounds on the bulk. Several special cases of gauge background on the torus are discussed and some simple fermionic zero modes are obtained.Comment: 8 pages, no figures, v2: more references, accepted by Mod.Phys.Lett.

The topological structure of the vortices in the O(n) symmetric TDGL model

In the light of $\phi$--mapping method and topological current theory, the topological structure of the vortex state in TDGL model and the topological quantization of the vortex topological charges are investigated. It is pointed out that the topological charges of the vortices in TDGL model are described by the Winding numbers of $\phi$--mapping which are determined in terms of the Hopf indices and the Brouwer degrees of $\phi$--mapping.Comment: 9 pages, LaTe

The association of HDL-apoCIII with coronary heart disease and the effect of statin treatment on it

Effect of statin treatment on lipid variables in CHD patients with DM or not. (DOC 37 kb

An Ultra-low Power TinyML System for Real-time Visual Processing at Edge

Tiny machine learning (TinyML), executing AI workloads on resource and power strictly restricted systems, is an important and challenging topic. This brief firstly presents an extremely tiny backbone to construct high efficiency CNN models for various visual tasks. Then, a specially designed neural co-processor (NCP) is interconnected with MCU to build an ultra-low power TinyML system, which stores all features and weights on chip and completely removes both of latency and power consumption in off-chip memory access. Furthermore, an application specific instruction-set is further presented for realizing agile development and rapid deployment. Extensive experiments demonstrate that the proposed TinyML system based on our model, NCP and instruction set yields considerable accuracy and achieves a record ultra-low power of 160mW while implementing object detection and recognition at 30FPS. The demo video is available on \url{https://www.youtube.com/watch?v=mIZPxtJ-9EY}.Comment: 5 pages, 5 figure