Local neuronal circuits that may shape the discharge patterns of inferior collicular neurons

The discharge patterns of neurons in auditory centers encode information about sounds.However,few studies have focused on the synaptic mechanisms underlying the shaping of discharge patterns using intracellular recording techniques.Here,we investigated the discharge patterns of inferior collicular（IC）neurons using intracellular recordings to further elucidate the mechanisms underlying the shaping of discharge patterns.Under in vivo intracellular recording conditions,recordings were obtained from 66 IC neurons in 18 healthy adult mice（Mus musculus,Km）under free field-stimulation.Fiftyeight of these neurons fired bursts of action potentials（APs）to auditory stimuli and the remaining eight just generated local responses such as excitatory（n=4）or inhibitory（n=4）postsynaptic potentials.Based on the APs and subthreshold responses,the discharge patterns were classified into seven types：phasic（24/58,41.4%）,phasic burst（8/58,13.8%）,pauser（4/58,6.9%）,phasic-pauser（1/58,1.7%）,chopper（2/58,3.4%）,primary-like tonic（14/58,24.1%）and sound-induced inhibitory（5/58,8.6%）.We concluded that（1）IC neurons exhibit at least seven distinct discharge patterns;（2）inhibition participates in shaping the discharge pattern of most IC neurons and plays a role in sculpting the pattern,except for the primary-like tonic pattern which was not shapedby inhibition;and（3）local neural circuits are the likely structural basis that shapes the discharge patterns of IC neurons and can be formed either in the IC or in lower-level auditory structures.

Cortical columns(barrels)display normal size in the brain’s primary somatosensory cortex of mice carrying null mutations of the insulin receptor substrate 1 gene:A preliminary report

Circuits in barrels of the rodent brain’s primary somatosensory (S1) cortex build up following constructivist rules. Previous evidence in mice supports that the precise addition of barrel neuropil is promoted by insulin-like growth factor-1 (IGF-1). The signaling cascades mediating this response remain undetermined. To address whether the effects of IGF-1 upon the growth of S1 circuits are mediated by insulin receptor substrate-1 (IRS-1), we studied barrel size in adult mice having the IRS-1 gene knocked out (IRS-1 ko). Our results reveal that barrel size is similar between wild type and IRS-1 ko mice suggesting that IRS-1 is not essential for barrel circuitry growth. Hence, investigations aimed at exploring other substrates activated by IGF-1, namely IRS-2 and IRS-4, are needed to reveal signaling pathways that mediate the precise addition of S1 neuronal circuitry.

Can the Glucose Central Control System Dysfunctions Induce Diabetes Mellitus?

We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art literature related to the subject, in order to cross, to compare, and to organize the relevant contents to create a logical and consistent support to the finds. We show that it is consistent to assume that persistent hyperglycemia and diabetes mellitus can have precursors not only in pancreas, but also in brain, mainly induced by noxious dysfunctions of hypothalamus sensor neurons circuits and external noxious elements, causing pancreas overload, and the consequent exhaustion—overburden.

Cluster synchronization in complex network of coupled chaotic circuits： An experimental study

By a small-size complex network of coupled chaotic Hindmarsh-Rose circuits, we study experimen- tally the stability of network synchronization to the removal of shortcut links. It is shown that the removal of a single shortcut link may destroy either completely or partially the network synchroniza- tion. Interestingly, when the network is partially desynchronized, it is found that the oscillators can be organized into different groups, with oscillators within each group being highly synchronized but are not for oscillators from different groups, showing the intriguing phenomenon of cluster synchro- nization. The experimental results are analyzed by the method of eigenvalue analysis, which implies that the formation of cluster synchronization is crucially dependent on the network symmetries. Our study demonstrates the observability of cluster synchronization in realistic systems, and indicates the feasibility of controlling network synchronization by adjusting network topology.

Core processing neuron-enabled circuit motifs for neuromorphic computing

Based on brain-inspired computing frameworks,neuromorphic systems implement large-scale neural networks in hardware.Although rapid advances have been made in the development of artificial neurons and synapses in recent years,further research is beyond these individual components and focuses on neuronal circuit motifs with specialized excitatory-inhibitory(E-I)connectivity patterns.In this study,we demonstrate a core processor that can be used to construct commonly used neuronal circuits.The neuron,featuring an ultracompact physical configuration,integrates a volatile threshold switch with a gate-modulated two-dimensional(2D)MoS_(2) field-effect channel to process complex E-I spatiotemporal spiking signals.Consequently,basic neuronal circuits are constructed for biorealistic neuromorphic computing.For practical applications,an algorithm-hardware co-design is implemented in a gatecontrolled spiking neural network with substantial performance improvement in human speech separation.

The Superior Colliculus:Cell Types,Connectivity,and Behavior

The superior colliculus(SC),one of the most well-characterized midbrain sensorimotor structures where visual,auditory,and somatosensory information are integrated to initiate motor commands,is highly conserved across vertebrate evolution.Moreover,cell-type-specific SC neurons integrate afferent signals within local networks to generate defined output related to innate and cognitive behaviors.This review focuses on the recent progress in understanding of phenotypic diversity amongst SC neurons and their intrinsic circuits and long-projection targets.We further describe relevant neural circuits and specific cell types in relation to behavioral outputs and cognitive functions.The systematic delineation of SC organization,cell types,and neural connections is further put into context across species as these depend upon laminar architecture.Moreover,we focus on SC neural circuitry involving saccadic eye movement,and cognitive and innate behaviors.Overall,the review provides insight into SC functioning and represents a basis for further understanding of the pathology associated with SC dysfunction.

Using optogenetics to translate the “inflammatory dialogue” between heart and brain in the context of stress

Inflammatory processes are an integral part of the stress response and are likely to result from a programmed adaptation that is vital to the organism＇s survival and well-being.The whole inflammatory response is mediated by largely overlapping circuits in the limbic forebrain,hypothalamus and brainstem,but is also under the control of the neuroendocrine and autonomic nervous systems.Genetically predisposed individuals who fail to tune the respective contributions of the two systems in accordance with stressor modality and intensity after adverse experiences can be at risk for stress-related psychiatric disorders and cardiovascular diseases.Altered glucocorticoid（GC） homeostasis due to GC resistance leads to the failure of neural and negative feedback regulation of the hypothalamic-pituitary-adrenal axis during chronic inflammation,and this might be the mechanism underlying the ensuing brain and heart diseases and the high prevalence of co-morbidity between the two systems.By the combined use of light and genetically-encoded lightsensitive proteins,optogenetics allows cell-type-specific,fast（millisecond-scale） control of precisely defined events in biological systems.This method is an important breakthrough to explore the causality between neural activity patterns and behavioral profiles relevant to anxiety,depression,autism and schizophrenia.Optogenetics also helps to understand the ＂inflammatory dialogue＂,the inflammatory processes in psychiatric disorders and cardiovascular diseases,shared by heart and brain in the context of stress.

Construction and characterization of a synthesized herpes simplex virus H129-Syn-G2

Herpes simplex virus type 1(HSV-1)causes lifelong infections worldwide,and currently there is no efficient cure or vaccine.HSV-1-derived tools,such as neuronal circuit tracers and oncolytic viruses,have been used exten-sively;however,further genetic engineering of HSV-1 is hindered by its complex genome structure.In the present study,we designed and constructed a synthetic platform for HSV-1 based on H129-G4.The complete genome was constructed from 10 fragments through 3 rounds of synthesis using transformation-associated recombination(TAR)in yeast,and was named H129-Syn-G2.The H129-Syn-G2 genome contained two copies of the gfp gene and was transfected into cells to rescue the virus.According to growth curve assay and electron microscopy results,the synthetic viruses exhibited more optimized growth properties and similar morphogenesis compared to the parental virus.This synthetic platform will facilitate further manipulation of the HSV-1 genome for the devel-opment of neuronal circuit tracers,oncolytic viruses,and vaccines.

Reconfigurable memristor based on SrTiO_(3) thin-film for neuromorphic computing

Neuromorphic computing aims to achieve artificial intelligence by mimicking the mechanisms of biological neurons and synapses that make up the human brain.However,the possibility of using one reconfigurable memristor as both artificial neuron and synapse still requires intensive research in detail.In this work,Ag/SrTiO_(3)(STO)/Pt memristor with low operating voltage is manufactured and reconfigurable as both neuron and synapse for neuromorphic computing chip.By modulating the compliance current,two types of resistance switching,volatile and nonvolatile,can be obtained in amorphous STO thin film.This is attributed to the manipulation of the Ag conductive filament.Furthermore,through regulating electrical pulses and designing bionic circuits,the neuronal functions of leaky integrate and fire,as well as synaptic biomimicry with spike-timing-dependent plasticity and paired-pulse facilitation neural regulation,are successfully realized.This study shows that the reconfigurable devices based on STO thin film are promising for the application of neuromorphic computing systems.