Search results for "circuits"

Multimodal determinants of phase-locked dynamics across deep-superficial hippocampal sublayers during theta oscillations

2020

Theta oscillations play a major role in temporarily defining the hippocampal rate code by translating behavioral sequences into neuronal representations. However, mechanisms constraining phase timing and cell-type-specific phase preference are unknown. Here, we employ computational models tuned with evolutionary algorithms to evaluate phase preference of individual CA1 pyramidal cells recorded in mice and rats not engaged in any particular memory task. We applied unbiased and hypothesis-free approaches to identify effects of intrinsic and synaptic factors, as well as cell morphology, in determining phase preference. We found that perisomatic inhibition delivered by complementary populations…

Synthetic biology: Engineered stable ecosystems

2017

International audience; Co-culture of bacterial cells engineered with quorum-sensing and self-lysis circuits allows coupled oscillatory dynamics and stable states, opening the way to engineered microbial ecosystems with targeted dynamics and extending gene circuits to the ecosystem level.

Synchronized Activity in The Main and Accessory Olfactory Bulbs and Vomeronasal Amygdala Elicited by Chemical Signals in Freely Behaving Mice

2017

AbstractChemosensory processing in mammals involves the olfactory and vomeronasal systems, but how the activity of both circuits is integrated is unknown. In our study, we recorded the electrophysiological activity in the olfactory bulbs and the vomeronasal amygdala in freely behaving mice exploring a battery of neutral and conspecific stimuli. The exploration of stimuli, including a neutral stimulus, induced synchronic activity in the olfactory bulbs characterized by a dominant theta rhythmicity, with specific theta-gamma coupling, distinguishing between vomeronasal and olfactory structures. The correlated activation of the bulbs suggests a coupling between the stimuli internalization in t…

parSRA: A framework for the parallel execution of short read aligners on compute clusters

2018

The growth of next generation sequencing datasets poses as a challenge to the alignment of reads to reference genomes in terms of both accuracy and speed. In this work we present parSRA, a parallel framework to accelerate the execution of existing short read aligners on distributed-memory systems. parSRA can be used to parallelize a variety of short read alignment tools installed in the system without any modification to their source code. We show that our framework provides good scalability on a compute cluster for accelerating the popular BWA-MEM and Bowtie2 aligners. On average, it is able to accelerate sequence alignments on 16 64-core nodes (in total, 1024 cores) with speedup of 10.48 …

Modulating Neuronal Competition Dynamics in the Dentate Gyrus to Rejuvenate Aging Memory Circuits.

2015

The neural circuit mechanisms underlying the integration and functions of adult-born dentate granule cell (DGCs) are poorly understood. Adult-born DGCs are thought to compete with mature DGCs for inputs to integrate. Transient genetic overexpression of a negative regulator of dendritic spines, Kruppel-like factor 9 (Klf9), in mature DGCs enhanced integration of adult-born DGCs and increased NSC activation. Reversal of Klf9 overexpression in mature DGCs restored spines and activity and reset neuronal competition dynamics and NSC activation, leaving the DG modified by a functionally integrated, expanded cohort of age-matched adult-born DGCs. Spine elimination by inducible deletion of Rac1 in …

À la recherche du circuit idéal : le discours sur les autodromes et circuits automobiles dans L'Auto (1900-1939)

2022

Distributed Adaptive Control for Asymptotically Consensus Tracking of Uncertain Nonlinear Systems With Intermittent Actuator Faults and Directed Comm…

2019

In this article, we investigate the output consensus tracking problem for a class of high-order nonlinear systems with unknown parameters, uncertain external disturbances, and intermittent actuator faults. Under the directed topology conditions, a novel distributed adaptive controller is proposed. The common time-varying trajectory is allowed to be totally unknown by part of subsystems. Therefore, the assumption on the linearly parameterized trajectory signal in most literature is no longer needed. To achieve the relaxation, extra distributed parameter estimators are introduced in all subsystems. Besides, to handle the actuator faults occurring at possibly infinite times, a new adaptive com…

Subthreshold low frequency repetitive transcranial magnetic stimulation selectively decreases facilitation in the motor cortex

2002

Objective: To investigate the modulatory effect of a subthreshold low frequency repetitive transcranial magnetic stimulation (rTMS) train on motor cortex excitability. Methods: The study consisted of two separate experiments. Subjects received a 10 min long subthreshold 1Hz rTMS train. In the first experiment, (single pulse paradigm), cortical excitability was assessed by measuring the amplitude of motor evoked potentials (MEPs) before and after the rTMS train. In the second experiment, a paired pulse paradigm was employed. Results: Corticospinal excitability, as measured by the MEP amplitude, was reduced by the rTMS train (experiment 1), with a significant effect lasting for about 10 min a…

Control of signal coherence in parametric frequency mixing with incoherent pumps: Narrowband mid-infrared light generation by downconversion of broad…

2012

International audience; We study, with numerical simulations using the generalized nonlinear envelope equation, the processes of optical parametric and difference- and sum-frequency generation (SFG) with incoherent pumps in optical media with both quadratic and third-order nonlinearity, such as periodically poled lithium niobate. With ultrabroadband amplified spontaneous emission pumps or continua (spectral widths > 10 THz), group-velocity matching of a near-IR pump and a short-wavelength mid-IR (MIR) idler in optical parametric generation may lead to more than 15-fold relative spectral narrowing of the generated MIR signal. Moreover, the SFG process may also lead to 6-fold signal coherence…

A Hardware and Secure Pseudorandom Generator for Constrained Devices

2018

Hardware security for an Internet of Things or cyber physical system drives the need for ubiquitous cryptography to different sensing infrastructures in these fields. In particular, generating strong cryptographic keys on such resource-constrained device depends on a lightweight and cryptographically secure random number generator. In this research work, we have introduced a new hardware chaos-based pseudorandom number generator, which is mainly based on the deletion of an Hamilton cycle within the $N$ -cube (or on the vectorial negation), plus one single permutation. We have rigorously proven the chaotic behavior and cryptographically secure property of the whole proposal: the mid-term eff…