scholarly journals Developmental experience-dependent plasticity in the first synapse of the Drosophila olfactory circuit

2016 ◽  
Vol 116 (6) ◽  
pp. 2730-2738 ◽  
Author(s):  
Randall M. Golovin ◽  
Kendal Broadie
Keyword(s):  
Sensory Input ◽  
Neural Circuit ◽  
Prolonged Exposure ◽  
Fragile X ◽  
Projection Neurons ◽  
Local Interneuron ◽  
Dependent Plasticity ◽  
Behavioral Adaptations ◽  
Developmental Experience ◽  
Mrna Binding

Evidence accumulating over the past 15 years soundly refutes the dogma that the Drosophila nervous system is hardwired. The preponderance of studies reveals activity-dependent neural circuit refinement driving optimization of behavioral outputs. We describe developmental, sensory input-dependent plasticity in the brain olfactory antennal lobe, which we term long-term central adaption (LTCA). LTCA is evoked by prolonged exposure to an odorant during the first week of posteclosion life, resulting in a persistently decreased response to aversive odors and an enhanced response to attractive odors. This limited window of early-use, experience-dependent plasticity represents a critical period of olfactory circuit refinement tuned by initial sensory input. Consequent behavioral adaptations have been associated with changes in the output of olfactory projection neurons to higher brain centers. Recent studies have indicated a central role for local interneuron signaling in LTCA presentation. Genetic and molecular analyses have implicated the mRNA-binding fragile X mental retardation protein and ataxin-2 regulators, Notch trans-synaptic signaling, and cAMP signal transduction as core regulatory steps driving LTCA. In this article, we discuss the structural, functional, and behavioral changes associated with LTCA and review our current understanding of the molecular pathways underlying these developmental, experience-dependent changes in the olfactory circuitry.

Supervised Spike-Timing-Dependent Plasticity: A Spatiotemporal Neuronal Learning Rule for Function Approximation and Decisions

2013 ◽  
Vol 25 (12) ◽  
pp. 3113-3130 ◽  
Author(s):  
Jan-Moritz P. Franosch ◽  
Sebastian Urban ◽  
J. Leo van Hemmen
Keyword(s):  
Function Approximation ◽  
Sensory Input ◽  
Learning Rule ◽  
Animal Learn ◽  
Spike Timing ◽  
Time Dependent ◽  
Stable Configuration ◽  
Spike Timing Dependent Plasticity ◽  
Dependent Plasticity ◽  
Tactile System

How can an animal learn from experience? How can it train sensors, such as the auditory or tactile system, based on other sensory input such as the visual system? Supervised spike-timing-dependent plasticity (supervised STDP) is a possible answer. Supervised STDP trains one modality using input from another one as “supervisor.” Quite complex time-dependent relationships between the senses can be learned. Here we prove that under very general conditions, supervised STDP converges to a stable configuration of synaptic weights leading to a reconstruction of primary sensory input.

scholarly journals High-throughput mapping of single-cell molecular and projection architecture of neurons by retrograde barcoded labelling

2021 ◽  
Author(s):  
Peibo Xu ◽  
Jian Peng ◽  
Tingli Yuan ◽  
Zhaoqin Chen ◽  
Ziyan Wu ◽  
...  
Keyword(s):  
Single Cell ◽  
Single Neuron ◽  
Neural Circuit ◽  
Brain Regions ◽  
Mammalian Brain ◽  
Projection Neurons ◽  
Proof Of Concept ◽  
Sequencing Technology ◽  
Modal Data ◽  
Projection Pattern

Deciphering mesoscopic connectivity of the mammalian brain is a pivotal step in neuroscience. Most imaging-based conventional neuroanatomical tracing methods identify area-to-area or sparse single neuronal labeling information. Although recently developed barcode-based connectomics has been able to map a large number of single-neuron projections efficiently, there is a missing link in single-cell connectome and transcriptome. Here, combining single-cell RNA sequencing technology, we established a retro-AAV barcode-based multiplexed tracing method called MEGRE-seq (Multiplexed projEction neuRons retroGrade barcodE), which can resolve projectome and transcriptome of source neurons simultaneously. Using the ventromedial prefrontal cortex (vmPFC) as a proof-of-concept neocortical region, we investigated projection patterns of its excitatory neurons targeting five canonical brain regions, as well as corresponding transcriptional profiles. Dedicated, bifurcated or collateral projection patterns were inferred by digital projectome. In combination with simultaneously recovered transcriptome, we find that certain projection pattern has a preferential layer or neuron subtype bias. Further, we fitted single-neuron two-modal data into a machine learning-based model and delineated gene importance by each projection target. In summary, we anticipate that the new multiplexed digital connectome technique is potential to understand the organizing principle of the neural circuit by linking projectome and transcriptome.

scholarly journals AAV9-Retro Mediates Efficient Transduction with Axon Terminal Absorption and Blood-brain Barrier Transportation

2020 ◽  
Author(s):  
Kunzhang Lin ◽  
Xin Zhong ◽  
Lei Li ◽  
Min Ying ◽  
Tian Yang ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Neural Circuit ◽  
Brain Barrier ◽  
Brain Diseases ◽  
Projection Neurons ◽  
Routes Of Administration ◽  
Functional Studies ◽  
Blood Brain ◽  
Wide Scale ◽  
Alternative Routes

Abstract Recombinant adeno-associated viruses (rAAVs), especially which permit efficient gene transfer to neurons from axonal terminals or across the blood-brain barrier, are useful vehicles for the structural and functional studies of neural circuit, and for the treatment of many gene-deficient brain diseases that needs to compensate for the correct genes to every cell in the whole brain. However, AAVs with these two advantages have not been reported. Here, we describe a new capsid engineering method, which draws on advantage combination of different capsids, and aims to yield a capsid that can provide more alternative routes of administration, which are more suitable for wide-scale transduction of the CNS. A new AAV variant, AAV9-Retro, was developed by inserting the 10-mer peptide fragment from AAV2-Retro into the capsid of AAV9, and the biodistribution properties were evaluated in mice. By intracranial and intravenous injection in the mice, we found that AAV9-Retro can retrogradely infect projection neurons with efficiency comparable to AAV2-Retro, and retains the characteristic of AAV9 that can transport across the nervous system. Our strategy provides a new tool for the manipulation of neural circuits, and for the future preclinical and clinical treatment of some neurological and neurodegenerative disorders.

scholarly journals Experience-dependent plasticity modulates ongoing activity in the antennal lobe and enhance odor representations

2021 ◽  
Author(s):  
Luis M. Franco ◽  
Emre Yaksi
Keyword(s):  
Antennal Lobe ◽  
Internal State ◽  
Brain Activity ◽  
Fruit Fly ◽  
Brain Regions ◽  
Projection Neurons ◽  
Ongoing Activity ◽  
Dependent Plasticity ◽  
Olfactory Glomeruli ◽  
The Brain

ABSTRACTOngoing neural activity has been observed across several brain regions and thought to reflect the internal state of the brain. Yet, it is not fully understood how ongoing brain activity interacts with sensory experience and shape sensory representations. Here, we show that projection neurons of the fruit fly antennal lobe exhibit spatiotemporally organized ongoing activity in the absence of odor stimulation. Upon repeated exposure to odors, we observe a gradual and long-lasting decrease in the amplitude and frequency of spontaneous calcium events, as well as a reorganization of correlations between olfactory glomeruli during ongoing activity. Accompanying these plastic changes, we find that repeated odor experience reduces trial-to-trial variability and enhances the specificity of odor representations. Our results reveal a previously undescribed experience-dependent plasticity of ongoing and sensory driven activity at peripheral levels of the fruit fly olfactory system.

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