scholarly journals Integration of Odor-Induced Activity of Kenyon Cells in an Electrotonically Compact Drosophila Mushroom Body Output Neuron (MBON)

2019 ◽  
Author(s):  
Omar Hafez ◽  
Benjamin Escribano ◽  
Jan Pielage ◽  
Ernst Niebur
Keyword(s):  
Mushroom Body ◽  
Behavioral Outcomes ◽  
Dendritic Structure ◽  
Internal Representation ◽  
Kenyon Cell ◽  
Sensory Stimuli ◽  
Output Neuron ◽  
Spatially Distributed ◽  
Functional Understanding ◽  
Distributed Cluster

AbstractThe formation of an ecologically useful lasting memory requires that the brain has an accurate internal representation of the surrounding environment. In addition, it must have the ability to integrate a variety of different sensory stimuli and associate them with rewarding and aversive behavioral outcomes. Over the previous years, a number of studies have dissected the anatomy and elucidated some of the working principles of the Drosophila mushroom body (MB), the fly’s center for learning and memory. As a consequence, we now have a functional understanding of where and how in the MB sensory stimuli converge and are associated. However, the molecular and cellular dynamics at the critical synaptic intersection for this process, the Kenyon cell-mushroom body output neuron (KC-MBON) synapse, are largely unknown. Here, we introduce a first approach to understand this integration process and the physiological changes occurring at the KC-MBON synapse during Kenyon cell (KC) activation. We use the published connectome of the Drosophila MB to construct a functional computational model of the MBON-α3-A dendritic structure. We simulate synaptic input by individual KC-MBON synapses by current injections into precisely (μm) identified local dendritic sections, and the input from a model population of KCs representing an odor by a spatially distributed cluster of current injections. By recording the effect of the simulated current injections on the membrane potential of the neuron, we show that the MBON-α3-A is electrotonically compact. This suggests that odor-induced MBON activity is likely governed by input strength while the positions of KC input synapses are largely irrelevant.

scholarly journals Neurogenetic dissection of the Drosophila lateral horn reveals major outputs, diverse behavioural functions, and interactions with the mushroom body

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Michael-John Dolan ◽  
Shahar Frechter ◽  
Alexander Shakeel Bates ◽  
Chuntao Dan ◽  
Paavo Huoviala ◽  
...  
Keyword(s):  
Mushroom Body ◽  
Cell Types ◽  
Olfactory Cues ◽  
Body Site ◽  
Olfactory Behavior ◽  
Gal4 Driver ◽  
Sensory Stimuli ◽  
Lateral Horn ◽  
Functional Understanding ◽  
Innate Behaviour

Animals exhibit innate behaviours to a variety of sensory stimuli including olfactory cues. In Drosophila, one higher olfactory centre, the lateral horn (LH), is implicated in innate behaviour. However, our structural and functional understanding of the LH is scant, in large part due to a lack of sparse neurogenetic tools for this region. We generate a collection of split-GAL4 driver lines providing genetic access to 82 LH cell types. We use these to create an anatomical and neurotransmitter map of the LH and link this to EM connectomics data. We find ~30% of LH projections converge with outputs from the mushroom body, site of olfactory learning and memory. Using optogenetic activation, we identify LH cell types that drive changes in valence behavior or specific locomotor programs. In summary, we have generated a resource for manipulating and mapping LH neurons, providing new insights into the circuit basis of innate and learned olfactory behavior.

Stochastic behavior of atrial and ventricular intrinsic cardiac neurons

2006 ◽  
Vol 101 (2) ◽  
pp. 413-419 ◽  
Author(s):  
M. Waldmann ◽  
G. W. Thompson ◽  
G. C. Kember ◽  
J. L. Ardell ◽  
J. A. Armour
Keyword(s):  
Nervous System ◽  
Correlation Coefficient ◽  
Cross Correlation ◽  
Mechanical Deformation ◽  
Short Term ◽  
Stochastic Behavior ◽  
Sensory Stimuli ◽  
Spatially Distributed ◽  
Tightly Coupled ◽  
Anesthetized Dogs

To quantify the concurrent transduction capabilities of spatially distributed intrinsic cardiac neurons, the activities generated by atrial vs. ventricular intrinsic cardiac neurons were recorded simultaneously in 12 anesthetized dogs at baseline and during alterations in the cardiac milieu. Few (3%) identified atrial and ventricular neurons (2 of 72 characterized neurons) responded solely to regional mechanical deformation, doing so in a tightly coupled fashion (cross-correlation coefficient r = 0.63). The remaining (97%) atrial and ventricular neurons transduced multimodal stimuli to display stochastic behavior. Specifically, ventricular chemosensory inputs modified these populations such that they generated no short-term coherence among their activities (cross-correlation coefficient r = 0.21 ± 0.07). Regional ventricular ischemia activated most atrial and ventricular neurons in a noncoupled fashion. Nicotinic activation of atrial neurons enhanced ventricular neuronal activity. Acute decentralization of the intrinsic cardiac nervous system obtunded its neuron responsiveness to cardiac sensory stimuli. Most atrial and ventricular intrinsic cardiac neurons generate concurrent stochastic activity that is predicated primarily upon their cardiac chemotransduction. As a consequence, they display relative independent short-term (beat-to-beat) control over regional cardiac indexes. Over longer time scales, their functional interdependence is manifest as the result of interganglionic interconnections and descending inputs.

scholarly journals Systematic functional characterization of the intellectual disability-associated SWI/SNF complex reveals distinct roles for the BAP and PBAP complexes in post-mitotic memory forming neurons of the Drosophila mushroom body

2018 ◽  
Author(s):  
Melissa C. Chubak ◽  
Max H. Stone ◽  
Nicholas Raun ◽  
Shelby L. Rice ◽  
Mohammed Sarikahya ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Mushroom Body ◽  
Functional Characterization ◽  
Long Term Memory ◽  
Term Memory ◽  
Functional Understanding ◽  
Short And Long Term ◽  
Cellular Components

AbstractTechnology has led to rapid progress in the identification of genes involved in neurodevelopmental disorders like intellectual disability (ID), but our functional understanding of the causative genes is lagging. Here, we show that the SWI/SNF chromatin remodeling complex is one of the most overrepresented cellular components disrupted in ID. We systematically investigated the role of individual subunits of this large protein complex in post-mitotic memory forming neurons of the Drosophila mushroom body (MB). Using this approach, we have identified novel differential roles for the two prominent conformations of the Drosophila SWI/SNF complex, known as BAP and PBAP. The PBAP conformation is required post-mitotically for remodeling of the MB γ neurons during morphogenesis and is essential for both short and long-term memory. In contrast, the BAP conformation appears to preferentially effect long-term memory and is associated with γ neuron survival. Our results suggest that different subunits of the SWI/SNF complex may influence learning and memory through diverse and distinct roles in regulating structural plasticity, survival, and functionality of post-mitotic neurons. This study provides novel insight into the neuronal function of individual SWI/SNF subunits and will serve as a basis for understanding SWI/SNF-mediated gene regulatory mechanisms in post-mitotic neurons.

scholarly journals Inhibitory muscarinic acetylcholine receptors enhance aversive olfactory conditioning in adult Drosophila

2018 ◽  
Author(s):  
Noa Bielopolski ◽  
Hoger Amin ◽  
Anthi A. Apostolopoulou ◽  
Eyal Rozenfeld ◽  
Hadas Lerner ◽  
...  
Keyword(s):  
Mushroom Body ◽  
Acetylcholine Receptors ◽  
Physiological Function ◽  
Muscarinic Acetylcholine Receptors ◽  
Kenyon Cell ◽  
Olfactory Conditioning ◽  
Muscarinic Acetylcholine ◽  
Kenyon Cells ◽  
Output Neurons ◽  
Adult Drosophila

AbstractOlfactory associative learning inDrosophilais mediated by synaptic plasticity between the Kenyon cells of the mushroom body and their output neurons. Both Kenyon cells and their inputs are cholinergic, yet little is known about the physiological function of muscarinic acetylcholine receptors in learning in adult flies. Here we show that aversive olfactory learning in adult flies requires type A muscarinic acetylcholine receptors (mAChR-A) specifically in the gamma subtype of Kenyon cells. Surprisingly, mAChR-A inhibits odor responses in both Kenyon cell dendrites and axons. Moreover, mAChR-A knockdown impairs the learning-associated depression of odor responses in a mushroom body output neuron. Our results suggest that mAChR-A is required at Kenyon cell presynaptic terminals to depress the synapses between Kenyon cells and their output neurons, and may suggest a role for the recently discovered axo-axonal synapses between Kenyon cells.

scholarly journals MicroCT-based phenomics in the zebrafish skeleton reveals virtues of deep phenotyping in a distributed organ system

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Matthew Hur ◽  
Charlotte A Gistelinck ◽  
Philippe Huber ◽  
Jane Lee ◽  
Marjorie H Thompson ◽  
...  
Keyword(s):  
Axial Skeleton ◽  
Thyroid Stimulating Hormone ◽  
Organ System ◽  
Genetic Screens ◽  
Spatially Distributed ◽  
Functional Understanding ◽  
Increase Productivity ◽  
Brittle Bone Disease ◽  
Mutant Phenotypes ◽  
Deep Phenotyping

Phenomics, which ideally involves in-depth phenotyping at the whole-organism scale, may enhance our functional understanding of genetic variation. Here, we demonstrate methods to profile hundreds of phenotypic measures comprised of morphological and densitometric traits at a large number of sites within the axial skeleton of adult zebrafish. We show the potential for vertebral patterns to confer heightened sensitivity, with similar specificity, in discriminating mutant populations compared to analyzing individual vertebrae in isolation. We identify phenotypes associated with human brittle bone disease and thyroid stimulating hormone receptor hyperactivity. Finally, we develop allometric models and show their potential to aid in the discrimination of mutant phenotypes masked by alterations in growth. Our studies demonstrate virtues of deep phenotyping in a spatially distributed organ system. Analyzing phenotypic patterns may increase productivity in genetic screens, and facilitate the study of genetic variants associated with smaller effect sizes, such as those that underlie complex diseases.

scholarly journals Embodied working memory during ongoing input streams

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244822
Author(s):  
Nareg Berberian ◽  
Matt Ross ◽  
Sylvain Chartier
Keyword(s):  
Working Memory ◽  
Neural Activity ◽  
Formal Model ◽  
Working Memory Capacity ◽  
Internal Representation ◽  
Stimulus Presentation ◽  
Sensory Stimuli ◽  
Memory Content ◽  
External Stimuli

Sensory stimuli endow animals with the ability to generate an internal representation. This representation can be maintained for a certain duration in the absence of previously elicited inputs. The reliance on an internal representation rather than purely on the basis of external stimuli is a hallmark feature of higher-order functions such as working memory. Patterns of neural activity produced in response to sensory inputs can continue long after the disappearance of previous inputs. Experimental and theoretical studies have largely invested in understanding how animals faithfully maintain sensory representations during ongoing reverberations of neural activity. However, these studies have focused on preassigned protocols of stimulus presentation, leaving out by default the possibility of exploring how the content of working memory interacts with ongoing input streams. Here, we study working memory using a network of spiking neurons with dynamic synapses subject to short-term and long-term synaptic plasticity. The formal model is embodied in a physical robot as a companion approach under which neuronal activity is directly linked to motor output. The artificial agent is used as a methodological tool for studying the formation of working memory capacity. To this end, we devise a keyboard listening framework to delineate the context under which working memory content is (1) refined, (2) overwritten or (3) resisted by ongoing new input streams. Ultimately, this study takes a neurorobotic perspective to resurface the long-standing implication of working memory in flexible cognition.

scholarly journals Sticks and Stones, a conserved cell surface ligand for the Type IIa RPTP Lar, regulates neural circuit wiring in Drosophila

2020 ◽  
Author(s):  
Namrata Bali ◽  
Hyung-Kook (Peter) Lee ◽  
Kai Zinn
Keyword(s):  
Cell Surface ◽  
Axon Guidance ◽  
Mushroom Body ◽  
Neural Circuit ◽  
Genetic Interaction ◽  
Protein Tyrosine Phosphatases ◽  
Essential Element ◽  
Immunoglobulin Superfamily ◽  
Kenyon Cell ◽  
Sticks And Stones

AbstractControl of tyrosine phosphorylation is an essential element of many cellular processes, including proliferation, differentiation neurite outgrowth, and synaptogenesis. Receptor-like protein-tyrosine phosphatases (RPTPs) have cytoplasmic phosphatase domains and cell adhesion molecule (CAM)-like extracellular domains that interact with cell-surface ligands and/or co-receptors. We identified a new ligand for the Drosophila Lar RPTP, the immunoglobulin superfamily CAM Sticks and Stones (Sns). Lar is orthologous to the three Type IIa mammalian RPTPs, PTPRF (LAR), PTPRD (PTPδ), and PTPRS (PTPσ). Lar and Sns bind to each other in embryos and in vitro. The human Sns ortholog, Nephrin, binds to PTPRD and PTPRF. Genetic interaction studies show that Sns is essential to Lar’s functions in several developmental contexts in the larval and adult nervous systems. In the larval neuromuscular system, Lar and sns transheterozygotes (Lar/sns transhets) have synaptic defects like those seen in Lar mutants and Sns knockdown animals. Lar and Sns reporters are both expressed in motor neurons and not in muscles, so Lar and Sns likely act in cis (in the same neurons). Lar mutants and Lar/sns transhets have identical axon guidance defects in the larval mushroom body in which Kenyon cell axons fail to stop at the midline and do not branch. Pupal Kenyon cell axon guidance is similarly affected, resulting in adult mushroom body defects. Lar is expressed in larval and pupal Kenyon cells, but Sns is not, so Lar-Sns interactions in this system must be in trans (between neurons). Lastly, R7 photoreceptor axons in Lar mutants and Lar/sns transhets fail to innervate the correct M6 layer of the medulla in the optic lobe. Lar acts cell-autonomously in R7s, while Sns is only in lamina and medulla neurons that arborize near the R7 target layer. Therefore, the Lar-Sns interactions that control R7 targeting also occur in trans.

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