scholarly journals Generating an Executable Model of the Drosophila Central Complex

2016 ◽  
Author(s):  
Lev E. Givon ◽  
Aurel A. Lazar
Keyword(s):  
Neural Circuit ◽  
Spatial Information ◽  
Level Structure ◽  
Neural Circuitry ◽  
Central Complex ◽  
Projection Neurons ◽  
Locomotor Control ◽  
Olfactory Systems ◽  
High Level ◽  
Available Information

AbstractThe central complex (CX) is a set of neuropils in the center of the fly brain that have been implicated as playing an important role in vision-mediated behavior and integration of spatial information for locomotor control. In contrast to currently available data regarding the neural circuitry of neuropils in the fly's vision and olfactory systems, comparable data for the CX neuropils is relatively incomplete; many categories of neurons remain only partly characterized, and the synaptic connectivity between CX neurons has yet to be experimentally determined. Successful modeling of the information processing functions of the CX neuropils therefore requires a means of easily constructing and testing a range of hypotheses regarding both the high-level structure of their neural circuitry and the properties of their constituent neurons and synapses. This document demonstrates how NeuroArch and Neurokernel may be used to algorithmically construct and evaluate executable neural circuit models of the CX neuropils and their interconnects based upon currently available information regarding the geometry and polarity of the arborizations of identified local and projection neurons in the CX.

scholarly journals Parallel visual pathways with topographic versus non-topographic organization connect the Drosophila eyes to the central brain

2020 ◽  
Author(s):  
Lorin Timaeus ◽  
Laura Geid ◽  
Gizem Sancer ◽  
Mathias F. Wernet ◽  
Thomas Hummel
Keyword(s):  
Visual Information ◽  
Visual Cues ◽  
Spatial Information ◽  
Central Complex ◽  
Structural Basis ◽  
Projection Neurons ◽  
Central Brain ◽  
Retinotopic Organization ◽  
Dendritic Fields ◽  
Parallel Visual Pathways

SummaryOne hallmark of the visual system is the strict retinotopic organization from the periphery towards the central brain, spanning multiple layers of synaptic integration. Recent Drosophila studies on the computation of distinct visual features have shown that retinotopic representation is often lost beyond the optic lobes, due to convergence of columnar neuron types onto optic glomeruli. Nevertheless, functional imaging revealed a spatially accurate representation of visual cues in the central complex (CX), raising the question how this is implemented on a circuit level. By characterizing the afferents to a specific visual glomerulus, the anterior optic tubercle (AOTU), we discovered a spatial segregation of topographic versus non-topographic projections from molecularly distinct classes of medulla projection neurons (medullo-tubercular, or MeTu neurons). Distinct classes of topographic versus non-topographic MeTus form parallel channels, terminating in separate AOTU domains. Both types then synapse onto separate matching topographic fields of tubercular-bulbar (TuBu) neurons which relay visual information towards the dendritic fields of central complex ring neurons in the bulb neuropil, where distinct bulb sectors correspond to a distinct ring domain in the ellipsoid body. Hence, peripheral topography is maintained due to stereotypic circuitry within each TuBu class, providing the structural basis for spatial representation of visual information in the central complex. Together with previous data showing rough topography of lobula projections to a different AOTU subunit, our results further highlight the AOTUs role as a prominent relay station for spatial information from the retina to the central brain.

scholarly journals AAV11 permits efficient retrograde targeting of projection neurons

2022 ◽  
Author(s):  
Zengpeng Han ◽  
Nengsong Luo ◽  
Jiaxin Kou ◽  
Lei Li ◽  
Wenyu Ma ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Neural Circuit ◽  
Brain Area ◽  
Brain Diseases ◽  
Projection Neurons ◽  
Recording Technology ◽  
Neural Connections ◽  
Host Immune Responses ◽  
Promising Tool ◽  
High Level

Viral tracers that permit efficient retrograde targeting of projection neurons are powerful vehicles for structural and functional dissections of the neural circuit and for the treatment of brain diseases. Recombinant adeno-associated viruses (rAAVs) are the most potential candidates because they are low-toxic with high-level transgene expression and minimal host immune responses. Currently, some rAAVs based on capsid engineering for retrograde tracing have been widely used in the analysis and manipulation of neural circuits, but suffer from brain area selectivity and inefficient retrograde transduction in certain neural connections. Here, we discovered that the recombinant adeno-associated virus 11 (rAAV11) exhibits potent retrograde labeling of projection neurons with enhanced efficiency to rAAV2-retro in some neural connections. Combined with calcium recording technology, rAAV11 can be used to monitor neuronal activities by expressing Cre recombinase or calcium-sensitive functional probe. In addition, we further showed the suitability of rAAV11 for astrocyte targeting. These properties make rAAV11 a promising tool for the mapping and manipulation of neural circuits and gene therapy of some neurological and neurodegenerative disorders.

scholarly journals A topographic visual pathway into the central brain of Drosophila

2017 ◽  
Author(s):  
Lorin Timaeus ◽  
Laura Geid ◽  
Thomas Hummel
Keyword(s):  
Visual Information ◽  
Spatial Representation ◽  
Spatial Information ◽  
Complex Structure ◽  
Central Complex ◽  
Structural Basis ◽  
Projection Neurons ◽  
Optic Lobes ◽  
Central Brain ◽  
Dendritic Fields

SummaryThe visual system is characterized by a strict topographic organization from the retina towards multiple layers of synaptic integration. Recent studies in Drosophila have shown that in the transition from the optic lobes to the central brain, due to convergence of columnar neurons onto optic glomeruli, distinct synaptic units employed in the computation of different visual features, the retinotopic representation is lost in these circuits. However, functional imaging revealed a spatial representation of visual cues in the Drosophila central complex, raising the question about the underlying circuitry, which bypasses optic glomerulus convergence.While characterizing afferent arborizations within Drosophila visual glomeruli, we discovered a spatial segregation of topographic and non-topographic projections from distinct molecular classes of medulla projection neurons, medullo-tubercular (MeTu) neurons, into a specific central brain glomerulus, the anterior optic tubercle (AOTu). Single cell analysis revealed that topographic information is organized by ensembles of MeTu neurons (type 1), forming parallel channels within the AOTu, while a separate class of MeTu neurons (type 2) displays convergent projection, associated with a loss of spatial resolution. MeTu afferents in the AOTu synapse onto a matching topographic field of output projection neurons, these tubercular-bulbar (TuBu) neurons relay visual information towards dendritic fields of central complex ring neurons in the bulb neuropil. Within the bulb, neuronal proximity of the topographic AOTu map as well as channel identity is maintained despite the absence of a stereotyped map organization, providing the structural basis for spatial representation of visual information in the central complex (CX). TuBu neurons project onto dendritic fields of efferent ring neurons, where distinct sectors of the bulb correspond to a distinct ring domain in the ellipsoid body. We found a stereotypic circuitry for each analyzed TuBu class, thus the individual channels of peripheral topography are maintained in the central complex structure. Together with previous data showing rough topography within the lobula AOTu domain, our results on the organization of medulla projection neurons define the AOTu neuropil as the main relay station for spatial information from the optic lobes into the central brain.

scholarly journals A hindbrain dopaminergic neural circuit prevents weight gain by reinforcing food satiation

2021 ◽  
Vol 7 (22) ◽  
pp. eabf8719
Author(s):  
Yong Han ◽  
Guobin Xia ◽  
Yanlin He ◽  
Yang He ◽  
Monica Farias ◽  
...  
Keyword(s):  
Weight Gain ◽  
Food Intake ◽  
Neural Circuit ◽  
Neural Circuitry ◽  
Dynamic Regulation ◽  
Satiety Response ◽  
Food Satiation ◽  
Lateral Parabrachial Nucleus ◽  
Genetic Deletion ◽  
Feeding Bout

The neural circuitry mechanism that underlies dopaminergic (DA) control of innate feeding behavior is largely uncharacterized. Here, we identified a subpopulation of DA neurons situated in the caudal ventral tegmental area (cVTA) directly innervating DRD1-expressing neurons within the lateral parabrachial nucleus (LPBN). This neural circuit potently suppresses food intake via enhanced satiation response. Notably, this cohort of DAcVTA neurons is activated immediately before the cessation of each feeding bout. Acute inhibition of these DA neurons before bout termination substantially suppresses satiety and prolongs the consummatory feeding. Activation of postsynaptic DRD1LPBN neurons inhibits feeding, whereas genetic deletion of Drd1 within the LPBN causes robust increase in food intake and subsequent weight gain. Furthermore, the DRD1LPBN signaling manifests the central mechanism in methylphenidate-induced hypophagia. In conclusion, our study illuminates a hindbrain DAergic circuit that controls feeding through dynamic regulation in satiety response and meal structure.

scholarly journals Diverse neuronal lineages make stereotyped contributions to the Drosophila locomotor control center, the central complex

2013 ◽  
Vol 521 (12) ◽  
pp. Spc1-Spc1 ◽  
Author(s):  
Jacob S. Yang ◽  
Takeshi Awasaki ◽  
Hung-Hsiang Yu ◽  
Yisheng He ◽  
Peng Ding ◽  
...  
Keyword(s):  
Central Complex ◽  
Control Center ◽  
Locomotor Control

scholarly journals Interpreting the Spatial-Temporal Structure of Turbulent Chemical Plumes Utilized in Odor Tracking by Lobsters

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 82
Author(s):  
Kyle W. Leathers ◽  
Brenden T. Michaelis ◽  
Matthew A. Reidenbach
Keyword(s):  
Spatial Information ◽  
Temporal Structure ◽  
Spiny Lobster ◽  
Search Time ◽  
The Body ◽  
Olfactory Receptor Neurons ◽  
Olfactory Systems ◽  
Receptor Neurons ◽  
Information Problem ◽  
Odor Signal

Olfactory systems in animals play a major role in finding food and mates, avoiding predators, and communication. Chemical tracking in odorant plumes has typically been considered a spatial information problem where individuals navigate towards higher concentration. Recent research involving chemosensory neurons in the spiny lobster, Panulirus argus, show they possess rhythmically active or ‘bursting’ olfactory receptor neurons that respond to the intermittency in the odor signal. This suggests a possible, previously unexplored olfactory search strategy that enables lobsters to utilize the temporal variability within a turbulent plume to track the source. This study utilized computational fluid dynamics to simulate the turbulent dispersal of odorants and assess a number of search strategies thought to aid lobsters. These strategies include quantification of concentration magnitude using chemosensory antennules and leg chemosensors, simultaneous sampling of water velocities using antennule mechanosensors, and utilization of antennules to quantify intermittency of the odorant plume. Results show that lobsters can utilize intermittency in the odorant signal to track an odorant plume faster and with greater success in finding the source than utilizing concentration alone. However, the additional use of lobster leg chemosensors reduced search time compared to both antennule intermittency and concentration strategies alone by providing spatially separated odorant sensors along the body.

Rehabilitation in Tehri Dam: An evaluation

Social Change ◽  
2001 ◽  
Vol 31 (1-2) ◽  
pp. 110-143 ◽  
Author(s):  
B. K. Sinha ◽  
H. C. Pokhriyal
Keyword(s):  
Common Property ◽  
Rehabilitation Process ◽  
Common Property Resources ◽  
Urban Households ◽  
Positive Externalities ◽  
Rural And Urban ◽  
Tehri Dam ◽  
High Level ◽  
Available Information ◽  
Ownership Rights

In the whole debate of ecological suitability of Tehri Dam, the rehabilitation aspect has been found ignored. Keeping in view of the significance of complete rehabilitation and resettlement of the oustees, the overall rehabilitation process including rural and urban population is analysed in the present paper. In total, 125 villages will be fully or partially submerged affecting more than one lakh population. More than twenty thousand urban populations will also be rehabilitated. It is expected that around 6000 cores of rupees (at 1993 price level) will be spent. Out of which 13% will be spent on the rehabilitation of the oustees. On the basis of the available information, it is found that only 33% of the rural families and 66% of the urban households have actually received the compensation or taken the possession of the land in the new sites. Non availability of land to the rest of the oustee households has been identified as the peculiar dimension of the rehabilitation process. The resettled households in Dehradun and Haridwar districts are facing the problem of geographic continuity, land owner shiprights and absence of institutional mechanism like panchayati raj institutions in the new settlements. The absence of non-farm employment and non-accessibility to the common property resources are the critical problems, including the availability of drinking water, irrigation, primary health and education, which can be observed seen in the rehabilitation sites. The resettlers are unable to adjust with the new environment including a high level of dependency on the market forces for each and every requirement. The partially submerged population is also facing peculiar problems. They will only be given cash compensation without any other compensatory measures. The ‘upstream cost and down stream benefits syndrome’ is strikingly visible in the rehabilitation process. In the urban resettlement process various issues Iike-the validity of survey, classification of urban households and cut off dates are relevant to mention. The positive externalities of the old Tehri town were completely missing in the new urban rehabilitation site. As a whole it can be tentatively said that the process of rehabilitation has been loosely coordinated and badly implemented. The issues of upstream cost, accessibility to common property resources and customary rights are the neglected aspects in the process. The re-organisation of the institutional frame work and granting land ownership rights to the resettlers and quality of the basic amenities are the other inevitable requirements need proper assessment and implementation. The present process of rehabilitation is largely non-participatory and non transparent, which can only be solved through radical measures. These measures are unlikely to be initiated in the present set of Tehri dam administration.

Levels of modeling of mechanisms of visually guided behavior

1987 ◽  
Vol 10 (3) ◽  
pp. 407-436 ◽  
Author(s):  
Michael A. Arbib
Keyword(s):  
Neural Circuits ◽  
Neural Circuitry ◽  
Learning Approach ◽  
Visually Guided ◽  
Visuomotor Coordination ◽  
Prey Recognition ◽  
High Level ◽  
Organizational Principles ◽  
Different Levels ◽  
Dextrous Hands

AbstractIntermediate constructs are required as bridges between complex behaviors and realistic models of neural circuitry. For cognitive scientists in general, schemas are the appropriate functional units; brain theorists can work with neural layers as units intermediate between structures subserving schemas and small neural circuits.After an account of different levels of analysis, we describe visuomotor coordination in terms of perceptual schemas and motor schemas. The interest of schemas to cognitive science in general is illustrated with the example of perceptual schemas in high-level vision and motor schemas in the control of dextrous hands.Rana computatrix, the computational frog, is introduced to show how one constructs an evolving set of model families to mediate flexible cooperation between theory and experiment. Rana computatrix may be able to do for the study of the organizational principles of neural circuitry what Aplysia has done for the study of subcellular mechanisms of learning. Approach, avoidance, and detour behavior in frogs and toads are analyzed in terms of interacting schemas. Facilitation and prey recognition are implemented as tectal-pretectal interactions, with the tectum modeled by an array of tectal columns. We show how layered neural computation enters into models of stereopsis and how depth schemas may involve the interaction of accommodation and binocular cues in anurans.

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