scholarly journals Diverse food-sensing neurons trigger idiothetic local search in Drosophila

2018 ◽  
Author(s):  
Román A. Corfas ◽  
Michael H. Dickinson
Keyword(s):  
Local Search ◽  
Path Integration ◽  
Neural System ◽  
Neural Pathways ◽  
Local Searches ◽  
Search Trajectories ◽  
Food Site ◽  
The Central Nervous System ◽  
Receptor Neurons ◽  
External Stimuli

ABSTRACTResources are often sparsely clustered in nature. Thus, foraging animals may benefit from remembering the location of a newly discovered food patch while continuing to explore nearby [1, 2]. For example, after encountering a drop of yeast or sugar, hungry flies often perform a local search consisting of frequent departures and returns to the food site [3, 4]. Fruit flies, Drosophila melanogaster, can perform this food-centered search behavior in the absence of external stimuli or landmarks, instead relying solely on internal (idiothetic) cues to keep track of their location [5]. This path integration behavior may represent a deeply conserved navigational capacity in insects [6, 7], but the neural pathways underlying food-triggered searches remain unknown. Here, we used optogenetic activation to screen candidate cell classes and found that local searches can be initiated by diverse sensory neurons including sugar-sensors, water-sensors, olfactory-receptor neurons, as well as hunger-signaling neurons of the central nervous system. Optogenetically-induced searches resemble those triggered by actual food and are modulated by starvation state. Furthermore, search trajectories exhibit key features of path integration: searches remain tightly centered around the fictive-food site, even during long periods without reinforcement, and flies re-center their searches when they encounter a new fictive-food site. Flies can even perform elaborate local searches within a constrained maze. Together, these results suggest that flies enact local searches in response to a wide variety of food-associated cues, and that these sensory pathways may converge upon a common neural system for path integration. Optogenetically induced local searches in Drosophila can now serve as a tractable system for the study of spatial memory and navigation in insects.

scholarly journals Anatomy and Neural Pathways Modulating Distinct Locomotor Behaviors in Drosophila Larva

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 90
Author(s):  
Swetha B. M. Gowda ◽  
Safa Salim ◽  
Farhan Mohammad
Keyword(s):  
Motor Neurons ◽  
Model Systems ◽  
Neural Pathways ◽  
Animal Movements ◽  
Drosophila Larvae ◽  
The Central Nervous System ◽  
Drosophila Larva ◽  
Locomotor Behaviors ◽  
Basic Level

The control of movements is a fundamental feature shared by all animals. At the most basic level, simple movements are generated by coordinated neural activity and muscle contraction patterns that are controlled by the central nervous system. How behavioral responses to various sensory inputs are processed and integrated by the downstream neural network to produce flexible and adaptive behaviors remains an intense area of investigation in many laboratories. Due to recent advances in experimental techniques, many fundamental neural pathways underlying animal movements have now been elucidated. For example, while the role of motor neurons in locomotion has been studied in great detail, the roles of interneurons in animal movements in both basic and noxious environments have only recently been realized. However, the genetic and transmitter identities of many of these interneurons remains unclear. In this review, we provide an overview of the underlying circuitry and neural pathways required by Drosophila larvae to produce successful movements. By improving our understanding of locomotor circuitry in model systems such as Drosophila, we will have a better understanding of how neural circuits in organisms with different bodies and brains lead to distinct locomotion types at the organism level. The understanding of genetic and physiological components of these movements types also provides directions to understand movements in higher organisms.

scholarly journals Methodology to Solve the Combination of the Generalized Assignment Problem and the Vehicle Routing Problem: A Case Study in Drug and Medical Instrument Sales and Service

2018 ◽  
Vol 9 (1) ◽  
pp. 3 ◽  
Author(s):  
Malichan Thongkham ◽  
Sasitorn Kaewman
Keyword(s):  
Local Search ◽  
Vehicle Routing ◽  
Vehicle Routing Problem ◽  
Routing Problem ◽  
Search Techniques ◽  
De Algorithm ◽  
Local Searches ◽  
Generalized Assignment ◽  
Linear Probability

This article presents algorithms for solving a special case of the vehicle routing problem (VRP). We define our proposed problem of a special VRP case as a combination of two hard problems: the generalized assignment and the vehicle routing problem. The different evolution (DE) algorithm is used to solve the problem. The recombination process of the original DE is modified by adding two more sets of vectors—best vector and random vector—and using two other sets—target vector and trial vector. The linear probability formula is proposed to potentially use one out of the four sets of vectors. This is called the modified DE (MDE) algorithm. Two local searches are integrated into the MDE algorithm: exchange and insert. These procedures create a DE and MDE that use (1) no local search techniques, (2) two local search techniques, (3) only the exchange procedure, and (4) only the insert procedure. This generates four DE algorithms and four MDE algorithms. The proposed methods are tested with 15 tested instances and one case study. The current procedure is compared with all proposed heuristics. The computational result shows that, in the case study, the best DE algorithm (DE-4) has a 1.6% better solution than that of the current practice, whereas the MDE algorithm is 8.2% better. The MDE algorithm that uses the same local search as the DE algorithms generates a maximum 5.814% better solution than that of the DE algorithms.

Relation to the Central Nervous System of Neural Pathways Mediating Histamine Flare and Nicotine Sweating

1957 ◽  
Vol 11 (3) ◽  
pp. 481-485 ◽  
Author(s):  
Ralph R. Sonnenschein ◽  
Maurice Bernstein
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Pathways ◽  
The Central Nervous System

scholarly journals Intranasal Borna Disease Virus (BoDV-1) Infection: Insights into Initial Steps and Potential Contagiosity

2019 ◽  
Vol 20 (6) ◽  
pp. 1318 ◽  
Author(s):  
Alexandra Kupke ◽  
Sabrina Becker ◽  
Konstantin Wewetzer ◽  
Barbara Ahlemeyer ◽  
Markus Eickmann ◽  
...  
Keyword(s):  
Viral Infections ◽  
Cell Types ◽  
Nerve Fibers ◽  
Olfactory Pathway ◽  
Adult Rats ◽  
The Central Nervous System ◽  
Receptor Neurons

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory pathway. However, (I) susceptible cell types that replicate the virus for successful spread, and (II) the role of olfactory ensheathing cells (OECs), remained unclear. To address this, we studied the intranasal infection of adult rats with BoDV-1 in vivo and in vitro, using olfactory mucosal (OM) cell cultures and the cultures of purified OECs. Strikingly, in vitro and in vivo, viral antigen and mRNA were present from four days post infection (dpi) onwards in the olfactory receptor neurons (ORNs), but also in all other cell types of the OM, and constantly in the OECs. In contrast, in vivo, BoDV-1 genomic RNA was only detectable in adult and juvenile ORNs, nerve fibers, and in OECs from 7 dpi on. In vitro, the rate of infection of OECs was significantly higher than that of the OM cells, pointing to a crucial role of OECs for infection via the olfactory pathway. Thus, this study provides important insights into the transmission of neurotropic viral infections with a zoonotic potential.

scholarly journals A New Approach to Population Sizing for Memetic Algorithms: A Case Study for the Multidimensional Assignment Problem

2011 ◽  
Vol 19 (3) ◽  
pp. 345-371 ◽  
Author(s):  
Daniel Karapetyan ◽  
Gregory Gutin
Keyword(s):  
Local Search ◽  
Population Size ◽  
Assignment Problem ◽  
Memetic Algorithm ◽  
Optimization Problems ◽  
Memetic Algorithms ◽  
Multidimensional Assignment Problem ◽  
Local Searches ◽  
Wide Range ◽  
Local Search Procedure

Memetic algorithms are known to be a powerful technique in solving hard optimization problems. To design a memetic algorithm, one needs to make a host of decisions. Selecting the population size is one of the most important among them. Most of the algorithms in the literature fix the population size to a certain constant value. This reduces the algorithm's quality since the optimal population size varies for different instances, local search procedures, and runtimes. In this paper we propose an adjustable population size. It is calculated as a function of the runtime of the whole algorithm and the average runtime of the local search for the given instance. Note that in many applications the runtime of a heuristic should be limited and, therefore, we use this bound as a parameter of the algorithm. The average runtime of the local search procedure is measured during the algorithm's run. Some coefficients which are independent of the instance and the local search are to be tuned at the design time; we provide a procedure to find these coefficients. The proposed approach was used to develop a memetic algorithm for the multidimensional assignment problem (MAP). We show that our adjustable population size makes the algorithm flexible to perform efficiently for a wide range of running times and local searches and this does not require any additional tuning of the algorithm.

Central losartan blocks natriuretic, vasopressin, and pressor responses to central hypertonic NaCl in sheep

1998 ◽  
Vol 275 (2) ◽  
pp. R548-R554 ◽  
Author(s):  
Michael L. Mathai ◽  
Mark D. Evered ◽  
Michael J. McKinley
Keyword(s):  
Arterial Pressure ◽  
Hypertonic Saline ◽  
Pressor Response ◽  
Electrolyte Balance ◽  
Neural Pathways ◽  
Intracerebroventricular Administration ◽  
Ang Ii ◽  
Intracerebroventricular Infusion ◽  
The Central Nervous System ◽  
Vasopressin Secretion

This study investigated the effect of intracerebroventricular administration of the angiotensin AT1 receptor antagonist losartan on the natriuresis, pressor effect, and arginine vasopressin (AVP) secretion caused by intracerebroventricular infusion of either ANG II, hypertonic saline, or carbachol. Losartan (1 mg/h) or artificial cerebrospinal fluid (CSF) was infused into the lateral ventricle before, during, and after infusions of either ANG II at 10 μg/h for 1 h, 0.75 mol/l NaCl at 50 μl/min for 20 min, or carbachol at 1.66 μg/min for 15 min. Intracerebroventricular infusions of ANG II, 0.75 mol/l NaCl, or carbachol caused increases in renal Na+ and K+ excretion, arterial pressure, and plasma AVP levels. Increases in arterial pressure, Na+ excretion, and plasma AVP concentration ([AVP]) in response to intracerebroventricular ANG II or intracerebroventricular 0.75 mol/l NaCl were either abolished or attenuated by intracerebroventricular infusion of losartan but not by intracerebroventricular infusion of artificial CSF or intravenous losartan. Intracerebroventricular losartan did not reduce the increase in plasma [AVP] or arterial pressure in response to intracerebroventricular carbachol, but it did attenuate the natriuretic response to intracerebroventricular carbachol. We conclude that an intracerebroventricular dose of losartan (1 mg/h) that inhibits responses to intracerebroventricular ANG II also inhibits vasopressin secretion, natriuresis, and the pressor response to intracerebroventricular hypertonic saline. These results suggest that common neural pathways are involved in the responses induced by intracerebroventricular administration of ANG II and intracerebroventricular hypertonic NaCl. We propose that intracerebroventricular infusion of hypertonic saline activates angiotensinergic pathways in the central nervous system subserving the regulation of fluid and electrolyte balance and arterial pressure in sheep.

Toward the Development of a Christian Psychology: Sensation and Perception

1978 ◽  
Vol 6 (3) ◽  
pp. 200-209 ◽  
Author(s):  
Ronald L. Koteskey
Keyword(s):  
Central Nervous System ◽  
Image Of God ◽  
Neural Pathways ◽  
Sensory Inputs ◽  
Extrasensory Perception ◽  
Christian Perspective ◽  
The Central Nervous System ◽  
Meaningful Experiences ◽  
The Image Of God ◽  
The Brain

A Christian perspective on psychology is briefly reviewed. Sensation is seen as emphasizing how humans are similar to animals. Human sensory organs are similar anatomically and physiologically to those of other mammals. Humans are sensitive to similar stimuli and have similar neural pathways to the brain. Perception is seen as emphasizing how humans are created in the image of God. The central nervous system is not simply a passive receiver of sensory inputs, but an organizer of sensations, cognitions, motivations, and emotions into meaningful experiences. Extrasensory perception, meditation, drugs, dreams, and visions are also discussed from this perspective.

Resection of a cystic brainstem hemangioblastoma via a retrosigmoid approach

2014 ◽  
Vol 36 (v1supplement) ◽  
pp. 1 ◽  
Author(s):  
Brian Lee ◽  
Yvette D. Marquez ◽  
Steven L. Giannotta
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neurological Dysfunction ◽  
Neural Pathways ◽  
Technical Challenge ◽  
Cystic Component ◽  
Complete Surgical Resection ◽  
Close Proximity ◽  
The Central Nervous System ◽  
Vascular Structures

Lesions of the brainstem pose a technical challenge due to their close proximity to critical vascular structures, neural pathways, and nuclei. Hemangioblastomas are rare lesions of the central nervous system and can cause significant neurological dysfunction, primarily due to enlargement of the cystic component. This is especially relevant when hemangioblastomas occur in eloquent brainstem regions. However, the outcomes after hemangioblastoma resection are good if complete surgical resection of the tumor of the mural nodule, can be achieved. This video demonstrates the excision of a brainstem hemangioblastoma via a left retrosigmoid craniotomy under Stealth guidance.The video can be found here: http://youtu.be/bCkuaPwMV20.

Poliovirus Spreads from Muscle to the Central Nervous System by Neural Pathways

1992 ◽  
Vol 166 (4) ◽  
pp. 747-752 ◽  
Author(s):  
Ruibao Ren ◽  
Vincent R. Racaniello
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Pathways ◽  
The Central Nervous System

scholarly journals Clutter Suppression Method for Off-Grid Effects Mitigation in Airborne Passive Radars with Contaminated Reference Signals

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6339
Author(s):  
Yaqi Deng ◽  
Wenguo Li ◽  
Saiwen Zhang ◽  
Fulong Wang ◽  
Weichu Xiao ◽  
...  
Keyword(s):  
Local Search ◽  
Measurement Model ◽  
Covariance Estimation ◽  
Passive Radar ◽  
Clutter Suppression ◽  
Reference Channel ◽  
Local Searches ◽  
Reference Signals ◽  
Suppression Method ◽  
Space Time Adaptive Processing

For an airborne passive radar with contaminated reference signals, the clutter caused by multipath (MP) signals involved in the reference channel (MP clutter) corrupts the covariance estimation in space-time adaptive processing (STAP). In order to overcome the severe STAP performance degradation caused by impure reference signals and off-grid effects, a novel MP clutter suppression method based on local search is proposed for airborne passive radar. In the proposed method, the global dictionary is constructed based on the sparse measurement model of MP clutter, and the global atoms that are most relevant to the residual are selected. Then, the local dictionary is designed iteratively, and local searches are performed to match real MP clutter points. Finally, the off-grid effects are mitigated, and the MP clutter is suppressed from all matched atoms. A range of simulations is conducted in order to demonstrate the effectiveness of the proposed method.

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