scholarly journals The functional organization of descending sensory-motor pathways in Drosophila

2017 ◽  
Author(s):  
Shigehiro Namiki ◽  
Michael H. Dickinson ◽  
Allan M. Wong ◽  
Wyatt Korff ◽  
Gwyneth M. Card
Keyword(s):  
Nerve Cord ◽  
Functional Organization ◽  
The Body ◽  
Connectivity Pattern ◽  
Neural Population ◽  
Layered System ◽  
Descending Pathways ◽  
Descending Neurons ◽  
Sensory Motor ◽  
The Brain

SUMMARYIn most animals, the brain controls the body via a set of descending neurons (DNs) that traverse the neck and terminate in post-cranial regions of the nervous system. This critical neural population is thought to activate, maintain and modulate locomotion and other behaviors. Although individual members of this cell class have been well-studied across species ranging from insects to primates, little is known about the overall connectivity pattern of DNs as a population. We undertook a systematic anatomical investigation of descending neurons in the fruit fly, Drosophila melanogaster, and created a collection of over 100 transgenic lines targeting individual cell types. Our methods allowed us to describe the morphology of roughly half of an estimated 400 DNs and create a comprehensive map of connectivity between the sensory neuropils in the brain and the motor neuropils in the ventral nerve cord. Like the vertebrate spinal cord, our results show that the fly nerve cord is a highly organized, layered system of neuropils, an organization that reflects the fact that insects are capable of two largely independent means of locomotion – walking and fight – using distinct sets of appendages. Our results reveal the basic functional map of descending pathways in flies and provide tools for systematic interrogation of sensory-motor circuits.

scholarly journals The functional organization of descending sensory-motor pathways in Drosophila

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Shigehiro Namiki ◽  
Michael H Dickinson ◽  
Allan M Wong ◽  
Wyatt Korff ◽  
Gwyneth M Card
Keyword(s):  
Nerve Cord ◽  
Functional Organization ◽  
Cell Types ◽  
The Body ◽  
Layered System ◽  
Descending Pathways ◽  
Motor Pathways ◽  
Transgenic Lines ◽  
Functional Map ◽  
The Brain

In most animals, the brain controls the body via a set of descending neurons (DNs) that traverse the neck. DN activity activates, maintains or modulates locomotion and other behaviors. Individual DNs have been well-studied in species from insects to primates, but little is known about overall connectivity patterns across the DN population. We systematically investigated DN anatomy in Drosophila melanogaster and created over 100 transgenic lines targeting individual cell types. We identified roughly half of all Drosophila DNs and comprehensively map connectivity between sensory and motor neuropils in the brain and nerve cord, respectively. We find the nerve cord is a layered system of neuropils reflecting the fly’s capability for two largely independent means of locomotion -- walking and flight -- using distinct sets of appendages. Our results reveal the basic functional map of descending pathways in flies and provide tools for systematic interrogation of neural circuits.

scholarly journals Descending pathways from the lateral accessory lobe and posterior slope in the brain of the silkmoth Bombyx mori

2018 ◽  
Author(s):  
Shigehiro Namiki ◽  
Ryohei Kanzaki
Keyword(s):  
Bombyx Mori ◽  
Critical Role ◽  
Olfactory Behavior ◽  
Descending Pathways ◽  
Posterior Slope ◽  
Descending Neurons ◽  
Accessory Lobe ◽  
Controlling Behavior ◽  
The Brain ◽  
Lateral Accessory Lobe

AbstractA population of descending neurons connect the brain and thoracic motor cener, playing a critical role in controlling behavior. We examined the anatomical organization of descending neurons (DNs) in the brain of the silkmoth Bombyx mori. Moth pheromone orientation is a good model to investigate the neuronal mechanisms of olfactory behavior. Based on mass staining and single-cell staining, we evaluated the anatomical organization of neurite distribution by DNs in the brain. Dense innervation was observed in the posterior–ventral part of the brain, called the posterior slope (PS). We examined the morphology of DNs innervating the lateral accessory lobe (LAL), which is assumed to be important for moth olfactory behavior. We observed that the LAL DNs also innervate the PS, suggesting the integration of signals from the LAL and PS. We also identified a set of DNs innervating the PS, but not the LAL. These DNs were sensitive to sex pheromones, suggesting a role of the PS in motor control for pheromone orientation. The organization of descending pathways for pheromone orientation is discussed.

Functional organization within the medullary reticular formation of intact unanesthetized cat. I. Movements evoked by microstimulation

1990 ◽  
Vol 64 (3) ◽  
pp. 767-781 ◽  
Author(s):  
T. Drew ◽  
S. Rossignol
Keyword(s):  
Brain Stem ◽  
Reticular Formation ◽  
Functional Organization ◽  
The Body ◽  
Large Area ◽  
Medullary Reticular Formation ◽  
Discrete Movements ◽  
The Brain ◽  
Flexion And Extension ◽  
Made In

1. The present article described the various patterns of movement evoked in the limbs and neck by microstimulation (33-ms trains, 330 Hz, 0.2-ms pulses at less than or equal to 35 microA) of the medullary reticular formation (MRF) of seven chronically implanted, unanesthetized, intact cats. Altogether 878 loci were stimulated in 83 penetrations. However, as stimulation in the more lateral regions of the MRF was less effective, the results are based on stimulation in 592 loci made in 56 penetrations at distances of between 0.5 and 2.5 mm lateral to the midline. 2. Of these 592 loci, movement of one or more parts of the body was evoked from a total of 539 (91%) sites. Most of these movements were compound in nature, involving movement of one or more limbs as well as the head. Discrete movements were observed only with respect to the head; limb movements were always accompanied by head movement. In addition, hindlimb movements were always accompanied by forelimb movements, although the inverse was generally not true. 3. The most common effects of the stimulation were as follows: a turning of the head to the ipsilateral side (79% of stimulated sites); flexion of the ipsilateral elbow (41%); and extension of the contralateral elbow (45%). Effects in the hindlimbs were more variable and less frequent, with the majority of the effective loci causing flexion of the ipsilateral knee (9%) together with extension of the contralateral knee (8%). In total, including both flexion and extension, 18% of the stimulated sites caused movement of the ipsilateral hindlimb and 11% of the contralateral hindlimb. 4. Although movements of the head were obtained from the whole extent of the brain stem, movements of the forelimbs showed a dorsoventral organization with flexion of the ipsilateral elbow being evoked from the more dorsal regions of the brain stem, whereas contralateral elbow extension was evoked more frequently from the ventral regions. There was a large area of overlap from which movements of both limbs could be obtained simultaneously. Movements of the hindlimbs were more frequently evoked from central and ventral areas of the brain stem and from the most rostral aspect of the explored region. 5. In examining the combinations of movements evoked by the MRF stimulation, it was found that the most commonly evoked pattern was movement of the head to the stimulated side together with flexion of the ipsilateral forelimb and extension of the contralateral forelimb (26.5% of sites).(ABSTRACT TRUNCATED AT 400 WORDS)

Penfield’s Homunculus and Other Grotesque Creatures from the Land of If

Nuncius ◽  
2012 ◽  
Vol 27 (1) ◽  
pp. 141-162 ◽  
Author(s):  
Claudio Pogliano
Keyword(s):  
Functional Organization ◽  
The Body ◽  
Medical Texts ◽  
Montreal Neurological Institute ◽  
Surgical Ablation ◽  
Cortical Areas ◽  
History Of ◽  
Mcgill University ◽  
The Brain ◽  
Different Parts

The neurosurgeon Wilder Graves Penfield (1891-1976) helped to develop a surgical treatment for epilepsy and used his results to investigate the functional organization of the brain. He was instrumental in founding the Montreal Neurological Institute at McGill University, which he directed from 1934 to 1960. There he studied, with his collaborators, the effects of stimulation and surgical ablation on different parts of the brain in order to localize their somatosensory functions. To visualize the results of this research, Hortense Pauline Cantlie drew images of a homunculus whose proportions reflected the extent of the cortical areas controlling different parts of the body. These images were published by Penfield in 1937; a modified version followed in 1950, opening the way for such developments as the diagrams of mammalian brains drawn by the neurophysiologist Clinton N. Woolsey in 1958. This article will reconstruct the history of Penfield’s map of the human brain, which was utilized in medical texts for many decades, but which eventually would be severely criticized.

Hemichordate Nervous System

2018 ◽  
Author(s):  
Norio Miyamoto ◽  
Hiroshi Wada
Keyword(s):  
Nervous System ◽  
Nerve Cord ◽  
The Body ◽  
Model Organisms ◽  
Lateral Side ◽  
Essential Information ◽  
System P ◽  
The Brain ◽  
Nerve Cords ◽  
Apical Ganglion

Hemichordates are marine invertebrates consisting of two distinct groups: the solitary enteropneusts and the colonial pterobranchs. Hemichordates are phylogenetically a sister group to echinoderm composing Ambulacraria. The adult morphology of hemichordates shares some features with chordates. For that reason, hemichordates have been considered key organisms to understand the evolution of deuterostomes and the origin of the chordate body plan. The nervous system of hemichordates is also important in the discussion of the origin of centralized nervous systems. However, unlike other deuterostomes, such as echinoderms and chordates, information on the nervous system of hemichordates is limited. Recent improvements in the accessibility of embryos, development of functional tools, and genomic resources from several model organisms have provided essential information on the nervous system organization and neurogenesis in hemichordates. The comparison of the nervous system between hemichordates and other bilaterians helps to elucidate the origin of the chordate central nervous system. Extant hemichordates are divided into two groups: enteropneusts and pterobranchs. The nervous system of adult enteropneusts consists of nerve cords and the basiepidermal nerve net. The two nerve cords run along the dorsal and ventral midlines. The dorsal nerve cord forms a tubular structure in the collar region. The two nerve cords are connected through the prebranchial nerve ring. The larval nervous system of enteropneusts develops along the ciliary band and there is a ganglion at the anterior end of the body called the apical ganglion. A pair of pigmented eyespots is situated at the lateral side of the apical ganglion. The adult nervous system of pterobranchs is basiepidermal and there are several condensations of plexuses. The most prominent one is the brain, located at the base of the tentaculated arms. From the brain, small fibers radiate and enter tentaculated arms to form a tentacle nerve in each. There is a basiepidermal nerve cord in the ventral midline of the trunk.

scholarly journals From embodying tool to embodying alien limb: sensory-motor modulation of personal and extrapersonal space

2021 ◽  
Vol 22 (S1) ◽  
pp. 121-126
Author(s):  
Anna Berti
Keyword(s):  
Neural Circuits ◽  
Personal Space ◽  
Peripersonal Space ◽  
The Body ◽  
Neural Systems ◽  
Body Representations ◽  
Alien Limb ◽  
Extrapersonal Space ◽  
Sensory Motor ◽  
The Brain

AbstractYears ago, it was demonstrated (e.g., Rizzolatti et al. in Handbook of neuropsychology, Elsevier Science, Amsterdam, 2000) that the brain does not encode the space around us in a homogeneous way, but through neural circuits that map the space relative to the distance that objects of interest have from the body. In monkeys, relatively discrete neural systems, characterized by neurons with specific neurophysiological responses, seem to be dedicated either to represent the space that can be reached by the hand (near/peripersonal space) or to the distant space (far/extrapersonal space). It was also shown that the encoding of spaces has dynamic aspects because they can be remapped by the use of tools that trigger different actions (e.g., Iriki et al. 1998). In this latter case, the effect of the tool depends on the modulation of personal space, that is the space of our body. In this paper, I will review and discuss selected research, which demonstrated that also in humans: 1 spaces are encoded in a dynamic way; 2 encoding can be modulated by the use of tool that the system comes to consider as parts of the own body; 3 body representations are not fixed, but they are fragile and subject to change to the point that we can incorporate not only the tools necessary for action, but even limbs belonging to other people. What embodiment of tools and of alien limb tell us about body representations is then briefly discussed.

Mind

2019 ◽  
pp. 25-57
Author(s):  
Paul Thagard
Keyword(s):  
The Body ◽  
Social Mechanisms ◽  
Mental Processes ◽  
Abstract Thought ◽  
The World ◽  
Sensory Motor ◽  
The Brain

Multilevel materialism contends that all mental processes are brain processes while allowing the importance of molecular, mental, and social mechanisms that complement neural ones. The Semantic Pointer Architecture provides a good candidate for explaining how the brain has thoughts and conscious feeling. Representation by patterns of firing in groups of neurons, binding of representations into more complex ones by convolution, and competition among semantic pointers serve to produce perception, inference, and consciousness. The conceivability of minds without brains and of mental processes without semantic pointers is of no relevance to how minds actually operate in this world. Because of their sensory-motor operations, semantic pointers naturally incorporate important aspects of embodiment and action embedded in the world, while also enabling minds to transcend the body in order to engage in abstract thought.

Vision, Its Development in Infant and Child

PEDIATRICS ◽  
1950 ◽  
Vol 6 (6) ◽  
pp. 921-922
Keyword(s):  
Human Action ◽  
The Body ◽  
Human Eye ◽  
Action System ◽  
Sensory Motor ◽  
The Brain

Those familiar with the previous writings of Dr. Gesell and his associates will undoubtedly greet this newest work with justifiable anticipation. Gesell views the human eye as virtually a vestibule of the brain and vision as pre-eminent in the sensory-motor construction of the human action system. The human eye develops just as the body develops and the development of the former plays an important role in the development of the latter. The book is another of Gesell's combinations of carefully recorded and intelligently reported observations documented with photographs of the subjects themselves.

scholarly journals Development of the Brain Functional Connectome Follows Puberty-Dependent Nonlinear Trajectories

2020 ◽  
Author(s):  
Zeus Gracia-Tabuenca ◽  
Martha Beatriz Moreno ◽  
Fernando Barrios ◽  
Sarael Alcauter
Keyword(s):  
Cognitive Flexibility ◽  
Functional Organization ◽  
Morphological Changes ◽  
Brain Network ◽  
The Body ◽  
Brain Organization ◽  
Functional Connectome ◽  
Nonlinear Trends ◽  
The Impact ◽  
The Brain

AbstractAdolescence is a developmental period that dramatically impacts body and behavior, with pubertal hormones playing an important role not only in the morphological changes in the body but also in brain structure and function. Understanding brain development during adolescence has become a priority in neuroscience because it coincides with the onset of many psychiatric and behavioral disorders. However, little is known about how puberty influences the brain functional connectome. In this study, taking a longitudinal human sample of typically developing children and adolescents (of both sexes), we demonstrate that the development of the brain functional connectome better fits pubertal status than chronological age. In particular, centrality, segregation, efficiency, and integration of the brain functional connectome increase after the onset of the pubertal markers. We found that these effects are stronger in attention and task control networks. Lastly, after controlling for this effect, we showed that functional connectivity between these networks is related to better performance in cognitive flexibility. This study points out the importance of considering longitudinal nonlinear trends when exploring developmental trajectories, and emphasizes the impact of puberty on the functional organization of the brain in adolescence.Significance StatementUnderstanding the brain organization along development is a crucial challenge for Neuroscience. In particular, during adolescence there is a great impact in body and cognitive functions as well as substantial incidence of mental health disruptions. Here, we tested how brain organization changes along this period based on the properties of the functional connectome in a longitudinal pediatric sample. We found a nonlinear increase in the connectivity and the brain network efficiency, particularly after the onset of puberty. These effects were more prominent in association networks. In addition, higher connectivity in those areas was associated with better performance in cognitive flexibility. These results demonstrate the importance of considering pubertal assessment as well as nonlinear trends in developmental studies.

scholarly journals A size principle for recruitment of Drosophila leg motor neurons

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Anthony W Azevedo ◽  
Evyn S Dickinson ◽  
Pralaksha Gurung ◽  
Lalanti Venkatasubramanian ◽  
Richard S Mann ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Functional Organization ◽  
Fruit Fly ◽  
The Body ◽  
Hierarchical Organization ◽  
Size Principle ◽  
And Behavior ◽  
In Vivo Calcium Imaging ◽  
The Brain

To move the body, the brain must precisely coordinate patterns of activity among diverse populations of motor neurons. Here, we use in vivo calcium imaging, electrophysiology, and behavior to understand how genetically-identified motor neurons control flexion of the fruit fly tibia. We find that leg motor neurons exhibit a coordinated gradient of anatomical, physiological, and functional properties. Large, fast motor neurons control high force, ballistic movements while small, slow motor neurons control low force, postural movements. Intermediate neurons fall between these two extremes. This hierarchical organization resembles the size principle, first proposed as a mechanism for establishing recruitment order among vertebrate motor neurons. Recordings in behaving flies confirmed that motor neurons are typically recruited in order from slow to fast. However, we also find that fast, intermediate, and slow motor neurons receive distinct proprioceptive feedback signals, suggesting that the size principle is not the only mechanism that dictates motor neuron recruitment. Overall, this work reveals the functional organization of the fly leg motor system and establishes Drosophila as a tractable system for investigating neural mechanisms of limb motor control.

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