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5 results on '"Samuel, Aravinthan DT"'

1. Connectomes across development reveal principles of brain maturation

Author

Witvliet, Daniel, Mulcahy, Ben, Mitchell, James K, Meirovitch, Yaron, Berger, Daniel R, Wu, Yuelong, Liu, Yufang, Koh, Wan Xian, Parvathala, Rajeev, Holmyard, Douglas, Schalek, Richard L, Shavit, Nir, Chisholm, Andrew D, Lichtman, Jeff W, Samuel, Aravinthan DT, and Zhen, Mei

Subjects
Neurosciences, Brain Disorders, 1.1 Normal biological development and functioning, Underpinning research, Neurological, Aging, Animals, Brain, Caenorhabditis elegans, Connectome, Individuality, Interneurons, Microscopy, Electron, Models, Neurological, Neural Pathways, Neurons, Stereotyped Behavior, Synapses, General Science & Technology
Abstract

An animal's nervous system changes as its body grows from birth to adulthood and its behaviours mature1-8. The form and extent of circuit remodelling across the connectome is unknown3,9-15. Here we used serial-section electron microscopy to reconstruct the full brain of eight isogenic Caenorhabditis elegans individuals across postnatal stages to investigate how it changes with age. The overall geometry of the brain is preserved from birth to adulthood, but substantial changes in chemical synaptic connectivity emerge on this consistent scaffold. Comparing connectomes between individuals reveals substantial differences in connectivity that make each brain partly unique. Comparing connectomes across maturation reveals consistent wiring changes between different neurons. These changes alter the strength of existing connections and create new connections. Collective changes in the network alter information processing. During development, the central decision-making circuitry is maintained, whereas sensory and motor pathways substantially remodel. With age, the brain becomes progressively more feedforward and discernibly modular. Thus developmental connectomics reveals principles that underlie brain maturation.

Published
2021

2. Corrigendum: A Pipeline for Volume Electron Microscopy of the Caenorhabditis elegans Nervous System

Author

Mulcahy, Ben, Witvliet, Daniel, Holmyard, Douglas, Mitchell, James, Chisholm, Andrew D, Meirovitch, Yaron, Samuel, Aravinthan DT, and Zhen, Mei

Subjects
Biological Psychology, Biomedical and Clinical Sciences, Neurosciences, Psychology, C. elegans, volume electron microscopy, connectome, nervous system, high-pressure freezing, Biological psychology
Abstract

[This corrects the article DOI: 10.3389/fncir.2018.00094.].

Published
2019

3. A Pipeline for Volume Electron Microscopy of the Caenorhabditis elegans Nervous System

Author

Mulcahy, Ben, Witvliet, Daniel, Holmyard, Douglas, Mitchell, James, Chisholm, Andrew D, Meirovitch, Yaron, Samuel, Aravinthan DT, and Zhen, Mei

Subjects
Biological Psychology, Biomedical and Clinical Sciences, Neurosciences, Psychology, Bioengineering, Brain Disorders, Underpinning research, 1.1 Normal biological development and functioning, Neurological, Animals, Caenorhabditis elegans, Connectome, Microscopy, Electron, Nerve Net, Nervous System, Vitrification, C. alegans, volume electron microscopy, connectome, nervous system, high-pressure freezing, C. elegans, Biological psychology
Abstract

The "connectome," a comprehensive wiring diagram of synaptic connectivity, is achieved through volume electron microscopy (vEM) analysis of an entire nervous system and all associated non-neuronal tissues. White et al. (1986) pioneered the fully manual reconstruction of a connectome using Caenorhabditis elegans. Recent advances in vEM allow mapping new C. elegans connectomes with increased throughput, and reduced subjectivity. Current vEM studies aim to not only fill the remaining gaps in the original connectome, but also address fundamental questions including how the connectome changes during development, the nature of individuality, sexual dimorphism, and how genetic and environmental factors regulate connectivity. Here we describe our current vEM pipeline and projected improvements for the study of the C. elegans nervous system and beyond.

Published
2018

4. Circuits for integrating learned and innate valences in the insect brain

Author

Eschbach, Claire, Fushiki, Akira, Winding, Michael, Afonso, Bruno, Andrade, Ingrid V, Cocanougher, Benjamin T, Eichler, Katharina, Gepner, Ruben, Si, Guangwei, Valdes-Aleman, Javier, Fetter, Richard D, Gershow, Marc, Jefferis, Gregory Sxe, Samuel, Aravinthan Dt, Truman, James W, Cardona, Albert, and Zlatic, Marta

Subjects
Neurons, D. melanogaster, connectome, Brain, 3. Good health, action selection, neuroscience, learnt behavior, Drosophila melanogaster, Larva, Animals, Learning, valence, Mushroom Bodies
Abstract

Funder: Howard Hughes Medical Institute, Animal behavior is shaped both by evolution and by individual experience. Parallel brain pathways encode innate and learned valences of cues, but the way in which they are integrated during action-selection is not well understood. We used electron microscopy to comprehensively map with synaptic resolution all neurons downstream of all mushroom body (MB) output neurons (encoding learned valences) and characterized their patterns of interaction with lateral horn (LH) neurons (encoding innate valences) in Drosophila larva. The connectome revealed multiple convergence neuron types that receive convergent MB and LH inputs. A subset of these receives excitatory input from positive-valence MB and LH pathways and inhibitory input from negative-valence MB pathways. We confirmed functional connectivity from LH and MB pathways and behavioral roles of two of these neurons. These neurons encode integrated odor value and bidirectionally regulate turning. Based on this, we speculate that learning could potentially skew the balance of excitation and inhibition onto these neurons and thereby modulate turning. Together, our study provides insights into the circuits that integrate learned and innate valences to modify behavior.

5. Circuits for integrating learned and innate valences in the insect brain

Author

Ruben Gepner, Ingrid Andrade, Akira Fushiki, Aravinthan D. T. Samuel, Michael Winding, Javier Valdes-Aleman, Guangwei Si, Bruno Afonso, Marc Gershow, Gregory S.X.E. Jefferis, Albert Cardona, Claire Eschbach, Richard D. Fetter, Katharina Eichler, James W Truman, Marta Zlatic, Benjamin T. Cocanougher, Eschbach, Claire [0000-0002-8092-3440], Fushiki, Akira [0000-0002-7987-6405], Winding, Michael [0000-0003-1965-3266], Cocanougher, Benjamin T [0000-0003-0648-554X], Eichler, Katharina [0000-0002-7833-8621], Fetter, Richard D [0000-0002-1558-100X], Gershow, Marc [0000-0001-7528-6101], Jefferis, Gregory Sxe [0000-0002-0587-9355], Samuel, Aravinthan Dt [0000-0002-1672-8720], Truman, James W [0000-0002-9209-5435], Cardona, Albert [0000-0003-4941-6536], Zlatic, Marta [0000-0002-3149-2250], Apollo - University of Cambridge Repository, Cocanougher, Benjamin [0000-0003-0648-554X], and Jefferis, Gregory [0000-0002-0587-9355]

Subjects
QH301-705.5, media_common.quotation_subject, Science, Insect, Biology, ENCODE, Inhibitory postsynaptic potential, Action selection, General Biochemistry, Genetics and Molecular Biology, action selection, neuroscience, 03 medical and health sciences, 0302 clinical medicine, Animals, Learning, Biology (General), valence, Mushroom Bodies, 030304 developmental biology, media_common, Neurons, 0303 health sciences, General Immunology and Microbiology, D. melanogaster, General Neuroscience, Functional connectivity, connectome, Brain, General Medicine, 3. Good health, learnt behavior, Drosophila melanogaster, nervous system, Larva, Mushroom bodies, Excitatory postsynaptic potential, Connectome, Medicine, Neuroscience, 030217 neurology & neurosurgery, Research Article
Abstract

Animal behavior is shaped both by evolution and by individual experience. Parallel brain pathways encode innate and learned valences of cues, but the way in which they are integrated during action-selection is not well understood. We used electron microscopy to comprehensively map with synaptic resolution all neurons downstream of all mushroom body (MB) output neurons (encoding learned valences) and characterized their patterns of interaction with lateral horn (LH) neurons (encoding innate valences) in Drosophila larva. The connectome revealed multiple convergence neuron types that receive convergent MB and LH inputs. A subset of these receives excitatory input from positive-valence MB and LH pathways and inhibitory input from negative-valence MB pathways. We confirmed functional connectivity from LH and MB pathways and behavioral roles of two of these neurons. These neurons encode integrated odor value and bidirectionally regulate turning. Based on this, we speculate that learning could potentially skew the balance of excitation and inhibition onto these neurons and thereby modulate turning. Together, our study provides insights into the circuits that integrate learned and innate valences to modify behavior.

Published
2021

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