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Papers by Irene Pallucchi

Research paper thumbnail of Molecular blueprints for spinal circuit modules controlling locomotor speed in zebrafish

Nature Neuroscience, Nov 1, 2023

Research paper thumbnail of Multiple Rhythm-Generating Circuits Act in Tandem with Pacemaker Properties to Control the Start and Speed of Locomotion

Neuron, Mar 1, 2020

Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module... more Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module V2a connections show a faster-to-slower hierarchy of strength d A subset of V2a interneurons displays intrinsic pacemaker properties d Pacemaker properties and connectivity rules underlie locomotor start and speed

Research paper thumbnail of A spinal organ of proprioception for integrated motor action feedback

Neuron, Apr 1, 2021

Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mech... more Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mechanosensitive neurons sense lateral bending of spinal cord d These are inhibitory commissural neurons targeting the locomotor rhythm generator d Intraspinal proprioceptive feedback aligns movements with motor commands

Research paper thumbnail of A specialized spinal circuit for command amplification and directionality during escape behavior

Proceedings of the National Academy of Sciences of the United States of America, Oct 18, 2021

Research paper thumbnail of Principles Governing Locomotion in Vertebrates: Lessons From Zebrafish

Frontiers in Neural Circuits, Sep 13, 2018

Locomotor behaviors are critical for survival and enable animals to navigate their environment, f... more Locomotor behaviors are critical for survival and enable animals to navigate their environment, find food and evade predators. The circuits in the brain and spinal cord that initiate and maintain such different modes of locomotion in vertebrates have been studied in numerous species for over a century. In recent decades, the zebrafish has emerged as one of the main model systems for the study of locomotion, owing to its experimental amenability, and work in zebrafish has revealed numerous new insights into locomotor circuit function. Here, we review the literature that has led to our current understanding of the neural circuits controlling swimming and escape in zebrafish. We highlight recent studies that have enriched our comprehension of key topics, such as the interactions between premotor excitatory interneurons (INs) and motoneurons (MNs), supraspinal and spinal circuits that coordinate escape maneuvers, and developmental changes in overall circuit composition. We also discuss roles for neuromodulators and sensory inputs in modifying the relative strengths of constituent circuit components to provide flexibility in zebrafish behavior, allowing the animal to accommodate changes in the environment. We aim to provide a coherent framework for understanding the circuitry in the brain and spinal cord of zebrafish that allows the animal to flexibly transition between different speeds, and modes, of locomotion.

Research paper thumbnail of Transformation of an early-established motor circuit during maturation in zebrafish

Cell Reports, Apr 1, 2022

Locomotion is mediated by spinal circuits that generate movements with a precise coordination and... more Locomotion is mediated by spinal circuits that generate movements with a precise coordination and vigor. The assembly of these circuits is defined early during development; however, whether their organization and function remain invariant throughout development is unclear. Here, we show that the first established fast circuit between two dorsally located V2a interneuron types and the four primary motoneurons undergoes major transformation in adult zebrafish compared with what was reported in larvae. There is a loss of existing connections and establishment of new connections combined with alterations in the mode, plasticity, and strength of synaptic transmission. In addition, we show that this circuit no longer serves as a swim rhythm generator, but instead its components become embedded within the spinal escape circuit and control propulsion following the initial escape turn. Our results thus reveal significant changes in the organization and function of a motor circuit as animals develop toward adulthood.

Research paper thumbnail of Protocol to visualize distinct motoneuron pools in adult zebrafish via injection of retrograde tracers

STAR protocols, Dec 1, 2022

Research paper thumbnail of Developmental switch in the function of inhibitory commissural V0d interneurons in zebrafish

Current Biology, Aug 1, 2022

Research paper thumbnail of Protocol to visualize distinct motoneuron pools in adult zebrafish via injection of retrograde tracers

Research paper thumbnail of Developmental switch in the function of inhibitory commissural V0d interneurons in zebrafish

Current Biology

Highlights d V0d interneurons in larval zebrafish participate in high-speed locomotion d V0d inte... more Highlights d V0d interneurons in larval zebrafish participate in high-speed locomotion d V0d interneurons undergo a functional switch during development d In adult zebrafish, V0d interneurons participate in slow-speed swimming d Ablation of V0d diminishes mid-cycle inhibition during swimming in adult zebrafish

Research paper thumbnail of A specialized spinal circuit for command amplification and directionality during escape behavior

Proceedings of the National Academy of Sciences, 2021

Significance We are constantly faced with a choice moving to the left or right; understanding how... more Significance We are constantly faced with a choice moving to the left or right; understanding how the brain solves the selection of action direction is of tremendous interest both from biological and clinical perspectives. In vertebrates, action selection is often considered to be the realm of higher cognitive processing. However, by combining electrophysiology, serial block-face electron microscopy, and behavioral analyses in zebrafish, we have revealed a pivotal role, as well as the full functional connectome of a specialized spinal circuit relying on strong axo-axonic synaptic connections. This includes identifying a class of cholinergic V2a interneurons and establishing that they act as a segmentally repeating hub that receives and amplifies escape commands from the brain to ensure the appropriate escape directionality.

Research paper thumbnail of A spinal organ of proprioception for integrated motor action feedback

Neuron, 2021

Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mech... more Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mechanosensitive neurons sense lateral bending of spinal cord d These are inhibitory commissural neurons targeting the locomotor rhythm generator d Intraspinal proprioceptive feedback aligns movements with motor commands

Research paper thumbnail of Multiple Rhythm-Generating Circuits Act in Tandem with Pacemaker Properties to Control the Start and Speed of Locomotion

Neuron, 2020

Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module... more Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module V2a connections show a faster-to-slower hierarchy of strength d A subset of V2a interneurons displays intrinsic pacemaker properties d Pacemaker properties and connectivity rules underlie locomotor start and speed

Research paper thumbnail of Principles Governing Locomotion in Vertebrates: Lessons From Zebrafish

Frontiers in Neural Circuits, 2018

Locomotor behaviors are critical for survival and enable animals to navigate their environment, f... more Locomotor behaviors are critical for survival and enable animals to navigate their environment, find food and evade predators. The circuits in the brain and spinal cord that initiate and maintain such different modes of locomotion in vertebrates have been studied in numerous species for over a century. In recent decades, the zebrafish has emerged as one of the main model systems for the study of locomotion, owing to its experimental amenability, and work in zebrafish has revealed numerous new insights into locomotor circuit function. Here, we review the literature that has led to our current understanding of the neural circuits controlling swimming and escape in zebrafish. We highlight recent studies that have enriched our comprehension of key topics, such as the interactions between premotor excitatory interneurons (INs) and motoneurons (MNs), supraspinal and spinal circuits that coordinate escape maneuvers, and developmental changes in overall circuit composition. We also discuss roles for neuromodulators and sensory inputs in modifying the relative strengths of constituent circuit components to provide flexibility in zebrafish behavior, allowing the animal to accommodate changes in the environment. We aim to provide a coherent framework for understanding the circuitry in the brain and spinal cord of zebrafish that allows the animal to flexibly transition between different speeds, and modes, of locomotion.

Research paper thumbnail of Transformation of an early-established motor circuit during maturation in zebrafish

Cell Reports

Locomotion is mediated by spinal circuits that generate movements with a precise coordination and... more Locomotion is mediated by spinal circuits that generate movements with a precise coordination and vigor. The assembly of these circuits is defined early during development; however, whether their organization and function remain invariant throughout development is unclear. Here, we show that the first established fast circuit between two dorsally located V2a interneuron types and the four primary motoneurons undergoes major transformation in adult zebrafish compared with what was reported in larvae. There is a loss of existing connections and establishment of new connections combined with alterations in the mode, plasticity, and strength of synaptic transmission. In addition, we show that this circuit no longer serves as a swim rhythm generator, but instead its components become embedded within the spinal escape circuit and control propulsion following the initial escape turn. Our results thus reveal significant changes in the organization and function of a motor circuit as animals develop toward adulthood.

Research paper thumbnail of Molecular blueprints for spinal circuit modules controlling locomotor speed in zebrafish

Nature Neuroscience, Nov 1, 2023

Research paper thumbnail of Multiple Rhythm-Generating Circuits Act in Tandem with Pacemaker Properties to Control the Start and Speed of Locomotion

Neuron, Mar 1, 2020

Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module... more Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module V2a connections show a faster-to-slower hierarchy of strength d A subset of V2a interneurons displays intrinsic pacemaker properties d Pacemaker properties and connectivity rules underlie locomotor start and speed

Research paper thumbnail of A spinal organ of proprioception for integrated motor action feedback

Neuron, Apr 1, 2021

Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mech... more Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mechanosensitive neurons sense lateral bending of spinal cord d These are inhibitory commissural neurons targeting the locomotor rhythm generator d Intraspinal proprioceptive feedback aligns movements with motor commands

Research paper thumbnail of A specialized spinal circuit for command amplification and directionality during escape behavior

Proceedings of the National Academy of Sciences of the United States of America, Oct 18, 2021

Research paper thumbnail of Principles Governing Locomotion in Vertebrates: Lessons From Zebrafish

Frontiers in Neural Circuits, Sep 13, 2018

Locomotor behaviors are critical for survival and enable animals to navigate their environment, f... more Locomotor behaviors are critical for survival and enable animals to navigate their environment, find food and evade predators. The circuits in the brain and spinal cord that initiate and maintain such different modes of locomotion in vertebrates have been studied in numerous species for over a century. In recent decades, the zebrafish has emerged as one of the main model systems for the study of locomotion, owing to its experimental amenability, and work in zebrafish has revealed numerous new insights into locomotor circuit function. Here, we review the literature that has led to our current understanding of the neural circuits controlling swimming and escape in zebrafish. We highlight recent studies that have enriched our comprehension of key topics, such as the interactions between premotor excitatory interneurons (INs) and motoneurons (MNs), supraspinal and spinal circuits that coordinate escape maneuvers, and developmental changes in overall circuit composition. We also discuss roles for neuromodulators and sensory inputs in modifying the relative strengths of constituent circuit components to provide flexibility in zebrafish behavior, allowing the animal to accommodate changes in the environment. We aim to provide a coherent framework for understanding the circuitry in the brain and spinal cord of zebrafish that allows the animal to flexibly transition between different speeds, and modes, of locomotion.

Research paper thumbnail of Transformation of an early-established motor circuit during maturation in zebrafish

Cell Reports, Apr 1, 2022

Locomotion is mediated by spinal circuits that generate movements with a precise coordination and... more Locomotion is mediated by spinal circuits that generate movements with a precise coordination and vigor. The assembly of these circuits is defined early during development; however, whether their organization and function remain invariant throughout development is unclear. Here, we show that the first established fast circuit between two dorsally located V2a interneuron types and the four primary motoneurons undergoes major transformation in adult zebrafish compared with what was reported in larvae. There is a loss of existing connections and establishment of new connections combined with alterations in the mode, plasticity, and strength of synaptic transmission. In addition, we show that this circuit no longer serves as a swim rhythm generator, but instead its components become embedded within the spinal escape circuit and control propulsion following the initial escape turn. Our results thus reveal significant changes in the organization and function of a motor circuit as animals develop toward adulthood.

Research paper thumbnail of Protocol to visualize distinct motoneuron pools in adult zebrafish via injection of retrograde tracers

STAR protocols, Dec 1, 2022

Research paper thumbnail of Developmental switch in the function of inhibitory commissural V0d interneurons in zebrafish

Current Biology, Aug 1, 2022

Research paper thumbnail of Protocol to visualize distinct motoneuron pools in adult zebrafish via injection of retrograde tracers

Research paper thumbnail of Developmental switch in the function of inhibitory commissural V0d interneurons in zebrafish

Current Biology

Highlights d V0d interneurons in larval zebrafish participate in high-speed locomotion d V0d inte... more Highlights d V0d interneurons in larval zebrafish participate in high-speed locomotion d V0d interneurons undergo a functional switch during development d In adult zebrafish, V0d interneurons participate in slow-speed swimming d Ablation of V0d diminishes mid-cycle inhibition during swimming in adult zebrafish

Research paper thumbnail of A specialized spinal circuit for command amplification and directionality during escape behavior

Proceedings of the National Academy of Sciences, 2021

Significance We are constantly faced with a choice moving to the left or right; understanding how... more Significance We are constantly faced with a choice moving to the left or right; understanding how the brain solves the selection of action direction is of tremendous interest both from biological and clinical perspectives. In vertebrates, action selection is often considered to be the realm of higher cognitive processing. However, by combining electrophysiology, serial block-face electron microscopy, and behavioral analyses in zebrafish, we have revealed a pivotal role, as well as the full functional connectome of a specialized spinal circuit relying on strong axo-axonic synaptic connections. This includes identifying a class of cholinergic V2a interneurons and establishing that they act as a segmentally repeating hub that receives and amplifies escape commands from the brain to ensure the appropriate escape directionality.

Research paper thumbnail of A spinal organ of proprioception for integrated motor action feedback

Neuron, 2021

Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mech... more Highlights d A central organ of proprioception exists in the spinal cord d Piezo2-expressing mechanosensitive neurons sense lateral bending of spinal cord d These are inhibitory commissural neurons targeting the locomotor rhythm generator d Intraspinal proprioceptive feedback aligns movements with motor commands

Research paper thumbnail of Multiple Rhythm-Generating Circuits Act in Tandem with Pacemaker Properties to Control the Start and Speed of Locomotion

Neuron, 2020

Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module... more Highlights d V2a interneurons form three recurrent speed-dependent circuit modules d Inter-module V2a connections show a faster-to-slower hierarchy of strength d A subset of V2a interneurons displays intrinsic pacemaker properties d Pacemaker properties and connectivity rules underlie locomotor start and speed

Research paper thumbnail of Principles Governing Locomotion in Vertebrates: Lessons From Zebrafish

Frontiers in Neural Circuits, 2018

Locomotor behaviors are critical for survival and enable animals to navigate their environment, f... more Locomotor behaviors are critical for survival and enable animals to navigate their environment, find food and evade predators. The circuits in the brain and spinal cord that initiate and maintain such different modes of locomotion in vertebrates have been studied in numerous species for over a century. In recent decades, the zebrafish has emerged as one of the main model systems for the study of locomotion, owing to its experimental amenability, and work in zebrafish has revealed numerous new insights into locomotor circuit function. Here, we review the literature that has led to our current understanding of the neural circuits controlling swimming and escape in zebrafish. We highlight recent studies that have enriched our comprehension of key topics, such as the interactions between premotor excitatory interneurons (INs) and motoneurons (MNs), supraspinal and spinal circuits that coordinate escape maneuvers, and developmental changes in overall circuit composition. We also discuss roles for neuromodulators and sensory inputs in modifying the relative strengths of constituent circuit components to provide flexibility in zebrafish behavior, allowing the animal to accommodate changes in the environment. We aim to provide a coherent framework for understanding the circuitry in the brain and spinal cord of zebrafish that allows the animal to flexibly transition between different speeds, and modes, of locomotion.

Research paper thumbnail of Transformation of an early-established motor circuit during maturation in zebrafish

Cell Reports

Locomotion is mediated by spinal circuits that generate movements with a precise coordination and... more Locomotion is mediated by spinal circuits that generate movements with a precise coordination and vigor. The assembly of these circuits is defined early during development; however, whether their organization and function remain invariant throughout development is unclear. Here, we show that the first established fast circuit between two dorsally located V2a interneuron types and the four primary motoneurons undergoes major transformation in adult zebrafish compared with what was reported in larvae. There is a loss of existing connections and establishment of new connections combined with alterations in the mode, plasticity, and strength of synaptic transmission. In addition, we show that this circuit no longer serves as a swim rhythm generator, but instead its components become embedded within the spinal escape circuit and control propulsion following the initial escape turn. Our results thus reveal significant changes in the organization and function of a motor circuit as animals develop toward adulthood.