Related Experiment Video
Updated: Aug 15, 2026
09:36
Optical Imaging of Neurons in the Crab Stomatogastric Ganglion with Voltage-sensitive Dyes
Published on: March 23, 2011
Multiple types of control by identified interneurons in a sensory-activated rhythmic motor pattern
G Kemenes1, K Staras, P R Benjamin
1Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Falmer, Brighton, United Kingdom, BN1 9QG. G.Kemenes@sussex.ac.uk
Summary
Modulatory interneurons (CV1a, SO) do not initiate feeding rhythms in Lymnaea, contrary to expectations. Instead, a central pattern generator (CPG) interneuron (N1M) is crucial for initiating feeding behavior, with CV1a and SO modulating the output.
Area of Science:
- Neuroscience
- Animal Behavior
- Computational Biology
Background:
- Modulatory interneurons are candidates for decision-making in rhythmic behaviors.
- Their role in sensory activation of central pattern generator (CPG)-driven behaviors is unclear.
- In Lymnaea, CV1a and SO cells activate feeding patterns via intracellular stimulation.
Purpose of the Study:
- Investigate the role of CV1a and SO interneurons in natural, food-activated feeding behavior.
- Determine their contribution to the initiation and shaping of rhythmic motor output.
- Understand sensory activation of CPG-driven behaviors.
Main Methods:
- Utilized a lip-CNS preparation in Lymnaea.
- Elicited feeding behavior using a natural chemostimulant (sucrose).
- Recorded neural activity to identify interneuron involvement and roles.
Main Results:
- Neither CV1a nor SO interneurons were involved in the initial activation of sucrose-evoked fictive feeding.
- The CPG interneuron N1M was consistently active first in initiating feeding.
- CV1a modulated motoneuron burst duration, and SO set the rhythm frequency.
Conclusions:
- CPG interneurons, not modulatory interneurons, play a critical role in initiating sensory-evoked rhythmic feeding.
- CV1a and SO interneurons differentially shape motor output characteristics rather than initiating the behavior.
- This highlights a distributed system where artificial activation differs from natural sensory input in governing rhythmic behaviors.
Related Concept Videos
00:46Motor Units
A motor unit consists of two main components: a single efferent motor neuron (i.e., a neuron that carries impulses away from the central nervous system) and all of the muscle fibers it innervates. The motor neuron may innervate multiple muscle fibers, which are single cells, but only one motor neuron innervates a single muscle fiber.
01:13Motor Units
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...
Motor units come in different sizes, with smaller units...
01:20Motor Unit Stimulation
When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
01:25Neural Circuits
Neural circuits and neuronal pools are two of the main structures found in the nervous system. Neural circuits are networks of neurons that work together to carry out a specific task or process. They consist of interconnected neurons and glial cells, which provide structural and metabolic support.
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
01:18Hierarchy of Motor Control
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
01:22Indirect Motor Pathways
The indirect motor or extrapyramidal pathways originate in the brainstem, the lower portion of the brain that connects it to the spinal cord. They consist of several distinct tracts, each with specialized functions. The four main tracts of the indirect motor pathways are the vestibulospinal tract, the reticulospinal tract, the tectospinal tract, and the rubrospinal tract.
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...