Contextual modulation of multifunctional central pattern generator

Ramakrishnan, Siddharth; Arnett, Bridgette C.; Murphy, A. D.

doi:10.1242/jeb.086751

Cited by 3 publications

(3 citation statements)

References 59 publications

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“…Before starting the dissection, anesthetize a snail in cold saline (Ramakrishnan et al, 2014). Alternatively, use a solution of 5% ethanol in pond water but do not leave the snail in ethanol for more than three minutes.…”

Section: Dissectionmentioning

confidence: 99%

“…Students may notice variability in extracellular spike sizes (Figure 6B) and ask whether different sizes represent activity in different axons. In this case, they reflect change in the sizes of action potentials during a burst; this often occurs in bursting neurons (see Figures 6, 9, 14 of Benjamin and Rose, 1979; Figure 1 of Quinlan et al, 1997;Figure 3 of Murphy, 2001; Figure 7 of Ramakrishnan et al, 2014).…”

Section: Data and Analysismentioning

confidence: 99%

“…[Considering the triphasic motor pattern, we would not expect simultaneous excitation in all nerves; there should at least be phase differences. For the most part, the behavior is symmetric, and many of the neurons described by Ramakrishnan et al (2014) project bilaterally through the motor nerves. Therefore, we predict similar activity in nerves on the left and right in this case.…”

Section: Questionsmentioning

confidence: 99%

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Recording from Snail Motor Nerves to Investigate Central Pattern Generation

Wyttenbach,

Johnson

2022

JUNE

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Feeding in pond snails has long been a model system for central pattern generation and its modulation. The pattern is generated by a small set of neurons in the buccal ganglia, which innervate the buccal mass, esophagus, and salivary glands. In this exercise, students observe feeding behavior and then record and quantify rhythmic motor activity and its response to feeding stimulants and neuromodulators. In a standard three-hour class period, students do a dissection, record from several nerves, and perform experimental manipulations such as adding feeding stimulants, serotonin, or dopamine to the preparation. Depending on the course goals, data can be presented qualitatively or cyclic measurements and spike-rate analysis can be done. This exercise leads to discussion of neural circuitry and intrinsic properties that support pattern generation for rhythmic activities such as feeding, locomotion, and respiration.

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Section: Dissectionmentioning

confidence: 99%

Section: Data and Analysismentioning

confidence: 99%

Section: Questionsmentioning

confidence: 99%

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Recording from Snail Motor Nerves to Investigate Central Pattern Generation

Wyttenbach,

Johnson

2022

JUNE

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Peptidergic modulation of a multi-functional central pattern generator in the pulmonate snail

Ramakrishnan

Murphy

2022

Journal of Experimental Biology

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Egg laying in pulmonate snails is a well orchestrated process that involves a period of reduced locomotion, followed by substrate cleaning with rhythmic rasping of the surface to make tiny grooves, into which eggs are deposited. While the neurohormonal control of initiating egg-laying has been well established, the signals that modulate the buccal central pattern generator to substrate cleaning during egg-laying are not known. Neuropeptides of the invertebrate Gonadotropin-Releasing Hormone/Corazonin family (invGnRH/CRZ) have been shown to be involved in reproduction and allied behaviors in many vertebrates and invertebrates. Here we show that the buccal motor pattern underlying substrate cleaning during egg-laying is altered by a vetebrate GnRH-agonist. Signals from the intestinal nerve innervating reproductive structures, previously shown to be both necessary and sufficient for egg-laying behaviors, are blocked by a vertebrate GnRH-antagonist. Further, the vertebrate GnRH triggered response elicits rhythmic, phase 2 and non-phase 2 activity in the buccal motor pattern, with a shut down of phase 3, indicative of repetitive rasping without accompanied swallowing behavior. Using immunohistochemistry, intracellular electrophysiology and extracellular nerve stimulation, we show that a member of the invGnRH/CRZ-family of neuropeptides could be the signal that contextually switches the multifunctional buccal CPG to a biphasic rasping rhythm that underlies substrate cleaning behavior during egg-laying in pulmonate snail Planorbella (Helisoma) trivolvis.

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Role of the basal ganglia in innate and learned behavioural sequences

Favila

Gurney

Overton

2023

Reviews in the Neurosciences

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Integrating individual actions into coherent, organised behavioural units, a process called chunking, is a fundamental, evolutionarily conserved process that renders actions automatic. In vertebrates, evidence points to the basal ganglia – a complex network believed to be involved in action selection – as a key component of action sequence encoding, although the underlying mechanisms are only just beginning to be understood. Central pattern generators control many innate automatic behavioural sequences that form some of the most basic behaviours in an animal’s repertoire, and in vertebrates, brainstem and spinal pattern generators are under the control of higher order structures such as the basal ganglia. Evidence suggests that the basal ganglia play a crucial role in the concatenation of simpler behaviours into more complex chunks, in the context of innate behavioural sequences such as chain grooming in rats, as well as sequences in which innate capabilities and learning interact such as birdsong, and sequences that are learned from scratch, such as lever press sequences in operant behaviour. It has been proposed that the role of the striatum, the largest input structure of the basal ganglia, might lie in selecting and allowing the relevant central pattern generators to gain access to the motor system in the correct order, while inhibiting other behaviours. As behaviours become more complex and flexible, the pattern generators seem to become more dependent on descending signals. Indeed, during learning, the striatum itself may adopt the functional characteristics of a higher order pattern generator, facilitated at the microcircuit level by striatal neuropeptides.

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Contextual modulation of multifunctional central pattern generator

Cited by 3 publications

References 59 publications

Recording from Snail Motor Nerves to Investigate Central Pattern Generation

Recording from Snail Motor Nerves to Investigate Central Pattern Generation

Peptidergic modulation of a multi-functional central pattern generator in the pulmonate snail

Role of the basal ganglia in innate and learned behavioural sequences

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