Rhythmic activity of feline dorsal and ventral spinocerebellar tract neurons during fictive motor actions

2013 ◽  
Vol 109 (2) ◽  
pp. 375-388 ◽  
Author(s):  
Brent Fedirchuk ◽  
Katinka Stecina ◽  
Kasper Kyhl Kristensen ◽  
Mengliang Zhang ◽  
Claire F. Meehan ◽  
...  
Keyword(s):  
Central Pattern Generator ◽  
Sensory Input ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Afferent Feedback ◽  
Fictive Locomotion ◽  
Decerebrate Cat ◽  
Motor Behaviors ◽  
Spinocerebellar Tract ◽  
Motor Actions

Neurons of the dorsal spinocerebellar tracts (DSCT) have been described to be rhythmically active during walking on a treadmill in decerebrate cats, but this activity ceased following deafferentation of the hindlimb. This observation supported the hypothesis that DSCT neurons primarily relay the activity of hindlimb afferents during locomotion, but lack input from the spinal central pattern generator. The ventral spinocerebellar tract (VSCT) neurons, on the other hand, were found to be active during actual locomotion (on a treadmill) even after deafferentation, as well as during fictive locomotion (without phasic afferent feedback). In this study, we compared the activity of DSCT and VSCT neurons during fictive rhythmic motor behaviors. We used decerebrate cat preparations in which fictive motor tasks can be evoked while the animal is paralyzed and there is no rhythmic sensory input from hindlimb nerves. Spinocerebellar tract cells with cell bodies located in the lumbar segments were identified by electrophysiological techniques and examined by extra- and intracellular microelectrode recordings. During fictive locomotion, 57/81 DSCT and 30/30 VSCT neurons showed phasic, cycle-related activity. During fictive scratch, 19/29 DSCT neurons showed activity related to the scratch cycle. We provide evidence for the first time that locomotor and scratch drive potentials are present not only in VSCT, but also in the majority of DSCT neurons. These results demonstrate that both spinocerebellar tracts receive input from the central pattern generator circuitry, often sufficient to elicit firing in the absence of sensory input.

Deletions of Rhythmic Motoneuron Activity During Fictive Locomotion and Scratch Provide Clues to the Organization of the Mammalian Central Pattern Generator

2005 ◽  
Vol 94 (2) ◽  
pp. 1120-1132 ◽  
Author(s):  
Myriam Lafreniere-Roula ◽  
David A. McCrea
Keyword(s):  
Central Pattern Generator ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Cycle Period ◽  
Fictive Locomotion ◽  
Integer Multiple ◽  
Extensor Motoneuron ◽  
Complete Failure ◽  
Motoneuron Activity ◽  
Decerebrate Cats

We examined the features of spontaneous deletions of bursts of motoneuron activity that can occur within otherwise rhythmic alternating flexor and extensor activity during fictive locomotion and scratch in adult decerebrate cats. Deletions of activity were observed both in hindlimb flexor and extensor motoneuron pools during brain stem–stimulation-evoked fictive locomotion but only in extensors during fictive scratch. Paired intracellular motoneuron recordings showed that deletions reduced the depolarization of homonymous motoneurons in qualitatively similar ways. Differences occurred in the extent to which activity in synergist motoneuron pools operating at other joints within the limb was reduced during deletions. The timing of the rhythmic activity that followed a deletion was often at an integer multiple of the preexisting locomotor or scratch cycle period. This maintenance of cycle period was also seen during deletions in which there was a complete failure of motoneuron depolarization. The activity of antagonist motoneurons was usually sustained during deletions with some rhythmic modulation at intervals of the preexisting cycle period. We discuss an organization of the central pattern generator for locomotion and scratch that functions as a single rhythm generator with separate and multiple pattern formation modules for controlling the hyper- and depolarization of subsets of motoneurons within the limb.

Entrainment of the Swimmeret Rhythm of the Crayfish to Controlled Movements of Some of the Appendages

1989 ◽  
Vol 144 (1) ◽  
pp. 257-278
Author(s):  
SIMON R. T. DELLER ◽  
DAVID L. MACMILLAN
Keyword(s):  
Central Pattern Generator ◽  
Small Proportion ◽  
Nerve Cord ◽  
Sensory Input ◽  
Pattern Generator ◽  
Nerve Cords

Please send reprint requests and enquiries to this author A machine was used to impose controlled movements, closely resembling natural movements, on some of the swimmerets of crayfish with their ventral nerve cords cut between thorax and abdomen. The rhythm of the unrestrained swimmerets could be entrained to the imposed frequency. Full entrainment occurred most readily when three or four swimmerets were controlled and was uncommon with two. When one was controlled, only partial entrainment was seen. A small proportion of preparations could not be entrained irrespective of the number of swimmerets controlled. Entrainment of the neural rhythm also occurred when movement was imposed on one or more swimmerets attached to an otherwise isolated nerve cord. This is the first demonstration that sensory input affects the periodicity of the swimmeret rhythm. In the light of this result, the hypothesis that swimmeret rhythm is largely controlled by a central pattern generator should be viewed with caution. It now appears that there is also an influential sensory component responsible for stabilizing and adjusting the timing of the swimmeret rhythm.

Gating of Afferent Input by a Central Pattern Generator

1999 ◽  
Vol 81 (2) ◽  
pp. 950-953 ◽  
Author(s):  
Ralph A. DiCaprio
Keyword(s):  
Central Pattern Generator ◽  
Sensory Input ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Afferent Input ◽  
Inhibitory Input ◽  
Cycle Period ◽  
Intracellular Recordings ◽  
Afferent Fibers ◽  
Sufficient Magnitude

Gating of afferent input by a central pattern generator. Intracellular recordings from the sole proprioceptor (the oval organ) in the crab ventilatory system show that the nonspiking afferent fibers from this organ receive a cyclic hyperpolarizing inhibition in phase with the ventilatory motor pattern. Although depolarizing and hyperpolarizing current pulses injected into a single afferent will reset the ventilatory motor pattern, the inhibitory input is of sufficient magnitude to block afferent input to the ventilatory central pattern generator (CPG) for ∼50% of the cycle period. It is proposed that this inhibitory input serves to gate sensory input to the ventilatory CPG to provide an unambiguous input to the ventilatory CPG.

scholarly journals Shining light into the black box of spinal locomotor networks

2010 ◽  
Vol 365 (1551) ◽  
pp. 2383-2395 ◽  
Author(s):  
Patrick J. Whelan
Keyword(s):  
Spinal Cord ◽  
Central Pattern Generator ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Black Box ◽  
Motor Functions ◽  
Network Function ◽  
Stepping Pattern

Rhythmic activity is responsible for numerous essential motor functions including locomotion, breathing and chewing. In the case of locomotion, it has been realized for some time that the spinal cord contains sufficient circuitry to produce a sophisticated stepping pattern. However, the central pattern generator for locomotion in mammals has remained a ‘black box’ where inputs to the network were manipulated and the outputs interpreted. Over the last decade, new genetic approaches and techniques have been developed that provide ways to identify and manipulate the activity of classes of interneurons. The use of these techniques will be critically discussed and related to current models of network function.

scholarly journals Dynamics of episodic and continuous rhythmic activities from a developing central pattern generator

2020 ◽  
Author(s):  
Simon A. Sharples ◽  
Alex Vargas ◽  
Adam P. Lognon ◽  
Leanne Young ◽  
Anchita Shonak ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Central Pattern Generator ◽  
Narrow Range ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Newborn Mouse ◽  
Spinal Motor ◽  
State Dependent ◽  
Insight Into

AbstractDeveloping spinal motor networks produce a diverse array of outputs, including episodic and continuous patterns of rhythmic activity. Variation in excitability state and neuromodulatory tone can facilitate transitions between episodic and continuous rhythms; however, the intrinsic mechanisms that govern these rhythms and transitions are poorly understood. Here, we tested the capacity of a single central pattern generator (CPG) circuit with tunable properties to generate multiple outputs. To address this, we deployed a computational model composed of an inhibitory half-centre oscillator. We tested the contributions of key properties predicted by the model to the generation of an episodic rhythm produced by isolated spinal cords of the newborn mouse. The model was capable of reproducing the diverse state-dependent rhythms evoked by dopamine in the neonatal mouse spinal cord. In the model, episodic bursting depended predominantly on the endogenous oscillatory properties of neurons, with persistent Na+(INaP), Na+-K+ ATPase pump (IPump), and hyperpolarization-activated currents (Ih) playing key roles. Modulation of all three currents produced transitions between episodic and continuous rhythms and silence. Pharmacological manipulation of these properties in vitro led to consistent changes in spinally generated rhythmic outputs elicited by dopamine. The model also showed multistable zones within a narrow range of parameter space for IPump and Ih, where switches between rhythms were rapidly triggered by brief but specific perturbations. Outside of those zones, brief perturbations could reset episodic and continuous rhythmicity generated by the model. Our modelling and experimental results provide insight into mechanisms that govern the generation of multiple patterns of rhythmicity by a single CPG. We propose that neuromodulators alter circuit properties to position the network within regions of state-space that favour stable outputs or, in the case of multistable zones, facilitate rapid transitions between states.Significance statementThe ability of a single CPG to produce and transition between multiple rhythmic patterns of activity is poorly understood. We deployed a complementary computational half-centre oscillator model and an isolated spinal cord experimental model to identify key currents whose interaction produced episodic and continuous rhythmic activity. Combined, our experimental and modelling approaches suggest mechanisms that govern generating and transitioning between diverse rhythms in mammalian spinal networks. This work sheds light on the ability of a single CPG to produce episodic bouts often observed in behavioural contexts.

scholarly journals The locust frontal ganglion: a central pattern generator network controlling foregut rhythmic motor patterns

2002 ◽  
Vol 205 (18) ◽  
pp. 2825-2832 ◽  
Author(s):  
Amir Ayali ◽  
Yael Zilberstein ◽  
Netta Cohen
Keyword(s):  
Central Pattern Generator ◽  
Schistocerca Gregaria ◽  
Physiological State ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Rhythmic Pattern ◽  
Stomatogastric Nervous System ◽  
Motor Patterns ◽  
Frontal Ganglion

SUMMARYThe frontal ganglion (FG) is part of the insect stomatogastric nervous system and is found in most insect orders. Previous work has shown that in the desert locust, Schistocerca gregaria, the FG constitutes a major source of innervation to the foregut. In an in vitro preparation,isolated from all descending and sensory inputs, the FG spontaneously generated rhythmic multi-unit bursts of action potentials that could be recorded from all its efferent nerves. The consistent endogenous FG rhythmic pattern indicates the presence of a central pattern generator network. We found the appearance of in vitro rhythmic activity to be strongly correlated with the physiological state of the donor locust. A robust pattern emerged only after a period of saline superfusion, if the locust had a very full foregut and crop, or if the animal was close to ecdysis. Accordingly,haemolymph collected at these stages inhibited an ongoing rhythmic pattern when applied onto the ganglion. We present this novel central pattern generating system as a basis for future work on the neural network characterisation and its role in generating and controlling behaviour.

The Swimming Circuit in the Pteropod Mollusk Clione limacina

2017 ◽  
pp. 569-574
Author(s):  
Yuri I. Arshavsky ◽  
Tatiana G. Deliagina ◽  
Grigory N. Orlovsky
Keyword(s):  
Nervous System ◽  
Central Pattern Generator ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Neuronal Circuit ◽  
Basic Pattern ◽  
Marine Mollusk ◽  
Clione Limacina ◽  
Two Phases

The pelagic marine mollusk Clione limacina (class Gastropoda, subclass Opisthobranchaea, order Pteropoda), 3–5 cm in length, swims by rhythmically moving (1–2-Hz) two winglike appendages. Each swim cycle consists of two phases—the dorsal (D) and ventral (V) wing flexions. The nervous system of Clione consists of five pairs of ganglia. The wing movements are controlled by the pedal ganglia giving rise to the wing nerves. The neuronal circuit of the swim central pattern generator (CPG) is located in the pedal ganglia, which is able to generate the basic pattern of rhythmic activity after isolation from the organism (fictive swimming). Approximately 120 pedal neurons exhibit rhythmic activity during fictive swimming. According to their morphology, rhythmic neurons are divided into motoneurons (MNs), with axons exiting via the wing nerves to wing muscles, and interneurons (INs), with axons projecting to the contralateral ganglion.

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