scholarly journals The generation of rhythmic activity in a distributed motor system

1983 ◽  
Vol 102 (1) ◽  
pp. 25-42
Author(s):  
C. S. Cohan ◽  
G. J. Mpitsos
Keyword(s):  
Rhythmic Activity ◽  
Motor Output ◽  
Buccal Ganglion ◽  
Nerve Roots ◽  
Pleurobranchaea Californica ◽  
Buccal Ganglia ◽  
Neuronal Oscillators ◽  
The Brain ◽  
Tonic Stimulation ◽  
Stimulation Of

Rhythmic activity that is distributed to the brain and buccal ganglia and which underlies several types of behaviour, can be evoked from isolated nervous systems of Pleurobranchaea californica by tonic nerve stimulation. The experiments presented here were designed to test whether this rhythmic activity is produced by independent neuronal oscillators located in each ganglion or whether the rhythmic activity arises from a single oscillatory locus in the buccal ganglion and is transmitted passively to the brain. By interrupting the conduction of activity in the cerebrobuccal connectives (CBC) between brain and buccal ganglia we show that motor output from the brain depends on sustained, cycle to cycle input from the buccal ganglion and cannot be reset with respect to the buccal activity. The production of rhythmic activity in the brain depends on the generation of rhythmic activity in the buccal ganglia whether the rhythms are activated by stimulation of buccal roots or paracerebral command cells in the brain. Simultaneous intracellular recordings from brain motoneurones and buccal interneurones which project to the brain indicate that these interneurones provide both the drive and the pattern for rhythmic motor output in the brain. Tonic stimulation of the CBC can produce rhythmic activity in isolated brains in which all nerve roots and connectives have been cut. This can be explained by the fact that tonic stimulation of the connectives is transformed into phasic activity by the axons within the connective. We conclude therefore, that rhythmic, coordinated activity in the brain and buccal ganglia of Pleurobranchaea arises from oscillatory circuits that are located only in the buccal ganglia.

Serotonergic Modulation of Patterned Motor Output in Lymnaea Stagnalis

1988 ◽  
Vol 135 (1) ◽  
pp. 473-486
Author(s):  
M. D. TUERSLEY ◽  
C. R. McCROHAN
Keyword(s):  
Lymnaea Stagnalis ◽  
Rhythmic Activity ◽  
Motor Output ◽  
Buccal Ganglia ◽  
Apparent Decrease ◽  
Inactive Phase ◽  
The Mean ◽  
Timing Of Onset ◽  
Serotonergic Modulation ◽  
Stimulation Of

Rhythmic feeding motor output from the buccal ganglia of Lymnaea stagnalis was evoked by tonic depolarization of the pattern-initiating interneurone SO in the isolated central nervous system. Perfusion with 10−4moll−1 serotonin (5-HT) led to a reduction in frequency of the SO-driven rhythm, and in some cases rhythmic activity was completely blocked. The frequency reduction was predominantly due to an increase in duration of the ‘inactive’ phase of the rhythm. In a number of preparations, the normal buccal rhythm was replaced by an ‘atypical’ pattern of bursting in buccal motoneurones in the presence of 5.HT. This was characterized by the absence of one phase (N2) of interneuronal activity in the feeding pattern generator. Stimulation of the serotonergic giant cerebral interneurones (CGCs), to increase the mean spike frequency from 1.0 to 2.5 Hz, mimicked some of the effects of 5-HT perfusion. However, the timing of onset of CGC stimulation in relation to depolarization of SO was critical; prolonged activation of a CGC led to an apparent decrease in its effectiveness in suppressing the buccal rhythm.

Control of feeding motor output by paracerebral neurons in brain of Pleurobranchaea californica

1982 ◽  
Vol 47 (5) ◽  
pp. 885-908 ◽  
Author(s):  
R. Gillette ◽  
M. P. Kovac ◽  
W. J. Davis
Keyword(s):  
Feeding Behavior ◽  
Action Potentials ◽  
Tactile Stimulation ◽  
Natural Food ◽  
Buccal Ganglion ◽  
Pleurobranchaea Californica ◽  
Feeding Rhythm ◽  
Intracellular Stimulation ◽  
Motor Rhythm ◽  
Stimulation Of

1. A population of interneurons that control feeding behavior in the mollusk Pleurobranchaea has been analyzed by dye injection and intracellular stimulation/recording in whole animals and reduced preparations. The population consists of 12-16 somata distributed in two bilaterally symmetrical groups on the anterior edge of the cerebropleural ganglion (brain). On the basis of their position adjacent to the cerebral lobes, these cells have been named paracerebral neurons (PCNs). This study concerns pme subset pf [MCs. the large, phasic ones, which have the strongest effect on the feeding rhythm (21). 2. Each PCN sends a descending axon via the ipsilateral cerebrobuccal connective to the buccal ganglion. Axon branches have not been detected in other brain or buccal nerves and hence the PCNs appear to be interneurons. 3. In whole-animal preparations, tonic intracellular depolarization of the PNCs causes them to discharge cyclic bursts of action potentials interrupted by a characteristic hyperpolarization. In all specimens that exhibit feeding behavior, the interburst hyperpolarization is invariably accompanied by radula closure and the beginning of proboscis retraction (the "bite"). No other behavorial effect of PCN stimulation has been observed. 4. In whole-animal preparations, the PCNs are excited by food and tactile stimulation of the oral veil, rhinophores, and tentacles. When such stimuli induce feeding the PCNs discharge in the same bursting pattern seen during tonic PCN depolarization, with the cyclic interburst hyperpolarization phase locked to the bit. When specimens egest an unpalatable object by cyclic buccal movements, however, the PCNs are silent. The PCNs therefore exhibit properties expected of behaviorally specific "command" neurons for feeding. 5. Silencing one or two PCNs by hyperpolarization may weaken but does not prevent feeding induced by natural food stimuli. Single PCNs therefore can be sufficient but are not necessary to induction of feeding behavior. Instead the PCNs presumably operate as a population to control feeding. 6. In isolated nervous system preparations tonic extracellular stimulation of the stomatogastric nerve of the buccal ganglion elicits a cyclic motor rhythm that is similar in general features to the PNC-induced motor rhythm. Bursts of PCN action potentials intercalated at the normal phase position in this cycle intensify the buccal rhythm. Bursts of PCN impulses intercalated at abnormal phase positions reset the buccal rhythm. The PCNs, therefore, also exhibit properties expected of pattern-generator elements and/or coordinating neurons for the buccal rhythm. 7. The PCNs are recruited into activity when the buccal motor rhythm is elicited by stomatogastric nerve stimulation or stimulation of the reidentifiable ventral white cell. The functional synergy between the PCNs and the buccal rhythm is therefore reciprocal. 8...

scholarly journals Brain oscillator(s) underlying rhythmic cerebral and buccal motor output in the mollusc, Pleurobranchaea californica

1984 ◽  
Vol 110 (1) ◽  
pp. 1-15
Author(s):  
W. J. Davis ◽  
M. P. Kovac ◽  
R. P. Croll ◽  
E. M. Matera
Keyword(s):  
Neural Control ◽  
Brain Activity ◽  
Neural Oscillator ◽  
Neural Oscillation ◽  
Buccal Ganglion ◽  
Pleurobranchaea Californica ◽  
Long Latency ◽  
Before And After ◽  
The Central Nervous System ◽  
The Brain

Tonic (d.c.) intracellular depolarization of the previously identified phasic paracerebral feeding command interneurones (PCps) in the brain of the carnivorous gastropod Pleurobranchaea causes oscillatory neural activity in the brain, both before and after transecting the cerebrobuccal connectives. Therefore, cycle-by-cycle ascending input from the buccal ganglion is not essential to cyclic brain activity. Instead the brain contains an independent neural oscillator(s), in addition to the oscillator(s) demonstrated previously in the buccal ganglion (Davis et al. 1973). Transection of the cerebrobuccal connectives immediately reduces the previously demonstrated (Kovac, Davis, Matera & Croll, 1983) long-latency polysynaptic excitation of the PCps by the polysynaptic excitors (PSEs) of the PCps. Therefore polysynaptic excitation of the PCps by the PSEs is mediated by an ascending neurone(s) from the buccal ganglion. The capacity of feeding command interneurones to induce neural oscillation in the isolated brain declines to near zero within 1 h after transection of the cerebrobuccal connectives, suggesting that this capacity is normally maintained by ascending information from the buccal ganglion. The results show that this motor system conforms to a widely applicable general model of the neural control of rhythmic behaviour, by which independent neural oscillators distributed widely in the central nervous system are coupled together to produce coordinated movement.

scholarly journals INTEROCEPTIVE INFORMATION OF PHYSICAL VIGOR: OREXIN NEURONS GAUGE CIRCULATING IGF-I FOR MOTIVATIONAL MOTOR OUTPUT

2021 ◽  
Author(s):  
Jonathan Adrian Zegarraa Valdivia ◽  
Jansen Fernandes ◽  
Julio Esparza ◽  
Kentaro Suda ◽  
Maria Estrella Fernandez de Sevilla ◽  
...  
Keyword(s):  
Physical Activity ◽  
Motor Output ◽  
Feedback Signal ◽  
Igf I ◽  
Spontaneous Physical Activity ◽  
Monoaminergic Neurons ◽  
Response To Exercise ◽  
The Brain ◽  
Low Serum ◽  
Stimulation Of

Brain regulation of bodily functions requires interoceptive feedback signals carrying information about the periphery. As mice with low serum IGF-I levels (LID mice) show reduced spontaneous physical activity, we speculated that body vigor information might be conveyed by circulating IGF-I, a regulator of skeletal muscle and bone mass that enters the brain during physical activity. Since hypothalamic orexin neurons, that are involved in regulating physical activity, express IGF-I receptors (IGF-IR), we hypothesized that these neurons might gauge circulating IGF-I levels. Inactivation of IGF-IR in mouse orexin neurons (Firoc mice) reduced spontaneous activity. Firoc mice maintain normal physical fitness but show anxiety- and depressive-like behaviors that seems to interfere with the rewarding effects of exercise, as they were less sensitive to the rewarding actions of exercise. Further, in response to exercise, Firoc mice showed reduced activation of hypothalamic orexin neurons and ventro-tegmental area (VTA) monoaminergic neurons, as indicated by c-fos staining. Collectively, these results suggest that circulating IGF-I is gauged by orexin neurons to modulate physical activity in part by stimulation of the VTA to motivate motor output. Hence, serum IGF-I may constitute a feedback signal, informing orexin neurons to adapt physical activity to physical vigor.

Functional and structural correlates of cell size in paracerebral neurons of Pleurobranchaea californica

1982 ◽  
Vol 47 (5) ◽  
pp. 909-927 ◽  
Author(s):  
M. P. Kovac ◽  
W. J. Davis ◽  
E. Matera ◽  
R. Gillette
Keyword(s):  
Cell Size ◽  
Motor Neurons ◽  
Lucifer Yellow ◽  
Motor Output ◽  
Morphological Properties ◽  
Spontaneous Discharge ◽  
Buccal Ganglion ◽  
Size Principle ◽  
Motor Effects ◽  
The Brain

1. The paracerebral neurons (PCNs) in the brain of the mollusk Pleurobranchaea are a population of 12-16 interneurons that send axons to the buccal ganglion and control cyclic feeding behavior (9). In the present study we show that the PCNs differ in size and that a number of functional and structural properties of the PCNs are closely correlated with cell size. 2. PCN soma diameter varies from about 30 to 120 micrometers. The diameters segregate into two distinct but overlapping populations, which correspond to independently assigned functional classifications of "tonic" and "phasic" PCNs. The mean soma diameters of two populations were 63 and 84 micrometers, respectively. 3. Two morphological features vary systematically with PCN soma size. First, soma diameter, axonal conduction velocity, and extracellular spike amplitude were positively correlated; therefore, PCN axon diameter presumably increases with soma diameter. Second, intrasomatic injection of lucifer yellow revealed that the small, tonic PCNs are multipolar, while the large, phasic PCNs are generally monopolar neurons. 4. Small PCNs discharge tonically in response to sustained current injection and have a weak effect on cyclic motor output recorded from nerves that innervate feeding muscles. In contrast, the large PCNs discharge phasically in bursts of action potentials that are coordinated with the cyclic motor output and have a comparatively strong effect on the rhythm. The motor effects of simultaneous tonic and phasic PCN stimulation are additive. 5. Tonic and phasic PCNs innervate different but partially overlapping populations of feeding motor neurons. Phasic PCNs typically inhibit motor neurons exiting buccal root 3, while tonic PCNs either have no effect or are weakly excitatory. 6. Tonic and phasic PCNs exhibit different intrinsic properties. In comparison with phasic PCNs, tonic PCNs have higher input resistances, higher spontaneous discharge rates at rest potential, lower firing thresholds to intrasomatically injected current, lower absolute voltage thresholds, greater pacemaker sensitivity, and greater total capacitance. 7. Tonic and phasic PCNs exhibit different input properties. Tonic PCNs are recruited before phasic ones during cycylic buccal motor output induced by stomatogastric nerve stimulation. Phasic PCNs receive powerful, cycylic inhibition that is not shared by tonic PCNs. In addition, extracellular stimulation of the large oral veil nerve of the brain excites tonic PCNs but causes a biphasic postsynaptic potential (PSP) in phasic PCNs that has a net inhibitory effect. Some excitatory synaptic input to phasic and tonic PCNs is unshared, while some is shared. 8. It is concluded that these command interneurons obey the size principle discovered earlier in motor neurons (4, 13-16). Cell size per se is not the causal variable, however; instead the underlying causes of the differences between small and large PCNs include different input and output organizations as well as different intrinsic functional and morphological properties.

Interactions of the slow oscillator interneuron with feeding pattern-generating interneurons in Lymnaea stagnalis

1985 ◽  
Vol 54 (6) ◽  
pp. 1412-1421 ◽  
Author(s):  
C. J. Elliott ◽  
P. R. Benjamin
Keyword(s):  
Motor System ◽  
Lymnaea Stagnalis ◽  
Pond Snail ◽  
Excitatory Synapses ◽  
Feeding System ◽  
Buccal Ganglion ◽  
Buccal Ganglia ◽  
Feeding Rhythm ◽  
The Right ◽  
Stimulation Of

We have used intracellular recording from groups of interneurons in the feeding system of the pond snail, Lymnaea stagnalis, to examine the connections of a modulatory interneuron, the slow oscillator (SO), with the network of pattern-generating interneurons (N1, N2, and N3). The SO is an interneuron whose axon branches solely within the buccal ganglia. There is only one such cell in each snail. In half the snails the cell body is in the right buccal ganglion and in the other half in the left buccal ganglion. Stimulation of either the SO or one of the N1 pattern-generating interneurons elicits the feeding rhythm, but of all the buccal neurons, only the SO can drive the feeding rhythm at the frequency seen in the intact snail. The SO makes reciprocal excitatory synapses with the N1 interneurons that drive the protraction of the radula. This ensures strong activation of the feeding system. The SO inhibits the N2 interneurons. Postsynaptic potentials evoked by stimulation of the SO facilitate without spike broadening in the SO. The SO is strongly inhibited by N2 and N3 interneurons, which are active during the retraction phase. This gates any excitatory inputs to the SO, probably preventing protraction of the radula while retraction is underway. The results support the idea of a single interneuron capable of driving a hierarchically organized motor system.

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

2008 ◽  
Vol 100 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Ian T. Gordon ◽  
Mary J. Dunbar ◽  
Kimberly J. Vanneste ◽  
Patrick J. Whelan
Keyword(s):  
Spinal Cord ◽  
Brain Stem ◽  
Rhythmic Activity ◽  
The Other ◽  
Neonatal Mice ◽  
Complete Transection ◽  
Synchronous Oscillations ◽  
Rhythm Stability ◽  
The Brain ◽  
Stimulation Of

At birth, thoracosacral spinal cord networks in mouse can produce a coordinated locomotor-like pattern. In contrast, less is known about the cervicothoracic networks that generate forelimb locomotion. Here we show that cervical networks can produce coordinated rhythmic patterns in the brain stem-spinal cord preparation of the mouse. Segmentally the C5 and C8 neurograms were each found to be alternating left-right, and the ipsilateral C5 and C8 neurograms also alternated. Collectively these patterns were suggestive of locomotor-like activity. This pattern was not dependent on the presence of thoracosacral segments because they could be evoked following a complete transection of the spinal cord at T5. We next demonstrated that activation of thoracosacral networks either pharmacologically or by stimulation of sacrocaudal afferents could produce rhythmic activity within the C5 and C8 neurograms. On the other hand, pharmacological activation of cervical networks did not evoke alternating cervical rhythmic activity either in isolated cervicothoracic or -sacral preparations. Under these conditions, we found that activation of cervicothoracic networks could alter the timing of thoracosacral locomotor-like patterns. When thoracosacral networks were not activated pharmacologically but received rhythmic drive from cervicothoracic networks, a pattern of slow bursts with superimposed fast synchronous oscillations became the dominant lumbar neurogram pattern. Our data suggest that in neonatal mice the cervical CPG is capable of producing coordinated rhythmic patterns in the absence of input from lumbar segments, but caudorostral drive contributes to cervical patterns and rhythm stability.

Respiratory Control and Stimulation of Spontaneous Breathing

1991 ◽  
Vol 7 (S1) ◽  
pp. 47-51 ◽  
Author(s):  
Hugo Lagercrantz
Keyword(s):  
Brain Stem ◽  
Spontaneous Breathing ◽  
Respiratory Control ◽  
Rhythmic Activity ◽  
Neonatal Rat ◽  
Peripheral Chemoreceptors ◽  
Neuronal Groups ◽  
The Brain ◽  
Respiratory Movements ◽  
Stimulation Of

Respiratory movements are controlled by two pairs of neuronal groups in the brain stem: nucl. tractus solitarius and nucl. paraambigualis. These neuronal pools receive drive inputs from the forebrain and hypothalamus, and from central and peripheral chemoreceptors (9). Whether there is endogenous spontaneous respiratory rhythmic activity has been a matter of controversy, but this has recently been discovered in brainstem preparations of the neonatal rat in studies by Onimaru and Homma (27).

Fictive swimming elicited by electrical stimulation of the midbrain in goldfish

1993 ◽  
Vol 70 (2) ◽  
pp. 765-780 ◽  
Author(s):  
J. R. Fetcho ◽  
K. R. Svoboda
Keyword(s):  
Brain Stimulation ◽  
Beat Frequency ◽  
Motor Pattern ◽  
The Body ◽  
Motor Output ◽  
Stimulus Strength ◽  
Motor Nerves ◽  
Tail Beat ◽  
The Brain ◽  
Stimulation Of

1. We developed a fictive swimming preparation of goldfish that will allow us to study the cellular basis of interactions between swimming and escape networks in fish. 2. Stimulation of the midbrain in decerebrate goldfish produced rhythmic alternating movements of the body and tail similar to swimming movements. The amplitude and frequency of the movements were dependent on stimulus strength. Larger current strengths or higher frequencies of stimulation produced larger-amplitude and/or higher-frequency movements. Tail-beat frequency increased roughly linearly with current strength over a large range, with plateaus in frequency sometimes evident at the lowest and highest stimulus strengths. 3. Electromyographic (EMG) recordings from axial muscles on opposite sides at the same rostrocaudal position showed that stimulation of the midbrain led to alternating EMG bursts, with bursts first on one side, then the other. These bursts occurred at a frequency equal to the tail-beat frequency and well below the frequency of brain stimulation. EMG bursts recorded from rostral segments preceded those recorded from caudal segments on the same side of the body. The interval between individual spikes within EMG bursts sometimes corresponded to the interval between brain stimuli. Thus, whereas the frequency of tail beats and EMG bursts was always much slower than the frequency of brain stimulation, there was evidence of individual brain stimuli in the pattern of spikes within bursts. 4. After paralyzing fish that produced rhythmic movement on midbrain stimulation, we monitored the motor output during stimulation of the midbrain by using extracellular recordings from spinal motor nerves. We characterized the motor pattern in detail to determine whether it showed the features present in the motor output of swimming fish. The fictive preparations showed all of the major features of the swimming motor pattern recorded in EMGs from freely swimming fish. 5. The motor nerves, like the EMGs produced by stimulating midbrain, showed rhythmic bursting at a much lower frequency than the brain stimulus. Bursts on opposite sides of the body alternated. The frequency of bursting ranged from 1.5 to 13.6 Hz and was dependent on stimulus strength, with higher strengths producing faster bursting. Activity in rostral segments preceded activity in caudal ones on the same side of the body. Some spikes within bursts of activity occurred at the same frequency as the brain stimulus, but individual brain stimuli were not as evident as those seen in some of the EMGs. 6. The duration of bursts of activity in a nerve was positively and linearly correlated with the time between successive bursts (cycle time).(ABSTRACT TRUNCATED AT 400 WORDS)

Psychotropic Drug Effects on Self-Stimulation of the Brain: A Control for Motor Output

1966 ◽  
Vol 19 (1) ◽  
pp. 79-82 ◽  
Author(s):  
B. P. H. Poschel ◽  
F. W. Ninteman
Keyword(s):  
Brain Stimulation ◽  
Drug Effects ◽  
Motor Output ◽  
Reward Value ◽  
Strong Stimulation ◽  
Weak Stimulation ◽  
Rewarding Brain ◽  
Self Stimulation ◽  
The Brain ◽  
Stimulation Of

Rats with electrodes in the posterior lateral hypothalamus were trained in a chamber having two platforms. When standing on one platform, S received rewarding brain stimulation continuously. Switching to the other platform turned stimulation off. The proportion of time spent on the positive platform indicated the reward value of stimulation. Preliminary tests determined that the time measure was positively related to stimulation intensity. Drug tests determined that tranylcypromine and methamphetamine greatly increased the reward value of weak stimulation, while chlorpromazine greatly decreased the reward value of strong stimulation. Since Ss were not required to work for brain stimulation, these effects on reward value were shown not to be mere artifacts of the drugs' effects on motor output.

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