scholarly journals THE MULTISEGMENTAL MOTOR SUPPLY TO TRANSVERSE MUSCLES DIFFERS IN A CRICKET AND A BUSHCRICKET

1993 ◽  
Vol 185 (1) ◽  
pp. 335-355 ◽  
Author(s):  
C. Consoulas ◽  
R. Hustert ◽  
G. Theophilidis
Keyword(s):  
Single Unit ◽  
Muscle Contractions ◽  
Gryllus Bimaculatus ◽  
Postsynaptic Potentials ◽  
Segmental Ganglion ◽  
Bilateral Pair ◽  
Left And Right ◽  
Adjacent Segments ◽  
Whole Muscle ◽  
Transverse Muscle

Most abdominal sternites of the cricket Gryllus bimaculatus and the bushcricket Decticus albifrons are bridged by a transverse muscle (TM) which supports expiratory movements. In the cricket, ventilatory contractions are controlled both within each segment, by a bilateral pair of excitatory motoneurones in the abdominal ganglion supplying the left and right halves of the TM independently, and intersegmentally, by peripheral collaterals of homologous motoneurones from adjacent segments. The axons of these motoneurones run in the ipsilateral paramedian nerve. This unique divergence of excitatory motoneurones to different muscles also results in massive convergence of excitatory inputs from different ganglia, especially on the TMs of the middle abdominal segments. TM contraction rates are increased by this intersegmentally divergent and convergent motor supply, especially in the middle abdominal segments. In bushcrickets, each transverse muscle in segments 3–7 is innervated bilaterally by four pairs of neurones: (i) two pairs of contralateral excitatory motoneurones with axons that diverge, supplying two adacent muscles; (ii) one pair of contralateral excitatory neurones found in the second anterior ganglion and (iii) a pair of median inhibitory neurones in the segmental ganglion. Transverse muscles 2 and 8 receive reduced innervation. The excitatory motoneurones generate slow excitatory postsynaptic potentials (EPSPs), which must sum to cause muscle contractions. During ventilation, contralateral paired transverse motoneurones fire at similar frequencies, thus sychronizing the contractions of the left and right halves of the muscle so that the whole muscle acts as a single unit.

Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones

1991 ◽  
Vol 158 (1) ◽  
pp. 37-62 ◽  
Author(s):  
N. I. Syed ◽  
W. Winlow
Keyword(s):  
Body Wall ◽  
Lymnaea Stagnalis ◽  
The Body ◽  
Whole Body ◽  
Pond Snail ◽  
Selective Ablation ◽  
The Central Nervous System ◽  
Body Wall Muscles ◽  
Bilateral Pair ◽  
Left And Right

1. The morphology and electrophysiology of a newly identified bilateral pair of interneurones in the central nervous system of the pulmonate pond snail Lymnaea stagnalis is described. 2. These interneurones, identified as left and right pedal dorsal 11 (L/RPeD11), are electrically coupled to each other as well as to a large number of foot and body wall motoneurones, forming a fast-acting neural network which coordinates the activities of foot and body wall muscles. 3. The left and right sides of the body wall of Lymnaea are innervated by left and right cerebral A cluster neurones. Although these motoneurones have only ipsilateral projections, they are indirectly electrically coupled to their contralateral homologues via their connections with L/RPeD11. Similarly, the activities of left and right pedal G cluster neurones, which are known to be involved in locomotion, are also coordinated by L/RPeD11. 4. Selective ablation of both neurones PeD11 results in the loss of coordination between the bilateral cerebral A clusters. 5. Interneurones L/RPeD11 are multifunctional. In addition to coordinating motoneuronal activity, they make chemical excitatory connections with heart motoneurones. They also synapse upon respiratory motoneurones, hyperpolarizing those involved in pneumostome opening (expiration) and depolarizing those involved in pneumostome closure (inspiration). 6. An identified respiratory interneurone involved in pneumostome closure (visceral dorsal 4) inhibits L/RPeD11 together with all their electrically coupled follower cells. 7. Both L/RPeD11 have strong excitatory effects on another pair of electrically coupled neurones, visceral dorsal 1 and right parietal dorsal 2, which have previously been shown to be sensitive to changes in the partial pressure of environmental oxygen (PO2). 8. Although L/RPeD11 participate in whole-body withdrawal responses, electrical stimulation applied directly to these neurones was not sufficient to induce this behaviour.

An atlas of the thoracic ganglia in the stick insect, Carausius morosus

1991 ◽  
Vol 331 (1260) ◽  
pp. 101-121 ◽  
Keyword(s):  
Single Unit ◽  
Present Report ◽  
Stick Insect ◽  
Functional Specialization ◽  
Carausius Morosus ◽  
Thoracic Ganglia ◽  
The Third ◽  
Metathoracic Ganglion ◽  
The Subject ◽  
Left And Right

The present report describes the neuroanatomy of the three thoracic ganglia in the stick insect, Carausius morosus , the subject of numerous behavioural and neurobiological studies. The structure of the ganglia is summarized in an atlas of the major features. The results are compared with published descriptions of other insects and arthropods. Numerous similarities with locusts encourage the use of a common nomenclature even where minor differences make homology uncertain pending detailed investigation. Five out of the nine longitudinal tracts described in locusts can be readily identified in the stick insect. Three major tracts (LDT, DIT, VIT) and two smaller tracts (MDT, DMT) are compact and well defined. The VMT and MVT are also prominent but these two tracts are not clearly separated except near the rostral margin of the neuropile. An eighth tract, the VLT, is much less distinct: it is represented by scattered fibres in neuropile lateral to the DIT. The iLVT apd oLVT, the two parts of the ninth tract, are quite inconspicuous: in some, but not all, preparations they can be identified as two thin bands running along the ventral and ventrolateral margins of the ganglion. As in locusts, six dorsal commissures (DCI-DCVI) and five ventral commissures (VCI, vVCII, dVCII, SMC, PVC) connecting the left and right hemiganglia have been named although the two most dorsal commissures, DCII and DCIV, are often subdivided. The VCII is retained as a single unit with dorsal and ventral parts. Of the dorsal-ventral tracts only the transverse tract (TT) and the circle tract (CT) are well-defined. Roots of lateral nerves are left unnamed pending more detailed study but several conspicuous branches are included in the drawings as guides to orientation in the lateral neuropile. The ventral association centre (VAC) and several other neuropile divisions are described. Pro- and mesothoracic ganglia derive from single neuromeres. The metathoracic ganglion results from the fusion of the third thoracic and the first abdominal neuromeres: each part contains its own set of commissures and dorsoventral tracts. The results underline the qualitative similarities of the thoracic ganglia in insects; they provide a basis for more precise descriptions of identified neurons and functional specialization within the ganglia of the stick insect.

Conditional Rhythmicity and Synchrony in a Bilateral Pair of Bursting Motor Neurons in Aplysia

2006 ◽  
Vol 96 (4) ◽  
pp. 2056-2071 ◽  
Author(s):  
Geidy E. Serrano ◽  
Mark W. Miller
Keyword(s):  
Motor Neurons ◽  
Aplysia Californica ◽  
Burst Activity ◽  
Feeding System ◽  
Postsynaptic Potentials ◽  
Potential Source ◽  
Bath Application ◽  
Bilateral Pair ◽  
Driver Potential ◽  
Rhythmic Burst

This investigation examined the activity of a bilateral pair of motor neurons (B67) in the feeding system of Aplysia californica. In isolated ganglia, B67 firing exhibited a highly stereotyped bursting pattern that could be attributed to an underlying TTX-resistant driver potential (DP). Under control conditions, this bursting in the two B67 neurons was infrequent, irregular, and asynchronous. However, bath application of the neuromodulator dopamine (DA) increased the duration, frequency, rhythmicity, and synchrony of B67 bursts. In the absence of DA, depolarization of B67 with injected current produced rhythmic bursting. Such depolarization-induced rhythmic burst activity in one B67, however, did not entrain its contralateral counterpart. Moreover, when both B67s were depolarized to potentials that produced rhythmic bursting, their synchrony was significantly lower than that produced by DA. In TTX, dopamine increased the DP duration, enhanced the amplitude of slow signaling between the two B67s, and increased DP synchrony. A potential source of dopaminergic signaling to B67 was identified as B65, an influential interneuron with bilateral buccal projections. Firing B65 produced bursts in the ipsilateral and contralateral B67s. Under conditions that attenuated polysynaptic activity, firing B65 evoked rapid excitatory postsynaptic potentials in B67 that were blocked by sulpiride, an antagonist of synaptic DA receptors in this system. Finally, firing a single B65 was capable of producing a prolonged period of rhythmic synchronous bursting of the paired B67s. It is proposed that modulatory dopaminergic signaling originating from B65 during consummatory behaviors can promote rhythmicity and bilateral synchrony in the paired B67 motor neurons.

Interspike interval relationship among flight muscle fibres in Drosophila

1980 ◽  
Vol 87 (1) ◽  
pp. 137-147 ◽  
Author(s):  
J. H. Koenig ◽  
K. Ikeda
Keyword(s):  
Interspike Interval ◽  
Flight Muscle ◽  
Motor Units ◽  
Muscle Fibres ◽  
Interspike Intervals ◽  
Neural Input ◽  
Flight Muscles ◽  
Bilateral Pair ◽  
Left And Right ◽  
Driving Source

Simultaneous intracellular recordings were made from the 10 motor units (12 fibres) comprising the bilateral pair of dorsal longitudinal flight muscles in Drosophila melanogaster while in stationary flight. The neural input which commonly drives these units was characterized by observing the influence which this input has on the interspike intervals of the various units. It was observed that the intervals of these units (both ipsilateral and contralateral), when considered collectively (that is, as a series of successively occurring intervals without regard for which unit represents which interval), fluctuate in a serially correlated manner. These interval fluctuations collectively define a fluctuation of complex waveform. The characteristics of this waveform suggest that two (or more) oscillating inputs are involved in commonly driving these units. In addition, a coupling in frequency and timing was observed between certain pairs of ipsilateral units, as well as between the units of one side relative to those of the other side. This coupling suggests that the neural pathway leading from the oscillating driving source might diverge, first to left and right sides, and then at a more peripheral level into three separate pathways, one leading to units 1 and 2, another to units 3 and 4, and a third to unit 5/6.

Presynaptic Inhibition at the Crustacean Neuromuscular Junction

Physiology ◽  
1986 ◽  
Vol 1 (2) ◽  
pp. 47-50
Author(s):  
FW Tse ◽  
HL Atwood
Keyword(s):  
Neuromuscular Junction ◽  
Presynaptic Inhibition ◽  
Single Unit ◽  
Crustacean Muscle ◽  
Graded Response ◽  
Whole Muscle

Many crustacean muscles are innervated by only one or a few excitatory axons that make the whole muscle act much as a single unit. Modulation of contraction and a graded response is achieved through inhibitory impulses, mostly at the presynaptic level. Crustacean muscle is therefore remarkably well suited for studies of presynaptic inhibition.

Sampling the Edible Muscle of the Swordfish (Xiphias gladius) for Total Mercury Analysis

1973 ◽  
Vol 30 (8) ◽  
pp. 1251-1252 ◽  
Author(s):  
H. C. Freeman ◽  
D. A. Horne
Keyword(s):  
Muscle Tissue ◽  
Total Mercury ◽  
Small Sample ◽  
Mercury Analysis ◽  
The Mean ◽  
Xiphias Gladius ◽  
Whole Muscle ◽  
Transverse Muscle

Total mercury was uniformly distributed in the edible muscle tissue of three swordfish, demonstrating that a small sample of muscle tissue taken from any region is representative of the whole muscle tissue when used for mercury analysis. The mean ± SE total mercury concentrations of longitudinal, depth, and transverse muscle sections from three swordfish were: 1.07 ± 0.04, 1.03 ± 0.04, and 0.99 ± 0.08 μg/g; 0.15 ± 0.01, 0.15 ± 0.03, and 0.14 ± 0.02 μg/g; and 0.55 ± 0.01, 0.61 ± 0.04, and 0.54 ± 0.06 μg/g, respectively.

Timing and Co-Ordination of Repetitive Bimanual Movements

1982 ◽  
Vol 34 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Alan M. Wing
Keyword(s):  
Single Unit ◽  
Time Sequence ◽  
Bimanual Movement ◽  
Timing Control ◽  
Motor Delay ◽  
Low Level ◽  
Bimanual Movements ◽  
Response Pair ◽  
Repetitive Movements ◽  
Left And Right

Similar timing of movements of the two hands has been observed when they are moved to separate targets (Kelso et al., 1979). This was taken as evidence for a low-level, co-ordinative structure that constrains the muscles of the arms to function as a single unit. An experiment to investigate the relation between voluntary timing control and timing in bimanual movement is described. The task required subjects to make repetitive movements of unequal difficulty for the two hands with the hands arriving synchronously at their respective targets. Estimates of the covariance of successive intervals defined by pairs of left-right responses (arrivals at the targets) were not negative. It is shown that this indicates that the motor delay between the timer regulating repetition rate and the overt responses has no component common to left- and right-responses. Although the co-ordinative structure is described as low-level, in terms of the time sequence of operations associated with each response pair, the data indicate its place is before, not after, the timer.

A separate local pattern-generating circuit controls the movements of each swimmeret in crayfish

1993 ◽  
Vol 70 (6) ◽  
pp. 2620-2631 ◽  
Author(s):  
D. Murchison ◽  
A. Chrachri ◽  
B. Mulloney
Keyword(s):  
Membrane Potential ◽  
Motor Neurons ◽  
Motor Pattern ◽  
Oscillatory Activity ◽  
Power Stroke ◽  
Return Stroke ◽  
Potential Oscillations ◽  
Segmental Ganglion ◽  
Left And Right ◽  
Membrane Potential Oscillations

1. Within an abdominal segment, the motor output from the segmental ganglion to the swimmerets consists of coordinated bursts of impulses in the separate pools of motor neurons innervating the left and right limbs. This coordinated motor pattern features alternating (out-of-phase) bursts of impulses in the power-stroke (PS) and return-stroke (RS) motor axons that innervate each swimmeret. PS bursts on both sides of each segment occur simultaneously (in-phase), and so RS bursts on both sides are also in-phase. 2. With all intersegmental connections interrupted, isolated abdominal ganglia were able to sustain the normal swimmeret motor pattern of alternating PS/RS activity that was bilaterally in-phase. 3. After an isolated ganglion was surgically bisected down the midline, the isolated hemiganglia that resulted could produce stable, coordinated alternation of PS and RS bursts. 4. The neuropeptide proctolin could induce rhythmic oscillations of membrane potential in swimmeret neurons when spiking was blocked by tetrodotoxin (TTX). For neurons within the same hemiganglion, these oscillations retained the same phase relations they displayed in controls, but the oscillations of neurons in different hemiganglia became uncoordinated. 5. Synaptic transmission between swimmeret neurons in the same hemiganglion persisted in the presence of TTX. Swimmeret interneurons that could activate the pattern-generating circuitry under control conditions could induce membrane-potential oscillations in swimmeret neurons of the same hemiganglion when TTX was present. 6. We conclude that a separate hemisegmental pattern-generating circuit controls the rhythmic PS and RS movements of each swimmeret. Each circuit is located in the same hemiganglion as the population of motor neurons that innervates the local swimmeret. Graded transmission is sufficient to coordinate the timing of oscillatory activity within the hemisegmental circuitry. These hemisegmental circuits are coupled by intersegmental and bilateral coordinating pathways that are dependent on sodium action potentials for their operation.

scholarly journals Heterogeneous Integration of Bilateral Whisker Signals by Neurons in Primary Somatosensory Cortex of Awake Rats

2005 ◽  
Vol 93 (5) ◽  
pp. 2966-2973 ◽  
Author(s):  
Michael C. Wiest ◽  
Nick Bentley ◽  
Miguel A. L. Nicolelis
Keyword(s):  
Somatosensory Cortex ◽  
Single Unit ◽  
Temporal Integration ◽  
Primary Somatosensory Cortex ◽  
Neural Responses ◽  
Hemispheric Processing ◽  
Tactile Stimuli ◽  
The Face ◽  
Left And Right ◽  
High Level

Bilateral single-unit recordings in primary somatosensory cortex (S1) of anesthetized rats have revealed substantial cross talk between cortical hemispheres, suggesting the possibility that behaviorally relevant bilateral integration could occur in S1. To determine the extent of bilateral neural responses in awake animals, we recorded S1 multi- and single-unit activity in head-immobilized rats while stimulating groups of 4 whiskers from the same column on both sides of the head. Results from these experiments confirm the widespread presence of single units responding to tactile stimuli on either side of the face in S1 of awake animals. Quantification of bilateral integration by multiunits revealed both facilitative and suppressive integration of bilateral inputs. Varying the interval between left and right whisker stimuli between 0 and 120 ms showed the temporal integration of bilateral stimuli to be dominated on average by suppression at intervals around 30 ms, in agreement with comparable recordings in anesthetized animals. Contrary to the anesthetized data, in the awake animals we observed a high level of heterogeneity of bilateral responses and a strong interaction between synchronous bilateral stimuli. The results challenge the traditional conception of highly segregated hemispheric processing channels in the rat S1 cortex, and support the hypothesis that callosal cross-projections between the two hemispheres mediate rats' known ability to integrate bilateral whisker signals.

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