Synaptic Drive to Motoneurons During Fictive Swimming in the Developing Zebrafish

2001 ◽  
Vol 86 (1) ◽  
pp. 197-210 ◽  
Author(s):  
Robert R. Buss ◽  
Pierre Drapeau
Keyword(s):  
High Speed ◽  
Activity Patterns ◽  
Average Frequency ◽  
Synaptic Activity ◽  
Glutamate Antagonists ◽  
Correlated Activity ◽  
Cell Current ◽  
Burst Swimming ◽  
Tonic Pattern ◽  
Synaptic Drive

The development of swimming behavior and the correlated activity patterns recorded in motoneurons during fictive swimming in paralyzed zebrafish larvae were examined and compared. Larvae were studied from when they hatch (after 2 days) and are first capable of locomotion to when they are active swimmers capable of capturing prey (after 4 days). High-speed (500 Hz) video imaging was used to make a basic behavioral characterization of swimming. At hatching and up to day 3, the larvae swam infrequently and in an undirected fashion. They displayed sustained bursts of contractions (‘burst swimming’) at an average frequency of 60–70 Hz that lasted from several seconds to a minute in duration. By day 4 the swimming had matured to a more frequent and less erratic “beat-and-glide” mode, with slower (∼35 Hz) beats of contractions for ∼200 ms alternating with glides that were twice as long, lasting from just a few cycles to several minutes overall. In whole cell current-clamp recordings, motoneurons displayed similar excitatory synaptic activity and firing patterns, corresponding to either fictive burst swimming (day 2–3) or beat-and-glide swimming (day 4). The resting potentials were similar at all stages (about −70 mV) and the motoneurons were depolarized (to about −40 mV) with generally non-overshooting action potentials during fictive swimming. The frequency of sustained inputs during fictive burst swimming and of repetitive inputs during fictive beat-and glide swimming corresponded to the behavioral contraction patterns. Fictive swimming activity patterns were eliminated by application of glutamate antagonists (kynurenic acid or 6-cyano-7-nitroquinoxalene-2,3-dione anddl-2-amino-5-phosphonovaleric acid) and were modified but maintained in the presence of the glycinergic antagonist strychnine. The corresponding synaptic currents underlying the synaptic drive to motoneurons during fictive swimming could be isolated under voltage clamp and consisted of cationic [glutamatergic postsynaptic currents (PSCs)] and anionic inputs (glycinergic PSCs). Either sustained or interrupted patterns of PSCs were observed during fictive burst or beat-and-glide swimming, respectively. During beat-and-glide swimming, a tonic inward current and rhythmic glutamatergic PSCs (∼35 Hz) were observed. In contrast, bursts of glycinergic PSCs occurred at a higher frequency, resulting in a more tonic pattern with little evidence for synchronized activity. We conclude that a rhythmic glutamatergic synaptic drive underlies swimming and that a tonic, shunting glycinergic input acts to more closely match the membrane time constant to the fast synaptic drive.

The C-start escape response ofPolypterus senegalus: bilateral muscle activity and variation during stage 1 and 2

2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
High Speed ◽  
Wave Speed ◽  
Activity Patterns ◽  
Motor Pattern ◽  
The Body ◽  
Wide Range ◽  
Fast Start ◽  
Stage 1

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.

Multi-Objective Topological Optimization of Support Frame for High-Speed and Heavy-Load Triangle Track Wheel Based on Analytic Hierarchy Process

2018 ◽  
Author(s):  
Fenghe Wu ◽  
Zhaohua Wang ◽  
Yinxu Sun ◽  
Yulin Yang ◽  
Yongxin Li ◽  
...  
Keyword(s):  
Topology Optimization ◽  
High Speed ◽  
Working Condition ◽  
Average Frequency ◽  
Frequency Method ◽  
Analytic Hierarchy ◽  
Heavy Load ◽  
Multi Objective ◽  
Support Frame ◽  
Hierarchy Process

The high-speed, heavy-load and changeable triangle track wheel is a motion device that can carry out interchange between the track wheel and tire in an ordinary vehicle. The topology optimization for the support frame can reduce weight and improve the maneuverability of the vehicle. However, it is difficult to consider simultaneously its weight, stiffness and modal in the process of the structure optimization. Thus, a topology optimization method for multi-objective and multi-working-condition is proposed based on the AHP (analytic hierarchy process) and average frequency method. Firstly, considering the static multi-stiffness target and dynamic vibration frequency target, using the compromise programming method and average frequency method, the objective function of the multi-objective and multi-working-condition topology optimization is established. Then, based on the optimization target, design criteria and indexes, the lightweight hierarchical structure model of the support frame consisting of three levels and eight weight factors is established. Values of 8 weight coefficients of the multi-objective topology optimization are determined through solving the weight factor judgment matrix. Finally, considering the multi-working-condition, taking the minimum objective function of the static and dynamic characteristics as target, and the volume ratio is 50% as boundary, the mathematical model of the topology optimization is established. Simulation results show that the stiffness and strength of the support frame are improved respectively by 74.3% and 1.3% while its weight is reduced by 16.3%. This method also provides a new way to the lightweight design for other large, heavy and multi-condition equipment.

TAIL MUSCLE ACTIVITY PATTERNS IN WALKING AND FLYING PIGEONS (COLUMBA LIVIA)

1993 ◽  
Vol 176 (1) ◽  
pp. 55-76 ◽  
Author(s):  
S. M. Gatesy ◽  
K. P. Dial
Keyword(s):  
Muscle Activity ◽  
High Speed ◽  
Activity Patterns ◽  
Columba Livia ◽  
Trunk Muscles ◽  
Avian Evolution ◽  
Terrestrial Locomotion ◽  
Temporal Flexibility ◽  
High Speed Cinematography ◽  
Tail Muscle

The electrical activity of major caudal muscles of the pigeon (Columba livia) was recorded during five modes of aerial and terrestrial locomotion. Tail muscle electromyograms were correlated with movement using high-speed cinematography and compared to activity in selected muscles of the wings, legs and trunk. During walking, the pectoralis and most tail muscles are normally inactive, but levator muscle activity alternates with the striding legs. In flight, caudal muscles are phasically active with each wingbeat and undergo distinct changes in electromyographic pattern between liftoff, takeoff, slow level flapping and landing modes. The temporal flexibility of tail muscle activity differs significantly from the stereotypic timing of wing muscles in pigeons performing the same flight modes. These neural programs may represent different solutions to the control of flight surfaces in the rapidly oscillating wing and the relatively stationary caudal skeleton. Birds exhibit a novel alliance of tail and forelimb use during aerial locomotion. We suggest that there is evidence of anatomical and functional decoupling of the tail from adjacent hindlimb and trunk muscles during avian evolution to facilitate its specialization for rectricial control in flight.

Synaptic integration in an excitable dendritic tree

1993 ◽  
Vol 70 (3) ◽  
pp. 1086-1101 ◽  
Author(s):  
B. W. Mel
Keyword(s):  
Pyramidal Cell ◽  
Neuronal Response ◽  
Dendritic Tree ◽  
Pattern Discrimination ◽  
Synaptic Activity ◽  
Visual Neurons ◽  
Voltage Dependent ◽  
Sum Of Products ◽  
Very High ◽  
Synaptic Drive

1. Compartmental modeling experiments were carried out in an anatomically characterized neocortical pyramidal cell to study the integrative behavior of a complex dendritic tree containing active membrane mechanisms. Building on a previously presented hypothesis, this work provides further support for a novel principle of dendritic information processing that could underlie a capacity for nonlinear pattern discrimination and/or sensory processing within the dendritic trees of individual nerve cells. 2. It was previously demonstrated that when excitatory synaptic input to a pyramidal cell is dominated by voltage-dependent N-methyl-D-aspartate (NMDA)-type channels, the cell responds more strongly when synaptic drive is concentrated within several dendritic regions than when it is delivered diffusely across the dendritic arbor. This effect, called dendritic "cluster sensitivity," persisted under wide-ranging parameter variations and directly implicated the spatial ordering of afferent synaptic connections onto the dendritic tree as an important determinant of neuronal response selectivity. 3. In this work, the sensitivity of neocortical dendrites to spatially clustered synaptic drive has been further studied with fast sodium and slow calcium spiking mechanisms present in the dendritic membrane. Several spatial distributions of the dendritic spiking mechanisms were tested with and without NMDA synapses. Results of numerous simulations reveal that dendritic cluster sensitivity is a highly robust phenomenon in dendrites containing a sufficiency of excitatory membrane mechanisms and is only weakly dependent on their detailed spatial distribution, peak conductances, or kinetics. Factors that either work against or make irrelevant the dendritic cluster sensitivity effect include 1) very high-resistance spine necks, 2) very large synaptic conductances, 3) very high baseline levels of synaptic activity, and 4) large fluctuations in level of synaptic activity on short time scales. 4. The functional significance of dendritic cluster sensitivity has been previously discussed in the context of associative learning and memory. Here it is demonstrated that the dendritic tree of a cluster-sensitive neuron implements an approximative spatial correlation, or sum of products operation, such as that which could underlie nonlinear disparity tuning in binocular visual neurons.

Muscle coordination in cycling: effect of surface incline and posture

1998 ◽  
Vol 85 (3) ◽  
pp. 927-934 ◽  
Author(s):  
Li Li ◽  
Graham E. Caldwell
Keyword(s):  
Lower Extremity ◽  
High Speed ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extensors ◽  
Emg Activity ◽  
Muscle Coordination

The purpose of the present study was to examine the neuromuscular modifications of cyclists to changes in grade and posture. Eight subjects were tested on a computerized ergometer under three conditions with the same work rate (250 W): pedaling on the level while seated, 8% uphill while seated, and 8% uphill while standing (ST). High-speed video was taken in conjunction with surface electromyography (EMG) of six lower extremity muscles. Results showed that rectus femoris, gluteus maximus (GM), and tibialis anterior had greater EMG magnitude in the ST condition. GM, rectus femoris, and the vastus lateralis demonstrated activity over a greater portion of the crank cycle in the ST condition. The muscle activities of gastrocnemius and biceps femoris did not exhibit profound differences among conditions. Overall, the change of cycling grade alone from 0 to 8% did not induce a significant change in neuromuscular coordination. However, the postural change from seated to ST pedaling at 8% uphill grade was accompanied by increased and/or prolonged muscle activity of hip and knee extensors. The observed EMG activity patterns were discussed with respect to lower extremity joint moments. Monoarticular extensor muscles (GM, vastus lateralis) demonstrated greater modifications in activity patterns with the change in posture compared with their biarticular counterparts. Furthermore, muscle coordination among antagonist pairs of mono- and biarticular muscles was altered in the ST condition; this finding provides support for the notion that muscles within these antagonist pairs have different functions.

scholarly journals Phase-Amplitude Markers of Synchrony and Noise: A Resting-State and TMS-EEG Study of Schizophrenia

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Dominik Freche ◽  
Jodie Naim-Feil ◽  
Shmuel Hess ◽  
Avraham Peled ◽  
Alexander Grinshpoon ◽  
...  
Keyword(s):  
Resting State ◽  
Narrow Band ◽  
Signal To Noise Ratio ◽  
Phase Locking ◽  
Activity Patterns ◽  
Neuronal Populations ◽  
Correlated Activity ◽  
Amplitude Fluctuations ◽  
Phase Amplitude ◽  
External Stimuli

Abstract The electroencephalogram (EEG) of schizophrenia patients is known to exhibit a reduction of signal-to-noise ratio and of phase locking, as well as a facilitation of excitability, in response to a variety of external stimuli. Here, we demonstrate these effects in transcranial magnetic stimulation (TMS)-evoked potentials and in the resting-state EEG. To ensure veracity, we used 3 weekly sessions and analyzed both resting-state and TMS-EEG data. For the TMS responses, our analysis verifies known results. For the resting state, we introduce the methodology of mean-normalized variation to the EEG analysis (quartile-based coefficient of variation), which allows for a comparison of narrow-band EEG amplitude fluctuations to narrow-band Gaussian noise. This reveals that amplitude fluctuations in the delta, alpha, and beta bands of healthy controls are different from those in schizophrenia patients, on time scales of tens of seconds. We conclude that the EEG-measured cortical activity patterns of schizophrenia patients are more similar to noise, both in alpha- and beta-resting state and in TMS responses. Our results suggest that the ability of neuronal populations to form stable, locally, and temporally correlated activity is reduced in schizophrenia, a conclusion, that is, in accord with previous experiments on TMS-EEG and on resting-state EEG.

Amino acid-mediated regulation of spontaneous synaptic activity patterns in the rat basolateral amygdala

1996 ◽  
Vol 76 (3) ◽  
pp. 1958-1967 ◽  
Author(s):  
B. N. Smith ◽  
F. E. Dudek
Keyword(s):  
Receptor Antagonist ◽  
Time Constant ◽  
Decay Time ◽  
Basolateral Amygdala ◽  
Activity Patterns ◽  
Nmda Receptor Antagonist ◽  
Synaptic Activity ◽  
Gamma Aminobutyric Acid ◽  
Postsynaptic Currents ◽  
Local Circuitry

1. Spontaneous postsynaptic currents (PSCs) were examined in the basolateral amygdala using whole cell patch-clamp recordings in coronal slices (400 microns) from young rats (postnatal day 6-25). In most cells, Cs+ was used in the electrode to block putative voltage-activated K(+)-currents. Both inward and outward spontaneous PSCs were examined. 2. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonist, 6,7-nitroquinoxaline-2,3-dione (DNQX) blocked all inward PSCs, which reversed near 0 mV. They therefore were considered to be glutamate-mediated excitatory postsynaptic currents (EPSCs). Averaged EPSCs had a rapid 10-90% rise time (1.0 +/- 0.04 ms; mean +/- SD) and monoexponential decay (tau = 3.6 +/- 0.18 ms) at potentials negative to about -50 mV. Above this potential, a second, slower time constant (tau 1 = 41 +/- 4.5 ms at -30 mV), accounting for 10-30% of the total EPSC amplitude was resolved in 8 of 10 cells examined. The slower decay time constant was sensitive to the N-methyl-D-aspartate (NMDA)-receptor antagonist, DL-2-amino-5-phosphonovaleric acid (AP5) and therefore probably was due to activation of NMDA receptors. 3. The gamma-aminobutyric acid-A (GABAA) antagonist, bicuculline, blocked all outward PSCs, which reversed near -70 mV. They therefore were considered to be GABA-mediated inhibitory postsynaptic currents (IPSCs). Averaged IPSCs displayed rapid 10-90% rise times (1.0 +/- 0.03 ms) and monoexponential decay time constants (tau = 5.16 +/- 0.14 ms). 4. Tetrodotoxin (TTX) reduced the frequency of synaptic activity and eliminated the largest PSCs, thus reducing slightly the mean EPSC and IPSC amplitude. Most cells received bursts of spontaneous IPSCs and/or EPSCs (30-68 Hz lasting 0.5-6 s), which were also TTX sensitive. The TTX data suggest that the somata of the cells responsible for the largest PSCs and the PSC bursts were contained within the slice. 5. In addition to blocking EPSCs, DNQX blocked the bursts of IPSCs, but not all individual IPSCs. DNQX had similar effects as TTX on the bursts and frequency of the IPSCs. 6. Bicuculline enhanced spontaneous EPSC frequency (231 +/- 90%). Much of this increase was due to an increase in the bursts of EPSCs. 7. Neurons in the basolateral amygdala therefore appear to receive both excitatory (glutamatergic) and inhibitory (GABAergic) synaptic input from local neurons. The activity of the neurons responsible for these inputs are themselves largely regulated by glutamatergic and GABAergic inputs. The relevance of this local circuitry to seizures and epilepsy is discussed briefly.

scholarly journals Self-organization of cortical areas in the development and evolution of neocortex

2020 ◽  
Vol 117 (46) ◽  
pp. 29212-29220 ◽  
Author(s):  
Nabil Imam ◽  
Barbara L. Finlay
Keyword(s):  
Activity Patterns ◽  
Basic Mechanism ◽  
Physical Parameters ◽  
Network Growth ◽  
Cortical Areas ◽  
Mirror Reversal ◽  
Correlated Activity ◽  
The Matrix ◽  
Characteristic Features ◽  
Development And Evolution

While the mechanisms generating the topographic organization of primary sensory areas in the neocortex are well studied, what generates secondary cortical areas is virtually unknown. Using physical parameters representing primary and secondary visual areas as they vary from monkey to mouse, we derived a network growth model to explore if characteristic features of secondary areas could be produced from correlated activity patterns arising from V1 alone. We found that V1 seeded variable numbers of secondary areas based on activity-driven wiring and wiring-density limits within the cortical surface. These secondary areas exhibited the typical mirror-reversal of map topography on cortical area boundaries and progressive reduction of the area and spatial resolution of each new map on the caudorostral axis. Activity-based map formation may be the basic mechanism that establishes the matrix of topographically organized cortical areas available for later computational specialization.

Activation of Embryonic Red and White Muscle Fibers During Fictive Swimming in the Developing Zebrafish

2002 ◽  
Vol 87 (3) ◽  
pp. 1244-1251 ◽  
Author(s):  
Robert R. Buss ◽  
Pierre Drapeau
Keyword(s):  
Muscle Activation ◽  
White Muscle ◽  
Developmental Stages ◽  
Muscle Fibers ◽  
Synaptic Activity ◽  
Body Movements ◽  
Early Developmental ◽  
Whole Cell Recordings ◽  
Myotomal Muscle ◽  
Synaptic Drive

Sub-threshold, motoneuron-evoked synaptic activity was observed in zebrafish embryonic red (ER) and white (EW) muscle fibers paralyzed with a dose of d-tubocurarine insufficient to abolish synaptic activity to determine whether muscle activation was coordinated to produce the undulating body movements required for locomotion. Paired whole-cell recordings revealed a synaptic drive that alternated between ipsilateral and contralateral myotomes and exhibited a rostral-caudal delay in timing appropriate for swimming. Both ER and EW muscle were activated during fictive swimming. However, at the fastest fictive swimming rates, ER fibers were de-recruited, whereas they could be active in isolation of EW fibers at the slowest fictive swimming rates. Prior to hatching, fictive swimming was preceded by a lower frequency, more robust and rhythmic synaptic drive resembling the “coiling” behavior of fish embryos. The motor activity observed in paralyzed zebrafish closely resembled the swimming and coiling behaviors observed in these developing fishes. At the early developmental stages examined in this study, myotomal muscle recruitment and coordination were similar to that observed in adult fishes during swimming. Our results indicate that the patterned activation of myotomal muscle is set from the onset of development.

scholarly journals Activity Patterns of Interneurons in the Caudal Ganglion of the Crayfish

1960 ◽  
Vol 43 (3) ◽  
pp. 655-670 ◽  
Author(s):  
Donald Kennedy ◽  
James B. Preston
Keyword(s):  
Activity Patterns ◽  
Receptive Fields ◽  
Synaptic Activity ◽  
Constant Frequency ◽  
Natural Stimuli ◽  
Synaptic Potentials ◽  
Tactile Stimuli ◽  
Afferent Inputs ◽  
Degree Of Convergence ◽  
High Degree

Responses of ascending interneurons from the caudal ganglion of crayfish have been recorded from single units isolated by dissection from the ventral nerve cord; in addition, post-synaptic activity within the ganglionic neuropile has been studied with intracellular micropipettes. The following classes of interneurons have been found: (1) Large fibers which responded to tactile stimuli with single spikes or phasic bursts. These units usually showed broad receptive fields; and spontaneous activity, when present, showed transitory depressions following responses to natural stimuli. (2) A group of fibers, including many small ones, which responded to proprioceptive stimuli with tonic discharges of varying adaptation rate. (3) Interneurons which showed responses both to tactile stimuli and to activation of the sixth ganglion photoreceptor; and (4) units with constant frequency discharges which were unmodifiable by any of the above afferent inputs. Intracellular recording of post-synaptic activity has shown (1) that widely graded excitatory post-synaptic potentials occur; (2) that multiple firing from single synaptic potentials is usual; (3) that the post-synaptic responses to phasic natural stimuli and to electrical stimulation of ganglionic roots are similar. The existence of widely graded post-synaptic potentials and of extensive receptive fields suggests a high degree of convergence from primary afferents to interneurons. The activation of such post-synaptic units involves integrative synaptic transfer, without 1:1 correspondence between pre- and post-fiber activity.

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