Intracellular stimulation of sensory cells elicits swimming activity in the medicinal leech

1987 ◽  
Vol 160 (4) ◽  
pp. 447-457 ◽  
Author(s):  
Elizabeth A. Debski ◽  
W. Otto Friesen
Keyword(s):  
Medicinal Leech ◽  
Swimming Activity ◽  
Sensory Cells ◽  
Intracellular Stimulation ◽  
Stimulation Of

scholarly journals Habituation of swimming activity in the medicinal leech

1985 ◽  
Vol 116 (1) ◽  
pp. 169-188
Author(s):  
E. A. Debski ◽  
W. O. Friesen
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Body Wall ◽  
Spontaneous Recovery ◽  
Medicinal Leech ◽  
The Body ◽  
Swimming Activity ◽  
Stimulus Generalization ◽  
Anterior Segments ◽  
Stimulation Of

Tactile stimulation (light stroking) of a body wall flap attached to the ventral nerve cord of the medicinal leech evokes episodes of swimming activity. This swimming response undergoes habituation, involving changes in swim initiation and swim maintenance. Repeated stimulation of the body wall flap evoked swimming activity between three and 39 times before this response failed. During repetitive stimulation, the length of swim episodes decreased by about 50%. The number of swim episodes which could be elicited was not correlated with swim episode length. Following habituation, swim initiation showed significant spontaneous recovery, but swim episode length returned only to 60% of control values. In preparations where spontaneous recovery was followed by rehabituation, the number of swim episodes elicited declined with each habituation-recovery sequence. Additional stimulation immediately following habituation trials had a dual effect: recovery of the swimming response was delayed, but the lengths of swim episodes following spontaneous recovery were increased. Pinching the body wall flap immediately restored the swimming response in an habituated preparation. Swim initiation habituated more rapidly during stimulation of anterior body wall flaps than during stimulation of mid-body or posterior flaps. However, swim length was independent of this regional variation in swim responsiveness. The number of swim episodes elicited by stimulation of body wall flaps attached to posterior or anterior segments depended upon whether this segment was stimulated before or after other flaps. In contrast, in mid-body segments there was no evidence for such stimulus generalization. The lengths of swim episodes elicited during sequential stimulation of several body wall flaps were independent of the stimulation sequence. We propose that separate processes control swim initiation and swim maintenance. These processes must be repeated in most, if not all, of the segmental ganglia of the leech ventral nerve cord.

Role of central interneurons in habituation of swimming activity in the medicinal leech

1986 ◽  
Vol 55 (5) ◽  
pp. 977-994 ◽  
Author(s):  
E. A. Debski ◽  
W. O. Friesen
Keyword(s):  
Tactile Stimulation ◽  
Body Wall ◽  
The Body ◽  
Swimming Activity ◽  
Cycle Period ◽  
Direct Stimulation ◽  
Impulse Frequency ◽  
Neuronal Mechanisms ◽  
Intracellular Stimulation ◽  
Stimulation Of

Swimming activity evoked by light tactile stimulation of a body wall flap in dissected leech preparations undergoes habituation (5). In this study, we examine the activity of several interneurons (cell 204, cell 205, the S cell, and cell 208) during habituation trials to study further the neuronal mechanisms that mediate this decline in responsiveness. Light tactile stimulation of the leech body wall evoked initially a marked excitatory response in cell 204 homologs (segmental swim-initiating neurons) that preceded the initiation of swimming activity. This response decreased over the course of repeated stimulus trials; however, no marked decline in cell 204 activity accompanied the cessation of swim initiation. A similar activity pattern was observed in cell 205. Thus the habituation of swimming activity to stroking of the body wall is not due solely to reduced input to cell 204 and cell 205. The early activity of cell 204 was not correlated to the duration of subsequent swim episodes. However, the impulse frequency of cell 204 during swim episodes was negatively correlated to the period of swim cycles. This correlation between cell 204 activity and cycle period occurred both within individual episodes as well as between trials in a habituation series. Direct stimulation of cell 204 with current pulses evoked swimming activity reliably for an average of 72 trials. Therefore, habituation that results from stroking the body wall (which occurs after approximately 6 trials) is not mediated by plasticity in the connections between cell 204 and the swim oscillator. The S cell fired repeatedly in response to light tactile stimulation. This response declined with repeated trials. Intense intracellular stimulation of the S cell was sufficient to initiate swimming activity in some preparations. The magnitude and duration of the excitation required to initiate swimming by this means were far greater, however, than that which occurred during stroking the body wall. The response of cell 208 (a swim oscillator cell) to body wall stimulation during habituation trials was variable; usually an initial hyperpolarization was followed by some depolarization. No aspect of this response correlated with the onset of habituation. Our results are consistent with the idea that cell 204 and cell 205 are part of the pathway that mediates swimming activity in response to light tactile stimulation of the leech body wall, and that habituation occurs, in part, as the result of reduced sensory input to this cell.(ABSTRACT TRUNCATED AT 400 WORDS)

Activities of identified interneurons, motoneurons, and muscle fibers during fictive swimming in the lamprey and effects of reticulospinal and dorsal cell stimulation

1982 ◽  
Vol 47 (5) ◽  
pp. 948-960 ◽  
Author(s):  
J. T. Buchanan ◽  
A. H. Cohen
Keyword(s):  
Spinal Cord ◽  
Muscle Fibers ◽  
Membrane Potentials ◽  
Pattern Generation ◽  
The Body ◽  
Swimming Activity ◽  
Burst Intensity ◽  
Intracellular Stimulation ◽  
Dorsal Cells ◽  
Stimulation Of

1. Application of D-glutamate to the isolated spinal cord of the lamprey produces phasic activity in ventral roots, which is similar to that of the muscles of the intact swimming animal (5,18). Therefore, the isolated spinal cord may be used as a convenient model for the investigation of the generation of locomotor rhythms in a vertebrate. 2. Almost all slow muscle fibers exhibited excitatory junctional potentials (EJPs) during swimming activity. The number of EJPs per cycle increased with the intensity of ventral root (VR) bursting. Few twitch fibers were active, and these fired action potentials only during high intensities of VR bursts. 3. As was found by Russell and Wallen (25), myotomal motoneurons had oscillating membrane potentials during fictive swimming which, on the average, reached a peak depolarization in the middle of the VR burst (phi = 0.21 +/- 0.05; phi = 0 is defined as the onset of the VR burst, and the duration of the cycle is set equal to 1). Membrane potential oscillations in fin motoneurons were antiphasic to those of nearby myotomal motoneurons (peak depolarization phi = 0.68 +/- 0.05). 4. Lateral interneurons had oscillating membrane potentials in synchrony with those of myotomal motoneurons (peak depolarization phi = 0.21 +/- 0.10). Interneurons with axons projecting contralaterally and caudally (CC interneurons) had oscillating membrane potentials that peaked significantly earlier in the cycle (peak depolarization phi = 0.06 +/- 0.12). 5. Edge cells were only weakly modulated during fictive swimming. Their peak depolarizations occurred near the end of the VR burst (phi = 0.33 +/- 0.10). Most giant interneurons were not phasically modulated during fictive swimming. 6. Repetitive intracellular stimulation of Muller cells during fictive swimming generally evoked an increased burst intensity in ipsilateral VRs and a decreased burst intensity in contralateral VRs. The cells M3, B1, and B2 also produced increases or decreases in the frequency of VR bursts. Repetitive intracellular stimulation of sensory dorsal cells could also change the intensities and timing of VR bursts. 7. This study is an initial survey of lamprey spinal interneurons that participate in swimming activity. Lateral interneurons and CC interneurons are active during fictive swimming and probably help coordinate the undulations of the body, but their roles in pattern generation are not known. The central pattern generator is subject to modification by descending and sensory inputs.

Initiation, Maintenance and Modulation of Swimming in the Medicinal Leech by the Activity of a Single Neurone

1978 ◽  
Vol 77 (1) ◽  
pp. 71-88 ◽  
Author(s):  
JAMS C. WEEKS ◽  
WILLIAM B. KRISTAN JR.
Keyword(s):  
Horseradish Peroxidase ◽  
Nerve Cord ◽  
Tactile Stimulation ◽  
Medicinal Leech ◽  
Swimming Activity ◽  
Cycle Period ◽  
Impulse Frequency ◽  
Contraction Phase ◽  
Pattern Characteristic ◽  
Stimulation Of

A neurone (designated cell 204) has been identified in the segmental ganglia of the leech which, when stimulated intracellularly in isolated nerve cords, reliably initiates and maintains the neuronal activity pattern characteristic of swimming. In a minimally dissected leech, cell 204 activity results in normal swimming movements. Cell 204 is an unpaired, intersegmental interneurone which is present in most, if not all, of the segmental ganglia. Horseradish peroxidase injections indicate that cell 204 has extensive arborizations in its own ganglion and sends an axon both anteriorly and posteriorly via Faivre's Nerve. Cell 204 is normally quiescent, but during swimming activity becomes depolarized and produces impulse bursts in the ventral contraction phase of its own segment. Such activity is observed in every cell 204 in the nerve cord and is independent of the stimulus used to evoke the swimming episode. Activity in any cell 204 is sufficient for initiation and maintenance of swimming activity, whereas activity in any two of them is not necessary for swimming. During swimming activity, imposed increases in the impulse frequency of any cell 204 cause a decrease in the swim cycle period of the entire nerve cord. Tactile stimulation of the skin, which is an effective method of eliciting swimming episodes, excites cell 204. Our findings indicate that cell 204 may activate swimming in the intact leech.

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...

Identification of Mechanoafferent Neurons in Terrestrial Snail: Response Properties and Synaptic Connections

2002 ◽  
Vol 87 (5) ◽  
pp. 2364-2371 ◽  
Author(s):  
Aleksey Y. Malyshev ◽  
Pavel M. Balaban
Keyword(s):  
Avoidance Behavior ◽  
Receptive Fields ◽  
Dorsal Surface ◽  
Mechanical Stimulus ◽  
Terrestrial Snail ◽  
Mechanosensory Neurons ◽  
Intracellular Stimulation ◽  
Pleural Ganglion ◽  
Withdrawal Response ◽  
Stimulation Of

In this study, we describe the putative mechanosensory neurons, which are involved in the control of avoidance behavior of the terrestrial snail Helix lucorum. These neurons, which were termed pleural ventrolateral (PlVL) neurons, mediated part of the withdrawal response of the animal via activation of the withdrawal interneurons. Between 15 and 30 pleural mechanosensory neurons were located on the ventrolateral side of each pleural ganglion. Intracellular injection of neurobiotin revealed that all PlVL neurons sent their axons into the skin nerves. The PlVL neurons had no spontaneous spike activity or fast synaptic potentials. In the reduced “CNS-foot” preparations, mechanical stimulation of the skin covering the dorsal surface of the foot elicited spikes in the PlVL neurons without any noticeable prepotential activity. Mechanical stimulus-induced action potentials in these cells persisted in the presence of high-Mg2+/zero-Ca2+ saline. Each neuron had oval-shaped receptive field 5–20 mm in length located on the dorsal surface of the foot. Partial overlapping of the receptive fields of different neurons was observed. Intracellular stimulation of the PlVL neurons produced excitatory inputs to the parietal and pleural withdrawal interneurons, which are known to control avoidance behavior. The excitatory postsynaptic potentials (EPSPs) in the withdrawal interneurons were induced in 1:1 ratio to the PlVL neuron spikes, and spike-EPSP latency was short and highly stable. These EPSPs also persisted in the high-Mg2+/high-Ca2+ saline, suggesting monosynaptic connections. All these data suggest that PlVL cells were the primary mechanosensory neurons.

Organization of rat vibrissa motor cortex and adjacent areas according to cytoarchitectonics, microstimulation, and intracellular stimulation of identified cells

2004 ◽  
Vol 479 (4) ◽  
pp. 360-373 ◽  
Author(s):  
Michael Brecht ◽  
Andreas Krauss ◽  
Sajjad Muhammad ◽  
Laleh Sinai-Esfahani ◽  
Sebastiano Bellanca ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Intracellular Stimulation ◽  
Stimulation Of

The Input-Output Organization Of a Pair of Giant Neurones in the Mollusc, Anisodoris Nobilis (MACFARLAND)

1969 ◽  
Vol 51 (3) ◽  
pp. 615-634
Author(s):  
A. L. F. GORMAN ◽  
M. MIROLLI
Keyword(s):  
Synaptic Contact ◽  
Excitatory Input ◽  
Cell Functions ◽  
G Cells ◽  
G Cell ◽  
Intracellular Stimulation ◽  
Peripheral Cells ◽  
P Cells ◽  
Post Synaptic Potential ◽  
Stimulation Of

1. Each of the two gastro-oesophageal ganglia of the nudibranch mollusc, Anisodoris nobilis, contains one giant neurone (G cell) whose axon is directed toward the oesophagus in the gastro-oesophageal nerve. 2. In the absence of stimulation the G cells are normally silent. However, they receive inhibitory and excitatory synaptic inputs from more central ganglia and a predominantly excitatory input from the periphery. The inputs from the central ganglia are bilaterally distributed to both G cells, whereas the inputs from the periphery are limited to the ipsilateral G cell. 3. Intracellular stimulation shows that there is no interaction between the G cells, nor between the G cell and other cells in the same or contralateral gastro-oesophageal ganglia. 4. The axon of the G cell makes synaptic contact with a series of peripheral cells (P cells). In most P cells the post-synaptic potential elicited by intracellular stimulation of the G cell is constant in amplitude and latency and probably results from a unitary monosynaptic contact. Intracellular stimulation shows that the P cells are not connected to the G cell. 5. The P cells are inter-connected by low-resistance electrotonic junctions which allow slow potentials of either polarity to spread between cells. These junctions exist between distant as well as adjacent peripheral neurones. 6. Our results show that the G cell functions as a command interneurone for an aggregate of electrically interconnected peripheral neurones.

Reconfiguration of the Respiratory Network at the Onset of Locust Flight

1998 ◽  
Vol 80 (6) ◽  
pp. 3137-3147 ◽  
Author(s):  
Jan-Marino Ramirez
Keyword(s):  
Respiratory Activity ◽  
Respiratory Rhythm ◽  
Quiescent State ◽  
Suboesophageal Ganglion ◽  
Rhythm Generator ◽  
Locust Flight ◽  
Respiratory Network ◽  
Intracellular Stimulation ◽  
Tonic Stimulation ◽  
Stimulation Of

Ramirez, Jan-Marino. Reconfiguration of the respiratory network at the onset of locust flight. J. Neurophysiol. 80: 3137–3147, 1998. The respiratory interneurons 377, 378, 379 and 576 were identified within the suboesophageal ganglion (SOG) of the locust. Intracellular stimulation of these neurons excited the auxillary muscle 59 (M59), a muscle that is involved in the control of thoracic pumping in the locust. Like M59, these interneurons did not discharge during each respiratory cycle. However, the SOG interneurons were part of the respiratory rhythm generator because brief intracellular stimulation of these interneurons reset the respiratory rhythm and tonic stimulation increased the frequency of respiratory activity. At the onset of flight, the respiratory input into M59 and the SOG interneurons was suppressed, and these neurons discharged in phase with wing depression while abdominal pumping movements remained rhythmically active in phase with the slower respiratory rhythm (Fig. 9 ). The suppression of the respiratory input during flight seems to be mediated by the SOG interneuron 388. This interneuron was tonically activated during flight, and intracellular current injection suppressed the respiratory rhythmic input into M59. We conclude that the respiratory rhythm generator is reconfigured at flight onset. As part of the rhythm-generating network, the interneurons in the SOG are uncoupled from the rest of the respiratory network and discharge in phase with the flight rhythm. Because these SOG interneurons have a strong influence on thoracic pumping, we propose that this neural reconfiguration leads to a behavioral reconfiguration. In the quiescent state, thoracic pumping is coupled to the abdominal pumping movements and has auxillary functions. During flight, thoracic pumping is coupled to the flight rhythm and provides the major ventilatory movements during this energy-demanding locomotor behavior.

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