scholarly journals Giant fiber activation of an intrinsic muscle in the mesothoracic leg of Drosophila melanogaster

1993 ◽  
Vol 177 (1) ◽  
pp. 149-167 ◽  
Author(s):  
J. R. Trimarchi ◽  
A. M. Schneiderman
Keyword(s):  
Drosophila Melanogaster ◽  
Electrical Stimulation ◽  
Motor Neuron ◽  
Cell Body ◽  
Escape Response ◽  
Large Cell ◽  
Giant Fiber ◽  
Leg Muscle ◽  
Muscle Responses ◽  
Stimulation Of

Cinematographic analysis reveals that an important component of the light-elicited escape response of Drosophila melanogaster is the extension of the femur-tibia joint of the mesothoracic leg. During the jumping phase of the response, this extension works synergistically with extension of the femur. Femur extension is generated by contraction of the tergotrochanteral muscle (TTM), one of four previously described escape response muscles. Femur-tibia joint extension in the mesothoracic leg has been thought to be controlled by contraction of the tibial levator (TLM), an intrinsic leg muscle. We investigated the activation of the TLM during the escape response. Electrical stimulation of the giant fiber interneuron that mediates the escape response results in activation of the TLM with a latency of 1.46 +/− 0.02 ms. The TLM is innervated by a motor neuron (TLMn) with a large cell body in the mesothoracic ganglion. The TLMn has extensive arborizations in the lateral mesothoracic leg neuromere and has a prominent medially directed neurite. To investigate possible presynaptic inputs activating the TLMn during the escape response, we analyzed the muscle responses of two mutants, giant fiber A1 and bendless. Our analysis suggests that the TLMn is activated by a novel pathway.

scholarly journals Intraoperative monitoring for tethered cord surgery: an update

2004 ◽  
Vol 16 (2) ◽  
pp. E8 ◽  
Author(s):  
Karl F. Kothbauer ◽  
Klaus Novak
Keyword(s):  
Electrical Stimulation ◽  
Anal Sphincter ◽  
External Anal Sphincter ◽  
Continuous Monitoring ◽  
Pudendal Nerve ◽  
Tethered Cord ◽  
Sensory Pathways ◽  
Functional Integrity ◽  
Muscle Responses ◽  
Stimulation Of

Object Intraoperative neurophysiological recording techniques have found increasing use in neurosurgical practice. The development of new recording techniques feasible while the patient receives a general anesthetic have improved their practical use in a similar way to the use of digital recording, documentation, and video technology. This review intends to provide an update on the techniques used and their validity. Methods Two principal methods are used for intraoperative neurophysiological testing during tethered cord release. Mapping identifies functional neural structures, namely nerve roots, and monitoring provides continuous information on the functional integrity of motor and sensory pathways as well as reflex circuitry. Mapping is performed mostly by using direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle. Sensory mapping can also be performed with peripheral stimulation and recording within the surgical site. Monitoring of the motor system is achieved with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from limb muscles and the external anal sphincter. The presence or absence of muscle responses are the parameters monitored. Sensory potentials evoked by tibial or pudendal nerve stimulation and recorded from the dorsal columns via an epidurally inserted electrode and/or from the scalp as cortical responses are used to access the integrity of sensory pathways. Amplitudes and latencies of these responses are then interpreted. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording of muscle responses in the external anal sphincter, is used for continuous monitoring of the reflex circuitry. Presence or absence of this response is the pertinent parameter that is monitored. Conclusions Intraoperative neurophysiology provides a wide and reliable set of techniques for intraoperative identification of neural structures and continuous monitoring of their functional integrity.

Magnetically Evoked Facial Nerve Potential

1989 ◽  
Vol 100 (4) ◽  
pp. 345-347 ◽  
Author(s):  
Ian M. Windmill ◽  
Serge A. Martinez ◽  
Christopher B. Shields ◽  
Markku Paloheimo
Keyword(s):  
Electrical Stimulation ◽  
Facial Nerve ◽  
Nerve Stimulation ◽  
Magnetic Stimulation ◽  
Electrical Current ◽  
Facial Muscle ◽  
Facial Nerve Stimulation ◽  
Muscle Responses ◽  
Stimulation Of

Facial nerve stimulation by electrical current is painful and tends to discourage serial studies. Transcutaneous magnetic stimulation of the facial nerve is painless, easily reproducible, and elicits facial muscle responses identical to electrical stimulation.

scholarly journals A computational model of the escape response latency in the Giant Fiber System of Drosophila melanogaster

2018 ◽  
Author(s):  
Hrvoje Augustin ◽  
Asaph Zylbertal ◽  
Linda Partridge
Keyword(s):  
Drosophila Melanogaster ◽  
Computational Model ◽  
Response Latency ◽  
Escape Response ◽  
Membrane Conductance ◽  
Signal Propagation ◽  
Neuronal Membrane ◽  
Giant Fiber ◽  
Fiber System ◽  
Giant Fiber System

ABSTRACTThe Giant Fiber System (GFS) is a multi-component neuronal pathway mediating rapid escape response in the adult fruit-fly Drosophila melanogaster, usually in the face of a threatening visual stimulus. Two branches of the circuit promote the response by stimulating an escape jump followed by flight initiation. Our recent work demonstrated an age-associated decline in the speed of signal propagation through the circuit, measured as the stimulus-to-muscle depolarization response latency. The decline is likely due to the diminishing number of interneuronal gap junctions in the GFS of ageing flies. In this work, we presented a realistic conductance-based, computational model of the GFS that recapitulates our experimental results and identifies some of the critical anatomical and physiological components governing the circuit’s response latency. According to our model, anatomical properties of the GFS neurons have a stronger impact on the transmission than neuronal membrane conductance densities. The model provides testable predictions for the effect of experimental interventions on the circuit’s performance in young and ageing flies.

Descending control of nonspiking local interneurons in the terminal abdominal ganglion of the crayfish

1994 ◽  
Vol 72 (1) ◽  
pp. 235-247 ◽  
Author(s):  
H. Namba ◽  
T. Nagayama ◽  
M. Hisada
Keyword(s):  
Electrical Stimulation ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Sensory Stimulation ◽  
Full Extension ◽  
Sensory Inputs ◽  
Reflex Pathways ◽  
Local Interneurons ◽  
Parallel Connections ◽  
Stimulation Of

1. Electrical stimulation of afferents innervating an exopodite causes a closing pattern of activity in the uropod motor neurons. In this reflex two distinct types of nonspiking local interneurons, posterolateral (PL) and anterolateral (AL) types, classified by their gross morphology and somata location, receive sensory inputs and control the motor output to the uropod. 2. In the sensory-motor pathway, the PL and AL nonspiking local interneurons formed opposing and parallel connections with uropod motor neurons. For example, the PL interneurons that excited the closer, reductor motor neuron by injecting depolarizing current received depolarizing postsynaptic potentials (PSPs), whereas the AL interneurons of the same output received hyperpolarizing PSPs. The PL interneurons that inhibited the reductor motor neuron received hyperpolarizing PSPs, whereas the AL interneurons of the similar output received depolarizing PSPs. 3. During fictive abdominal extension, induced by electrical stimulation of extension-evoking command fibers in the second-third abdominal connective, the uropod motor neurons show an opening pattern of activity that is opposite to the pattern elicited by sensory stimulation. Furthermore, sensory stimulation during ongoing fictive abdominal extension has little effect on the uropod motor neurons. 4. Except for the nonspiking local interneurons, the majority of other local circuit neurons, i.e., spiking local interneurons and ascending interneurons, are not driven by the descending inputs during abdominal extension. 5. A comparison of the responses of the nonspiking local interneurons to both sensory and descending inputs reveals that the majority of nonspiking local interneurons receive both inputs, but the sign of response to each is frequently opposite. This study suggests that the degree of excitability of two distinct types of PL and AL nonspiking local interneurons induced by sensory inputs changes depending on whether the crayfish is in a resting posture or is active with full extension of the abdomen. Ongoing abdominal extension in swimming or defensive crayfish would shift the gain of reflex pathways through the PL and AL interneurons, and motor response resulting from sensory inputs would be modulated.

Modulation of Laryngeal Responses to Superior Laryngeal Nerve Stimulation by Volitional Swallowing in Awake Humans

2000 ◽  
Vol 83 (3) ◽  
pp. 1264-1272 ◽  
Author(s):  
Julie M. Barkmeier ◽  
Steve Bielamowicz ◽  
Naoya Takeda ◽  
Christy L. Ludlow
Keyword(s):  
Electrical Stimulation ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Internal Branch ◽  
Increased Risk ◽  
Main Effect ◽  
Laryngeal Vestibule ◽  
Electrical Stimuli ◽  
Muscle Responses ◽  
Stimulation Of

Laryngeal sensori-motor closure reflexes are important for the protection of the airway and prevent the entry of foreign substances into the trachea and lungs. The purpose of this study was to determine how such reflexes might be modulated during volitional swallowing in awake humans, when persons are at risk of entry of food or liquids into the airway. The frequency and the amplitude of laryngeal adductor responses evoked by electrical stimulation of the internal branch of the superior laryngeal nerve (ISLN) were studied during different phases of volitional swallowing. Subjects swallowed water on command while electrical stimuli were presented to the ISLN at various intervals from 500 ms to 5 s following the command. Laryngeal adductor responses to unilateral ISLN stimulation were recorded bilaterally in the thyroarytenoid muscles using hooked wire electrodes. Early ipsilateral R1 responses occurred at 17 ms, and later bilateral R2 began around 65 ms. The muscle responses to stimuli occurring during expiration without swallowing were quantified as control trials. Responses to stimulation presented before swallowing, during the swallow, within 3 s after swallowing, and between 3 and 5 s after a swallow were measured. The frequency and amplitude of three responses (ipsilateral R1 and bilateral R2) relative to the control responses were compared across the different phases relative to the occurrence of swallowing. Results demonstrated that a reduction occurred in both the frequency and amplitude of the later bilateral R2 laryngeal responses to electrical stimulation for up to 3 s after swallowing ( P= 0.005). The amplitude and frequency of ipsilateral R1 laryngeal responses, however, did not show a significant main effect following the swallow ( P = 0.28), although there was a significant time by measure interaction ( P = 0.006) related to reduced R1 response amplitude up to 3 s after swallowing ( P = 0.021). Therefore, the more rapid and shorter unilateral R1 responses continued to provide some, albeit reduced, laryngeal protective functions after swallowing, whereas the later bilateral R2 responses were suppressed both in occurrence and amplitude for up to 3 s after swallowing. The results suggest that R2 laryngeal adductor responses are suppressed following swallowing when residues may remain in the laryngeal vestibule putting persons at increased risk for the entry of foreign substances into the airway.

A visually elicited escape response in the fly that does not use the giant fiber pathway

1994 ◽  
Vol 11 (6) ◽  
pp. 1149-1161 ◽  
Author(s):  
Mats H. Holmqvist
Keyword(s):  
Escape Response ◽  
Compound Eye ◽  
Visual Stimulation ◽  
Giant Fiber ◽  
Single Spike ◽  
Freely Behaving ◽  
Freely Moving ◽  
Escape Responses ◽  
The Brain ◽  
Stimulation Of

AbstractA housefly elicits an escape in response to an approaching target (Holmqvist & Srinivasan, 1991). This study tests if the giant fiber pathway, which mediates a light-off escape response in a fruitfly (Wyman et al., 1985), also mediates escape to an approaching target in a housefly. Visual stimuli simulating an approaching or receding dark disk were presented to houseflies, Musca domestica, in both behavioral and physiological experiments. Freely behaving flies escaped in response to an expanding dark disk but not to a contracting dark disk. In restrained flies, the giant fiber, here called the giant descending neuron (GDN), was recorded from intracellularly and the tergotrochanteral muscle (TTM), which provides the main thrust in an escape jump, was recorded from extracellularly. During electrical stimulation of the brain, by means of stimulating electrodes inserted into the ventral part of each compound eye, a single spike in the GDN drives the TTM. However, when the TTM responds to visual stimulation that elicits an escape response in a behaving fly, the GDN shows no activity. Similarly to the behavioral results, the TTM of restrained flies showed muscle potentials in response to an expanding dark disk, but not to a contracting disk. However, freely moving flies elicit escapes more than 100 ms on average before the first TTM spike, suggesting that this type of escape does not start with a jump powered by the TTM. In conclusion, this visually evoked escape response in the housefly is not likely to be mediated by the giant fiber pathway. The findings suggest that there exist at least two pathways mediating visually evoked escape responses in flies.

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