Motor innervation within supernumerary legs of cockroaches

1975 ◽  
Vol 63 (2) ◽  
pp. 497-503
Author(s):  
J. Westin ◽  
J. M. Camhi

1. Clusters of legs having prothoracic and metathoracic origins were grown from the metathoracic coxa of the cockroach. 2. Or occasionally two, of the three major nerves innervating the cockroach leg. 3. Stimulation of a particular leg nerve (no. 3, 5 or 6) evoked movement at the same joints and in the same directions in a leg having only one nerve as in a normal leg. 4. Stimulation of a particular metathoracic nerve generally produced the same movements in a prothoracic leg transplanted to the metathoracic site as it did in a regenerated or intact metathoracic leg.

1997 ◽  
Vol 106 (7) ◽  
pp. 594-598 ◽  
Author(s):  
Sina Nasri ◽  
Joel A. Sercarz ◽  
Pouneh Beizai ◽  
Young-Mo Kim ◽  
Ming Ye ◽  
...  

The neuroanatomy of the larynx was explored in seven dogs to assess whether there is motor innervation to the thyroarytenoid (TA) muscle from the external division of the superior laryngeal nerve (ExSLN). In 3 animals, such innervation was identified. Electrical stimulation of microelectrodes applied to the ExSLN resulted in contraction of the TA muscle, indicating that this nerve is motor in function. This was confirmed by electromyographic recordings from the TA muscle. Videolaryngostroboscopy revealed improvement in vocal fold vibration following stimulation of the ExSLN compared to without it. Previously, the TA muscle was thought to be innervated solely by the recurrent laryngeal nerve. This additional pathway from the ExSLN to the TA muscle may have important clinical implications in the treatment of neurologic laryngeal disorders such as adductor spasmodic dysphonia.


1976 ◽  
Vol 231 (4) ◽  
pp. 1272-1278 ◽  
Author(s):  
JL Morris

The sphincter pupillae muscle cells in the iris of Bufo marinus contract autonomously in response to bright light, causing a rapid constriction of the pupil. A strong sympathetic beta-adrenergic inhibition of the sphincter pupillae is apparent in this species. The inhibitory fibers can originate in the second, third, or fourth ventral spinal roots. No strong, consistent excitatory innervation of the toad iris was detected, even by transmural stimulation of the isolated iris. Pupilloconstriction occasionally resulted from stimulation of the 3rd or 5th cranial nerves, but the effect was small (10-20% of the magnitude of the light response) and inconsistent. It therefore appears that the toad must regulate pupillary diameter by balancing myogenic contraction, in direct response to light, against neurogenic (sympathetic) relaxation of the sphincter pupillae.


2017 ◽  
Vol 126 (3) ◽  
pp. 913-921 ◽  
Author(s):  
Andrei Brînzeu ◽  
Marc Sindou

OBJECTIVE Classically the 11th cranial nerve (CN XI, or accessory nerve) is described as having a cranial and a spinal root, the latter arising from the upper segments of the spinal cord through a number of very fine rootlets. According to classical knowledge, the cranial root gives motor innervation to the vocal cords, whereas the spinal root provides the motor innervation of the sternocleidomastoid muscle (SCM) and of the upper portions of the trapezius muscle (TZ). The specific function of each of the rootlets of the spinal component is not well known. Therefore the authors aimed to map, using intraoperative direct electrical stimulation and electromyographic (EMG) recordings, the innervation territory of these rootlets in relation to their exit level from the CNS. METHODS Forty-nine patients undergoing surgery with intradural exposure at the craniocervical junction were enrolled in the study. The EMG recordings included the sternal and clavicular parts of the SCM (SCM-S and SCM-C), the superior and middle parts of the TZ (TZ-S and TZ-M), and whenever possible the vocal cords. The main trunk of CN XI, its roots (both cranial and spinal), and when possible the fine cervical rootlets, were stimulated at predetermined locations, from the jugular foramen down to the lowest cervical level exposed. The EMG responses were collected, and a map of the responses was drawn up. RESULTS Monitoring and stimulation of the spinal root were performed in all cases, whereas for the cranial root this was possible in only 19 cases. A total of 262 stimulation sites were explored: 70 at the common trunk of the nerve, 19 at the cranial root, 136 at various levels on the spinal root, and 37 at the cervical rootlets. A vocal cord response was obtained by stimulation of the cranial root in 84.2% (16/19); absence of response was considered to have a technical origin. In no case did the vocal cords respond to the stimulation of the spinal root or rootlets. Stimulation of the cervical rootlets yielded responses that differed according to the level of stimulation: at C-1 the SCM-S responded 95.8% of the time (23/24); at C-2 the SCM-C responded 90.0% of the time (9/10); at C-3 the TZ-S responded 66.6% of the time (2/3); and below that level only the TZ-M responded. The spinal root stimulated at its various levels responded accordingly. CONCLUSIONS The function of each of the rootlets of CN XI appears to be specific. The cranial root contributes, independently of the spinal root, to the innervation of the vocal cords, which makes it a specific entity. The spinal root innervates the SCM and TZ with a cranio-caudal motor organization of its cervical rootlets.


1938 ◽  
Vol 22 (2) ◽  
pp. 193-206 ◽  
Author(s):  
W. R. Bergren ◽  
C. A. G. Wiersma

An investigation has been made of the phosphate and lactic acid changes in the adductor muscle of the cheliped of the crayfish Cambarus clarkii upon stimulation of the isolated axons for the fast and slow contractions at determined frequencies. The data obtained point to the following conclusions: 1. When the mechanical effects of the two types of contraction are the same, the chemical changes are of the same order. If the mechanical effects are different, the chemical changes likewise are not equivalent. This is especially to be seen in the case of stimulation at 50 shocks per second: a slowly rising, long continued, strong slow contraction takes place with no apparent change in the phosphate content; a quickly rising fast contraction occurs with a large increase in the phosphate. 2. Since equivalent chemical changes accompany equivalent mechanical action, the two types of contraction do not differ in the essential mechanism of the chemical changes involved, and only one type of contractile substance is present. 3. Even when a contraction has taken place to the maximum extent obtainable, only enough phosphate is found to correspond to one-fifth to one-third of the available phosphagen.


1997 ◽  
Vol 83 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Carol Smith Hammond ◽  
Paul W. Davenport ◽  
Alastair Hutchison ◽  
Randall A. Otto

Hammond, Carol Smith, Paul W. Davenport, Alastair Hutchison, and Randall A. Otto. Motor innervation of the cricopharyngeus muscle by the recurrent laryngeal nerve. J. Appl. Physiol. 83(1): 89–94, 1997.—Patients with recurrent laryngeal nerve (RLN) paresis demonstrate impaired function of laryngeal muscles and swallowing. The cricopharyngeus muscle (CPM) is a major component of the upper esophageal sphincter. It was hypothesized that the RLN innervates this muscle. A nerve branch leading from the RLN to the CPM was found in adult sheep by anatomic dissection. Electrical stimulation of the RLN elicited a muscle action potential recorded by electrodes placed in the ipsilateral CPM. Swallowing was investigated by mechanical stimulation of oropharynx pre- and postsectioning of the RLN. Severing of the RLN resulted in a loss of the early phases of swallow-related CPM electromyographic activity; however, late-phase CPM electromyographic activity persisted. The RLN provides motor innervation of the CPM, which also has innervation from the pharyngeal plexus.


1939 ◽  
Vol 16 (4) ◽  
pp. 398-402
Author(s):  
A. VAN HARREVELD

The crustacean muscle is extremely sensitive to mechanical injury. This is due to the fact that the muscle fibres are innervated by a feltwork of nerve fibres which surrounds them. Apparéntly, there is a lack of a muscular conduction process in these muscles. Contractions have been observed in the same muscle fibres during stimulation of the axon for the fast contraction as well as during stimulation of the fibre for the slow contraction.


In a previous paper on concurrent mechanical and electrical responses to stimulation of the motor cortex in the monkey (3), we reported the transmission of stimulus rates of 18 to 68 a second. We were unable at that time to carry the enquiry farther owing to lack of means of obtaining higher variable rates of stimulus. Since then we have improvised apparatus giving higher rates and have been able to continue this part of our investigation, using rates up to 290 a second. The object was to determine the upper limit of rate of stimulus which would be transmitted directly to the muscle. We have also been able to collect much information as to the effects of low rates of stimulus, latent periods and the nature of cortical motor innervation as a whole. In the course of the work six further monkeys were used, all small Macacus Rhesus . Of these two had also been used for experiments having no bearing on the present subject and not of a nature to affect our results. The animals were prepared as previously described and the muscles from which records were obtained were M. brachialis anticus , M. flexor profundus digitorum , M. extensor carpi radialis and M. triceps brachii .


1966 ◽  
Vol 44 (3) ◽  
pp. 589-605 ◽  
Author(s):  
C. H. FRASER ROWELL

1. A method for recording nervous activity from the nervous system of the arm of Octopus is given. Difficulties of mobility and vasoconstriction are reduced by brain lesions. 2. Three areas were recorded: afferent sucker nerves, axial ganglia, and the dorsolateral axial cord. 3. The sucker nerves include large tactile units corresponding to discrete parts of the sucker rim. These are fast-adapting, phasic, not very sensitive, and are located in the area of motor innervation of the same nerve. 4. Two types of interneurones were found in the axial ganglia, responding to either tactile stimulation of their own or neighbouring suckers, or to proprioceptive input from their own sucker. Motor units to the sucker musculature were also found. 5. Almost all recorded units in the dorsolateral axial cord were interneurones receiving tactile input. They have the following characteristics: (a) they are rapidly adapting, often phasic, and show little or no ‘spontaneous’ activity. (b) they habituate rapidly to even complex patterns of stimulation and discriminate between them, behaving as ‘novelty units’. (c) different sites of stimulation are discriminated by change in both the number of active units and their temporal patterning. The smallest area shown to be separately represented is the rim of one sucker. (d) prolonged activity can be initiated by a brief initial stimulus, which is without apparent correlated motor output. (e) stimulation of areas outside a unit's sensory field can lead to activity in that unit or to dehabituation in a previously active unit. No proprioceptive representation was found.


1991 ◽  
Vol 260 (5) ◽  
pp. G720-G723 ◽  
Author(s):  
J. Herdmann ◽  
K. Bielefeldt ◽  
P. Enck

The motor innervation of the pelvic floor plays a major role in defecation disorders such as fecal incontinence. It consists of central motor pathways and peripheral nerve fibers. Transcranial magnetoelectric stimulation of the brain and magnetoelectric stimulation of the lumbosacral motor roots were performed in 10 healthy volunteers. Motor evoked potentials were recorded from the external anal sphincter. This procedure allowed differentiation between a predominantly central and a solely peripheral component of the motor innervation of the external and sphincter. To compare these recordings with well-established data, motor evoked potentials were also recorded from the anterior tibial muscle. The central motor conduction time was 20.9 +/- 2.4 ms to the external anal sphincter and 14.8 +/- 2.3 ms to the anterior tibial muscles. Central motor conduction velocities were 40.7 +/- 5.2 and 55.5 +/- 7.6 m/s, respectively. This showed that conduction in the central fibers to the external anal sphincter was significantly slower than in those to the anterior tibial muscle. We conclude 1) that magnetoelectric stimulation allows differentiation between central and peripheral portions of the motor innervation of the pelvic floor, and 2) that central motor pathways innervating the pelvic floor differ significantly in their physiological properties from those innervating limb muscles.


1938 ◽  
Vol 15 (1) ◽  
pp. 18-31
Author(s):  
C. A. G. WIERSMA ◽  
A. VAN HARREVELD

A double motor innervation has been shown for several muscles of marine crustaceans. The adductors of the claws of Randallia and Blepharipoda and the adductor of the dactylopodite of the walking leg of Cancer were studied physiologically. The two motor axons which innervate these muscles have a different diameter (ratio 1.4: 1). Stimulation of the thick fibre causes a response, which, though it is not always faster than the response of the thin fibre, must be considered as a "fast" contraction. In Randallia and in Blepharipoda the slow contraction is higher than the fast with frequencies of less than ± 50 per sec., in Cancer with frequencies less than 100 per sec. The action currents of the two kinds of contraction are different. Both show facilitation, but under the same conditions of stimulation the fast-action currents are higher. The first stimulus of the thick fibre causes an action current top which is clearly distinguishable, the action currents of the slow contraction show up only after a number of stimuli. Even when the mechanical reaction on stimulation of the thick fibre is smaller than on similar stimulation of the thin fibre, the action currents are higher in the first case. A single impulse in the thick fibre does not cause a contraction, but sets up a muscle-action current. The chronaxie of this action current in Blepharipoda and Randallia is 0.8σ and is about the same as that found for the action current of the nerve. Two impulses in the thick fibre may cause a mechanical response, as is shown by summation experiments. The pseudo-chronaxie of this contraction was measured as 3.5 σ. The second action current shows facilitation, when it follows the first within 1 sec.; a mechanical reaction results with summation intervals of two stimuli of less than 10σ. The facilitation of the action current increases with decrease of the time interval between the two impulses; with the shortest intervals that give summation the resulting action current is a smooth high spike.


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