Resistance reflex that maintains upright head posture in the flesh fly neobellieria bullata (Sarcophagidae)

In flesh flies Neobellieria bullata, we investigated a resistance reflex that maintains upright head posture around the roll axis relative to the thorax. The gain of the reflex depends upon the fly's behavioral state: moving flies immediately correct 90 % of the amplitude of experimentally imposed roll perturbations, returning the head almost to the fully upright position; motionless flies allow perturbations to persist for minutes before correcting only 70 % of perturbation amplitude. To investigate the role of various neural pathways, we examined the control of head posture after sectioning relevant propriosensory or motor nerves. Excision of the prosternal chordotonal organ causes no decrements in the control of head posture. Unilateral deafferentation of a cervical propriosensory organ, the prosternal organ, induces roll towards the cut side. Unilateral section of the frontal nerve, a mixed motor nerve that supplies the neck depressors and levators, leads to unilateral deficits in correcting perturbations towards the contralateral side. After bilateral propriosensory or frontal motor nerve section, approximately 40 % of perturbation amplitude is still corrected. To determine the contributions of the passive elastic properties of the neck skeleto-muscular system, flies were tested under reversible nitrogen anesthesia. They immediately corrected 40 % of perturbation amplitude. Taken together, the results demonstrate that passive elasticity plus active prosternal nerve afference to contralateral depressors innervated by the frontal nerve in combination constitute a sufficient and necessary reflex loop to control head roll posture.

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The effect of sensory feedback on crayfish posture and locomotion: II. Neuromechanical simulation of closing the loop

Journal of Neurophysiology ◽

10.1152/jn.00870.2014 ◽

2015 ◽

Vol 113 (6) ◽

pp. 1772-1783 ◽

Cited By ~ 2

Author(s):

Julien Bacqué-Cazenave ◽

Bryce Chung ◽

David W. Cofer ◽

Daniel Cattaert ◽

Donald H. Edwards

Keyword(s):

Sensory Feedback ◽

Feedback Loop ◽

Motor Nerve ◽

Proprioceptive Feedback ◽

Chordotonal Organ ◽

Quiescent State ◽

Reflex Reversal ◽

Closing The Loop ◽

Recorded Activity

Neuromechanical simulation was used to determine whether proposed thoracic circuit mechanisms for the control of leg elevation and depression in crayfish could account for the responses of an experimental hybrid neuromechanical preparation when the proprioceptive feedback loop was open and closed. The hybrid neuromechanical preparation consisted of a computational model of the fifth crayfish leg driven in real time by the experimentally recorded activity of the levator and depressor (Lev/Dep) nerves of an in vitro preparation of the crayfish thoracic nerve cord. Up and down movements of the model leg evoked by motor nerve activity released and stretched the model coxobasal chordotonal organ (CBCO); variations in the CBCO length were used to drive identical variations in the length of the live CBCO in the in vitro preparation. CBCO afferent responses provided proprioceptive feedback to affect the thoracic motor output. Experiments performed with this hybrid neuromechanical preparation were simulated with a neuromechanical model in which a computational circuit model represented the relevant thoracic circuitry. Model simulations were able to reproduce the hybrid neuromechanical experimental results to show that proposed circuit mechanisms with sensory feedback could account for resistance reflexes displayed in the quiescent state and for reflex reversal and spontaneous Lev/Dep bursting seen in the active state.

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The Effect of Systemic Triamcinolone Acetonide on Nerve Repair

Otolaryngology ◽

10.1177/019459988709600208 ◽

1987 ◽

Vol 96 (2) ◽

pp. 158-164 ◽

Cited By ~ 6

Author(s):

Stephen F. Bansberg ◽

Thomas V. Mccaffrey

Keyword(s):

Action Potential ◽

Nerve Regeneration ◽

Triamcinolone Acetonide ◽

Motor Nerve ◽

Nerve Repair ◽

Compound Action Potential ◽

Contralateral Side ◽

Muscle Twitch ◽

Index Ratio ◽

Compound Action

The effects of timed-release pellets of triamcinolone acetonide on sciatic nerve regeneration were studied. Bilateral nerve defects were created in 18 rats. One defect was sutured primarily, while the contralateral side was grafted with a 1 cm autogenous graft. Nerve regeneration was assessed at 20 weeks by muscle-twitch strength and compound action potential parameters measured proximal and distal to the repair site. Conduction velocity and regenerative index (ratio of distal to proximal compound action potential area) were calculated. Significant improvement of the regenerative index and twitch strength occurred in animals treated with a 0.5 mg 21-day-release pellet. Improvement occurred in animals treated with 0.5 mg 60-day pellets, but the difference was not significant. The findings suggest that regeneration was enhanced as a result of increased numbers of axons that made distal connections in the animals that received 21-day-release triamcinolone systemically. Corticosteroid therapy may benefit motor nerve repair.

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Human path navigation in a three-dimensional world

Behavioral and Brain Sciences ◽

10.1017/s0140525x13000319 ◽

2013 ◽

Vol 36 (5) ◽

pp. 544-545 ◽

Cited By ~ 4

Author(s):

Michael Barnett-Cowan ◽

Heinrich H. Bülthoff

Keyword(s):

Path Integration ◽

Dimensional Space ◽

Three Dimensional ◽

Two Dimensions ◽

Neural Representation ◽

Head Posture ◽

Computational Load ◽

Path Navigation ◽

Upright Head ◽

Three Dimensional Space

AbstractJeffery et al. propose a non-uniform representation of three-dimensional space during navigation. Fittingly, we recently revealed asymmetries between horizontal and vertical path integration in humans. We agree that representing navigation in more than two dimensions increases computational load and suggest that tendencies to maintain upright head posture may help constrain computational processing, while distorting neural representation of three-dimensional navigation.

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PROPRIOCEPTIVE INPUT FROM TWO BASAL JOINT STRETCH RECEPTORS TO LEG MOTONEURONES IN THE ISOLATED THORACIC GANGLION OF THE SHORE CRAB

Journal of Experimental Biology ◽

10.1242/jeb.163.1.187 ◽

1992 ◽

Vol 163 (1) ◽

pp. 187-208

Author(s):

STEWART I. HEAD ◽

BRIAN M.H. BUSH

Keyword(s):

Motor Nerve ◽

Carcinus Maenas ◽

Thoracic Ganglion ◽

Shore Crab ◽

Chordotonal Organ ◽

Leg Muscles ◽

Receptor Organ ◽

Motor Nerves

The reflex effects and interactions of two proprioceptors upon motoneurones supplying the four basal leg muscles of the shore crab Carcinus maenas have been studied in a new in vitro preparation consisting of the thoracic-coxal muscle receptor organ (TCMRO) and the coxo-basal chordotonal organ (CBCO) isolated together with the whole thoracic ganglion complex to which they were still connected by their afferent nerves. Each receptor strand was stimulated mechanically, while recording intracellularly from motoneurones in the ganglion, and extracellularly from the cut motor nerves innervating the promotor and remotor muscles of the thoracic-coxal (T—C) joint and the levator and depressor muscles of the coxo-basal (C—B) joint. Stretch of the TCMRO evoked reflex firing in several units in the promotor motor nerve, confirming previous studies. In addition to this ‘intrajoint’ reflex, however, TCMRO stretch also elicited ‘interjoint’ reflex responses in motoneurones of both the levator and depressor muscles. Similarly, stretch and release of the CBCO produced intrajoint resistance reflexes in levator and depressor motoneurones, respectively, as well as interjoint reflexes in promotor and remotor motoneurones. In general, the CBCO produced stronger reflex effects in all four motor nerves than did the TCMRO. Intracellular recordings from individual motoneurones of all four muscles revealed that the majority of them received convergent input from both proprioceptors. The importance of such convergent input in vivo is discussed

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Mechanoreceptors and Minimal Reflex Activity Determining Claw Laterality In Developing Lobsters

Journal of Experimental Biology ◽

10.1242/jeb.171.1.149 ◽

1992 ◽

Vol 171 (1) ◽

pp. 149-162

Author(s):

C. K. GOVIND ◽

JOANNE PEARCE

Keyword(s):

Critical Period ◽

Homarus Americanus ◽

Contralateral Side ◽

Reflex Activity ◽

Chordotonal Organ ◽

Minimal Amount ◽

Bilateral Asymmetry ◽

Intact Side ◽

In The Wild ◽

Juvenile Stages

Bilateral asymmetry of the paired claws of the lobster Homarus americanus is determined during the fourth and fifth juvenile stages by differential reflex activity; the side with the greater activity becomes the crusher while the contralateral side becomes the cutter. Juvenile lobsters reared during this critical period with a substratum that could not be grasped or with reduced input from predominantly internal mechanoreceptors (proprioceptors) (achieved by cutting the dactyl and its chordotonal organ or by tenotomizing the claw opener or closer muscles) failed to develop a crusher claw and hence remained bilaterally symmetrical: they developed paired cutter claws. Therefore, the proprioceptive component of the reflex activity is implicated in bringing about the initial lateralization of the claw ganglion into a crusher and a cutter side. Moreover, lobsters with a single claw reared without a substratum developed a crusher on the intact side only if the intact claw was exercised. In the unexercised condition, differences in reflex activity between the side with a claw and the side without one were insufficient for the development of a crusher claw on the intact side. A minimal amount of reflex activity is necessary for the development of a crusher. Lobsters reared with this minimal amount of activity in both claws developed asymmetrical claws rather than paired crusher claws. This means that initial lateralization of the claw ganglion into a crusher side, on a random basis, inhibited the opposite side from also becoming a crusher. This would explain why we failed to produce lobsters with paired crusher claws and why they were seldom found in the wild.

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Upright head roll test: A new contribution for the diagnosis of lateral semicircular canal benign paroxysmal positional vertigo

Audiology Research ◽

10.4081/audiores.2020.236 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Pasquale Malara ◽

Andrea Castellucci ◽

Salvatore Martellucci

Keyword(s):

Semicircular Canal ◽

Benign Paroxysmal Positional Vertigo ◽

Spontaneous Nystagmus ◽

Lateral Semicircular Canal ◽

Recent Onset ◽

Positional Vertigo ◽

Affected Side ◽

Head Roll ◽

Upright Head ◽

Paroxysmal Positional Vertigo

Diagnosing the affected side in Benign Paroxysmal Positional Vertigo (BPPV) involving the Lateral Semicircular Canal (LSC) is often challenging and uncomfortable in patients with recent onset of vertigo and intense autonomic symptoms. The Minimum Stimulus Strategy (MSS) aims to diagnose side and canal involved by BPPV causing as little discomfort as possible to the patient. The strategy applied for LSC-BPPV includes the evaluation of pseudo-spontaneous nystagmus and oculomotor responses to the Head Pitch Test (HPT) in upright position, to the seated-supine test and to the Head Yaw Test (HYT) while supine. Matching data obtained by these tests enables clinicians to diagnose the affected side in LSC-BPPV. The purpose of this preliminary study is to propose a new diagnostic test for LSC-BPPV complimentary to the HPT, the Upright Head Roll Test (UHRT), to easily determine the affected ear and the involved arm in the sitting position and to evaluate its efficiency. Our results suggest that the UHRT can increase the sensitivity of the MSS without resorting to the HYT, thus reducing patient’s discomfort.

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Adaptive and Maladaptive Neural Plasticity Due to Facial Nerve Palsy

Zeitschrift für Psychologie ◽

10.1027/2151-2604/a000244 ◽

2016 ◽

Vol 224 (2) ◽

pp. 102-111 ◽

Cited By ~ 1

Author(s):

Carsten M. Klingner ◽

Stefan Brodoehl ◽

Gerd F. Volk ◽

Orlando Guntinas-Lichius ◽

Otto W. Witte

Keyword(s):

Facial Nerve ◽

Neural Plasticity ◽

Cortical Plasticity ◽

Brain Plasticity ◽

Motor Nerve ◽

Predictive Coding ◽

Theoretical Framework ◽

Cortical Reorganization ◽

Nerve Lesion ◽

Peripheral Facial Palsy

Abstract. This paper reviews adaptive and maladaptive mechanisms of cortical plasticity in patients suffering from peripheral facial palsy. As the peripheral facial nerve is a pure motor nerve, a facial nerve lesion is causing an exclusive deefferentation without deafferentation. We focus on the question of how the investigation of pure deefferentation adds to our current understanding of brain plasticity which derives from studies on learning and studies on brain lesions. The importance of efference and afference as drivers for cortical plasticity is discussed in addition to the crossmodal influence of different competitive sensory inputs. We make the attempt to integrate the experimental findings of the effects of pure deefferentation within the theoretical framework of cortical responses and predictive coding. We show that the available experimental data can be explained within this theoretical framework which also clarifies the necessity for maladaptive plasticity. Finally, we propose rehabilitation approaches for directing cortical reorganization in the appropriate direction and highlight some challenging questions that are yet unexplored in the field.

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