scholarly journals A dorsal light reflex in a squid.

1995 ◽  
Vol 198 (5) ◽  
pp. 1157-1159 ◽  
Author(s):  
T Preuss ◽  
B U Budelmann
Keyword(s):  
Postural Control ◽  
Dorsal Side ◽  
Modal Interaction ◽  
Free Swimming ◽  
Light Reflex ◽  
Receptor Organ ◽  
Proprioceptive Inputs ◽  
Lolliguncula Brevis

A dorsal light reflex is described in the squid Lolliguncula brevis. When illuminated from the side in visually homogeneous surroundings, a free-swimming squid rolls the dorsal side of its head and trunk 10-20 degrees towards the light. With the trunk restricted in a holder, the squid rolls its head 4-5 degrees towards the light; this reaction increases by about 50% when the statocysts are bilaterally removed and increases further when the neck receptor organ is also destroyed. The results indicate a multi-modal interaction of visual, statocyst and proprioceptive inputs during postural control.

Postural Control in the Lamprey: A Study With a Neuro-Mechanical Model

2000 ◽  
Vol 84 (6) ◽  
pp. 2880-2887 ◽  
Author(s):  
P. V. Zelenin ◽  
T. G. Deliagina ◽  
S. Grillner ◽  
G. N. Orlovsky
Keyword(s):  
Spinal Cord ◽  
Postural Control ◽  
Mechanical Model ◽  
Dorsal Side ◽  
Postural Control System ◽  
Lateral Tilt ◽  
Normal Orientation ◽  
Postural Stabilization ◽  
Left And Right ◽  
Vestibular Organs

The swimming lamprey normally maintains the dorsal-side-up orientation due to activity of the postural control system driven by vestibular organs. Commands for postural corrections are transmitted from the brain stem to the spinal cord mainly by the reticulospinal (RS) pathways. As shown in previous studies, RS neurons are activated by contralateral roll tilt, they exhibit a strong dynamic response, but much weaker static response. Here we test a hypothesis that decoding of these commands in the spinal cord is based on the subtraction of signals in the left and right RS pathways. In this study, we used a neuro-mechanical model. An intact lamprey was mounted on a platform that restrained its postural activity but allowed lateral locomotor undulations to occur. The activity in the left and right RS pathways was recorded by implanted electrodes. These natural biological signals were then used to control an electrical motor rotating the animal around its longitudinal axis toward the stronger signal. It was found that this “hybrid” system automatically stabilized a normal orientation of the lamprey in the gravitational field. The system compensated for large postural disturbances (lateral tilt up to ±180°) due to wide angular zones of the gravitational sensitivity of RS neurons. In the nonswimming lamprey, activity of RS neurons and their vestibular responses were considerably reduced, and the system was not able to stabilize the normal orientation. However, the balance could be restored by imposing small oscillations on the lamprey, which elicited additional activation of the vestibular organs. This finding indicates that head oscillations caused by locomotor movements may contribute to postural stabilization. In addition to postural stabilization, the neuro-mechanical model reproduced a number of postural effects characteristic of the lamprey: 1) unilateral eye illumination elicited a lateral tilt (“dorsal light response”) due to a shift of the equilibrium point in the vestibular-driven postural network; 2) removal of one labyrinth resulted in a loss of postural control due to an induced left-right asymmetry in the vestibulo-reticulospinal reflexes, which 3) could be compensated for by asymmetrical visual input. The main conclusion of the present study is that natural supraspinal commands for postural corrections in the roll plane can be effectively decoded on the basis of subtraction of the effects of signals delivered by the left and right RS pathways. Possible mechanisms for this transformation are discussed.

Hypnotizability-dependent modulation of postural control: effects of alteration of the visual and leg proprioceptive inputs

2008 ◽  
Vol 191 (3) ◽  
pp. 331-340 ◽  
Author(s):  
Enrica Laura Santarcangelo ◽  
E. Scattina ◽  
G. Carli ◽  
A. Macerata ◽  
D. Manzoni
Keyword(s):  
Postural Control ◽  
Proprioceptive Inputs

scholarly journals Postural Strategy in Elderly, Middle-Aged, and Young People during Local Vibratory Stimulation for Proprioceptive Inputs

Geriatrics ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 93 ◽  
Author(s):  
Tadashi Ito ◽  
Yoshihito Sakai ◽  
Kazunori Yamazaki ◽  
Reiya Nishio ◽  
Yohei Ito ◽  
...  
Keyword(s):  
Young People ◽  
Postural Control ◽  
Elderly People ◽  
Center Of Pressure ◽  
Balance Control ◽  
The Elderly ◽  
Middle Aged ◽  
Aged People ◽  
Eyes Closed ◽  
Proprioceptive Inputs

Proprioceptive input may greatly affect postural stability. However, the proprioceptive postural strategy in elderly, middle-aged, and young people has not been investigated sufficiently. Hence, in this study, we aimed to investigate differences in proprioceptive postural strategies of elderly, middle-aged, and young people. The center of pressure displacement was determined in 23 elderly, 23 middle-aged, and 23 young people during upright stance on a balance board with their eyes closed. Vibratory stimulations at 30, 60, and 240 Hz were applied to the lumbar multifidus (LM) and gastrocnemius (GS) muscles to evaluate the contributions of different proprioceptive signals used in balance control. Compared with middle-aged and young people, elderly people showed a high dependence on postural control of the GS at 30 Hz (p-values: Young and elderly: 0.033; middle-aged and elderly: 0.001). Moreover, compared with young people, elderly people were more dependent on postural control of the LM at 240 Hz (p = 0.016). There were no significant differences with respect to the GS at 60 and 240 Hz, and with respect to the LM at 30 and 60 Hz between the elderly, young, and middle-aged people. Thus, the postural control strategy of elderly people depends on the GS at 30 Hz.

scholarly journals Pupil light reflex in the Atlantic brief squid, Lolliguncula brevis

2012 ◽  
Vol 215 (15) ◽  
pp. 2677-2683 ◽  
Author(s):  
L. R. McCormick ◽  
J. H. Cohen
Keyword(s):  
Light Reflex ◽  
Pupil Light Reflex ◽  
Lolliguncula Brevis

Impairment and Recovery of Postural Control in Rabbits With Spinal Cord Lesions

2005 ◽  
Vol 94 (6) ◽  
pp. 3677-3690 ◽  
Author(s):  
V. F. Lyalka ◽  
P. V. Zelenin ◽  
A. Karayannidou ◽  
G. N. Orlovsky ◽  
S. Grillner ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Postural Control ◽  
Spinal Cord Injuries ◽  
Frontal Plane ◽  
Dorsal Side ◽  
Knee Joints ◽  
Crucial Importance ◽  
Postural Reflexes ◽  
Video Recordings ◽  
Hind Limbs

The aim of this study was to characterize impairment and subsequent recovery of postural control after spinal cord injuries. Experiments were carried out on rabbits with three types of lesion—a dorsal (D), lateral (L), or ventral (V) hemisection (HS) at T12 level. The animals were maintaining equilibrium on a platform periodically tilted in the frontal plane. We assessed the postural limb/trunk configuration from video recordings and postural reflexes in the hindquarters from kinematical and electromyographic (EMG) recordings. We found that for a few days after DHS or LHS, the animals were not able to maintain the dorsal-side-up position of their hindquarters. This ability was then gradually restored, and the dynamic postural reflexes reached the prelesion value within 2–3 wk. By contrast, a VHS almost completely abolished postural reflexes, and they did not recover for ≥7 wk. The DHS, LHS, and VHS caused immediate and slowly compensated changes in the postural limb/trunk configuration as well as gradually developing changes. After DHS, both hind limbs were placed in an abnormal rostral and medial position. After LHS, the limb on the undamaged side was turned inward and occurred at the abnormal medial position; LHS also caused a gradually developing twisting of the caudal trunk. VHS caused gradually developing extension of the ankle and knee joints. These findings show that ventral spinal pathways are of crucial importance for postural control. When a part of these pathways is spared, postural reflexes can be restored rapidly, but not the postural limb/trunk configuration. Spinal and supraspinal mechanisms responsible for postural deficits and their compensation are discussed.

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

High-voltage EM description of the types and distribution of sensory endings in the inner conical body of the rat vibrissal follicle-sinus complex

1990 ◽  
Vol 48 (3) ◽  
pp. 410-411
Author(s):  
Tony M. Mosconi ◽  
Min J. Song ◽  
Frank L. Rice
Keyword(s):  
Mammalian Species ◽  
Dorsal Side ◽  
Hair Shaft ◽  
Sensory Innervation ◽  
Conical Body ◽  
Adult Rats ◽  
Perpendicular Plane ◽  
Ultrastructural Studies ◽  
Unmyelinated Axons ◽  
Sensory Endings

Whiskers or vibrissal follicle-sinus complexes (F-SCs) on the snouts of many mammalian species are structures that have complex, dense sensory innervation. The innervation of F-SCs is remarkably similar in all species with the exception of one site - the inner conical body (ICB). The ICB is an elongated cylindrical structure that encircles the hair shaft near the neck of the follicle. This site has received only cursory attention in ultrastructural studies of the F-SCAdult rats were perfused after the method of Renehan and Munger2. F-SCs were quartered longitudinally and embedded separately in Epon-Araldite. Serial 0.25 μm sections were cut in either the longitudinal or perpendicular plane through the ICB and examined with an AEI EM7 1.2 MV HVEM (Albany, NY) at 1000 KV. Sensory endings were reconstructed from serial micrographs through at least 20 μm in the longitudinal plane and through 10 μm in the perpendicular plane.From two to six small superficial vibrissal nerves converge upon the neck of the F-SC and descend into the ICB. The nerves branch into smaller bundles of myelinated and unmyelinated axons along the dorsal side of the hair shaft.

Effect of localized muscle fatigue induced at different joints on postural control

2005 ◽  
Author(s):  
Navrag B. Singh ◽  
Maury A. Nussbaum ◽  
Dingding Lin ◽  
Michael L. Madigan
Keyword(s):  
Postural Control ◽  
Muscle Fatigue ◽  
Localized Muscle Fatigue
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