Tonic neck reflex of the decerebrate cat: response of spinal interneurons to natural stimulation of neck and vestibular receptors

1984 ◽  
Vol 51 (3) ◽  
pp. 567-577 ◽  
Author(s):  
V. J. Wilson ◽  
K. Ezure ◽  
S. J. Timerick
Keyword(s):  
Dynamic Behavior ◽  
Vestibular Stimulation ◽  
Whole Body ◽  
Type I ◽  
Type Ii ◽  
Vestibular Input ◽  
Ipsilateral Side ◽  
Neck Rotation ◽  
Roll Tilt ◽  
Tonic Neck Reflex

In order to investigate the neural basis of the tonic neck reflex, we studied the response of neurons in the cervical spinal cord of decerebrate, paralyzed cats to neck rotation about the longitudinal axis (roll), to vestibular stimulation produced by roll tilt, and to a combination of these stimuli. Most neurons were outside the motoneuron nuclei and were arbitrarily classified as interneurons. Three types of preparation were used--one with intact labyrinths, one acutely labyrinthectomized, and one with acute spinal transection. The activity of 115 neurons recorded extracellularly was modulated by sinusoidal neck rotation in the range 0.02-4 Hz; their behavior was sufficiently linear for sinusoidal analysis. The phase and gain of the responses of neurons in all three preparations were similar except that the absolute gain in cats with intact labyrinths was higher than that of the others. The location of neurons in segments C4-C8 was mainly in laminae 7-8. Some neurons were excited by rotation of the chin to the ipsilateral side (type I) and others by contralateral chin rotation (type II). The dynamic behavior of type I and type II neurons was the same; phase was flat over most of the frequency range and close to the phase of peak neck rotation, while gain enhancement occurred at higher frequencies. This behavior was similar to that of the neckforelimb reflex evoked in unparalyzed intact-labyrinth and labyrinthectomized cats. In cats with intact labyrinths, vestibular input to neurons whose activity was modulated by the neck stimulus was studied using whole-body roll tilt. Many neurons received otolith input; some received canal input. Neck and vestibular inputs to spinal neurons always had opposite polarities (complementary inputs). Thus, type I neurons were always excited by tilt to the ipsilateral side (ipsilateral ear down) while type II neurons were excited by tilt to the contralateral side. Combined neck and vestibular stimulation indicated that the dynamic behavior of neurons was determined by a linear summation of the responses to these stimuli. Interaction of neck and vestibular input at the neuron level was similar to that observed previously at the reflex level in forelimb extensor muscles.(ABSTRACT TRUNCATED AT 400 WORDS)

Responses of neurons of the cat central cervical nucleus to natural neck and vestibular stimulation

1996 ◽  
Vol 76 (4) ◽  
pp. 2786-2789 ◽  
Author(s):  
D. B. Thomson ◽  
N. Isu ◽  
V. J. Wilson
Keyword(s):  
Vestibular Nuclei ◽  
Vestibular Stimulation ◽  
Body Tilt ◽  
Whole Body ◽  
Vestibular Input ◽  
Preferred Direction ◽  
Central Cervical Nucleus ◽  
Neck Rotation ◽  
Vector Orientation ◽  
To Receive

1. The central cervical nucleus (CCN) is known to receive neck and vestibular input and to project to the contralateral cerebellum and vestibular nuclei. To investigate the processing of neck and vestibular input by cells in the CCN, we studied their responses to sinusoidal neck rotation and to whole-body tilt in vertical planes in decerebrate, paralyzed cats. CCN neurons were identified by antidromic stimulation with electrodes placed in or near the contralateral restiform body. 2. For every neuron, we first identified the preferred direction of neck rotation (response vector orientation), then studied the neuron's dynamics with rotations in a plane close to this direction at 0.05-1 Hz. 3. Responses of CCN neurons to neck rotation resembled those of previously studied neck spindle primary afferents in terms of their dynamics and nonlinear responses to stimuli of differing amplitudes. They also resembled the neck responses of Deiters' neurons studied in similar preparations. 4. The activity of two-thirds of CCN neurons also was modulated by natural vestibular stimulation. Orientation and dynamics of vestibular responses were characterized in the same way as neck responses. Labyrinthine input originated predominantly from the contralateral vertical canals, and there was no evidence of otolith input. Neck and vestibular inputs were always antagonistic, but the gain of the vestibular response was lower than that of the neck response at all frequencies studied. 5. The quantitative aspects of the interaction between neck and vestibular inputs can be expected to vary with the type of preparation and with stimulus parameters, and its functional significance remains to be investigated.

Tilt responses of neurons in the caudal descending nucleus of the decerebrate cat: influence of the caudal cerebellar vermis and of neck receptors

1996 ◽  
Vol 75 (3) ◽  
pp. 1242-1249 ◽  
Author(s):  
V. J. Wilson ◽  
H. Ikegami ◽  
R. H. Schor ◽  
D. B. Thomson
Keyword(s):  
Head Rotation ◽  
Muscle Spindles ◽  
Vestibular Nuclei ◽  
Vestibular Stimulation ◽  
Cerebellar Vermis ◽  
Neck Muscle ◽  
Vestibular Input ◽  
Decerebrate Cat ◽  
Neck Rotation ◽  
Vertical Semicircular Canal

1. In decerebrate cats with intact cerebellums, we studied the responses of neurons in the caudal areas of the vestibular nuclei to natural vestibular stimulation in vertical planes and to neck rotation. The activity of most neurons was recorded in the caudal half of the descending nucleus. 2. One goal of our experiments was to compare the dynamic and spatial properties of responses to sinusoidal vestibular stimulation with those seen in previous experiments in which the caudal cerebellar vermis, including the nodulus and uvula, was removed. This part of the cerebellum receives vestibular input and projects to the caudal areas of the vestibular nuclei, suggesting that it could influence responses to stimulation of the labyrinth. 3. As in our previous experiments, most neurons could be classified as receiving predominant input either from the otoliths or from one vertical semicircular canal. When mean gain and phase and response vector orientations were compared, there were no obvious differences between the behavior of neurons in the partially decerebellate preparation and the one with the cerebellum intact, demonstrating that in the decerebrate cat the nodulus and uvula have little or no influence on the processing of vertical vestibular input in this region of the vestibular nuclei. 4. Only 23 of 74 (31%) of neurons tested responded to neck rotation. This contrasts with the much larger fractions that respond to this stimulus in Deiters' nucleus and in the rostral descending nucleus. We also recorded from neurons near the vestibular nuclei, mainly in the external cuneate nucleus. All of them (9 of 9) responded to neck rotation. 5. Responses to neck rotation also differed in their dynamics from those found more rostrally in the vestibular nuclei. Dynamics of more rostral neurons resemble those of neck muscle spindles, as do those of external cuneate neurons. The dynamics of caudal vestibular neurons, on the other hand, have a steeper gain slope and more advanced phases than do those of neurons in the more rostral vestibular nuclei. This suggests the possibility of involvement of additional receptors in the production of these responses. 6. In the more rostral vestibular nuclei, responses to vestibular and neck rotation are most often antagonistic, so that head rotation results in little or no response. This is not the case in the caudal areas of the vestibular nuclei, where less than half the neurons tested displayed antagonistic behavior. Further experiments are required to put the neck projection to the caudal vestibular nuclei in a functional context.

scholarly journals Gravity dependence of the effect of optokinetic stimulation on the subjective visual vertical

2017 ◽  
Vol 117 (5) ◽  
pp. 1948-1958 ◽  
Author(s):  
Bryan K. Ward ◽  
Christopher J. Bockisch ◽  
Nicoletta Caramia ◽  
Giovanni Bertolini ◽  
Alexander Andrea Tarnutzer
Keyword(s):  
Bayesian Theory ◽  
Roll Angle ◽  
Whole Body ◽  
Optokinetic Stimulation ◽  
Subjective Visual Vertical ◽  
Vestibular Input ◽  
Stimulus Velocity ◽  
Visual Vertical ◽  
Observer Model ◽  
Roll Tilt

Accurate and precise estimates of direction of gravity are essential for spatial orientation. According to Bayesian theory, multisensory vestibular, visual, and proprioceptive input is centrally integrated in a weighted fashion based on the reliability of the component sensory signals. For otolithic input, a decreasing signal-to-noise ratio was demonstrated with increasing roll angle. We hypothesized that the weights of vestibular (otolithic) and extravestibular (visual/proprioceptive) sensors are roll-angle dependent and predicted an increased weight of extravestibular cues with increasing roll angle, potentially following the Bayesian hypothesis. To probe this concept, the subjective visual vertical (SVV) was assessed in different roll positions (≤ ± 120°, steps = 30°, n = 10) with/without presenting an optokinetic stimulus (velocity = ± 60°/s). The optokinetic stimulus biased the SVV toward the direction of stimulus rotation for roll angles ≥ ± 30° ( P < 0.005). Offsets grew from 3.9 ± 1.8° (upright) to 22.1 ± 11.8° (±120° roll tilt, P < 0.001). Trial-to-trial variability increased with roll angle, demonstrating a nonsignificant increase when providing optokinetic stimulation. Variability and optokinetic bias were correlated ( R2 = 0.71, slope = 0.71, 95% confidence interval = 0.57–0.86). An optimal-observer model combining an optokinetic bias with vestibular input reproduced measured errors closely. These findings support the hypothesis of a weighted multisensory integration when estimating direction of gravity with optokinetic stimulation. Visual input was weighted more when vestibular input became less reliable, i.e., at larger roll-tilt angles. However, according to Bayesian theory, the variability of combined cues is always lower than the variability of each source cue. If the observed increase in variability, although nonsignificant, is true, either it must depend on an additional source of variability, added after SVV computation, or it would conflict with the Bayesian hypothesis. NEW & NOTEWORTHY Applying a rotating optokinetic stimulus while recording the subjective visual vertical in different whole body roll angles, we noted the optokinetic-induced bias to correlate with the roll angle. These findings allow the hypothesis that the established optimal weighting of single-sensory cues depending on their reliability to estimate direction of gravity could be extended to a bias caused by visual self-motion stimuli.

scholarly journals Prolonged exercise training increases intramuscular lipid content and perilipin 2 expression in type I muscle fibers of patients with type 2 diabetes

2012 ◽  
Vol 303 (9) ◽  
pp. E1158-E1165 ◽  
Author(s):  
C. S. Shaw ◽  
S. O. Shepherd ◽  
A. J. M. Wagenmakers ◽  
D. Hansen ◽  
P. Dendale ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Exercise Training ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Whole Body ◽  
Type I ◽  
Type Ii ◽  
Perilipin 2 ◽  
Diabetes Patients

The aim of the present study was to investigate changes in intramuscular triglyceride (IMTG) content and perilipin 2 expression in skeletal muscle tissue following 6 mo of endurance-type exercise training in type 2 diabetes patients. Ten obese male type 2 diabetes patients (age 62 ± 1 yr, body mass index BMI 31 ± 1 kg/m2) completed three exercise sessions/week consisting of 40 min of continuous endurance-type exercise at 75% V̇o2 peak for a period of 6 mo. Muscle biopsies collected at baseline and after 2 and 6 mo of intervention were analyzed for IMTG content and perilipin 2 expression using fiber type-specific immunofluorescence microscopy. Endurance-type exercise training reduced trunk body fat by 6 ± 2% and increased whole body oxygen uptake capacity by 13 ± 7% ( P < 0.05). IMTG content increased twofold in response to the 6 mo of exercise training in both type I and type II muscle fibers ( P < 0.05). A threefold increase in perilipin 2 expression was observed from baseline to 2 and 6 mo of intervention in the type I muscle fibers only (1.1 ± 0.3, 3.4 ± 0.6, and 3.6 ± 0.6% of fibers stained, respectively, P < 0.05). Exercise training induced a 1.6-fold increase in mitochondrial content after 6 mo of training in both type I and type II muscle fibers ( P < 0.05). In conclusion, this is the first study to report that prolonged endurance-type exercise training increases the expression of perilipin 2 alongside increases in IMTG content in a type I muscle fiber-type specific manner in type 2 diabetes patients.

scholarly journals Nursing Analysis of Traumatic Spinal Injury in Emergency Nursing

2015 ◽  
Vol 4 (3) ◽  
pp. 27
Author(s):  
Yanli Wu
Keyword(s):  
Vertebral Fractures ◽  
Spinal Injury ◽  
Whole Body ◽  
Type I ◽  
Emergency Nursing ◽  
Type Ii ◽  
Neurological Damage ◽  
Ligament Rupture ◽  
Cord Injury ◽  
Multiple Vertebral Fractures

<p>Spinal injuries account for about 4.2% of the whole body fractures, usually occur in the young, middle-aged, the vast majority are caused by indirect forces, and direct violence is relatively rare. Spinal injury was common in T12~L1, followed by C1~2, C5~7, but there are about 20% spinal injury are multiple vertebral fractures. In addition to vertebral fractures, spinal injury is often associated with combined injury of accessory fracture, ligament rupture, etc. If associated with spinal cord injury, it may cause paraplegia. The purpose of this paper is to explore the nursing measures of traumatic spinal injury. In this paper, 134 cases of spinal injury patients adopted nursing measures were summarized. Results showed that among the 33 cases of type I patients, there was no case died in the emergency department or with increased neurological damage. There was also no case with aggravated neurological damage in 31 cases of type II patients, and finally smooth admission. In the 21 patients with type III, 7 patients had poor spine stability, and had a certain tendency of neurological damage, and then transferred to the department of orthopedics. 5 cases had delayed neurological symptoms and transferred to the department of orthopedics. The other 5 cases had no abnormal changes over 3 days observation and went home to conduct conservative treatment and got better results.</p>

A Novel Naturally Fractured Reservoirs Classification Plot Through the Liaison of Dynamic Data, Depositional Environments and Rock Texture

2021 ◽  
Author(s):  
Ricardo Alcantara ◽  
Luis Humberto Santiago ◽  
Jorge Enrique Paredes ◽  
Juan Ricardo Alcantara
Keyword(s):  
Dynamic Behavior ◽  
Fractured Reservoirs ◽  
Petroleum Industry ◽  
Effective Porosity ◽  
Depositional Environments ◽  
Naturally Fractured Reservoirs ◽  
Type I ◽  
Type Ii ◽  
Naturally Fractured ◽  
Rock Texture

Abstract Naturally Fractured Reservoirs (NFR) represent a challenge for petroleum industry because they are characterized by complex dynamics associated to the fluids motion and geological events that originated them million years ago, where diagenetic processes have played a transcendental role. In carbonates, the movement of fluids within the reservoir is highly influenced by the fracture systems present in the formation, however, these are intimately related to rock texture and quality, depositional environments, facies changes, regional and local stresses, tectonism and of course, diagenesis. Regarding the dynamic behavior, we can highlight the importance of the type of fluid present in the system and the acting drive indices, which govern the behavior of pressure and production in this type of reservoirs, whose analysis usually goes further of conventional techniques commonly used for its evaluation. One of the problems faced by reservoir engineers is the classification or categorization of these types of reservoirs to know their true potential and try to estimate the recoverable reserves as accurately as possible, since the complex dynamic behavior of NFR hinders its exploitation when the most important parameters for its correct evaluation are not known. From the above, a novel and practical Naturally Fractured Reservoirs (NFR) classification plot is proposed based on the Nelson's classification (2001) and a full revision of other author's technical reviews. The plot is generated through the information obtained from a full reservoir characterization to acquire petrophysical evaluations and Pressure Transient Analysis (PTA) to find the product of the effective porosity and the average flow capacity of each of the fields tested in order to plot them against the recovery factor; this analysis considered more than 200 carbonate fields from more than 40 countries around the world. When plotting the data involved, it is clear to see that they are grouped in different zones for its reclassification as Naturally Fractured Reservoirs, where we added a subcategorization of type II reservoirs (type II A and type II B) and also the influence of vugs in type I reservoirs and the gas and condensates region; all attributed to the dynamic behavior associated to the type of fluid, the acting drive indices, the depositional environments and the rock texture. The results obtained were fully coupled to a probability distribution and have shown to be consistent with the observed behavior, being a useful tool for determining the actual type of NFR, the expected production rates, the range of possible recovery factors to be achieved and the characterization of reservoirs. Likewise, the proposed plot can be applied to the analysis of sectors in the same reservoir or formation to try to identify the variations regarding the type of NFR by zones, blocks or compartments according to the location of each well in the field, considering their respective recovery factors concerning its cumulative production and original reserves.

Satellite cell and myonuclear accretion is related to training-induced skeletal muscle fiber hypertrophy in young males and females

2021 ◽  
Author(s):  
Sidney Abou Sawan ◽  
Nathan Hodson ◽  
Paul Babits ◽  
Julia M. Malowany ◽  
Dinesh A. Kumbhare ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Whole Body ◽  
Type I ◽  
Type Ii ◽  
Young Males ◽  
Males And Females ◽  
Type Ii Fibers

Satellite cells (SC) play an integral role in the recovery from skeletal muscle damage and supporting muscle hypertrophy. Acute resistance exercise typically elevates type I and type II SC content 24-96 hours post-exercise in healthy young males, although comparable research in females is lacking. We aimed to elucidate whether sex-based differences exist in fiber type-specific SC content after resistance exercise in the untrained (UT) and trained (T) states. Ten young males (23.0 ± 4.0y) and females (23.0 ± 4.8y) completed an acute bout of resistance exercise before and after 8 weeks of whole-body resistance training. Muscle biopsies were taken from the vastus lateralis immediately prior to and 24 and 48-hours after each bout to determine SC and myonuclear content by immunohistochemistry. Males had greater SC associated with type II fibers (P ≤ 0.03). There was no effect of acute resistance exercise on SC content in either fiber type (P ≥ 0.58) for either sex, however, training increased SC in type II fibers (P < 0.01) irrespective of sex. The change in mean 0-48 h type II SC was positively correlated with muscle fiber hypertrophy in type II fibers (r = 0.47; P = 0.035). Furthermore, the change in myonuclei per fiber was positively correlated with type I and type II fiber hypertrophy (both r = 0.68; P < 0.01). Our results suggest that SC responses to acute and chronic resistance exercise are similar in males and females and that SC and myonuclear accretion is related to training-induced muscle fiber hypertrophy.

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

1970 ◽  
Vol 28 ◽  
pp. 106-107 ◽  
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
New Zealand ◽  
General Hospital ◽  
Massachusetts General Hospital ◽  
Type I ◽  
Type Ii ◽  
Collaborative Effort ◽  
Temperature And Pressure ◽  
The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

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