scholarly journals Mechanisms controlling human head stabilization during random rotational perturbations in the horizontal plane revisited

2016 ◽  
Vol 4 (10) ◽  
pp. e12745 ◽  
Author(s):  
Ann-Katrin Stensdotter ◽  
Morten DinhoffPedersen ◽  
Ingebrigt Meisingset ◽  
Ottar Vasseljen ◽  
Øyvind Stavdahl
Keyword(s):  
Horizontal Plane ◽  
Human Head ◽  
Head Stabilization

Horizontal Plane Head Stabilization During Locomotor Tasks

2001 ◽  
Vol 33 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Ronita L. Cromwell ◽  
Roberta A. Newton ◽  
Les G. Carlton
Keyword(s):  
Horizontal Plane ◽  
Head Stabilization

Mechanisms controlling human head stabilization. I. Head-neck dynamics during random rotations in the horizontal plane

1995 ◽  
Vol 73 (6) ◽  
pp. 2293-2301 ◽  
Author(s):  
F. A. Keshner ◽  
B. W. Peterson
Keyword(s):  
Visual Feedback ◽  
Horizontal Plane ◽  
Mental Arithmetic ◽  
Human Head ◽  
The Body ◽  
Myoelectric Activity ◽  
Head Tracking ◽  
Arithmetic Task ◽  
Head Velocity ◽  
Head Neck

1. Potential mechanisms for controlling stabilization of the head and neck include voluntary movements, vestibular (VCR) and proprioceptive (CCR) neck reflexes, and system mechanics. In this study we have tested the hypothesis that the relative importance of those mechanisms in producing compensatory actions of the head-neck motor system depends on the frequency of an externally applied perturbation. Angular velocity of the head with respect to the trunk (neck) and myoelectric activity of three neck muscles were recorded in seven seated subjects during pseudorandom rotations of the trunk in the horizontal plane. Subjects were externally perturbed with a random sum-of-sines stimulus at frequencies ranging from 0.185 to 4.11 Hz. Four instructional sets were presented. Voluntary mechanisms were examined by having the subjects actively stabilize the head in the presence of visual feedback as the body was rotated (VS). Visual feedback was then removed, and the subjects attempted to stabilize the head in the dark as the body was rotated (NV). Reflex mechanisms were examined when subjects performed a mental arithmetic task during body rotations in the dark (MA). Finally, subjects performed a voluntary head tracking task while the body was kept stationary (VT). 2. Gains and phases of head velocity indicated good compensation to the stimulus in VS and NV at frequencies < 1 Hz. Gains dropped and phases advanced between 1 and 2 Hz, suggesting interference between neural and mechanical components. Above 3 Hz, the gains of head velocity increased steeply and exceeded unity, suggesting the emergence of mechanical resonance.(ABSTRACT TRUNCATED AT 250 WORDS)

Visual, vestibular and voluntary contributions to human head stabilization

1986 ◽  
Vol 64 (1) ◽  
Author(s):  
D. Guitton ◽  
R.E. Kearney ◽  
N. Wereley ◽  
B.W. Peterson
Keyword(s):  
Human Head ◽  
Voluntary Contributions ◽  
Head Stabilization

Predicting control mechanisms for human head stabilization by altering the passive mechanics

1999 ◽  
Vol 9 (6) ◽  
pp. 423-434
Author(s):  
E.A. Keshner ◽  
T.C. Hain ◽  
K.J. Chen
Keyword(s):  
Model Simulation ◽  
Human Head ◽  
Optimization Methods ◽  
Control Mechanisms ◽  
Response Dynamics ◽  
Head Stabilization ◽  
Trunk Motion ◽  
Mechanics Model ◽  
Head Neck ◽  
Passive Mechanics

The purpose of this study was to clarify the mechanisms controlling head and neck stabilization in the horizontal (yaw) and vertical (pitch) planes by changing the passive mechanics of the head-neck motor system. Angular velocities of the head and trunk in space were recorded in seated subjects during external perturbations of the trunk with pseudorandom sum-of-sines (SSN) stimuli. Four subjects in yaw and nine subjects in pitch actively stabilized their heads in the dark, and performed a mental distraction task in the dark both with and without a weight atop the head. In yaw, the behavior of the head was found to change relatively little with added inertia. As adding inertia to a passive mechanical system should cause substantial changes in dynamics, we inferred that neural mechanisms were invoked to maintain the constant response dynamics. A mathematical model of head-neck control [11] was applied to predict the relative influence of the vestibulocollic and cervicocollic reflexes, and of inertia, stiffness, and viscosity. Using optimization methods to fit the model to experimental data, we identified stiffness and vestibulocollic reflex gain as the primary contributors to the control of head stabilization in space. In pitch, increasing inertia accentuated phase shifts at higher frequencies. Because our pitch model was insufficiently constrained, we only simulated responses due to passive mechanics. Model simulation predicted unstable head motion at all test frequencies. Subjects were able to compensate for trunk motion at most frequencies, however, suggesting that neural components were modulated to exert compensatory responses both with and without additional weight.

MOLECULAR STUDY OF HUMAN HEAD LICE, PEDICULUS HUMANUS CAPITIS COMPARISON WITH GOAT SUCKING LICE, LINOGNATHUS STENOPSIS (BURMEISTER) STRAINS

2020 ◽  
pp. 132-139
Keyword(s):  
Genetic Difference ◽  
Human Head ◽  
Molecular Study ◽  
Head Lice ◽  
Pediculus Humanus Capitis ◽  
School Students ◽  
Pediculus Humanus ◽  
Sucking Lice ◽  
Pcr Products ◽  
Amplicon Size

In this study, only (122) out of (915) primary school students were shown to be infected with head lice Pediculus. humanus capitis. The number and percentage of infected males were 46 (11.3%), while the number and percentage of infected females were 76 (14.9%). The results in our study also showed that the number and percentage of goats infected with goat sucking lice, Linognathus stenopsis was 70 (21.7%) of the total 322 animals, with the highest number and percentage among female goats 44 (62.9%) compared to the male goats 26 (37.1%). The study demonstrated that the rate of genetic difference between the studied samples was 89% and the similarity rate was 11%. Detection of OP-K01 gene pieces by PCR products showed that the amplicon size was 520 bp for P. humanus capitis isolated from humans, while the detection of OP-E20 and OP-M05 gene pieces with PCR product showed the lowest amplicon size 230 bp for Linognathus stenosis isolated from goats.

Sound Localization in the Horizontal Plane in Patients with Supratentorial Cerebrovascular Disorders.

1995 ◽  
Vol 32 (1) ◽  
pp. 50-58
Author(s):  
Hirotaka TANAKA ◽  
Kenji HACHISUKA ◽  
Yoshinori IMAMURA ◽  
Hajime OGATA ◽  
Jinro INOUE
Keyword(s):  
Sound Localization ◽  
Horizontal Plane ◽  
Cerebrovascular Disorders

A SPLINES BASED METHOD FOR MODELING THE HUMAN HEAD FOR USE IN FINITE ELEMENTS ANALYSIS

2017 ◽  
Author(s):  
Daniel Ponce ◽  
Eduardo Szpoganicz ◽  
Leonardo Mejia Rincon ◽  
Ernesto Ponce Lopez
Keyword(s):  
Finite Elements ◽  
Human Head ◽  
Finite Elements Analysis
Sign in / Sign up

Export Citation Format

Share Document