Visual, vestibular and voluntary contributions to human head stabilization

D. Guitton; R.E. Kearney; N. Wereley; B.W. Peterson

doi:10.1007/bf00238201

Visual, vestibular and voluntary contributions to human head stabilization

Experimental Brain Research ◽

10.1007/bf00238201 ◽

1986 ◽

Vol 64 (1) ◽

Cited By ~ 82

Author(s):

D. Guitton ◽

R.E. Kearney ◽

N. Wereley ◽

B.W. Peterson

Keyword(s):

Human Head ◽

Voluntary Contributions ◽

Head Stabilization

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

Physiological Reports ◽

10.14814/phy2.12745 ◽

2016 ◽

Vol 4 (10) ◽

pp. e12745 ◽

Cited By ~ 3

Author(s):

Ann-Katrin Stensdotter ◽

Morten DinhoffPedersen ◽

Ingebrigt Meisingset ◽

Ottar Vasseljen ◽

Øyvind Stavdahl

Keyword(s):

Horizontal Plane ◽

Human Head ◽

Head Stabilization

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

Journal of Vestibular Research ◽

10.3233/ves-1999-9604 ◽

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.

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

Anbar Journal of Agricultural Sciences ◽

10.32649/ajas/2020/12 ◽

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.

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