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  • Force and rate of force change  (1)
  • Hypothalamus  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Morphofunctional study of the effects of fetal exposure to cyproterone acetate on the hypothalamo-pituitary-gonadal axis of adult rats (1991)
    Springer
    Experimental brain research 83 (1991), S. 349-356 
    Details
    ISSN: 1432-1106
    Keywords: Cyproterone ; Hypothalamus ; Pituitary ; Morphology ; Function ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fetal exposure to cyproterone acetate (CPA), while allowing, normal sexual morphogenesis, has previously been shown to lead to functional endocrine abnormalities in adult rats of both sexes. Because of this, we examined morphologically and morphometrically the hypothalamic nuclei involved in sexual dimorphism as well as the pituitary lactotropes of rats exposed in utero from day 15 to 20 of gestation to CPA. Male and female offspring was studied at the age of 70–80 days. In both sexes the brain weight was lower (p〈0.05) in CPA-treated than in control rats. Morphometrical investigations showed that the surface density (Sv) and the volume density (Vv) of the ventromedial nucleus were higher (p〈0.05) in CPA-treated male than in control rats. By comparing sexes the Sv and Vv of the ventromedial nucleus were higher (p〈0.01) in CPA-treated male than in corresponding female rats. Also the nuclear surface of the tyrosine hydroxylase-immunoreactive neurons of the arcuate nucleus was higher (p〈0.05) in CPA-treated male than in female rats. In lactotropes of the pituitary gland the immunoreactive prolactin (PRL) was densitometrically increased (p〈 0.05) in CPA-treated female compared with control rats. By electron microscopy, PRL granules and autophagocytosis appeared to be more abundant in CPA-treated rats of both sexes. These data show that fetal exposure to CPA results in long-term anatomical and physiological alterations of hypothalamic and preoptic nuclei as well as of the pituitary lactotropes. These permanent changes support the functional endocrine abnormalities observed in adult rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231158
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Relation of activity in precentral cortical neurons to force and rate of force change during isometric contractions of finger muscles (1975)
    Springer
    Experimental brain research 23 (1975), S. 315-332 
    Details
    ISSN: 1432-1106
    Keywords: Precentral motor cortex ; Unit recording ; Isometric precision grip ; Force and rate of force change ; Microstimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The activity of single neurons within the hand area of the precentral motor cortex of primates was recorded during the performance of a maintained precision grip between the thumb and forefinger. The finger opposition forces were exerted against a strain gauge which allowed force changes to be studied under near isometric conditions. Task performance required the generation of a force ramp (the dynamic phase) and thereafter the maintenance of a stable force for one second (the static phase). Intracortical stimulation through the recording electrode was used to verify that the recordings were made from the appropriate somatotopographic area of the motor cortex. From a total of 221 recorded neurons, 76 were found to be either activated or deactivated during performance of the task. Among the 51 activated neurons, most discharged at higher frequencies during the dynamic phase, than during the static phase. The discharge of some of these neurons could be related to both force (F) and rate of force change (df/dt) whereas certain others could only be correlated with df/dt. The change in discharge frequency for these neurons generally occurred prior to the onset of EMG activity. Eight neurons were more active during maintained force than during the force ramp. The discharge frequency could not be correlated with df/dt and only one showed a significant positive relation to force. The change in discharge frequency for these neurons either coincided or occurred after the onset of EMG activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239743
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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