Search results for "reflex"
showing 10 items of 622 documents
Reversal of prenatal diazepam-induced deficit in a spatial-object learning task by brief, periodic maternal separation in adult rats.
2005
In the rat, prenatal exposure to diazepam (DZ) induces a permanent reduction in GABA/BZ receptor (R) function and behavioural abnormalities. Environmental modifications during early stages of life can influence brain development and induce neurobiological and behavioural changes throughout adulthood. Indeed, a subtle, periodic, postnatal manipulation increases GABA/BZ R activity and produces facilitatory effects on neuroendocrine and behavioural responses. We here investigated the impact of prenatal treatment with DZ on learning performance in adult 3- and 8-month-old male rats and the influence of a brief, periodic maternal separation on the effects exerted by prenatal DZ exposure. Learnin…
Hyperekplexia caused by dominant-negative suppression of glyra1 function.
2007
Hyperekplexia (HE; startle disease; OMIM#149400) is a rare inheritable neurologic disorder characterized by an exaggerated response to sudden stimuli, muscular rigidity, and hyperreflexia, leading to chronic injuries due to unprotected falls. All symptoms are present at birth but gradually decline during the first year of life, although an exaggerated startle response remains during adulthood.1 Dysfunctional inhibitory neurotransmission by glycine (Gly) plays a central role in HE pathogenesis. All patients with HE carry mutations in genes encoding either for α1 (GLYRA1) or β (GLYRB) Gly receptor subunits, presynaptic Gly transporters (SLC6A5), or proteins involved in Gly receptor (GLYR) clu…
Effects of 10 weeks of military training on neuromuscular function in non-overreached and overreached conscripts
2018
The purpose of the study was to examine how military training influences neuromuscular function in non-overreached and overreached conscripts. A total of 24 male conscripts participated in the study (8 weeks basic training + 2 weeks specialized training). All measurements were conducted during weeks 1, 5, 8 and 10. After the training period, non-overreached (NOR, n = 16) and overreached (OR, n = 8) groups were compared. Isometric maximal forces (bench press, elbow flexion and knee extension), single twitch (plantar flexors), H-reflex, M-wave (Hmax/Mmax) and V-wave (V/Mmax) (soleus) were measured. In knee extension, force production increased in NOR by 22.5 ± 20.5% (p 0.01) between weeks 1 …
Pelvic floor stress response: reflex contraction with pressure transmission to the urethra.
1987
There is still controversy regarding the active role of striated intramural and periurethral muscles and their relative share of function for urinary continence under stress conditions. To evaluate the function of the periurethral muscles, we subjected a dog model to the physiologic stress condition created by sneezing. Simultaneous measurements of intravesical and three urethral pressures were obtained in the intact urinary tract and in a noncontractile substitute urethra, which was pulled through the pelvic floor and studied with and without additional pelvic floor suspension. The data clearly confirm the active role of striated sphincteric muscles for continence under stress conditions. …
Effect of Intraperitoneal Sterile Urine Injection on Abdominal Myoelectrical Activity in the Spinal Rat Model
1991
The abdominal muscle reflex contractions in response to intraperitoneal injection of homologous sterile urine and acid, alkaline, hypo- and hyperosmolar solutions are studied in an acute spinal rat model by conventional and integrated electromyographic techniques. Intraperitoneal injection of homologous sterile urine causes a powerful and almost immediate abdominal muscle contracture of relative short duration. This response seems not to be related to urine pH or osmolarity, since only when solutions with extreme variations in these parameters are injected intraperitoneally are significant abdominal muscle contractions observed.
Corticospinal Modulations during Motor Imagery of Concentric, Eccentric, and Isometric Actions
2019
PURPOSE It is not known yet whether the neurophysiological specificity of eccentric, concentric, and isometric contractions can also be observed when these are mentally simulated. Therefore, our aim was to assess corticospinal excitability during motor imagery (MI) of different contraction types and to test whether a passive movement during MI could have additional effects. METHODS Twelve young participants imagined contractions of the wrist flexors, firstly with the arm motionless (static mode) and second, with a congruent passive movement (wrist extension during eccentric MI and wrist flexion during concentric MI). Motor-evoked potentials (MEP) and H-reflexes were elicited in flexor carpi…
Intellectual engagements of accounting academics: The ‘forecasted losses' intervention
2022
This paper explores the social and political potential of accounting scholarship, presenting and discussing an intellectual intervention challenging a legislative reform that significantly affected Spanish industrial relations. In this reform, an accounting artifact (forecasted losses) played an unexpected role and was misrepresented, prompting a sizeable number of scholars to sign two manifestos in 2010 and 2012 against the use of forecasted losses made by the new legislation. As promoters of this manifesto, we perform in this paper a collaborative autoethnography to reflect on the context, events, reactions, and significance of this intervention for both the academic and the industrial re…
Measuring the refractive state of an eye based on the intensity of the retinal reflex
2017
AbstractWhen examining the fundus of the eye with an ophthalmoscope, the intensity of the retinal reflex depends on the refractive state of the eye. In this study, application of this phenomenon for measuring the refractive state of the eye is demonstrated. First, a calibration curve relating the intensity of the retinal reflex and the refractive state was obtained using a model eye. Next, the intensity of the retinal reflex was measured while subjects were viewing a checker-board pattern, the distance of which was varied within the range from 0.17 to 1 m. Further, the relation between the refractive state and the optical power of the stimulus could be determined based on the measured light…
Geometry of spaces of compact operators
2008
We introduce the notion of compactly locally reflexive Banach spaces and show that a Banach space X is compactly locally reflexive if and only if $\mathcal{K}(Y,X^{**})\subseteq\mathcal{K}(Y,X)^{**}$ for all reflexive Banach spaces Y. We show that X * has the approximation property if and only if X has the approximation property and is compactly locally reflexive. The weak metric approximation property was recently introduced by Lima and Oja. We study two natural weak compact versions of this property. If X is compactly locally reflexive then these two properties coincide. We also show how these properties are related to the compact approximation property and the compact approximation prope…
Nonlinear effects of respiration on the crosstalk between cardiovascular and cerebrovascular control systems.
2016
Cardiovascular and cerebrovascular regulatory systems are vital control mechanisms responsible for guaranteeing homeostasis and are affected by respiration. This work proposes the investigation of cardiovascular and cerebrovascular control systems and the nonlinear influences of respiration on both regulations through joint symbolic analysis (JSA), conditioned or unconditioned on respiration. Interactions between cardiovascular and cerebrovascular regulatory systems were evaluated as well by performing correlation analysis between JSA indexes describing the two control systems. Heart period, systolic and mean arterial pressure, mean cerebral blood flow velocity and respiration were acquired…