Search results for "reflex"
showing 10 items of 622 documents
Inactivation of the interpositus nucleus blocks the conditioned response acquired by a somatosensory conditioned stimulus in rabbit eyeblink conditio…
2001
1. Earlier studies suggest that the memory trace for the conditioned eyeblink reflex is formed and maintained in the interpositus nucleus (IPN) in the deep cerebellar nuclei when either an auditory or visual stimulus is used as a conditioned stimulus (CS). 2. In the present study, the eyeblink reflex of the rabbit was conditioned to a somatosensory CS (an airpuff onto the back). 3. In well-trained animals, the IPN was reversibly inactivated by local cooling and the existence of the learned responses to the CS was then tested. 4. The reversible IPN inactivation blocked the memory trace the somatosensory CS. The finding further supports the view that IPN-mediated memory trace formation is not…
Topical capsaicin application and axon reflex vasodilatation of the tongue: A videocapillaroscopic study
2006
The aim of this study was to evaluate the effects of topical capsaicin application on human lingual mucosa and to assess if neurogenic inflammation might have a role in the pathogenesis of lingual diseases. Thirty patients (16 males and 14 females; mean age: 41.46 +/- 11.8 years; range: 23-60) were examined in our laboratory. The neurogenic inflammation was experimentally induced in the lingual mucosa close to 1) the left margin of the tongue and 2) the right margin of the tongue after ipsilateral nerve trunk anesthesia. The characteristics of lingual microcirculation were observed using computerized videocapillaroscopic techniques. The vasodilatation was observed close to the left margin o…
Influence of carbenoxolone on the anticonvulsant efficacy of conventional antiepileptic drugs against audiogenic seizures in DBA/2 mice
2004
Carbenoxolone, the succinyl ester of glycyrrhetinic acid, is an inhibitor of 11beta-hydroxy steroid dehydrogenase and gap junctional intercellular communication. It is currently used in clinical treatment of ulcer diseases. Systemic administration of carbenoxolone (1-40 mg/kg, intraperitoneally (i.p.)) was able to produce a dose-dependent decrease in DBA/2 audiogenic seizure severity score. Glycyrrhizin, an analogue of carbenoxolone inactive at the gap-junction level, was unable to affect audiogenic seizures at doses up to 30 mg/kg. In combination with conventional antiepileptic drugs, carbenoxolone, 0.5 mg/kg, i.p., which per se did not significantly affect the occurrence of audiogenic sei…
Effect of angular velocity on soleus and medial gastrocnemius H-reflex during maximal concentric and eccentric muscle contraction.
2009
At rest, the H-reflex is lower during lengthening than shortening actions. During passive lengthening, both soleus (SOL) and medial gastrocnemius (MG) H-reflex amplitudes decrease with increasing angular velocity. This study was designed to investigate whether H-reflex amplitude is affected by angular velocity during concentric and eccentric maximal voluntary contraction (MVC). Experiments were performed on nine healthy men. At a constant angular velocity of 60 degrees /s and 20 degrees /s, maximal H-reflex and M-wave potentials were evoked at rest (i.e., H(max) and M(max), respectively) and during concentric and eccentric MVC (i.e., H(sup) and M(sup), respectively). Regardless of the muscl…
Influence of gravity vector on eye movement elicited by linear acceleration.
1991
When the body/head motion is sensed by otolith organs, they respond not only to the resultant acceleration of the motion but also to the gravitational force. We investigated the influence of the gravity vector on the otolithic-ocular reflex caused by motion in normal subjects. The sled type linear accelerator, moving back and forth with a frequency of 0.25 Hz and an amplitude of 2 m, generated right-left linear acceleration with a maximum magnitude of 0.5 g. We tested every subject under seven different postures: 1) 135 degrees forward tilted (F.T.), 2) 90 degrees F.T., 3) 45 degrees F.T., 4) upright sitting, 5) 45 degrees backward tilted (B.T.), 6) 90 degrees B.T., and 7) 135 degrees B.T. …
Vestibular adaptation to centrifugation does not transfer across planes of head rotation
2008
Out-of-plane head movements performed during fast rotation produce non-compensatory nystagmus, sensations of illusory motion, and often motion sickness. Adaptation to this cross-coupled Coriolis stimulus has previously been demonstrated for head turns made in the yaw (transverse) plane of motion, during supine head-on-axis rotation. An open question, however, is if adaptation to head movements in one plane of motion transfers to head movements performed in a new, unpracticed plane of motion. Evidence of transfer would imply the brain builds up a generalized model of the vestibular sensory-motor system, instead of learning a variety of individual input/output relations separately. To investi…
Midbrain vs. pontine medial longitudinal fasciculus lesions: The utilization of masseter and blink reflexes
1991
Masseter (MR) and blink reflexes (BL) were investigated in 51 patients with internuclear ophthalmoplegia (INO) due to multiple sclerosis (28) and lacunar infarction (23). The MR was abnormal in 20 of 23 cases with bilateral INO and in 21 of 28 with unilateral INO. The R1 component of the BL (BL-R1) was abnormal in 7 of 23 patients with bilateral INO and 10 of 28 with unilateral INO. Combined MR and BL-R1 changes occurred in 8 of 28 cases with unilateral INO and 7 of 23 with bilateral INO. The findings provide evidence for a rostral/caudal localization of lesions within the medial longitudinal fasciculus causing INO on the basis of MR and BL-R1 abnormalities. An abnormality limited to MR sug…
Convergence of nociceptive and non-nociceptive inputs onto spinal reflex pathways to the tibialis anterior muscle in humans
1998
The interaction of low-threshold mechanoreceptive and nociceptive inputs onto spinal neurones probably plays a major role in the pathophysiology of the clinical sign of allodynia. This phenomenon was investigated by modulation of the early component of the flexor reflex (FR) in the tibialis anterior (TA) muscle, elicited by electrical stimulation of the medial plantar nerve at the sole of the foot, by homotopically applied painful heat in humans. This early reflex with an electrical threshold of 2.7-fold the detection threshold and a mean afferent conduction velocity of 49 m s-1 is a non-nociceptive FR. When applying conditioning painful heat (46 degrees C) to the sole of the foot this refl…
Academics as Politicians and as Operators of Global Governance
2018
In this chapter, the author scrutinizes the links between politics and academe in global governance. He analyzes two cases, those of former president of the European Commission Jose Manuel Barroso and philosopher Michel Foucault, that exemplify different types of political engagement. Social scientists play a key but concealed part in the steering of global governance. Under and beyond global institutions, they partake in the development of influential transnational professional groups. By producing practical knowledge for everyday or ‘banal’ global governance, social scientists shape the politically imaginable at more institutional levels. Yet others provide at a higher level of abstractio…
Conclusion: A Conversation
2017
In the concluding chapter the editors of the volume take a conversational look into the producing process of Nordic Girlhoods: New Perspectives and Outlooks. The authors discuss key contemporary issues and future perspectives in Nordic girlhood studies and foreground the political relevance of the research field in the contemporary societal situation. They call for reflexive and critical theorizations on what counts as the Nordic, especially when the girl is to be found in the middle of several nationalistic desires and conservative political discourses.