Search results for "STIMULATION"
showing 10 items of 2192 documents
Early Cellular Reactions in Mechanically Stimulated Gingival Connective Tissue
2001
Aim: The aim of this study was to describe early cellular reactions occuring in mechnically stimulated gingival connective tissue. Material and Method: Elastic bands were inserted between the maxillary first and second molars of male rats aged 8 weeks, which were pulse-labeled with 3H-thymidine and subsequently killed in groups together with labeled control animals after periods of 1–168 hours. Autoradiographs were prepared from plastic mesiodistal sections and parameters of cell proliferation determined in gingival connective tissue sampling areas coronal to the interdental bone crest and in the central zone of the body of the papilla between the second and third molars. The incidence of m…
Proliferative response of cells of the dentogingival junction to mechanical stimulation
2001
SUMMARY The aim of this research was to study the proliferative response of junctional epithelium (JE) and gingival connective tissue (GCT) to mechanical stimulation in vivo with regard to the potential occurrence of apical migration of JE and loss of GCT attachment during orthodontic tooth movement. Elastic bands were inserted between the maxillary first and second molars of male rats aged 8 weeks, which were pulse-labelled with 3 H-thymidine and subsequently killed in groups, together with labelled control animals (a total of 98 rats) after periods of 1‐168 hours. Autoradiographs were prepared from plastic mesiodistal sections, and parameters of cell proliferation for JE and GCT of the pa…
Long-term effects on motor cortical excitability induced by repeated muscle vibration during contraction in healthy subjects
2008
article i nfo Objective: The effects of a novel repeated muscle vibration intervention (rMV; 100 Hz, 90 min over 3 consecutive days) on corticomotor excitability were studied in healthy subjects. Methods: rMV was applied over the flexor carpi radialis (FCR) during voluntary contraction (experiment 1), during relaxation and during contraction without vibration (experiment 2). Focal transcranial magnetic stimulation (TMS) was applied before rMV and one hour, and one, two and three weeks after the last muscle vibration intervention. At each of these time points, we assessed the motor map area and volume in the FCR, extensor digitorum communis (EDC) and abductor digiti minimi (ADM). Short-inter…
Generic Inhibition of the Selected Movement and Constrained Inhibition of Nonselected Movements during Response Preparation
2014
Abstract Previous studies have identified two inhibitory mechanisms that operate during action selection and preparation. One mechanism, competition resolution, is manifest in the inhibition of the nonselected response and attributed to competition between candidate actions. The second mechanism, impulse control, is manifest in the inhibition of the selected response and is presumably invoked to prevent premature response. To identify constraints on the operation of these two inhibitory mechanisms, we manipulated the effectors used for the response alternatives, measuring changes in corticospinal excitability with motor-evoked potentials to TMS. Inhibition of the selected response (impulse …
Multivariate analysis of the modifications induced by an environmental acoustic cue on rat exploratory behavior.
2007
The aim of the present paper is to study by means of a multivariate analysis the modifications induced by an environmental acoustic cue on the structure of rat exploratory behavior. Adult male Wistar rats were observed during the exploration of a soundproof observation box. Each rat was acoustically stimulated after 150 s from the beginning of the experimental session, lasting 300 s, and recorded through a digital videocamera. A frame by frame analysis was thereafter carried out using a professional video-recording system. Thirteen behavioral patterns were selected: immobility, immobile-sniffing, walking, rearing, climbing, chewing, paw-licking, face-grooming, body-grooming, head-turning, t…
Lateral habenula and hippocampus: A complex interaction raphe cells-mediated
1997
The study has shown an excitatory influence exerted by lateral habenula (LH) on hippocampal pyramidal cells. The modulatory influence is paradoxically serotonine-mediated; in fact all LH stimulation effects were abolished by intrahippocampal iontophoretic methysergide application. The data suggest the involvement of dorsal raphe nucleus. In fact, the dorsal raphe nucleus stimulation caused on hippocampus an expected inhibitory effect antagonized by intrahippocampal iontophoretic methysergide application. In the context of this neural structure we have highlighted a disinhibitory relation between two types of cells: slow serotonergic efferent neurones and fast GABAergic interneurones. The di…
Acamprosate blocks the increase in dopamine extracellular levels in nucleus accumbens evoked by chemical stimulation of the ventral hippocampus.
2003
Recently, we have shown that acamprosate is able to modulate extracellular dopamine (DA) levels in the nucleus accumbens (NAc) and may act as an antagonist of N-methyl-D-aspartate (NMDA) receptors. Neurochemical studies show that chemical stimulation (using NMDA) of the ventral subiculum (vSub) of the hippocampus produces robust and sustained increases in extracellular DA levels in the NAc, an effect mediated through ionotropic glutamate (iGlu) receptors. The present study examines whether acamprosate locally infused in the NAc of rats could block or attenuate the increase in NAc extracellular DA elicited by chemical stimulation (with 5 mM NMDA) of the ventral subiculum of the hippocampus. …
Pattern analyses reveal separate experience-based fear memories in the human right Amygdala
2017
Learning fear via the experience of contingencies between a conditioned stimulus (CS) and an aversive unconditioned stimulus (US) is often assumed to be fundamentally different from learning fear via instructions. An open question is whether fear-related brain areas respond differently to experienced CS–US contingencies than to merely instructed CS–US contingencies. Here, we contrasted two experimental conditions where subjects were instructed to expect the same CS–US contingencies while only one condition was characterized by prior experience with the CS–US contingency. Using multivoxel pattern analysis of fMRI data, we found CS-related neural activation patterns in the right amygdala (but…
Intensity of GABA-evoked responses is modified by nitric oxide-active compounds in the subthalamic nucleus of the rat: a microiontophoretic study.
2009
We have previously described modulatory effects of nitric oxide (NO)-active drugs on subthalamic nucleus (STN) neurons. In this study, the effects of microiontophoretically applied NO-active compounds on GABA-evoked responses were investigated in subthalamic neurons extracellularly recorded from anesthetized rats: 45 of 62 cells were excited by S-nitroso-glutathione (SNOG), an NO donor, whereas 28 of 43 neurons were inhibited by N-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor. Nearly all neurons responding to SNOG and/or L-NAME showed significant inhibitory responses to the administration of iontophoretic GABA. In these cells, the changes induced by NO-active drugs in the magnitud…
Autophagic response to strenuous exercise in mouse skeletal muscle fibers.
1984
Strenuous physical exercise induces necrosis of skeletal muscle fibers and increases lysosomal enzyme activities in surviving muscle fibers. This study examines the ultrastructural basis of the stimulation of the lysosomal system in mouse vastus medialis muscle during the appearance and repair of exercise-induced (9 h of running) injuries. Necrotic fibers appeared the day after exercise and an inflammatory response with the replacement of necrotic fibers by phagocytes was highest 2-3 days after exertion. Ultrastructural study of surviving muscle fibers revealed numerous autophagic vacuoles, residual bodies, and spheromembranous structures at the periphery of myofibers, especially in fibers …