Search results for "STIMULATION"
showing 10 items of 2192 documents
Abnormal synchrony and effective connectivity in patients with schizophrenia and auditory hallucinations
2014
Auditory hallucinations (AH) are the most frequent positive symptoms in patients with schizophrenia. Hallucinations have been related to emotional processing disturbances, altered functional connectivity and effective connectivity deficits. Previously, we observed that, compared to healthy controls, the limbic network responses of patients with auditory hallucinations differed when the subjects were listening to emotionally charged words. We aimed to compare the synchrony patterns and effective connectivity of task-related networks between schizophrenia patients with and without AH and healthy controls. Schizophrenia patients with AH (n = 27) and without AH (n = 14) were compared with healt…
Changes in intracortical circuits of the human motor cortex following theta burst stimulation of the lateral cerebellum
2008
Objective: The cerebellum takes part in several motor functions through its influence on the motor cortex (M1). Here, we applied the theta burst stimulation (TBS) protocol, a novel form of repetitive Transcranial Magnetic Stimulation (rTMS) over the lateral cerebellum. The aim of this study was to test whether TBS of the lateral cerebellum could be able to modulate the excitability of the contralateral M1 in healthy subjects. Methods: Motor-evoked potentials (MEPs) amplitude, short intracortical inhibition (SICI), long intracortical inhibition (LICI) and short intracortical facilitation (SICF) were tested in the M1 before and after cerebellar continuous TBS (cTBS) or intermittent TBS (iTBS)…
New determinants of olfactory habituation
2017
AbstractHabituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to continuous or repetitive stimulation. In olfaction, the main question is whether habituation works the same way for any odorant or whether we habituate differently to each odorant? In particular, whether chemical, physical or perceptual cues can limit or increase habituation. To test this, the odour intensity of 32 odorants differing in physicochemical characteristics was rated by 58 participants continuously during 120s. Each odorant was delivered at a constant concentration. Results showed odorants differed significantl…
Acetylcholine overflow from isolated perfused hearts of various species in the absence of cholinesterase inhibition
1977
1. The content of acetylcholine in the tissue and effluent of isolated hearts of various birds and mammals was determined in the absence of inhibition of cholinesterase. 2. Stimulation of both vagus nerves for 15 min at 20 Hz caused marked negative chronotropic effects in all species. Spontaneous or stimulation-induced overflow of acetylcholine into the effluents was not detected in mammals. In the avian heart, the order of spontaneous overflow was: duck = chicken > pigeon, whereas the order of evoked overflow was: chicken > pigeon > duck. The acetylcholine overflow from the cat heart was below the limit of estimation (3 pmol g−1 min−1). In the chicken heart, the evoked overflow per min (28…
Chemical sympathectomy and clorgyline-induced stimulation of rat pineal melatonin synthesis
1989
The response to administration of the specific monoamine oxidase A (MAO-A) blocker clorgyline was investigated in adult male Sprague-Dawley rats which were sympathectomized by injection of the false neurotransmitter 6-hydroxydopamine as newborns. In intact animals which served as controls, the contents of pineal indoles melatonin, serotonin, 5-hydroxytryptophan were augmented, and the content of 5-hydroxyindoleacetic acid decreased 90 min following clorgyline injections when compared to saline receiving rats. Sympathectomized animals exhibited similar responses but these were less pronounced. It is suggested that blocking of the oxidation of both MAO-A substrates, noradrenaline and serotoni…
BDNF contributes to the facilitation of hippocampal synaptic plasticity and learning enabled by environmental enrichment
2014
Sensory, motor, and cognitive stimuli, resulting from interactions with the environment, play a key role in optimizing and modifying the neuronal circuitry required for normal brain function. An experimental animal model for this phenomenon comprises environmental enrichment (EE) in rodents. EE causes profound changes in neuronal and signaling levels of excitation and plasticity throughout the entire central nervous system and the hippocampus is particularly affected. The mechanisms underlying these changes are not yet fully understood. As brain-derived neurotrophic factor (BDNF) supports hippocampal long-term potentiation (LTP), we explored whether it participates in the facilitation of sy…
The visual orientation memory of Drosophila requires Foraging (PKG) upstream of Ignorant (RSK2) in ring neurons of the central complex
2012
Orientation and navigation in a complex environment requires path planning and recall to exert goal-driven behavior. Walking Drosophila flies possess a visual orientation memory for attractive targets which is localized in the central complex of the adult brain. Here we show that this type of working memory requires the cGMP-dependent protein kinase encoded by the foraging gene in just one type of ellipsoid-body ring neurons. Moreover, genetic and epistatic interaction studies provide evidence that Foraging functions upstream of the Ignorant Ribosomal-S6 Kinase 2, thus revealing a novel neuronal signaling pathway necessary for this type of memory in Drosophila.
Disentangling effects of auditory distraction and of stimulus-response sequence
2009
When we pay attention to one task, irrelevant changes may interfere. The effect of changes on behavioral and electrophysiological responses has been studied in two separate research fields: Research on Distraction states that a rare irrelevant change takes attention away from the primary task. Research on Sequences states that any change in stimulus or response incurs a cost or benefit depending on the kind of change. To disentangle distraction from sequence effects, we made task-irrelevant changes rare in one condition and frequent in another while also assessing stimulus and response changes from trial to trial. Participants used key presses to classify syllables presented in two differen…
A fronto-parietal network is mediating improvement of motor function related to repetitive peripheral magnetic stimulation: A PET-H2O15 study.
2006
Repetitive peripheral magnetic stimulation (RPMS) is a focused and painless stimulation method, in which muscle contractions are elicited by depolarization of the terminal motor branches. Clinical-experimental investigations on different disorders of sensorimotor integration in the last decade have shown that RPMS can be used for the rehabilitation of motor functions after stroke. It is supposed that this therapeutic effect is based on the RPMS-induced proprioceptive inflow to the CNS. To analyze the conditioning effects of RPMS on reorganization of the motor system on cortical level positron emission tomography (PET) is used. Regional cerebral blood flow (rCBF) has been measured using H(2)…
Integration of acoustical information in the perception of impacted sound sources. The role of information accuracy and exploitability.
2010
Sound sources are perceived by integrating information from multiple acoustical features. The factors influencing the integration of information are largely unknown. We measured how the perceptual weighting of different features varies with the accuracy of information and with a listener’s ability to exploit it. Participants judged the hardness of two objects whose interaction generates an impact sound: a hammer and a sounding object. In a first discrimination experiment, trained listeners focused on the most accurate information, although with greater difficulty when perceiving the hammer. We inferred a limited exploitability for the most accurate hammer-hardness information. In a second r…