Search results for "STIMULATION"
showing 10 items of 2192 documents
Cross-frequency coupling between gamma oscillations and deep brain stimulation frequency in Parkinson's disease.
2020
Abstract The disruption of pathologically enhanced beta oscillations is considered one of the key mechanisms mediating the clinical effects of deep brain stimulation on motor symptoms in Parkinson’s disease. However, a specific modulation of other distinct physiological or pathological oscillatory activities could also play an important role in symptom control and motor function recovery during deep brain stimulation. Finely tuned gamma oscillations have been suggested to be prokinetic in nature, facilitating the preferential processing of physiological neural activity. In this study, we postulate that clinically effective high-frequency stimulation of the subthalamic nucleus imposes cross-…
Synergy of features enables detection of texture defined figures
2006
Traditional theories of early visual processing suggest that elementary visual features are handled in parallel by independent neural pathways. We studied the interaction of orientation and spatial frequency in the discrimination of Gabor random fields. Target textures differed from reference textures either in mean feature value, showing an edge-like transition between both textures (edge defined), or in the degree of feature homogeneity with smooth transitions (region defined). Irrespective of the kind of texture definition, we found strong cue summation for targets defined by both cues simultaneously, provided two conditions were fulfilled. First, they were barely discriminable when defi…
Release of [3H]acetylcholine from a modified rat phrenic nerve-hemidiaphragm preparation
1986
Two different preparations of the rat phrenic nerve-hemidiaphragm (whole nerve-muscle preparation, end-plate preparation) were used for studying synthesis and release of radioactive acetylcholine in the absence and presence of cholinesterase inhibitors. When the whole nerve-muscle preparation (110-180 mg) was incubated with [3H]choline, only small amounts of radioactive acetylcholine were synthesized within the tissue. Electrical nerve stimulation of the whole nerve-muscle preparation produced no increase in tritium outflow. Incubation of the end-plate preparation (16-29 mg) which was obtained after removal of most of the muscle mass led to the formation of large amounts of [3H]acetylcholin…
Altered electrical activity in colonic smooth muscle cells from dystrophic (mdx) mice
2001
Because the colon from dystrophic (mdx) mice shows an altered motor pattern, probably due to neural disorders, our aim was to examine the electrophysiological properties of muscle cells and the functionality of nitrergic transmission in circular muscle from normal and mdx colon. Normal colonic cells (resting membrane potential [RMP] about -50 mV) showed spontaneous hyperpolarizations (inhibitory junction potentials; IJPs) and cyclic slow depolarizations were sometimes recorded. Mdx colon had a depolarized RMP (about -36 mV) and spontaneous IJPs, but the cyclic activity was never observed. In the normal colon, Nomega-nitro-L-arginine methyl ester (L-NAME) induced depolarization and abolished…
rTMS of supplementary motor area modulates therapy-induced dyskinesias in Parkinson disease
2005
The neural mechanisms and circuitry involved in levodopa-induced dyskinesia are unclear. Using repetitive transcranial magnetic stimulation (rTMS) over the supplementary motor area (SMA) in a group of patients with advanced Parkinson disease, the authors investigated whether modulation of SMA excitability may result in a modification of a dyskinetic state induced by continuous apomorphine infusion. rTMS at 1 Hz was observed to markedly reduce drug-induced dyskinesias, whereas 5-Hz rTMS induced a slight but not significant increase.
N1 and P2 components of auditory event-related potentials in children with and without reading disabilities.
2007
Abstract Objective The effects of within stimulus presentation rate and rise time on basic auditory processing were investigated in children with reading disabilities and typically reading children. Methods Children with reading disabilities (RD; N =19) and control children ( N =20) were studied using event-related potentials (ERPs). Paired stimuli were used with two different within-pair-intervals (WPI; 10 and 255ms) and two different rise times (10 and 130ms). Each stimulus was presented with equal probability and long between-pair inter-stimulus intervals (1–5s). The study focused on N1 and P2 components. Results The P2 responses to the first tone in the pair showed differences between c…
Electrolytic lesion of the nucleus incertus retards extinction of auditory conditioned fear
2013
Fear memory circuits in the brain function to allow animals and humans to recognize putative sources of danger and adopt an appropriate behavioral response; and research on animal models of fear have helped reveal the anatomical and neurochemical nature of these circuits. The nucleus (n.) incertus in the dorsal pontine tegmentum provides a strong GABAergic projection to forebrain ‘fear centers’ and is strongly activated by neurogenic stressors. In this study in adult male rats, we examined the effect of electrolytic lesions of n. incertus on different stages of the fear conditioning-extinction process and correlated the outcomes with anatomical data on the distribution of n. incertus-derive…
Detection of a temporal structure in the rat behavioural response to an aversive stimulation in the emotional object recognition (EOR) task.
2021
Abstract Aim of the research was to investigate whether a temporal structure could be detected in the behavioural response to an aversive stimulation. A fear-related memory task was used in rats, placed in a modified version of the Novel Object Recognition task known as Emotional Object Recognition task, i.e. a behavioural assay that orbits around the declarative memory for an aversive experience. To this purpose, twelve male Wistar rats, divided in two groups (Control and Aversive memory), observed after 4 h (OR4h) and after 24 h (OR24h) from the delivery of an aversive stimulation, associated to a specific object, were used. Data were evaluated both in terms of conventional quantitative a…
The effects of age and emotional valence on recognition memory: An ex-Gaussian components analysis
2014
[EN] The aim of this work was to study the effects of valence and age on visual image recognition memory. The International Affective Picture System (IAPS) battery was used, and response time data were analyzed using analysis of variance, as well as an ex-Gaussian fit method. Older participants were slower and more variable in their reaction times. Response times were longer for negative valence pictures, however this was statistically significant only for young participants. This suggests that negative emotional valence has a strong effect on recognition memory in young but not in old participants. The tau parameter, often related to attention in the literature, was smaller for young than …
The role of configural information in facial emotion recognition in schizophrenia
2005
International audience; The schizophrenia deficit in facial emotion recognition could be accounted for by a deficit in processing the configural information of the face. The present experiment was designed to further test this hypothesis by studying the face-inversion effect in a facial emotion recognition task. The ability of 26 schizophrenic patients and 26 control participants to recognize facial emotions on upright and upside-down faces was assessed. Participants were told to state whether faces expressed one of six possible emotions (happiness, anger, disgust, fear, sadness, neutrality) in two sessions, one with upright faces and the other with upside-down faces. Discriminability and t…