Search results for "STIMULATION"
showing 10 items of 2192 documents
Irrelevant task suppresses the N170 of automatic attention allocation to fearful faces
2021
AbstractRecent researches have provided evidence that stimulus-driven attentional bias for threats can be modulated by top-down goals. However, it is highlight essential to indicate whether and to what extent the top-down goals can affect the early stage of attention processing and its early neural mechanism. In this study, we collected electroencephalographic data from 28 healthy volunteers with a modified spatial cueing task. The results revealed that in the irrelevant task, there was no significant difference between the reaction time (RT) of the fearful and neutral faces. In the relevant task, we found that RT of fearful faces was faster than that of neutral faces in the valid cue condi…
Median and tibial nerve somatosensory evoked potentials: middle-latency components from the vicinity of the secondary somatosensory cortex in humans
1997
The topography of the middle-latency N110 after radial nerve stimulation suggested a generator in SII. To support this hypothesis, we have tried to identify a homologous component in the tibial nerve SEP (somatosensory evoked potential). Evoked potentials following tibial nerve stimulation (motor + sensory threshold) were recorded with 29 electrodes (bandpass 0.5-500 Hz, sampling rate 1000 Hz). For comparison, the median nerve was stimulated at the wrist. Components were identified as peaks in the global field power (GFP). Map series were generated around GFP peaks and amplitudes were measured from electrodes near map maxima. With median nerve stimulation, we recorded a negativity with a ma…
Dependence of Perceived Purity of a Chromatic Stimulus on Saturation Adaptation
2012
Background and Objective. The purpose of sensory adaptation of the visual system is to adjust sensitivity of the photoreceptors to optimize the dynamic range of response of the visual system. It has been shown in numerous research papers that chromatic adaptation influences both color appearance and color discrimination. However, there are almost no studies in which the influence of chromatic adaptation on perceived purity has been investigated. Therefore, the aim of this study was to investigate how chromatic adaptation to stimuli with certain saturation influences perceived purity of test stimuli with the same hue but different saturation. Material and Methods. As the stimuli were modulat…
Increased visual cortical excitability in ecstasy users: a transcranial magnetic stimulation study
2003
To test the presence of abnormalities of visual cortical excitability in people using ecstasy as a recreational drug.Ecstasy users and control subjects underwent single pulse transcranial magnetic stimulation (TMS) of the occipital cortex. The phosphene threshold was analysed and compared in the two groups.Phosphene thresholds were significantly lower in ecstasy users compared with control subjects, and were correlated negatively with frequency of ecstasy use. Frequency of use was positively correlated with the presence of visual hallucinations. The phosphene threshold of subjects with hallucinations was significantly lower than that of subjects without hallucinations.The use of ecstasy as …
Visual Attention Patterns Differ in Gynephilic and Androphilic Men and Women Depending on Age and Gender of Targets
2017
Visual attention patterns measured with eye-tracking techniques provide indirect clues about sexual response. This study aimed to test the category specificity of sexual responses to stimuli varying in gender and age by evaluating both early and late attention of gynephilic and androphilic men and women. We simultaneously presented sexually preferred and nonpreferred stimuli and measured time to first fixation and total duration of fixation on four areas of interest: entire body, then face, chest, and pelvis. Androphilic women's early attention patterns were nonspecific, whereas gynephilic women and both groups of men showed a category-specific pattern for the entire body. In contrast, all …
Neck Muscle Vibration and Spatial Orientation During Stepping in Place in Humans
2002
Unilateral long-lasting vibration was applied to the sternomastoid muscle to assess the influence of asymmetric neck proprioceptive input on body orientation during stepping-in-place. Blindfolded subjects performed 3 sequences of 3 trials, each lasting 60 s: control, vibration applied during stepping (VDS), and vibration applied before stepping (VBS). VDS caused clear-cut whole body rotation toward the side opposite to vibration. The body rotated around a vertical axis placed at about arm's length from the body. The rotation did not begin immediately on switching on the vibrator. The delay varied from subject to subject from a few seconds to about 10 s. Once initiated, the angular velocity…
Temporal expectation and spectral expectation operate in distinct fashion on neuronal populations
2013
The formation of temporal expectation (i.e., the prediction of ‘when’) is of prime importance to sensory processing. It can modulate sensory processing at early processing stages probably via the entrainment of low-frequency neuronal oscillations in the brain. However, sensory predictions involve not only temporal expectation but also spectral expectation (i.e., the prediction of ‘what’). Here we investigated how temporal expectation may interrelate with spectral expectation by explicitly setting up temporal expectation and spectral expectation in a target detection task. We found that temporal expectation and spectral expectation interacted on reaction time (RT). RT was shorter when target…
Brand Discrimination: An Implicit Measure of the Strength of Mental Brand Representations
2015
While mental associations between a brand and its marketing elements are an important part of brand equity, previous research has yet to provide a sound methodology to measure the strength of these links. The following studies present the development and validation of an implicit measure to assess the strength of mental representations of brand elements in the mind of the consumer. The measure described in this paper, which we call the Brand Discrimination task, requires participants to identify whether images of brand elements (e.g. color, logo, packaging) belong to a target brand or not. Signal detection theory (SDT) is used to calculate a Brand Discrimination index which gives a measure …
Transcranial direct current stimulation of the motor cortex induces distinct changes in thermal and mechanical sensory percepts
2009
Abstract Objective The aim of this single-blinded, complete crossover study was to evaluate the effects of tDCS on thermal and mechanical perception, as assessed by quantitative sensory testing (QST). Methods QST was performed upon the radial part of both hands of eight healthy subjects (3 female, 5 male, 25–41 years of age). These subjects were examined before and after cathodal, anodal or sham tDCS, applied in a random order. TDCS was administered for 15 min at a 1 mA current intensity, with the active electrode placed over the left primary motor cortex and the reference electrode above the right orbit. Results After cathodal tDCS, cold detection thresholds (CDT), mechanical detection thr…
Intraoperative brain mapping of language, cognitive functions, and social cognition in awake surgery of low-grade gliomas located in the right non-do…
2020
Abstract Objective The aim of our study was to evaluate the usefulness of cortical-subcortical intraoperative brain mapping (ioBM) in resective awake surgery of low-grade gliomas (LGG) of the right non-dominant hemisphere (RndH). It was estimated how ioBM may affect both the extent of resection and postoperative outcome of language, spatial cognition, social cognition, and executive functions including attention and working memory. Patients and Methods : Fifteen patients that underwent ioBM in resective awake surgery of LGG located on the RndH, were included. A cohort of 15 patients with the same tumour location operated under general anaesthesia without brain mapping was used as control. S…