Search results for "PPI"
showing 10 items of 7396 documents
Neural Mechanisms of Placebo Anxiolysis
2015
The beneficial effects of placebo treatments on fear and anxiety (placebo anxiolysis) are well known from clinical practice, and there is strong evidence indicating a contribution of treatment expectations to the efficacy of anxiolytic drugs. Although clinically highly relevant, the neural mechanisms underlying placebo anxiolysis are poorly understood. In two studies in humans, we tested whether the administration of an inactive treatment along with verbal suggestions of anxiolysis can attenuate experimentally induced states of phasic fear and/or sustained anxiety. Phasic fear is the response to a well defined threat and includes attentional focusing on the source of threat and concomitant …
Visual distraction: a behavioral and event-related brain potential study in humans.
2006
Recent studies reported that the detection of changes in the visual stimulation results in distraction of cognitive processing. From event-related brain potentials it was argued that distraction is triggered by the automatic detection of deviants. We tested whether distraction effects are confined to the detection of a deviation or can be triggered by changes per se, namely by rare stimuli that were not deviant with respect to the stimulation. The results obtained comparable early event-related brain potential effects for rare and deviant stimuli, suggesting an automatic detection of these changes. In contrast, behavioral distraction and attention-related event-related brain potential compo…
Neural correlates of working memory dysfunction in first-episode schizophrenia patients: an fMRI multi-center study.
2005
Working memory dysfunction is a prominent impairment in patients with schizophrenia. Our aim was to determine cerebral dysfunctions by means of functional magnetic resonance imaging (fMRI) in a large sample of first-episode schizophrenia patients during a working memory task. 75 first-episode schizophrenia patients and 81 control subjects, recruited within a multi-center study, performed 2- and 0-back tasks while brain activation was measured with fMRI. In order to guarantee comparability between data quality from different scanners, we developed and adopted a standardized, fully automated quality assurance of scanner hard- and software as well as a measure for in vivo data quality. After t…
Neural Architecture of Selective Stopping Strategies: Distinct Brain Activity Patterns Are Associated with Attentional Capture But Not with Outright …
2017
In stimulus-selective stop-signal tasks, the salient stop signal needs attentional processing before genuine response inhibition is completed. Differential prefrontal involvement in attentional capture and response inhibition has been linked to the right inferior frontal junction (IFJ) and ventrolateral prefrontal cortex (VLPFC), respectively. Recently, it has been suggested that stimulus-selective stopping may be accomplished by the following different strategies: individuals may selectively inhibit their response only upon detecting a stop signal (independent discriminate then stop strategy) or unselectively whenever detecting a stop or attentional capture signal (stop then discriminate s…
Anatomical correlates of visual and tactile extinction in humans: a clinical CT scan study.
1994
The anatomical correlates of tactile and visual extinction with double simultaneous stimulation were investigated in a series of 159 patients with right brain damage caused by stroke. Forty six patients showed extinction (22 tactile, 14 visual, 10 tactile and visual). Over 50% of the patients with extinction had deep lesions, which were found in about 25% of the patients with visuospatial neglect not associated with extinction. In the patients with extinction and cortico-subcortical damage the paraventricular occipital white matter and the dorsolateral frontal cortex were most often involved. By contrast, when neglect was also present, the lesions clustered in the inferior parietal lobule. …
Release of premotor activity after repetitive transcranial magnetic stimulation of prefrontal cortex
2008
In the present study we aimed to explore by means of repetitive transcranial magnetic stimulation (rTMS) the reciprocal influences between prefrontal cortex (PFC) and premotor cortex (PMC). Subjects were asked to observe on a computer monitor different pictures representing manipulations of different kind of tools. They had to produce a movement (go condition) or to keep the resting position (no-go condition) at the appearance of different cue signals represented by different colors shown alternatively on the hands manipulating the tools or on the picture background. Motor evoked potentials (MEPs) were collected at the offset of the visual stimuli before and after a 10 minute, 1 Hz rTMS tra…
Anger superiority effect for change detection and change blindness
2013
Abstract In visual search, an angry face in a crowd “pops out” unlike a happy or a neutral face. This “anger superiority effect” conflicts with views of visual perception holding that complex stimulus contents cannot be detected without focused top-down attention. Implicit visual processing of threatening changes was studied by recording event-related potentials (ERPs) using facial stimuli using the change blindness paradigm, in which conscious change detection is eliminated by presenting a blank screen before the changes. Already before their conscious detection, angry faces modulated relatively early emotion sensitive ERPs when appearing among happy and neutral faces, but happy faces only…
Exploring the relationship between semantics and space
2009
The asymmetric distribution of human spatial attention has been repeatedly documented in both patients and healthy controls. Biases in the distribution of attention and/or in the mental representation of space may also affect some aspects of language processing. We investigated whether biases in attention and/or mental representation of space affect semantic representations. In particular, we investigated whether semantic judgments could be modulated by the location in space where the semantic information was presented and the role of the left and right parietal cortices in this task. Healthy subjects were presented with three pictures arranged horizontally (one middle and two outer picture…
An assessment of the human nail plate pH.
2010
<i>Purpose of Study:</i> To measure the pH of the surface of healthy nail plates. <i>Procedures:</i> The surface pH of human fingernails and big toenails was measured in vivo using a skin pH meter. The influence of washing, anatomical site (fingers/toes), side (left/right), digit (digits 1–5) and gender was determined. The pH of the nail interior was also measured. <i>Results:</i> The pH of the nail plate surface was around 5, with toenails having a significantly higher pH than fingernails. Immediately after hand washing, the nail surface pH increased significantly, from pH 5.1 ± 0.4 to 5.3 ± 0.5. However, this was not sustained with time, and the pH retu…
Patterned functional network disruption in amyotrophic lateral sclerosis
2019
Abstract Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting motor function, with additional evidence of extensive nonmotor involvement. Despite increasing recognition of the disease as a multisystem network disorder characterised by impaired connectivity, the precise neuroelectric characteristics of impaired cortical communication remain to be fully elucidated. Here, we characterise changes in functional connectivity using beamformer source analysis on resting‐state electroencephalography recordings from 74 ALS patients and 47 age‐matched healthy controls. Spatiospectral characteristics of network changes in the ALS patient group were quantifi…