Search results for "Process"
showing 10 items of 22310 documents
Prospective, blinded comparison of cytology and DNA-image cytometry of brush biopsies for early detection of oral malignancy
2012
summary Objectives: Adjunctive techniques like DNA image cytometry (DNA-ICM) have been attributed to enhance the diagnostic performance of oral brush biopsies. The aim of the study was an evaluation of brush biopsies, analysed according to morphological criteria and by DNA-ICM vs. histological findings in a blinded prospective trial. Materials and methods: Eighty eight brush biopsies of 70 patients were sampled. Only clinical suspicious but not evident malignant oral lesions were included. Clinical diagnosis was leukoplakia (n = 36), lichen planus (n = 18), verruciform erythroplakia (n = 12), erythroleukoplakia (n = 9), erosion (n = 7) and induration (n = 6). Evaluation was conducted via hi…
Acute Alcohol Effects on Neuronal and Attentional Processing: Striatal Reward System and Inhibitory Sensory Interactions under Acute Ethanol Challenge
2004
The acute influence of ethanol on cerebral activity induces complex psycho-physiological effects that are considerably more pronounced during acute ethanol influx than during maximal blood alcohol concentration (elimination phase). Despite the psychiatric and forensic relevance of these different ethanol effects, the underlying neuronal mechanisms are still unclear. In total, 20 male healthy volunteers were investigated each with three different experimental conditions in a randomized order using an intravenous ethanol challenge (40 g bolus infusion): during influx phase, elimination phase, and under placebo condition. During and after the ethanol (or placebo) infusion, neuropsychological t…
Cognitive and Motor Loops of the Human Cerebro-cerebellar System
2010
Abstract We applied fMRI and diffusion-weighted MRI to study the segregation of cognitive and motor functions in the human cerebro-cerebellar system. Our fMRI results show that a load increase in a nonverbal auditory working memory task is associated with enhanced brain activity in the parietal, dorsal premotor, and lateral prefrontal cortices and in lobules VII–VIII of the posterior cerebellum, whereas a sensory-motor control task activated the motor/somatosensory, medial prefrontal, and posterior cingulate cortices and lobules V/VI of the anterior cerebellum. The load-dependent activity in the crus I/II had a specific relationship with cognitive performance: This activity correlated negat…
Hemispheric cerebellar rTMS to treat drug-resistant epilepsy: case reports.
2005
Electrical stimulation of the cerebellar cortex by implanted electrodes has been shown to ameliorate refractory epilepsy. We investigated the potential therapeutic role of high-frequency cerebellar rTMS in patients affected by refractory epilepsy due to single or multiple foci. Six patients, three with single and three with multiple epileptic foci, underwent 20 rTMS sessions. Each session was given daily, excluding weekends, and consisted of two trains of 50 stimuli (5 Hz frequency and 90% motor threshold intensity), separated by 50s interval. rTMS was delivered through a focal coil (2 cm below and lateral to the inion) bilaterally in patients with multiple foci (two trains for hemisphere: …
Increased facilitation of the primary motor cortex following 1 Hz repetitive transcranial magnetic stimulation of the contralateral cerebellum in nor…
2005
Connections between the cerebellum and the contralateral motor cortex are dense and important, but their physiological significance is difficult to measure in humans. We have studied a group of 10 healthy subjects to test whether a modulation of the excitability of the left cerebellum can affect the excitability of the contralateral motor cortex. We used repetitive transcranial magnetic stimulation (rTMS) at 1 Hz frequency to transiently depress the excitability of the left cerebellar cortex and paired-pulse TMS testing of intracortical inhibition (ICI) and intracortical facilitation (ICF) to probe the excitability of cortico-cortical connections in the right motor cortex. The cortical sile…
Role of the cerebellum in time perception: A TMS study in normal subjects
2007
The aim of this study was to investigate the role of the cerebellum in a temporal-discrimination task without movement production in healthy subjects. Ten healthy subjects underwent a time-perception task with somatosensory stimuli. Two pairs of electrical stimuli: the first considered the reference pair (rp) with a standard interval of 400 ms and the second, the test pair (tp), with variable intervals ranging from 300 to 500 ms, were applied by surface electrodes on the right forearm. Subjects were instructed to compare time intervals of rp and tp and to estimate whether the tp interval was shorter than, equal to, or longer than that of rp. The task was performed in baseline and after 1 Hz…
Topicality matters: Position-specific demands on Chinese discourse processing
2011
We report an event-related potential study designed to explore the nature of context-induced topicality in Chinese discourse processing. Topic is what an utterance is about and represents the most prominent discourse element, which occurs sentence-initially in Chinese. We tested question-answer pairs consisting of topic and non-topic questions followed by different continuations (Topic-Continuity, Topic-Shift, Novel-Topic). ERPs were measured at distinct sentential positions and revealed that sentence-initially information processing is guided by topicality, which affects N400 and Late Positivity effects alike. In non-initial positions, the given-new distinction is the dominant principle, a…
High opiate receptor binding potential in the human lateral pain system
2005
To determine how opiate receptor distribution is co-localized with the distribution of nociceptive areas in the human brain, eleven male healthy volunteers underwent one PET scan with the subtype-nonselective opioidergic radioligand [(18)F]fluoroethyl-diprenorphine under resting conditions. The binding potential (BP), a parameter for the regional cerebral opioid receptor availability, was computed using the occipital cortex as reference region. The following regions of interest (ROIs) were defined on individual MR images: thalamus, sensory motor strip (SI/MI area), frontal operculum, parietal operculum, anterior insular cortex, posterior insular cortex, anterior cingulate cortex (ACC; peri-…
Cognitive functioning after medial frontal lobe damage including the anterior cingulate cortex: A preliminary investigation
2006
Two patients with medial frontal lobe damage involving the anterior cingulate cortex (ACC) performed a range of cognitive tasks, including tests of executive function and anterior attention. Both patients lesions extended beyond the ACC, therefore caution needs to be exerted in ascribing observed deficits to the ACC alone. Patient performance was compared with age and education matched healthy controls. Both patients showed intact intellectual, memory, and language abilities. No clear-cut abnormalities were noted in visuoperceptual functions. Speed of information processing was mildly reduced only in Patient 2 (bilateral ACC lesion). The patients demonstrated weak or impaired performance on…
Clock genes beyond the clock: CLOCK genotype biases neural correlates of moral valence decision in depressed patients
2007
Gene polymorphisms in the mammalian biological clock system influence individual rhythms. A single nucleotide polymorphism (SNP) in the 3' flanking region of CLOCK (3111 T/C; rs1801260) influenced diurnal preference in healthy humans and caused sleep phase delay and insomnia in patients affected by bipolar disorder. Genes of the biological clock are expressed in many brain structures other than in the 'master clock' suprachiasmatic nuclei. These areas, such as cingulate cortex, are involved in the control of many human behaviors. Clock genes could then bias 'nonclock' functions such as information processing and decision making. Thirty inpatients affected by a major depressive episode under…