Search results for "HALO"
showing 10 items of 2623 documents
Seroquel (ICI 204 636), a putative "atypical" antipsychotic, in schizophrenia with positive symptomatology: results of an open clinical trial and cha…
1995
Preclinical data indicated that seroquel (ICI 204 636), a dibenzothiazepine with 5-HT2 and D2-like receptor antagonistic properties, might be an effective antipsychotic agent, causing fewer extrapyramidal side effects than typical neuroleptics. In the present study, 12 patients suffering from schizophrenia or schizophreniform disorder with predominantly positive symptomatology were treated in an open clinical trial for 4 weeks with seroquel at a maximum dosage of 750 mg/day. The drug was generally well tolerated, and virtually no adverse extrapyramidal side effects such as acute dystonia, parkinsonism or akathisia were observed. Total scores for BPRS (item score 0–6; baseline: 42.0±2.3; mea…
Subchronic haloperidol downregulates dopamine synthesis capacity in the brain of schizophrenic patients in vivo
2003
Udgivelsesdato: 2003-Apr The antipsychotic effect of neuroleptics cannot be attributed entirely to acute blockade of postsynaptic D(2)-like dopamine (DA) receptors, but may arise in conjunction with the delayed depolarization block of the presynaptic neurons and reduced DA synthesis capacity. Whereas the phenomenon of depolarization block is well established in animals, it is unknown if a similar phenomenon occurs in humans treated with neuroleptics. We hypothesized that haloperidol treatment should result in decreased DA synthesis capacity. We used 6-[(18)F]fluoro-L-dopa (FDOPA) and positron emission tomography (PET) in conjunction with compartmental modeling to measure the relative activi…
Cerebral potentials elicited by mechanical stimuli to the human leg: influence of artifacts
1992
Mechanical stimulation with a reflex hammer was applied to the quadriceps muscle tendon of healthy volunteers and patients. The time-locked electrical signals were recorded from the scalp. In all cases, reproducible potentials could be recorded, with latencies in a range of 20 ms to 100 ms. The potentials recorded in patients under complete spinal anesthesia were similar to those derived before the anesthesia. In brain dead patients who showed absence of median nerve or posterior tibial nerve SEP, reproducible potentials after mechanical stimuli could be recorded as well. The results suggest that the hammer taps lead to mechanical shock waves which are propagated along the body producing ti…
The pterygoid reflex in man and its clinical application
1992
A technique for eliciting and recording the stretch reflex (R) of the medial pterygoid muscle (Pter) is described. The latency was 6.9 ± 0.43 ms in 23 healthy volunteers (mean age 23.7 years) showing a side-to-side difference of 0.29 ± 0.21 ms. The PterR latencies were little shorter and side-to-side difference little greater than of the masseter reflex. Observations in 5 selected patients with small brainstem lesions suggest that the neurons of the PterR afferents form a cluster within the caudal portion of the trigeminal mesencephalic nucleus. Testing the masseter and pterygoid reflexes provides a more precise localization of small ponto-mesencephalic lesions. © 1992 John Wiley & Sons, In…
Event-related potential (ERP) responses to violations of inflectional and derivational rules of Finnish
2007
Event-related potentials (ERP) were used to investigate the electrophysiological correlates of inflectional and derivational morphology. The participants were presented with visual sentences containing critical words in which either inflectional, derivational or both rules (combined violation) of Finnish were violated. Inflectional anomalies violated a number agreement of a noun with a previous auxiliary word. Derivational violations included a word-internal selectional restriction violation, i.e., a root and suffix category violation. Combined violations contained both a number and a category violation. The phonemic length of the critical words was controlled. Inflectional violations elici…
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…
Analysis of sleep EEG microstructure in subchronic paroxetine treatment of healthy subjects
1997
Paroxetine is a selective and potent serotonin reuptake inhibitor and its efficacy for the treatment of depression has been proven. Under acute and subchronical treatment regimens, disturbances of the regular sleep pattern are a reported side effect of the drug. The present study was therefore performed to investigate the impact of subchronic treatment with the selective serotonin reuptake inhibitor paroxetine on the microstructure of the sleep EEG. The study especially addressed the question of subchronic effects of paroxetine medication (30 mg/day) in eight healthy male volunteers in a double blind, placebo-controlled crossover design. Conventional sleep EEG parameters and a spectral powe…
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…
Excitability and susceptibility of the brain's electrical activity during sleep: an analysis of late components of AEPs and VEPs.
1991
We investigated ten healthy male subjects and measured late components of AEPs and VEPs during sleep. According to Rechtschaffen and Kales (1968) we performed an off-line scoring procedure of sleep-EEG and averaged the AEPs and VEPs of five different periods, corresponding to sleep stages I, II, III, IV and REM. From the averaged evoked potentials we computed the amplitude-frequency-characteristic (AFC) of the brain (Basar, 1980) during different sleep stages. These AFCs characterize transfer properties of an oscillating system. A comparison of different AFCs has shown that the excitability of the brain depicts a clear alpha resonance during stage I, a pronounced delta resonance during stag…