78 research outputs found
Diffusion weighted magnetic resonance imaging demonstrates tumor response following palliative embolization of a recurrent shoulder plasmacytoma
We report the palliative embolization and functional imaging follow-up of a recurrent shoulder plasmacytoma. The multiple myeloma patient complained of severe pain and discomfort, while he could not tolerate further chemotherapy. The left shoulder lesion had earlier received a high dose of irradiation. Thus, the well-vascularized lesion was embolized via feeding arteries branching off from the left subclavian artery in two sessions. The patient's symptoms rapidly improved post-embolization and the serum free light chain ratio stabilized at a lower level. The follow-up magnetic resonance image showed increased diffusivity in previously restricted tumor foci. This has negatively correlated with the decreased fludeoxyglucose uptake on PET, suggesting post-embolization necrosis
ICN_Atlas: Automated description and quantification of functional MRI activation patterns in the framework of intrinsic connectivity networks.
Generally, the interpretation of functional MRI (fMRI) activation maps continues to rely on assessing their relationship to anatomical structures, mostly in a qualitative and often subjective way. Recently, the existence of persistent and stable brain networks of functional nature has been revealed; in particular these so-called intrinsic connectivity networks (ICNs) appear to link patterns of resting state and task-related state connectivity. These networks provide an opportunity of functionally-derived description and interpretation of fMRI maps, that may be especially important in cases where the maps are predominantly task-unrelated, such as studies of spontaneous brain activity e.g. in the case of seizure-related fMRI maps in epilepsy patients or sleep states. Here we present a new toolbox (ICN_Atlas) aimed at facilitating the interpretation of fMRI data in the context of ICN. More specifically, the new methodology was designed to describe fMRI maps in function-oriented, objective and quantitative way using a set of 15 metrics conceived to quantify the degree of 'engagement' of ICNs for any given fMRI-derived statistical map of interest. We demonstrate that the proposed framework provides a highly reliable quantification of fMRI activation maps using a publicly available longitudinal (test-retest) resting-state fMRI dataset. The utility of the ICN_Atlas is also illustrated on a parametric task-modulation fMRI dataset, and on a dataset of a patient who had repeated seizures during resting-state fMRI, confirmed on simultaneously recorded EEG. The proposed ICN_Atlas toolbox is freely available for download at http://icnatlas.com and at http://www.nitrc.org for researchers to use in their fMRI investigations
Impaired mixed emotion processing in the right ventrolateral prefrontal cortex in schizophrenia: an fMRI study
Background: Schizophrenia has a negative effect on the activity of the temporal and prefrontal cortices in the processing of emotional facial expressions. However no previous research focused on the evaluation of mixed emotions in schizophrenia, albeit they are frequently expressed in everyday situations and negative emotions are frequently expressed by mixed facial expressions. Methods: Altogether 37 subjects, 19 patients with schizophrenia and 18 healthy control subjects were enrolled in the study. The two study groups did not differ in age and education. The stimulus set consisted of 10 fearful (100%), 10 happy (100%), 10 mixed fear (70% fear and 30% happy) and 10 mixed happy facial expressions. During the fMRI acquisition pictures were presented in a randomized order and subjects had to categorize expressions by button press. Results: A decreased activation was found in the patient group during fear, mixed fear and mixed happy processing in the right ventrolateral prefrontal cortex (VLPFC) and the right anterior insula (RAI) at voxel and cluster level after familywise error correction. No difference was found between study groups in activations to happy facial condition. Patients with schizophrenia did not show a differential activation between mixed happy and happy facial expression similar to controls in the right dorsolateral prefrontal cortex (DLPFC). Conclusions: Patients with schizophrenia showed decreased functioning in right prefrontal regions responsible for salience signaling and valence evaluation during emotion recognition. Our results indicate that fear and mixed happy/fear processing are impaired in schizophrenia, while happy facial expression processing is relatively intact
Electrophysiological Correlates of Learning-Induced Modulation of Visual Motion Processing in Humans
Training on a visual task leads to increased perceptual and neural responses to visual features that were attended during training as well as decreased responses to neglected distractor features. However, the time course of these attention-based modulations of neural sensitivity for visual features has not been investigated before. Here we measured event related potentials (ERP) in response to motion stimuli with different coherence levels before and after training on a speed discrimination task requiring object-based attentional selection of one of the two competing motion stimuli. We found that two peaks on the ERP waveform were modulated by the strength of the coherent motion signal; the response amplitude associated with motion directions that were neglected during training was smaller than the response amplitude associated with motion directions that were attended during training. The first peak of motion coherence-dependent modulation of the ERP responses was at 300 ms after stimulus onset and it was most pronounced over the occipitotemporal cortex. The second peak was around 500 ms and was focused over the parietal cortex. A control experiment suggests that the earlier motion coherence-related response modulation reflects the extraction of the coherent motion signal whereas the later peak might index accumulation and readout of motion signals by parietal decision mechanisms. These findings suggest that attention-based learning affects neural responses both at the sensory and decision processing stages
Online kiegészítő ábra a Strukturált koponya-MR-leletezés neonatalis hypoxiásischaemiás encephalopathiában - a fejlesztés speciális kérdései és első tapasztalatok című közleményhez
Association between migraine frequency and neural response to emotional faces: An fMRI study
Previous studies have demonstrated that migraine is associated with enhanced perception and altered cerebralprocessing of sensory stimuli. More recently, it has been suggested that this sensory hypersensitivity mightreflect a more general enhanced response to aversive emotional stimuli. Using functional magnetic resonanceimaging and emotional face stimuli (fearful, happy and sad faces), we compared whole-brain activation between41 migraine patients without aura in interictal period and 49 healthy controls. Migraine patients showed in-creased neural activation to fearful faces compared to neutral faces in the right middle frontal gyrus and frontalpole relative to healthy controls. We also found that higher attack frequency in migraine patients was related toincreased activation mainly in the right primary somatosensory cortex (corresponding to the face area) to fearfulexpressions and in the right dorsal striatal regions to happy faces. In both analyses, activation differences re-mained significant after controlling for anxiety and depressive symptoms. Thesefindings indicate that enhancedresponse to emotional stimuli might explain the migraine trigger effect of psychosocial stressors that graduallyleads to increased somatosensory response to emotional clues and thus contributes to the progression orchronification of migrain
Preliminary data on the effect of semi-synthetic baits for Noctuidae (Lepidoptera) on the non-target Lepidoptera species
Noctuidae are one of the most important Lepidoptera groups containing dangerous pest species. Monitoring and detection of these pest species is routinely performed by traps baited with sex-pheromones. Baits that attract both males and females were developed for improved pest management. First the effectiveness of different synthetic compounds was evaluated. We also tested semi-synthetic baits that contained both synthetic and natural components (wine and beer). These were more attractive for moths considering species richness and abundance. Disadvantage of this increased effectiveness is that the traps catch more non target, rare and even protected species. In this study we analysed the effect of semi-synthetic baits developed for Noctuid moths containing wine on other non-target Lepidopterans. In the six sampling sites traps caught 17158 individuals of 183 Lepidoptera species. The number of Noctuidae species was 124, while their proportion was 84.4%. The traps caught 813 individuals of 9 protected and 20 valuable species, which was only 4.7% of all Lepidopterans. In contrast the mean proportion of 33 dangerous and potential pest species was 31.3% (5375 individuals). Number and abundance of both protected and pest species were affected by landscape structure. The risks of catching non-target species was higher in species rich natural and semi-natural landscape. In homogenous arable lands the number and proportion of valuable Lepidopterans was not significant
Altered neural activity to monetary reward/loss processing in episodic migraine
The dysfunctions of the mesolimbic cortical reward circuit have been proposed to contribute to migraine pain. Although supporting empirical evidence was mainly found in connection with primary rewards or in chronic migraine where the pain experience is (almost) constant. Our goal however was to investigate the neural correlates of secondary reward/loss anticipation and consumption using the monetary incentive delay task in 29 episodic migraine patients and 41 headache-free controls. Migraine patients showed decreased activation in one cluster covering the right inferior frontal gyrus during reward consumption compared to controls. We also found significant negative correlation between the time of the last migraine attack before the scan and activation of the parahippocampal gyrus and the right hippocampus yielded to loss anticipation. During reward/loss consumption, a relative increase in the activity of the visual areas was observed the more time passed between the last attack and the scan session. Our results suggest intact reward/loss anticipation but altered reward consumption in migraine, indicating a decreased reactivity to monetary rewards. The findings also raise the possibility that neural responses to loss anticipation and reward/loss consumption could be altered by the proximity of the last migraine attack not just during pre-ictal periods, but interictally as well
Increased activation of the pregenual anterior cingulate cortex to citalopram challenge in migraine: an fMRI study
Background: The anterior cingulate cortex (ACC) is a key structure of the pain processing network. Several structural and functional alterations of this brain area have been found in migraine. In addition, altered serotonergic neurotransmission has been repeatedly implicated in the pathophysiology of migraine, although the exact mechanism is not known. Thus, our aim was to investigate the relationship between acute increase of brain serotonin (5-HT) level and the activation changes of the ACC using pharmacological challenge MRI (phMRI) in migraine patients and healthy controls.
Methods: Twenty-seven pain-free healthy controls and six migraine without aura patients participated in the study. All participant attended to two phMRI sessions during which intravenous citalopram, a selective serotonin reuptake inhibitor (SSRI), or placebo (normal saline) was administered. We used region of interest analysis of ACC to compere the citalopram evoked activation changes of this area between patients and healthy participants.
Results: Significant difference in ACC activation was found between control and patient groups in the right pregenual
ACC (pgACC) during and after citalopram infusion compared to placebo. The extracted time-series showed that pgACC
activation increased in migraine patients compared to controls, especially in the first 8–10 min of citalopram infusion.
Conclusions: Our results demonstrate that a small increase in 5-HT levels can lead to increased phMRI signal in the
pregenual part of the ACC that is involved in processing emotional aspects of pain. This increased sensitivity of the pgACC to increased 5-HT in migraine may contribute to recurring headache attacks and increased stress-sensitivity in migraine
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