40 research outputs found

    Hungry brains: A meta-analytical review of brain activation imaging studies on food perception and appetite in obese individuals

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    The dysregulation of food intake in chronic obesity has been explained by different theories. To assess their explanatory power, we meta-analyzed 22 brain-activation imaging studies. We found that obese individuals exhibit hyper-responsivity of the brain regions involved in taste and reward for food-related stimuli. Consistent with a Reward Surfeit Hypothesis, obese individuals exhibit a ventral striatum hyper-responsivity in response to pure tastes, particularly when fasting. Furthermore, we found that obese subjects display more frequent ventral striatal activation for visual food cues when satiated: this continued processing within the reward system, together with the aforementioned evidence, is compatible with the Incentive Sensitization Theory. On the other hand, we did not find univocal evidence in favor of a Reward Deficit Hypothesis nor for a systematic deficit of inhibitory cognitive control. We conclude that the available brain activation data on the dysregulated food intake and food-related behavior in chronic obesity can be best framed within an Incentive Sensitization Theory. Implications of these findings for a brain-based therapy of obesity are briefly discussed

    Autonomic responses to emotional linguistic stimuli and amplitude of low-frequency fluctuations predict outcome after severe brain injury

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    An accurate prognosis on the outcome of brain-injured patients with disorders of consciousness (DOC) remains a significant challenge, especially in the acute stage. In this study, we applied a multiple-technique approach to provide accurate predictions on functional outcome after 6 months in 15 acute DOC patients. Electrophysiological correlates of implicit cognitive processing of verbal stimuli and data-driven voxel-wise resting-state fMRI signals, such as the fractional amplitude of low-frequency fluctuations (fALFF), were employed. Event-related electrodermal activity, an index of autonomic activation, was recorded in response to emotional words and pseudo-words at baseline (T0). On the same day, patients also underwent a resting-state fMRI scan. Six months later (T1), patients were classified as outcome-negative and outcome-positive using a standard functional outcome scale. We then revisited the baseline measures to test their predictive power for the functional outcome measured at T1. We found that only outcome-positive patients had an earlier, higher autonomic response for words compared to pseudo-words, a pattern similar to that of healthy awake controls. Furthermore, DOC patients showed reduced fALFF in the posterior cingulate cortex (PCC), a brain region that contributes to autonomic regulation and awareness. The event-related electrodermal marker of residual cognitive functioning was found to have a significant correlation with residual local neuronal activity in the PCC. We propose that a residual autonomic response to cognitively salient stimuli, together with a preserved resting-state activity in the PCC, can provide a useful prognostic index in acute DOC

    Rapid increase of carbapenemase-producing Klebsiella pneumoniae strains in a large Italian hospital: surveillance period 1 March - 30 September 2010.

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    The first case of carbapenemase-producing Enterobacteriaceae in Italy was reported in 2009. We performed a study over a period of seven months in 2010 to survey the circulation of Klebsiella pneumoniae carbapenemases (KPC) in a 1,500-bed university hospital in northern Italy and report the presence and rapid increase of these multidrug-resistant bacteria. The results raise a major concern about these pathogens and demonstrate the urgent need for infection control and antibiotic stewardship programmes

    Dual S-100-AE1/3 Immunohistochemistry to Detect Perineural Invasion in Nonmelanoma Skin Cancers

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    Background. Perineural invasion (PNI) is an adverse prognostic histologic finding and increases the risk of local recurrence and metastasis. Objective. We aimed to determine if dual immunohistochemical (IHC) staining with S-100 and AE1/3 would increase the detection of PNI on nonmelanoma skin cancers (NMSCs). Methods. We collected 45 specimens of NMSCs in which there was clinical suspicion for PNI. Two dermatopathologists independently reviewed the tumors for the unequivocal presence of PNI. Results. Unequivocal PNI was present on 10 of the 45 tumors by H&E staining and on 15 of the 45 tumors by IHC staining. Large nerves (>0.1 mm) were involved in 3 of 10 H&E-stained cases and 3 of 15 IHC-stained cases, with 2 of the 4 cases demonstrating large nerve involvement with both staining methods. Of the 8 cases of PNI detected only on IHC, 7 were small nerves (≤0.1 mm). Limitations. All cases were selected because they were clinically suspicious for PNI, and this may be considered selection bias. Conclusions. PNI detection may be increased using dual S-100 and AE1/3 staining, but the majority of additional cases detected were small nerves. The clinical significance, given the small size of the involved nerves, is unclear

    Neural intersections of the phonological, visual magnocellular and motor/cerebellar systems in normal readers: Implications for imaging studies on dyslexia.

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    We used fMRI to explore the extent of the anatomical overlap of three neural systems that the literature on developmental dyslexia associates with reading: the auditory phonological, the visual magnocellular, and the motor/cerebellar systems. Twenty-eight normal subjects performed four tasks during fMRI scans: word and pseudoword reading, auditory rhyming for letter names, visual motion perception, and a motor sequence learning task. We found that the left occipitotemporal cortex (OTC), which previous studies reported to be dysfunctional in dyslexia, can be fractionated into different functional areas: an anterior and lateral area that was activated by both reading and auditory rhyming tasks; a posterior area that was commonly activated by both the reading and the motion perception task and a medial/intermediate area, including the so-called Visual Word Form Area, which was specifically activated by the reading task. These results show that the left OTC is an area of segregated convergence of different functional systems. We compared our results with the hypoactivation pattern reported for reading in a previous cross-cultural PET study on 36 dyslexic subjects from three countries. The region of decreased activation in dyslexia overlapped with regions that are specific for reading and those activated during both the auditory rhyming task and the single word and pseudoword reading task described in the present fMRI study. No overlap was found with the activation patterns for the visual motion perception task or for the motor sequence learning task. These observations challenge current theories of dyslexia
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