Prefrontal response and frontostriatal functional connectivity to monetary reward in abstinent alcohol-dependent young adults

Although altered function in neural reward circuitry is widely proposed in models of addiction, more recent conceptual views have emphasized the role of disrupted response in prefrontal regions. Changes in regions such as the orbitofrontal cortex, medial prefrontal cortex, and dorsolateral prefrontal cortex are postulated to contribute to the compulsivity, impulsivity, and altered executive function that are central to addiction. In addition, few studies have examined function in these regions during young adulthood, when exposure is less chronic than in typical samples of alcohol-dependent adults. To address these issues, we examined neural response and functional connectivity during monetary reward in 24 adults with alcohol dependence and 24 psychiatrically healthy adults. Adults with alcohol dependence exhibited less response to the receipt of monetary reward in a set of prefrontal regions including the medial prefrontal cortex, lateral orbitofrontal cortex, and dorsolateral prefrontal cortex. Adults with alcohol dependence also exhibited greater negative correlation between function in each of these regions and that in the nucleus accumbens. Within the alcohol-dependent group, those with family history of alcohol dependence exhibited lower mPFC response, and those with more frequent drinking exhibited greater negative functional connectivity between the mPFC and the nucleus accumbens. These findings indicate that alcohol dependence is associated with less engagement of prefrontal cortical regions, suggesting weak or disrupted regulation of ventral striatal response. This pattern of prefrontal response and frontostriatal connectivity has consequences for the behavior patterns typical of addiction. Furthermore, brain-behavior findings indicate that the potential mechanisms of disruption in frontostriatal circuitry in alcohol dependence include family liability to alcohol use problems and more frequent use of alcohol. In all, these findings build on the extant literature on reward-circuit function in addiction and suggest mechanisms for disrupted function in alcohol dependence. © 2014 Forbes et al

Information-limiting correlations

Computational strategies used by the brain strongly depend on the amount of information that can be stored in population activity, which in turn strongly depends on the pattern of noise correlations. In vivo, noise correlations tend to be positive and proportional to the similarity in tuning properties. Such correlations are thought to limit information, which has led to the suggestion that decorrelation increases information. In contrast, we found, analytically and numerically, that decorrelation does not imply an increase in information. Instead, the only information-limiting correlations are what we refer to as differential correlations: correlations proportional to the product of the derivatives of the tuning curves. Unfortunately, differential correlations are likely to be very small and buried under correlations that do not limit information, making them particularly difficult to detect. We found, however, that the effect of differential correlations on information can be detected with relatively simple decoders

A WR3-band reflective-type phase shifter MMIC with integrated amplifier for error- and loss compensation

To enable beamsteering capabilities for millimeter-wave radar and communication systems, phase shifters are key components. In this paper a WR3-band (220-325 GHz) phase shifter MMIC is presented, which is based on reflective-type phase shifters and enhanced with an integrated variable gain amplifier for loss-compensation, RMS error optimization and antenna tapering. The circuit has an average loss of only 1.6 dB and a 3 dB bandwidth ranging from 218 to 268 GHz. In this frequency range the maximum phase shift is 247° with phase and amplitude RMS errors below 10.4° and 1.5 dB, respectively. The MMIC was processed in a 50 nm InGaAs metamorphic HEMT technology and has a chip size of only 0.75 × 0.75 mm2

Limbic P300s in temporal lobe epilepsy with and without Ammon's horn sclerosis

Limbic P300 potentials can be recorded within the mesial temporal robes of patients with temporal lobe epilepsy (TLE). To delineate possible mechanisms of their generation and pathological alteration, we analysed limbic P300s in 55 TLE patients with and 29 without Ammon's horn sclerosis (AHS) and correlated their amplitudes with neuronal cell counts in 30 histopathological specimens. Limbic P300 amplitudes were reduced on the side of the epileptogenic focus only in patients with AHS. Moreover, in AHS patients, limbic P300 latencies were prolonged bilaterally; and in patients with left-sided AHS, amplitudes were reduced bilaterally. Both findings suggest bilateral functional deficits in TLE with unilateral AHS. Limbic P300 areas correlated significantly with neuronal densities of dentate gyrus granule cells but not hippocampal pyramidal cells in the CA1-4 (cornu ammonia) subfields. This finding points to a potential mechanism for the bilateral effects of unilateral AHS as both dentate gyri exhibit strong reciprocal contralateral connectivity

Advances in renal cell carcinoma treatment

The treatment of advanced renal cell carcinoma has been completely changed by the development of new therapeutic modalities during the past 3 years. In this time period six targeted agents have been approved for the treatment of advanced or metastatic disease. Phase 3 data support the use of sunitinib, bevacizumab plus interferon-α and pazopanib for patients with low and intermediate risk of clear-cell renal cell carcinoma. In the pivotal study of temsirolimus a significant longer overall survival compared with interferon-α in high-risk disease including non-clear-cell histology was observed. Patients pretreated with cytokines will benefit from sorafenib and pazopanib while everolimus has been shown to increase significantly progression-free survival after previous anti-angiogenesis therapy. In addition to these phase 3 data-based recommendations, several other factors have to be considered for treatment selection, for example, side effect profile and patients’ comorbidities. Currently, the sequential use of the available targeted drugs and adjuvant treatment are the subject of ongoing clinical trials. However, medical treatment of renal cell carcinoma remains palliative and surgery remains the only curative approach in patients with localized, locally advanced and limited metastatic disease

Evidence relating human verbal memory to hippocampal N-methyl-d-aspartate receptors

Studies in rodents and nonhuman primates have linked the activity of N-methyl-d-aspartate (NMDA) receptors within the hippocampus to animals’ performance on memory-related tasks. However, whether these receptors are similarly essential for human memory is still an open question. Here we present evidence suggesting that hippocampal NMDA receptors, most likely within the CA1 region, do participate in human verbal memory processes. Words elicit a negative event-related potential (ERP) peaking around 400 ms within the anterior mesial temporal lobe (AMTL-N400). Ketamine, an NMDA-receptor antagonist, reduces the amplitude of the AMTL-N400 (in contrast to other hippocampal potentials) on initial presentation, eliminates the typical AMTL-N400 amplitude reduction with repetition, and leads to significant memory impairment. Of the various hippocampal subfields, only the density of CA1 neurons correlates with the word-related ERPs that are reduced by ketamine. Altogether, our behavioral, anatomical, and electrophysiological results indicate that hippocampal NMDA receptors are involved in human memory