Faculty Bibliography

Dopamine (DA) transporter (DAT) imaging has been studied as a diagnostic tool for degenerative parkinsonism. Our aim was to measure the prognostic value of imaging for motor and nonmotor outcomes in Parkinson's disease (PD). We prospectively evaluated a Parkinson's cohort after enrollment in a de novo clinical trial with a battery of motor (UPDRS), cognitive (Montreal Cognitive Assessment), and behavioral measures. DAT imaging with [(123)I][beta]-CIT and single-photon emission computerized tomography (SPECT) was performed at baseline and after 22 months. In total, 491 (91%) of the 537 subjects had evidence of DA deficiency on their baseline scan, consistent with PD, and were included in the analyses. The cohort was followed for 5.5 (0.8) years, with a mean duration of diagnosis of 6.3 (1.2). Lower striatal binding at baseline was independently associated with higher risk for clinical milestones and measures of disease severity, including motor-related disability, falling and postural instability, cognitive impairment, psychosis, and clinically important depressive symptoms. Subjects in the bottom quartile for striatal binding, compared to the top quartile, had an odds ratio (95% confidence interval) of 3.3 (1.7, 6.7) for cognitive impairment and 12.9 (2.6, 62.4) for psychosis. Change from baseline in imaging after 22 months was also independently associated with motor, cognitive, and behavioral outcomes. DAT imaging with [(123)I][beta]-CIT and SPECT, shortly after the diagnosis of PD, was independently associated with clinically important long-term motor and nonmotor outcomes. These results should be treated as hypothesis generating and require confirmation.

Neurophysiological evidence suggests that a specialized cortical network is involved in the visual perception of biological motion; however, the temporal dynamics underlying this network is largely unexplored. We used magnetoencephalography to determine the spatial distribution and task-related temporal dynamics of the oscillatory activity of random and human motion. We recorded cortical responses in healthy adults while they passively viewed point-light displays of static dots, random, and human motion. By analyzing differences in the time-frequency distributions between pairs of conditions, we found that: (a) the perception of both motion conditions resulted in a significant decrease in the alpha/beta band in the right superior occipital gyrus and a significant decrease in the beta band in the right insula and (b) the human motion condition was associated with specific alterations in alpha, beta, and gamma bands with significant reductions in the alpha band in the right superior temporal gyrus, right precuneus, and left inferior parietal lobule, significant reductions in the beta band in the bilateral superior temporal gyrus, together with a significant increase in the gamma band in the left inferior parietal lobule and superior temporal regions. These data suggest that although the perception of both random and human motion involves desynchronization of oscillatory activity in alpha and beta bands in similar cortical regions, only human motion is associated with a larger network and significant alterations in the alpha/beta band particularly in the right hemisphere.

There are two views on vertebrate retinogenesis: a deterministic model dependent on fixed lineages and a stochastic model in which choices of division modes and cell fates cannot be predicted. In this issue of Neuron, He et al. (2012) address this question in zebrafish using live imaging and mathematical modeling.

The conventional view of AD (Alzheimer's disease) is that much of the pathology is driven by an increased load of beta-amyloid in the brain of AD patients (the 'Amyloid Hypothesis'). Yet, many therapeutic strategies based on lowering beta-amyloid have so far failed in clinical trials. This failure of beta-amyloid-lowering agents has caused many to question the Amyloid Hypothesis itself. However, AD is likely to be a complex disease driven by multiple factors. In addition, it is increasingly clear that beta-amyloid processing involves many enzymes and signalling pathways that play a role in a diverse array of cellular processes. Thus the clinical failure of beta-amyloid-lowering agents does not mean that the hypothesis itself is incorrect; it may simply mean that manipulating beta-amyloid directly is an unrealistic strategy for therapeutic intervention, given the complex role of beta-amyloid in neuronal physiology. Another possible problem may be that toxic beta-amyloid levels have already caused irreversible damage to downstream cellular pathways by the time dementia sets in. We argue in the present review that a more direct (and possibly simpler) approach to AD therapeutics is to rescue synaptic dysfunction directly, by focusing on the mechanisms by which elevated levels of beta-amyloid disrupt synaptic physiology.

The variecolortides are a family of unusual natural products that combine motifs from a variety of biosynthetic streams. Herein, we present the gradual evolution of a convergent synthetic strategy that ultimately culminated in a reaction cascade featuring a hydrogen shift and a cycloaddition followed by a spontaneous air oxidation. Attempts to link an anthrone building block with an exo-methylene diketopiperazine using radical chemistry were ultimately unsuccessful, but led to interesting observations that shaped our successful strategy. The total synthesis of variecolortide C is presented for the first time.

To address the pending public health crisis due to Alzheimer's disease (AD) and related neurodegenerative disorders, the Marian S. Ware Alzheimer Program at the University of Pennsylvania held a meeting entitled "State of the Science Conference on the Advancement of Alzheimer's Diagnosis, Treatment and Care," on June 21-22, 2012. The meeting comprised four workgroups focusing on Biomarkers; Clinical Care and Health Services Research; Drug Development; and Health Economics, Policy, and Ethics. The workgroups shared, discussed, and compiled an integrated set of priorities, recommendations, and action plans, which are presented in this article.

High frequency oscillations (HFOs) constitute a novel trend in neurophysiology that is fascinating neuroscientists in general, and epileptologists in particular. But what are HFOs? What is the frequency range of HFOs? Are there different types of HFOs, physiological and pathological? How are HFOs generated? Can HFOs represent temporal codes for cognitive processes? These questions are pressing and this symposium volume attempts to give constructive answers. As a prelude to this exciting discussion, we summarize the physiological high frequency patterns in the intact brain, concentrating mainly on hippocampal patterns, where the mechanisms of high frequency oscillations are perhaps best understood.