Faculty Bibliography

A key technical barrier to furthering our understanding of complex neural networks has been the lack of tools for the simultaneous spatiotemporal control and detection of activity in a large number of neurons. Here, we report an all-optical system for achieving this kind of parallel and selective control and detection. We do this by delivering spatiotemporally complex optical stimuli through a digital micromirror spatiotemporal light modulator to cells expressing the light-activated ionotropic glutamate receptor (LiGluR), which have been labeled with a calcium dye to provide a fluorescent report of activity. Reliable and accurate spatiotemporal stimulation was obtained on HEK293 cells and cultured rat hippocampal neurons. This technique should be adaptable to in vivo applications and could serve as an optical interface for communicating with complex neural circuits.

OBJECTIVE: Proton magnetic resonance spectroscopy ((1)H-MRS) has been increasingly used to examine striatal neurochemistry in adult major depressive disorder. This study extends the use of this modality to pediatric major depression to test the hypothesis that adolescents with major depression have elevated concentrations of striatal choline and creatine and lower concentrations of N-acetylaspartate. METHOD: Fourteen adolescents (ages 12-19 years, eight female) who had major depressive disorder for at least 8 weeks and a severity score of 40 or higher on the Children's Depression Rating Scale-Revised and 10 healthy comparison adolescents (six female) group-matched for gender, age, and handedness were enrolled. All underwent three-dimensional 3-T (1)H-MRS at high spatial resolution (0.75-cm(3) voxels). Relative levels of choline, creatine, and N-acetylaspartate in the left and right caudate, putamen, and thalamus were scaled into concentrations using phantom replacement, and levels were compared for the two cohorts. RESULTS: Relative to comparison subjects, adolescents with major depressive disorder had significantly elevated concentrations of choline (2.11 mM versus 1.56 mM) and creatine (6.65 mM versus 5.26 mM) in the left caudate. No other neurochemical differences were observed between the groups. CONCLUSIONS: These findings most likely reflect accelerated membrane turnover and impaired metabolism in the left caudate. The results are consistent with prior imaging reports of focal and lateralized abnormalities in the caudate in adult major depression

Neuroimaging studies of decision-making have generally related neural activity to objective measures (such as reward magnitude, probability or delay), despite choice preferences being subjective. However, economic theories posit that decision-makers behave as though different options have different subjective values. Here we use functional magnetic resonance imaging to show that neural activity in several brain regions--particularly the ventral striatum, medial prefrontal cortex and posterior cingulate cortex--tracks the revealed subjective value of delayed monetary rewards. This similarity provides unambiguous evidence that the subjective value of potential rewards is explicitly represented in the human brain.

Autophagy allows cell survival during starvation through the bulk degradation of proteins and organelles by lysosomal enzymes. However, the mechanisms responsible for the induction and regulation of the autophagy program are poorly understood. Here we show that the FoxO3 transcription factor, which plays a critical role in muscle atrophy, is necessary and sufficient for the induction of autophagy in skeletal muscle in vivo. Akt/PKB activation blocks FoxO3 activation and autophagy, and this effect is not prevented by rapamycin. FoxO3 controls the transcription of autophagy-related genes, including LC3 and Bnip3, and Bnip3 appears to mediate the effect of FoxO3 on autophagy. This effect is not prevented by proteasome inhibitors. Thus, FoxO3 controls the two major systems of protein breakdown in skeletal muscle, the ubiquitin-proteasomal and autophagic/lysosomal pathways, independently. These findings point to FoxO3 and Bnip3 as potential therapeutic targets in muscle wasting disorders and other degenerative and neoplastic diseases in which autophagy is involved

Agrin activates MuSK, a receptor tyrosine kinase expressed in skeletal muscle, leading to tyrosine phosphorylation of the acetylcholine receptor (AChR) beta-subunit and clustering of AChRs. The importance of AChR beta-subunit tyrosine phosphorylation in clustering AChRs and regulating synaptic differentiation is poorly understood. We generated mice with targeted mutations in the three intracellular tyrosines of the AChR beta-subunit (AChR-beta(3F/3F)). Mice lacking AChR beta-subunit tyrosine phosphorylation thrive postnatally and have no overt behavioral defects, indicating that AChR beta-subunit tyrosine phosphorylation is not essential for the formation of neuromuscular synapses. Nonetheless, the size of synapses and the density of synaptic AChRs are reduced in AChR- beta(3F/3F) mutant mice. Moreover, synapses are structurally simplified and the organization of postjunctional folds is aberrant in mice lacking tyrosine phosphorylation of the AChR beta-subunit. Furthermore, mutant AChRs cluster poorly in response to agrin and are readily extracted from the cell surface of cultured myotubes by non-ionic detergent. These data indicate that tyrosine phosphorylation of the AChR beta-subunit has an important role in organizing AChRs and regulating synaptic differentiation

The macroscopic volume-regulated anion current (VRAC) is regulated by both intracellular and extracellular ATP, which has important implications in signaling and regulation of cellular excitability. The outwardly rectifying Cl(-) channel (ORCC) is a major contributor to the VRAC. This study investigated the effects of intracellular and extracellular ATP on the ORCCs expressed in the human cardiovascular system. With inside-out single-channel patch-clamp techniques, ORCCs were recorded from myocytes isolated from human atrium and septal ventricle and from primary cells originating from human coronary artery endothelium and human coronary artery smooth muscle. ORCCs from all of these tissues had similar biophysical properties, i.e., they were outwardly rectifying in symmetrical Cl(-) solutions, exhibited a slope conductance of approximately 90-100 pS at positive potentials and approximately 22 pS at negative potentials, and had a high open probability that was independent of voltage or time. The presence of ATP at the cytosolic face of the membrane increased the number of patches that contained functional ORCC but had no effect on gating. In contrast, 'extracellular' ATP (in pipette solution) had no effect on the proportion of patches in which ORCC was detected but strongly reduced the open probability by increasing the closed dwell time. The potency order for nucleotides to affect gating was ATPgammaS > ATP = UTP > ADP > AMP, which suggests that a negatively charged phosphate group is involved in ORCC block. Our findings are consistent with a role of ORCC in the human cardiovasculature (atrium, ventricle, and coronary arteries). Regulation of ORCC by extracellular ATP suggests that this channel may have an important role in maintaining electrical activity and membrane potential under conditions in which extracellular ATP levels are elevated, such as with ATP release from nerve endings or during pathophysiological conditions

BACKGROUND: Dysfunction of basocortical cholinergic projection neurons of the nucleus basalis (NB) correlates with cognitive deficits in Alzheimer disease (AD). Nucleus basalis neurons receive cholinergic inputs and express nicotinic acetylcholine receptors (nAChRs) and muscarinic AChRs (mAChRs), which may regulate NB neuron activity in AD. Although alterations in these AChRs occur in the AD cortex, there is little information detailing whether defects in nAChR and mAChR gene expression occur in cholinergic NB neurons during disease progression. OBJECTIVE: To determine whether nAChR and mAChR gene expression is altered in cholinergic NB neurons during the progression of AD. DESIGN: Individual NB neurons from subjects diagnosed ante mortem as having no cognitive impairment (NCI), mild cognitive impairment (MCI), or mild to moderate AD were analyzed by single-cell AChR expression profiling via custom-designed microarrays. SETTING: Academic research. PARTICIPANTS: Participants were members of the Rush Religious Orders Study cohort. MAIN OUTCOME MEASURES: Real-time quantitative polymerase chain reaction was performed to validate microarray findings. RESULTS: Cholinergic NB neurons displayed a statistically significant up-regulation of alpha7 nAChR messenger RNA expression in subjects with mild to moderate AD compared with those with NCI and MCI (P<.001). No differences were found for other nAChR and mAChR subtypes across the cohort. Expression levels of alpha7 nAChRs were inversely associated with Global Cognitive Score and with Mini-Mental State Examination performance. CONCLUSIONS: Up-regulation of alpha7 nAChRs may signal a compensatory response to maintain basocortical cholinergic activity during AD progression. Alternatively, putative competitive interactions of this receptor with beta-amyloid may provide a pathogenic mechanism for NB dysfunction. Increasing NB alpha7 nAChR expression may serve as a marker for the progression of AD.

Glycolysis is an evolutionary conserved metabolic pathway that provides small amounts of energy in the form of ATP when compared to other pathways such as oxidative phosphorylation or fatty acid oxidation. The ATP levels inside metabolically active cells are not constant and the local ATP level will depend on the site of production as well as the respective rates of ATP production, diffusion and consumption. Membrane ion transporters (pumps, exchangers and channels) are located at sites distal to the major sources of ATP formation (the mitochondria). We review evidence that the glycolytic complex is associated with membranes; both at the plasmalemma and with membranes of the endo/sarcoplasmic reticular network. We examine the evidence for the concept that many of the ion transporters are regulated preferentially by the glycolytic process. These include the Na(+)/K(+)-ATPase, the H(+)-ATPase, various types of Ca(2+)-ATPases, the Na(+)/H(+) exchanger, the ATP-sensitive K(+) channel, cation channels, Na(+) channels, Ca(2+) channels and other channels involved in intracellular Ca(2+) homeostasis. Regulation of these pumps, exchangers and ion channels by the glycolytic process has important consequences in a variety of physiological and pathophysiological processes, and a better understanding of this mode of regulation may have important consequences for developing future strategies in combating disease and developing novel therapeutic approaches

The aim of this study was to validate the published University of California San Francisco (UCSF) Oral Cancer Pain Questionnaire. To test for validity of the questionnaire, 16 patients with oral cancer completed the 8-item questionnaire immediately before and after treatment (surgical resection) of their oral cancer. For all 8 questions, the difference between mean preoperative and mean postoperative responses were statistically significant (P < .05), confirming the validity of the questionnaire to measure oral cancer pain. Internal consistency of the questionnaire was evaluated by using Cronbach's alpha, which provides an estimate of reliability based on all correlations between the items (questions) of the instrument (questionnaire). In the oral cancer pain questionnaire, questions 1, 3, and 5 evaluate the intensity, sharpness, and throbbing nature of pain when the patient is not engaged in oral function (talking, eating, and drinking). Questions 2, 4, and 6 measure the intensity, sharpness, and throbbing nature of pain during oral function. Cronbach's alpha for questions 1, 3, and 5 is 0.87 and Cronbach's alpha for questions 2, 4, and 6 is 0.94; values greater than 0.7 indicate reliability. In this study, we have validated the UCSF Oral Cancer Pain Questionnaire as an effective tool in quantifying pain from oral cancer. PERSPECTIVE: The study validates an oral cancer pain questionnaire. The questionnaire can be used to reliably measure pain levels before and after surgical resection in patients with oral cancer