Posts classified under: S

Kalyanam Shivkumar, Ph.D.

Dr. Shivkumar is a physician scientist who serves as the director of the UCLA Cardiac Arrhythmia Center & EP Programs (since its establishment in 2002). His is a graduate of the UCLA STAR Program (class of 2000) and his field of specialization is interventional cardiac electrophysiology. He leads a large group at UCLA (comprising a diverse group of fifteen faculty members, several trainees and sixty staff + allied health professionals) involved in clinical care, teaching, research and biomedical innovation. The team provides state of the art clinical care, has developed several innovative therapies (e.g. epicardial ablation, neuromodulation) for the non-pharmacological management of cardiac arrhythmias and other cardiac interventions. The team has a major focus on mechanistic research on the neural control of the mammalian heart. Dr. Shivkumar also serves as the director and chief of the UCLA Cardiovascular Interventional Programs. Dr. Shivkumar’s research work relates to mechanisms of cardiac arrhythmias in humans especially the role of the autonomic nervous system and his research work transcends the perspective of a single organ and has implications for neurovisceral sciences in general. The UCLA Neurocardiology Research Program of Excellence was established by him as the specialized research arm of the Arrhythmia Center in 2014. Dr. Shivkumar and his colleagues are actively involved in human mechanistic studies, development of new intellectual property and medical technology for cardiovascular therapeutics. His IP has been incorporated into medical devices that are now FDA approved and in clinical use. He serves as an editor for several journals in cardiology and cardiac electrophysiology, and is a peer reviewer for several basic science and clinical journals. He also serves as a peer reviewer for the NIH in evaluating cardiac arrhythmia & neuroscience research. His research has been supported by grants from the American Heart Association, the Doris Duke Foundation, private donors and from the NIH (continuously since 2006). Currently Dr. Shivkumar oversees a 15-university NIH consortium on neural control of the heart. Dr. Shivkumar has mentored several STAR awardees and has received several teaching awards. He has been appointed to serve on the board of examiners for Clinical Cardiac Electrophysiology Section of the ABIM (American Board of Internal Medicine). He has been elected to the membership of the American Society of Clinical Investigation (ASCI) and serves as the institutional representative of UCLA for the ASCI. He was elected as an honorary Fellow of the Royal College of Physicians (London) in 2016 & President of the ISAN (International Society of Autonomic Neuroscience) in 2019.…[Author]

Melissa Sharpe, Ph.D.


A selected list of publications:

Maes Etienne J P, Sharpe Melissa J, Usypchuk Alexandra A, Lozzi Megan, Chang Chun Yun, Gardner Matthew P H, Schoenbaum Geoffrey, Iordanova Mihaela D   Causal evidence supporting the proposal that dopamine transients function as temporal difference prediction errors Nature neuroscience, 2020; .
Sharpe Melissa J, Batchelor Hannah M, Mueller Lauren E, Yun Chang Chun, Maes Etienne J P, Niv Yael, Schoenbaum Geoffrey   Dopamine transients do not act as model-free prediction errors during associative learning Nature communications, 2020; 11(1): 106.
Sharpe Melissa J, Stalnaker Thomas, Schuck Nicolas W, Killcross Simon, Schoenbaum Geoffrey, Niv Yael   An Integrated Model of Action Selection: Distinct Modes of Cortical Control of Striatal Decision Making Annual review of psychology, 2019; 70(1): 53-76.
Sharpe Melissa J, Killcross Simon   Modulation of attention and action in the medial prefrontal cortex of rats Psychological review, 2018; 125(5): 822-843.
Sharpe Melissa J   What a relief! A role for dopamine in positive (but not negative) valence Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2018; 43(8): 1-2.
Langdon Angela J, Sharpe Melissa J, Schoenbaum Geoffrey, Niv Yael   Model-based predictions for dopamine Current opinion in neurobiology, 2018; 49(8): 1-7.
Sharpe Melissa J, Schoenbaum Geoffrey   Evaluation of the hypothesis that phasic dopamine constitutes a cached-value signal Neurobiology of learning and memory, 2017; 49(8): 1-7.
Sharpe Melissa J, Batchelor Hannah M, Schoenbaum Geoffrey   Preconditioned cues have no value eLife, 2017; 6(8): 1-7.
Sharpe Melissa J, Marchant Nathan J, Whitaker Leslie R, Richie Christopher T, Zhang Yajun J, Campbell Erin J, Koivula Pyry P, Necarsulmer Julie C, Mejias-Aponte Carlos, Morales Marisela, Pickel James, Smith Jeffrey C, Niv Yael, Shaham Yavin, Harvey Brandon K, Schoenbaum Geoffrey   Lateral Hypothalamic GABAergic Neurons Encode Reward Predictions that Are Relayed to the Ventral Tegmental Area to Regulate Learning Current biology : CB, 2017; 27(14): 2089-2100.e5.
Sharpe Melissa J, Chang Chun Yun, Liu Melissa A, Batchelor Hannah M, Mueller Lauren E, Jones Joshua L, Niv Yael, Schoenbaum Geoffrey   Dopamine transients are sufficient and necessary for acquisition of model-based associations Nature neuroscience, 2017; 20(5): 735-742.
Nasser Helen M, Calu Donna J, Schoenbaum Geoffrey, Sharpe Melissa J   The Dopamine Prediction Error: Contributions to Associative Models of Reward Learning Frontiers in psychology, 2017; 8(5): 244.
Sharpe Melissa J, Schoenbaum Geoffrey   Back to basics: Making predictions in the orbitofrontal-amygdala circuit Neurobiology of learning and memory, 2016; 131(5): 201-6.
Sharpe M J, Clemens K J, Morris M J, Westbrook R F   Daily Exposure to Sucrose Impairs Subsequent Learning About Food Cues: A Role for Alterations in Ghrelin Signaling and Dopamine D2 Receptors Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2016; 41(5): 1357-65.
Sharpe Melissa J, Wikenheiser Andrew M, Niv Yael, Schoenbaum Geoffrey   The State of the Orbitofrontal Cortex Neuron, 2015; 88(6): 1075-1077.
Sharpe Melissa J, Killcross Simon   The prelimbic cortex directs attention toward predictive cues during fear learning Learning & memory (Cold Spring Harbor, N.Y.), 2015; 22(6): 289-93.
Sharpe Melissa, Killcross Simon   The prelimbic cortex uses contextual cues to modulate responding towards predictive stimuli during fear renewal Neurobiology of learning and memory, 2015; 118(6): 20-9.
Sharpe Melissa J, Killcross Simon   The prelimbic cortex contributes to the down-regulation of attention toward redundant cues Cerebral cortex (New York, N.Y. : 1991), 2014; 24(4): 1066-74.
Sharpe Melissa J, Killcross Simon   The prelimbic cortex uses higher-order cues to modulate both the acquisition and expression of conditioned fear Frontiers in systems neuroscience, 2014; 8(6): 235.
Sharpe Melissa J, Fardell Joanna E, Vardy Janette, Johnston Ian N   The chemotherapy agent oxaliplatin impairs the renewal of fear to an extinguished conditioned stimulus in rats Behavioural brain research, 2012; 227(1): 295-9.

Felix Schweizer, Ph.D.


Felix E. Schweizer was born in Basel, Switzerland and conducted his graduate research in the laboratory of Prof. Max M. Burger under the direction of Dr. Theo Schafer. He received his PhD degree in biochemistry summa cum laude from the University of Basel in 1989. From 1990 to 1994, he was a post-doctoral fellow in the Department of Molecular and Cellular Physiology at Stanford University in the laboratory of Prof. Richard W. Tsien. From 1994 to 1998, he was postdoctoral fellow in the Department of Neurobiology at Duke University in the laboratory of Professor George J. Augustine. Dr. Schweizer joined the Department of Neurobiology in the David Geffen School of Medicine at UCLA in 1998 as Assistant Professor and was promoted to Full Professor in 2010. Dr. Schweizer’s research interests concern the molecular mechanisms by which neurons communicate, the regulation of communication by neurons and how alterations in neuronal communication might contribute to neuronal diseases. The Schweizer laboratory uses electrophysiological and optical tools to investigate the dynamic molecular mechanisms underlying the regulation of neurotransmitter release. We are particularly interested in the role of protein ubiquitination in regulating neuronal excitability and synaptic transmission. In collaboration with Dr. James Wohlschlegel, we used multiplexed SILAC and identified synaptic proteins that are dynamically regulated. More recently, in collaboration with Dr. David Krantz, we are using pesticides linked to neuro-degenerative disorders as unbiased tools identify novel pathways that might be involved in early signs of degeneration. In addition, we are characterizing transmission at the first synapse of the vestibular system, i.e. between utricular sensory hair cells and primary afferent neurons. In collaboration with Dr. Larry Hoffman we are finding that changing the gravitational load alters synaptic structures. We are now using serial EM and EM tomography in addition to physiology and cell biology to define in more detail the transfer function between head-movement input and afferent nerve-firing output.

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