Santhakumar, V. Wallner, M. Otis, T. S. Ethanol acts directly on extrasynaptic subtypes of GABAA receptors to increase tonic inhibition.
Alcohol.
2007;
41(3):
211-21.
Breese, G. R. Criswell, H. E. Carta, M. Dodson, P. D. Hanchar, H. J. Khisti, R. T. Mameli, M. Ming, Z. Morrow, A. L. Olsen, R. W. Otis, T. S. Parsons, L. H. Penland, S. N. Roberto, M. Siggins, G. R. Valenzuela, C. F. Wallner, M. Basis of the gabamimetic profile of ethanol.
Alcohol Clin Exp Res.
2006;
30(4):
731-44.
Otis, T. S. Jen, J. C. Blessed are the pacemakers.
Nat Neurosci.
2006;
9(3):
297-8.
Hanchar, H. J. Dodson, P. D. Olsen, R. W. Otis, T. S. Wallner, M. Alcohol-induced motor impairment caused by increased extrasynaptic GABAA receptor activity.
Nat Neurosci.
2005;
8(3):
339-45.
Meera, P. Dodson, P. D. Karakossian, M. H. Otis, T. S. Expression of GFP-tagged neuronal glutamate transporters in cerebellar Purkinje neurons.
Neuropharmacology.
2005;
49(6):
883-9.
Karakossian, M. H. Otis, T. S. Excitation of cerebellar interneurons by group I metabotropic glutamate receptors.
J Neurophysiol.
2004;
92(3):
1558-65.
Otis, T. S. Brasnjo, G. Dzubay, J. A. Pratap, M. Interactions between glutamate transporters and metabotropic glutamate receptors at excitatory synapses in the cerebellar cortex.
Neurochem Int.
2004;
45(4):
537-44.
Otis, T. S. Vesicular glutamate transporters in cognito.
Neuron.
2001;
29(1):
11-4.
Otis, T. S. Trussell, L. O. Inhibition of transmitter release shortens the duration of the excitatory synaptic current at a calyceal synapse.
J Neurophysiol.
1996;
76(5):
3584-8.
Mody, I. Otis, T. S. Bragin, A. Hsu, M. Buzsaki, G. GABAergic inhibition of granule cells and hilar neuronal synchrony following ischemia-induced hilar neuronal loss.
Neuroscience.
1995;
69(1):
139-50.
Mody, I. De Koninck, Y. Otis, T. S. Soltesz, I. Bridging the cleft at GABA synapses in the brain.
Trends Neurosci.
1994;
17(12):
517-25.
Otis, T. S. De Koninck, Y. Mody, I. Characterization of synaptically elicited GABAB responses using patch-clamp recordings in rat hippocampal slices.
J Physiol.
1993;
463:
391-407.
Otis, T. S. Mody, I. Differential activation of GABAA and GABAB receptors by spontaneously released transmitter.
J Neurophysiol.
1992;
67(1):
227-35.
Staley, K. J. Otis, T. S. Mody, I. Membrane properties of dentate gyrus granule cells: comparison of sharp microelectrode and whole-cell recordings.
J Neurophysiol.
1992;
67(5):
1346-58.
Otis, T. S. Mody, I. Modulation of decay kinetics and frequency of GABAA receptor-mediated spontaneous inhibitory postsynaptic currents in hippocampal neurons.
Neuroscience.
1992;
49(1):
13-32.
Mody, I. Otis, T. S. Staley, K. J. Kohr, G. The balance between excitation and inhibition in dentate granule cells and its role in epilepsy.
Epilepsy Res Suppl.
1992;
9:
331-9.
Otis, T. S. Gilly, W. F. Jet-propelled escape in the squid Loligo opalescens: concerted control by giant and non-giant motor axon pathways.
Proc Natl Acad Sci U S A.
1990;
87(8):
2911-5.
Meera Pratap, Olsen Richard W, Otis Thomas S, Wallner Martin Etomidate, propofol and the neurosteroid THDOC increase the GABA
efficacy of recombinant alpha4beta3delta and alpha4beta3 GABA(A)
receptors expressed in HEK cells..
Neuropharmacology.
2009;
56(1):
155-60.
Lutz Martin, Otis Martin, Desars Martin, Charpak Martin, Digregorio Martin, Emiliani Martin Holographic photolysis of caged neurotransmitters..
Nature methods.
2008;
56(1):
.
Otis Thomas S, Sofroniew Michael V Glia get excited..
Nature neuroscience.
2008;
11(4):
379-80.
Fortin Doris L, Banghart Matthew R, Dunn Timothy W, Borges Katharine, Wagenaar Daniel A, Gaudry Quentin, Karakossian Movses H, Otis Thomas S, Kristan William B, Trauner Dirk, Kramer Richard H Photochemical control of endogenous ion channels and cellular
excitability..
Nature methods.
2008;
5(4):
331-8.
Santhakumar, V. Hanchar, H. J. Wallner, M. Olsen, R. W. Otis, T. S. Contributions of the GABAA receptor alpha6 subunit to phasic and tonic inhibition revealed by a naturally occurring polymorphism in the alpha6 gene.
J Neurosci.
2006;
26(12):
3357-64.
Smith, S. L. Otis, T. S. Pattern-dependent, simultaneous plasticity differentially transforms the input-output relationship of a feedforward circuit.
Proc Natl Acad Sci U S A.
2005;
102(41):
14901-6.
Hausser, M. Raman, I. M. Otis, T. Smith, S. L. Nelson, A. du Lac, S. Loewenstein, Y. Mahon, S. Pennartz, C. Cohen, I. Yarom, Y. The beat goes on: spontaneous firing in mammalian neuronal microcircuits.
J Neurosci.
2004;
24(42):
9215-9.
Brasnjo, G. Otis, T. S. Isolation of glutamate transport-coupled charge flux and estimation of glutamate uptake at the climbing fiber-Purkinje cell synapse.
Proc Natl Acad Sci U S A.
2004;
101(16):
6273-8.
Smith, S. L. Judy, J. W. Otis, T. S. An ultra small array of electrodes for stimulating multiple inputs into a single neuron.
J Neurosci Methods.
2004;
133(1-2):
109-14.
Brasnjo, G. Otis, T. S. Glycine transporters not only take out the garbage, they recycle.
Neuron.
2003;
40(4):
667-9.
Smith, S. L. Otis, T. S. Persistent changes in spontaneous firing of Purkinje neurons triggered by the nitric oxide signaling cascade.
J Neurosci.
2003;
23(2):
367-72.
Dzubay, J. A. Otis, T. S. Climbing fiber activation of metabotropic glutamate receptors on cerebellar purkinje neurons.
Neuron.
2002;
36(6):
1159-67.
Otis, T. Helping thy neighbors: spillover at the mossy fiber glomerulus.
Neuron.
2002;
35(3):
412-4.
Brasnjo, G. Otis, T. S. Neuronal glutamate transporters control activation of postsynaptic metabotropic glutamate receptors and influence cerebellar long-term depression.
Neuron.
2001;
31(4):
607-16.
Otis, T. S. Kavanaugh, M. P. Isolation of current components and partial reaction cycles in the glial glutamate transporter EAAT2.
J Neurosci.
2000;
20(8):
2749-57.
Otis, T. S. Jahr, C. E. Anion currents and predicted glutamate flux through a neuronal glutamate transporter.
J Neurosci.
1998;
18(18):
7099-110.
Otis, T. S. Kavanaugh, M. P. Jahr, C. E. Postsynaptic glutamate transport at the climbing fiber-Purkinje cell synapse.
Science.
1997;
277(5331):
1515-8.
Otis, T. Zhang, S. Trussell, L. O. Direct measurement of AMPA receptor desensitization induced by glutamatergic synaptic transmission.
J Neurosci.
1996;
16(23):
7496-504.
Otis, T. S. Wu, Y. C. Trussell, L. O. Delayed clearance of transmitter and the role of glutamate transporters at synapses with multiple release sites.
J Neurosci.
1996;
16(5):
1634-44.
Buhl, E. H. Otis, T. S. Mody, I. Zinc-induced collapse of augmented inhibition by GABA in a temporal lobe epilepsy model.
Science.
1996;
271(5247):
369-73.
Otis, T. S. Raman, I. M. Trussell, L. O. AMPA receptors with high Ca2+ permeability mediate synaptic transmission in the avian auditory pathway.
J Physiol.
1995;
482 ( Pt 2):
309-15.
Otis, T. S. De Koninck, Y. Mody, I. Lasting potentiation of inhibition is associated with an increased number of gamma-aminobutyric acid type A receptors activated during miniature inhibitory postsynaptic currents.
Proc Natl Acad Sci U S A.
1994;
91(16):
7698-702.
Otis, T. S. Staley, K. J. Mody, I. Perpetual inhibitory activity in mammalian brain slices generated by spontaneous GABA release.
Brain Res.
1991;
545(1-2):
142-50.
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Our brains accomplish (or sometimes fail at) their jobs by generating coordinated patterns of electrical signals in groups of nerve cells. Research in my laboratory focuses on the general question of how this coordination occurs. Circuits, single connections (synapses) and electrical properties particular to individual nerve cells combine to allow neurons to generate the specific firing patterns that ultimately result in thoughts, feelings and behaviors. My work concentrates on the cerebellar cortex, a region of the brain involved in coordinating movements and in refining them through practice. While a great deal is known about the firing patterns of particular types of cells in this part of the brain, we have a rudimentary understanding of how its circuitry generates these signals and modifies them during learning.
The simple structure of the cerebellar cortex offers a remarkable context for studying these issues. It is made up of 6 types of neurons whose connectivity and ultrastructure are known in detail. There is one output and there are only two major inputs to the cerebellum. Surprisingly, most of this connectivity can be preserved in a 0.4 mm thick slice preparation of the cerebellum. In the reduced preparation, the output can be easily monitored, and each input can be reliably stimulated. Finally, well-defined patterns of stimulation can be used to recapitulate some of the circuit changes that occur during learning in an intact cerebellum.
One set of projects in the lab explores a curious feature of the main output neurons of the cerebellum, the Purkinje neurons (PNs). PNs fire at high rates (~ 50 impulses / s) in the absence of any synaptic input - it is as if the output of the cerebellar cortex is "halfway on". We are interested in how synaptic inputs to such intrinsically active neurons influence their firing output. We are also examining how learning induced changes in synaptic inputs alter output.
A second set of projects examines the process of neurotransmitter uptake at excitatory synaptic connections that use the neurotransmitter glutamate. Neurotransmitters transmit chemical signals between nerve cells. Such chemical signals cease only when neurotransmitter is actively taken back up into cells (hence the term "neurotransmitter uptake"). The process of neurotransmitter uptake is interesting to us because this mechanism is the target of action of very important classes of drugs including selective serotonin reuptake inhibitors (e.g. Prozac), amphetamines, and cocaine. Even so, we know very little about it. Unanswered questions include: How does neurotransmitter uptake influence the strength of synaptic signals? Does uptake help to determine which targets (i.e. types of neurotransmitter receptors) are signaled? Does the process of transmitter uptake change and are such changes involved in learning or disease? These and related questions are being addressed with a multidisciplinary approach combining electrophysiology, optical imaging of single neurons, and virus-mediated delivery of fluorescently-labeled signaling proteins.
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