Neuroinflammation Alters Integrative Properties of Rat Hippocampal Pyramidal Cells

Neuroinflammation is consistently found in many neurological disorders, but whether or not the inflammatory response independently affects neuronal network properties is poorly understood. Here, we report that intracerebroventricular injection of the prototypical inflammatory molecule lipopolysaccharide (LPS) in rats triggered a strong and long-lasting inflammatory response in hippocampal microglia associated with a concomitant upregulation of Toll-like receptor (TLR4) in pyramidal and hilar neurons. This, in turn, was associated with a significant reduction of the dendritic hyperpolarization-activated cyclic AMP-gated channel type 1 (HCN1) protein level while Kv4.2 channels were unaltered as assessed by western blot. Immunohistochemistry confirmed the HCN1 decrease in CA1 pyramidal neurons and showed that these changes were associated with a reduction of TRIP8b, an auxiliary subunit for HCN channels implicated in channel subcellular localization and trafficking. At the physiological level, this effect translated into a 50% decrease in HCN1-mediated currents (Ih) measured in the distal dendrites of hippocampal CA1 pyramidal cells. At the functional level, the band-pass-filtering properties of dendrites in the theta frequency range (4-12 Hz) and their temporal summation properties were compromised. We conclude that neuroinflammation can independently trigger an acquired channelopathy in CA1 pyramidal cell dendrites that alters their integrative properties. By directly changing cellular function, this phenomenon may participate in the phenotypic expression of various brain diseases.

Electrophoretic drug delivery for seizure control

The persistence of intractable neurological disorders necessitates novel therapeutic solutions. We demonstrate the utility of direct in situ electrophoretic drug delivery to treat neurological disorders. We present a neural probe incorporating a microfluidic ion pump (μFIP) for on-demand drug delivery and electrodes for recording local neural activity. The μFIP works by electrophoretically pumping ions across an ion exchange membrane and thereby delivers only the drug of interest and not the solvent. This "dry" delivery enables precise drug release into the brain region with negligible local pressure increase. The therapeutic potential of the μFIP probe is tested in a rodent model of epilepsy. The μFIP probe can detect pathological activity and then intervene to stop seizures by delivering inhibitory neurotransmitters directly to the seizure source. We anticipate that further tailored engineering of the μFIP platform will enable additional applications in neural interfacing and the treatment of neurological disorders.

Bs → Kℓv form factors with 2+1 flavors

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors f0 and f+ for the semileptonic Bs → Kℓv decay. A total of six ensembles with lattice spacing from ≈ 0.12 to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass m’l is one-tenth the strange quark mass m’s. At the intermediate lattice spacing, the ratio m’l/m’s ranges from 0.05 to 0.2. The valence b quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element |Vub|.

Semileptonic B-meson decays to light pseudoscalar mesons on the HISQ ensembles

We report the status of an ongoing lattice-QCD calculation of form factors for exclusive semileptonic decays of B mesons with both charged currents (B → πlv, Bs → Klv) and neutral currents (B → πl+l-, B → Kl+l-). The results are important for constraining or revealing physics beyond the Standard Model. This work uses MILC’s (2+1 + 1)-flavor ensembles with the HISQ action for the sea and light valence quarks and the clover action in the Fermilab interpretation for the b quark. Simulations are carried out at three lattice spacings down to 0.088 fm, with both physical and unphysical sea-quark masses. We present preliminary results for correlation-function fits.

Function-structure connectivity in patients with severe brain injury as measured by MRI-DWI and FDG-PET

A vast body of literature exists showing functional and structural dysfunction within the brains of patients with disorders of consciousness. However, the function (fluorodeoxyglucose FDG-PET metabolism)-structure (MRI-diffusion-weighted images; DWI) relationship and how it is affected in severely brain injured patients remains ill-defined. FDG-PET and MRI-DWI in 25 severely brain injured patients (19 Disorders of Consciousness of which 7 unresponsive wakefulness syndrome, 12 minimally conscious; 6 emergence from minimally conscious state) and 25 healthy control subjects were acquired here. Default mode network (DMN) function-structure connectivity was assessed by fractional anisotropy (FA) and metabolic standardized uptake value (SUV). As expected, a profound decline in regional metabolism and white matter integrity was found in patients as compared with healthy subjects. Furthermore, a function-structure relationship was present in brain-damaged patients between functional metabolism of inferior-parietal, precuneus, and frontal regions and structural integrity of the frontal-inferiorparietal, precuneus-inferiorparietal, thalamo-inferioparietal, and thalamofrontal tracts. When focusing on patients, a stronger relationship between structural integrity of thalamo-inferiorparietal tracts and thalamic metabolism in patients who have emerged from the minimally conscious state as compared with patients with disorders of consciousness was found. The latter finding was in line with the mesocircuit hypothesis for the emergence of consciousness. The findings showed a positive function-structure relationship within most regions of the DMN. Hum Brain Mapp 37:3707-3720, 2016. © 2016 Wiley Periodicals, Inc.

Commonalities in epileptogenic processes from different acute brain insults: Do they translate?

The most common forms of acquired epilepsies arise following acute brain insults such as traumatic brain injury, stroke, or central nervous system infections. Treatment is effective for only 60%-70% of patients and remains symptomatic despite decades of effort to develop epilepsy prevention therapies. Recent preclinical efforts are focused on likely primary drivers of epileptogenesis, namely inflammation, neuron loss, plasticity, and circuit reorganization. This review suggests a path to identify neuronal and molecular targets for clinical testing of specific hypotheses about epileptogenesis and its prevention or modification. Acquired human epilepsies with different etiologies share some features with animal models. We identify these commonalities and discuss their relevance to the development of successful epilepsy prevention or disease modification strategies. Risk factors for developing epilepsy that appear common to multiple acute injury etiologies include intracranial bleeding, disruption of the blood-brain barrier, more severe injury, and early seizures within 1 week of injury. In diverse human epilepsies and animal models, seizures appear to propagate within a limbic or thalamocortical/corticocortical network. Common histopathologic features of epilepsy of diverse and mostly focal origin are microglial activation and astrogliosis, heterotopic neurons in the white matter, loss of neurons, and the presence of inflammatory cellular infiltrates. Astrocytes exhibit smaller K+ conductances and lose gap junction coupling in many animal models as well as in sclerotic hippocampi from temporal lobe epilepsy patients. There is increasing evidence that epilepsy can be prevented or aborted in preclinical animal models of acquired epilepsy by interfering with processes that appear common to multiple acute injury etiologies, for example, in post-status epilepticus models of focal epilepsy by transient treatment with a trkB/PLCγ1 inhibitor, isoflurane, or HMGB1 antibodies and by topical administration of adenosine, in the cortical fluid percussion injury model by focal cooling, and in the albumin posttraumatic epilepsy model by losartan. Preclinical studies further highlight the roles of mTOR1 pathways, JAK-STAT3, IL-1R/TLR4 signaling, and other inflammatory pathways in the genesis or modulation of epilepsy after brain injury. The wealth of commonalities, diversity of molecular targets identified preclinically, and likely multidimensional nature of epileptogenesis argue for a combinatorial strategy in prevention therapy. Going forward, the identification of impending epilepsy biomarkers to allow better patient selection, together with better alignment with multisite preclinical trials in animal models, should guide the clinical testing of new hypotheses for epileptogenesis and its prevention.

Nrf2-dependent persistent oxidative stress results in stress-induced vulnerability to depression

Stressful life events produce a state of vulnerability to depression in some individuals. The mechanisms that contribute to vulnerability to depression remain poorly understood. A rat model of intense stress (social defeat (SD), first hit) produced vulnerability to depression in 40% of animals. Only vulnerable animals developed a depression-like phenotype after a second stressful hit (chronic mild stress). We found that this vulnerability to depression resulted from a persistent state of oxidative stress, which was reversed by treatment with antioxidants. This persistent state of oxidative stress was due to low brain-derived neurotrophic factor (BDNF) levels, which characterized the vulnerable animals. We found that BDNF constitutively controlled the nuclear translocation of the master redox-sensitive transcription factor Nrf2, which activates antioxidant defenses. Low BDNF levels in vulnerable animals prevented Nrf2 translocation and consequently prevented the activation of detoxifying/antioxidant enzymes, ultimately resulting in the generation of sustained oxidative stress. Activating Nrf2 translocation restored redox homeostasis and reversed vulnerability to depression. This mechanism was confirmed in Nrf2-null mice. The mice displayed high levels of oxidative stress and were inherently vulnerable to depression, but this phenotype was reversed by treatment with antioxidants. Our data reveal a novel role for BDNF in controlling redox homeostasis and provide a mechanistic explanation for post-stress vulnerability to depression while suggesting ways to reverse it. Because numerous enzymatic reactions produce reactive oxygen species that must then be cleared, the finding that BDNF controls endogenous redox homeostasis opens new avenues for investigation.

Fast-Slow Bursters in the Unfolding of a High Codimension Singularity and the Ultra-slow Transitions of Classes

Bursting is a phenomenon found in a variety of physical and biological systems. For example, in neuroscience, bursting is believed to play a key role in the way information is transferred in the nervous system. In this work, we propose a model that, appropriately tuned, can display several types of bursting behaviors. The model contains two subsystems acting at different time scales. For the fast subsystem we use the planar unfolding of a high codimension singularity. In its bifurcation diagram, we locate paths that underlie the right sequence of bifurcations necessary for bursting. The slow subsystem steers the fast one back and forth along these paths leading to bursting behavior. The model is able to produce almost all the classes of bursting predicted for systems with a planar fast subsystem. Transitions between classes can be obtained through an ultra-slow modulation of the model's parameters. A detailed exploration of the parameter space allows predicting possible transitions. This provides a single framework to understand the coexistence of diverse bursting patterns in physical and biological systems or in models.

Epilepsy as a Network Disorder (1): What can we learn from other network disorders such as autistic spectrum disorder and mood disorders?

Epilepsy is a neurologic condition which often occurs with other neurologic and psychiatric disorders. The relation between epilepsy and these conditions is complex. Some population-based studies have identified a bidirectional relation, whereby not only patients with epilepsy are at increased risk of suffering from some of these neurologic and psychiatric disorders (migraine, stroke, dementia, autism, depression, anxiety disorders, Attention deficit hyperactivity disorder (ADHD), and psychosis), but also patients with these conditions are at increased risk of suffering from epilepsy. The existence of common pathogenic mechanisms has been postulated as a potential explanation of this phenomenon. To reassess the relationships between neurological and psychiatric conditions in general, and specifically autism, depression, Alzheimer's disease, schizophrenia, and epilepsy, a recent meeting brought together basic researchers and clinician scientists entitled "Epilepsy as a Network Disorder." This was the fourth in a series of conferences, the "Fourth International Halifax Conference and Retreat". This manuscript summarizes the proceedings on potential relations between Epilepsy on the one hand and autism and depression on the other. A companion manuscript provides a summary of the proceedings about the relation between epilepsy and Alzheimer's disease and schizophrenia, closed by the role of translational research in clarifying these relationships. The review of the topics in these two manuscripts will provide a better understanding of the mechanisms operant in some of the common neurologic and psychiatric comorbidities of epilepsy.

Fermi surface map of large-scale single-orientation graphene on SiO2

Large scale tetraoctylammonium-assisted electrochemical transfer of graphene grown on single-crystalline Ir(1 1 1) films by chemical vapour deposition is reported. The transferred samples are characterized in air with optical microscopy, Raman spectroscopy and four point transport measurements, providing the sheet resistance and the Hall carrier concentration. In vacuum we apply low energy electron diffraction and photoelectron spectroscopy that indicate transferred large-scale single orientation graphene. Angular resolved photoemission reveals a Fermi surface and a Dirac point energy which are consistent with charge neutral graphene.

Methodological standards for in vitro models of epilepsy and epileptic seizures. A TASK1-WG4 report of the AES/ILAE Translational Task Force of the ILAE

In vitro preparations are a powerful tool to explore the mechanisms and processes underlying epileptogenesis and ictogenesis. In this review, we critically review the numerous in vitro methodologies utilized in epilepsy research. We provide support for the inclusion of detailed descriptions of techniques, including often ignored parameters with unpredictable yet significant effects on study reproducibility and outcomes. In addition, we explore how recent developments in brain slice preparation relate to their use as models of epileptic activity.

MULAN: Evaluation and ensemble statistical inference for functional connectivity

Many analysis methods exist to extract graphs of functional connectivity from neuronal networks. Confidence in the results is limited because, (i) different methods give different results, (ii) parameter setting directly influences the final result, and (iii) systematic evaluation of the results is not always performed. Here, we introduce MULAN (MULtiple method ANalysis), which assumes an ensemble based approach combining multiple analysis methods and fuzzy logic to extract graphs with the most probable structure. In order to reduce the dependency on parameter settings, we determine the best set of parameters using a genetic algorithm on simulated datasets, whose temporal structure is similar to the experimental one. After a validation step, the selected set of parameters is used to analyze experimental data. The final step cross-validates experimental subsets of data and provides a direct estimate of the most likely graph and our confidence in the proposed connectivity. A systematic evaluation validates our strategy against empirical stereotactic electroencephalography (SEEG) and functional magnetic resonance imaging (fMRI) data.

Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1

The reconstruction of the signal from hadrons and jets emerging from the proton-proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals. The resulting topological cell clusters have shape and location information, which is exploited to apply a local energy calibration and corrections depending on the nature of the cluster. Topological cell clustering is established as a well-performing calorimeter signal definition for jet and missing transverse momentum reconstruction in ATLAS.

West Nile virus infection in horses, Indian ocean

The circulation of West Nile virus (WNV) in horses was investigated in the Southwest Indian ocean. In 2010, blood samples were collected from a total of 303 horses originating from Madagascar, Mauritius, Reunion and the Seychelles and tested for WNV-specific antibodies. An overall seroprevalence of 27.39% was detected in the Indian Ocean with the highest WNV antibody prevalence of 46.22% (95% CI: [37.4-55.2%]) in Madagascar. The age and origin of the horses were found to be associated with the WNV infection risk. This paper presents the first seroprevalence study investigating WN fever in horses in the Southwest Indian Ocean area and indicates a potential risk of infection for humans and animals. In order to gain a better understanding of WN transmission cycles, WNV surveillance needs to be implemented in each of the countries.

The Safety of Ingested Caffeine: A Comprehensive Review

Caffeine is the most widely consumed psychoactive drug in the world. Natural sources of caffeine include coffee, tea, and chocolate. Synthetic caffeine is also added to products to promote arousal, alertness, energy, and elevated mood. Over the past decade, the introduction of new caffeine-containing food products, as well as changes in consumption patterns of the more traditional sources of caffeine, has increased scrutiny by health authorities and regulatory bodies about the overall consumption of caffeine and its potential cumulative effects on behavior and physiology. Of particular concern is the rate of caffeine intake among populations potentially vulnerable to the negative effects of caffeine consumption: pregnant and lactating women, children and adolescents, young adults, and people with underlying heart or other health conditions, such as mental illness. Here, we review the research into the safety and safe doses of ingested caffeine in healthy and in vulnerable populations. We report that, for healthy adults, caffeine consumption is relatively safe, but that for some vulnerable populations, caffeine consumption could be harmful, including impairments in cardiovascular function, sleep, and substance use. We also identified several gaps in the literature on which we based recommendations for the future of caffeine research.

Panagiotopoulou E, Pandini CE, Panduro Vazquez JG, Pani P, Panitkin S, Pantea D, Paolozzi L, Papadopoulou TD, Papageorgiou K, Paramonov A, Paredes Hernandez D, Parker MA, Parker KA, Parodi F, Parsons JA, Parzefall U, Pascuzzi VR, Pasqualucci E, Passaggio S, Pastore F, Pastore F, Pásztor G, Pataraia S, Patel ND, Pater JR, Pauly T, Pearce J, Pearson B, Pedersen LE, Pedersen M, Pedraza Lopez S, Pedro R, Peleganchuk SV, Pelikan D, Penc O, Peng C, Peng H, Penning B, Penwell J, Perepelitsa DV, Perez Codina E, Perini L, Pernegger H, Perrella S, Peschke R, Peshekhonov VD, Peters K, Peters RFY, Petersen BA, Petersen TC, Petit E, Petridis A, Petridou C, Petroff P, Petrolo E, Petrucci F, Pettersson NE, Peyaud A, Pezoa R, Phillips PW, Piacquadio G, Pianori E, Picazio A, Piccaro E, Piccinini M, Pickering MA, Piegaia R, Pilcher JE, Pilkington AD, Pin AWJ, Pina J, Pinamonti M, Pinfold JL, Pingel A, Pires S, Pirumov H, Pitt M, Pizio C, Plazak L, Pleier MA, Pleskot V, Plotnikova E, Plucinski P, Pluth D, Poettgen R, Poggioli L, Pohl D, Polesello G, Poley A, Policicchio A, Polifka R, Polini A, Pollard CS, Polychronakos V, Pommès K, Pontecorvo L, Pope BG, Popeneciu GA, Popovic DS, Poppleton A, Pospisil S, Potamianos K, Potrap IN, Potter CJ, Potter CT, Poulard G, Poveda J, Pozdnyakov V, Pozo Astigarraga ME, Pralavorio P, Pranko A, Prell S, Price D, Price LE, Primavera M, Prince S, Proissl M, Prokofiev K, Prokoshin F, Protopapadaki E, Protopopescu S, Proudfoot J, Przybycien M, Puddu D, Puldon D, Purohit M, Puzo P, Qian J, Qin G, Qin Y, Quadt A, Quarrie DR, Quayle WB, Queitsch-Maitland M, Quilty D, Raddum S, Radeka V, Radescu V, Radhakrishnan SK, Radloff P, Rados P, Ragusa F, Rahal G, Rajagopalan S, Rammensee M, Rangel-Smith C, Rauscher F, Rave S, Ravenscroft T, Raymond M, Read AL, Readioff NP, Rebuzzi DM, Redelbach A, Redlinger G, Reece R, Reeves K, Rehnisch L, Reichert J, Reisin H, Rembser C, Ren H, Rescigno M, Resconi S, Rezanova OL, Reznicek P, Rezvani R, Richter R, Richter S, Richter-Was E, Ricken O, Ridel M, Rieck P, Riegel CJ, Rieger J, Rifki O, Rijssenbeek M, Rimoldi A, Rinaldi L, Ristić B, Ritsch E, Riu I, Rizatdinova F, Rizvi E, Robertson SH, Robichaud-Veronneau A, Robinson D, Robinson JEM, Robson A, Roda C, Rodina Y, Rodriguez Perez A, Roe S, Rogan CS, Røhne O, Romaniouk A, Romano M, Romano Saez SM, Romero Adam E, Rompotis N, Ronzani M, Roos L, Ros E, Rosati S, Rosbach K, Rose P, Rosenthal O, Rossetti V, Rossi E, Rossi LP, Rosten JHN, Rosten R, Rotaru M, Roth I, Rothberg J, Rousseau D, Royon CR, Rozanov A, Rozen Y, Ruan X, Rubbo F, Rubinskiy I, Rud VI, Rudolph MS, Rühr F, Ruiz-Martinez A, Rurikova Z, Rusakovich NA, Ruschke A, Russell HL, Rutherfoord JP, Ruthmann N, Ryabov YF, Rybar M, Rybkin G, Ryder NC, Ryzhov A, Saavedra AF, Sabato G, Sacerdoti S, Sadrozinski HFW, Sadykov R, Safai Tehrani F, Saha P, Sahinsoy M, Saimpert M, Saito T, Sakamoto H, Sakurai Y, Salamanna G, Salamon A, Salazar Loyola JE, Salek D, De Bruin PHS, Salihagic D, Salnikov A, Salt J, Salvatore D, Salvatore F, Salvucci A, Salzburger A, Sammel D, Sampsonidis D, Sanchez A, Sánchez J, Sanchez Martinez V, Sandaker H, Sandbach RL, Sander HG, Sanders MP, Sandhoff M, Sandoval C, Sandstroem R, Sankey DPC, Sannino M, Sansoni A, Santoni C, Santonico R, Santos H, Castillo IS, Sapp K, Sapronov A, Saraiva JG, Sarrazin B, Sasaki O, Sasaki Y, Sato K, Sauvage G, Sauvan E, Savage G, Savard P, Sawyer C, Sawyer L, Saxon J, Sbarra C, Sbrizzi A, Scanlon T, Scannicchio DA, Scarcella M, Scarfone V, Schaarschmidt J, Schacht P, Schaefer D, Schaefer R, Schaeffer J, Schaepe S, Schaetzel S, Schäfer U, Schaffer AC, Schaile D, Schamberger RD, Scharf V, Schegelsky VA, Scheirich D, Schernau M, Schiavi C, Schillo C, Schioppa M, Schlenker S, Schmieden K, Schmitt C, Schmitt S, Schmitt S, Schmitz S, Schneider B, Schnellbach YJ, Schnoor U, Schoeffel L, Schoening A, Schoenrock BD, Schopf E, Schorlemmer ALS, Schott M, Schouten D, Schovancova J, Schramm S, Schreyer M, Schuh N, Schultens MJ, Schultz-Coulon HC, Schulz H, Schumacher M, Schumm BA, Schune P, Schwanenberger C, Schwartzman A, Schwarz TA, Schwegler P, Schweiger H, Schwemling P, Schwienhorst R, Schwindling J, Schwindt T, Sciolla G, Scuri F, Scutti F, Searcy J, Seema P, Seidel SC, Seiden A, Seifert F, Seixas JM, Sekhniaidze G, Sekhon K, Sekula SJ, Seliverstov DM, Semprini-Cesari N, Serfon C, Serin L, Serkin L, Sessa M, Seuster R, Severini H, Sfiligoj T, Sforza F, Sfyrla A, Shabalina E, Shaikh NW, Shan LY, Shang R, Shank JT, Shapiro M, Shatalov PB, Shaw K, Shaw SM, Shcherbakova A, Shehu CY, Sherwood P, Shi L, Shimizu S, Shimmin CO, Shimojima M, Shiyakova M, Shmeleva A, Shoaleh Saadi D, Shochet MJ, Shojaii S, Shrestha S, Shulga E, Shupe MA, Sicho P, Sidebo PE, Sidiropoulou O, Sidorov D, Sidoti A, Siegert F, Sijacki D, Silva J, Silverstein SB, Simak V, Simard O, Simic L, Simion S, Simioni E, Simmons B, Simon D, Simon M, Simoniello R, Sinervo P, Sinev NB, Sioli M, Siragusa G, Sivoklokov SY, Sjölin J, Sjursen TB, Skinner MB, Skottowe HP, Skubic P, Slater M, Slavicek T, Slawinska M, Sliwa K, Smakhtin V, Smart BH, Smestad L, Smirnov SY, Smirnov Y, Smirnova LN, Smirnova O, Smith MNK, Smith RW, Smizanska M, Smolek K, Snesarev AA, Snidero G, Snyder S, Sobie R, Socher F, Soffer A, Soh DA, Sokhrannyi G, Solans Sanchez CA, Solar M, Soldatov EY, Soldevila U, Solodkov AA, Soloshenko A, Solovyanov OV, Solovyev V, Sommer P, Song HY, Soni N, Sood A, Sopczak A, Sopko V, Sorin V, Sosa D, Sotiropoulou CL, Soualah R, Soukharev AM, South D, Sowden BC, Spagnolo S, Spalla M, Spangenberg M, Spanò F, Sperlich D, Spettel F, Spighi R, Spigo G, Spiller LA, Spousta M, St. Denis RD, Stabile A, Stahlman J, Stamen R, Stamm S, Stanecka E, Stanek RW, Stanescu C, Stanescu-Bellu M, Stanitzki MM, Stapnes S, Starchenko EA, Stark GH, Stark J, Staroba P, Starovoitov P, Stärz S, Staszewski R, Steinberg P, Stelzer B, Stelzer HJ, Stelzer-Chilton O, Stenzel H, Stewart GA, Stillings JA, Stockton MC, Stoebe M, Stoicea G, Stolte P, 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Thompson PD, Thompson RJ, Thompson AS, Thomsen LA, Thomson E, Thomson M, Tibbetts MJ, Ticse Torres RE, Tikhomirov VO, Tikhonov YA, Timoshenko S, Tiouchichine E, Tipton P, Tisserant S, Todome K, Todorov T, Todorova-Nova S, Tojo J, Tokár S, Tokushuku K, Tolley E, Tomlinson L, Tomoto M, Tompkins L, Toms K, Tong B, Torrence E, Torres H, Torró Pastor E, Toth J, Touchard F, Tovey DR, Trefzger T, Tricoli A, Trigger IM, Trincaz-Duvoid S, Tripiana MF, Trischuk W, Trocmé B, Trofymov A, Troncon C, Trottier-McDonald M, Trovatelli M, Truong L, Trzebinski M, Trzupek A, Tseng JCL, Tsiareshka PV, Tsipolitis G, Tsirintanis N, Tsiskaridze S, Tsiskaridze V, Tskhadadze EG, Tsui KM, Tsukerman II, Tsulaia V, Tsuno S, Tsybychev D, Tudorache A, Tudorache V, Tuna AN, Tupputi SA, Turchikhin S, Turecek D, Turgeman D, Turra R, Turvey AJ, Tuts PM, Tylmad M, Tyndel M, Ueda I, Ueno R, Ughetto M, Ukegawa F, Unal G, Undrus A, Unel G, Ungaro FC, Unno Y, Unverdorben C, Urban J, Urquijo P, Urrejola P, Usai G, Usanova A, 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Performance of algorithms that reconstruct missing transverse momentum in [Formula: see text]= 8 TeV proton-proton collisions in the ATLAS detector

The reconstruction and calibration algorithms used to calculate missing transverse momentum ([Formula: see text] ) with the ATLAS detector exploit energy deposits in the calorimeter and tracks reconstructed in the inner detector as well as the muon spectrometer. Various strategies are used to suppress effects arising from additional proton-proton interactions, called pileup, concurrent with the hard-scatter processes. Tracking information is used to distinguish contributions from the pileup interactions using their vertex separation along the beam axis. The performance of the [Formula: see text] reconstruction algorithms, especially with respect to the amount of pileup, is evaluated using data collected in proton-proton collisions at a centre-of-mass energy of 8 [Formula: see text] during 2012, and results are shown for a data sample corresponding to an integrated luminosity of [Formula: see text]. The simulation and modelling of [Formula: see text]  in events containing a Z boson decaying to two charged leptons (electrons or muons) or a W boson decaying to a charged lepton and a neutrino are compared to data. The acceptance for different event topologies, with and without high transverse momentum neutrinos, is shown for a range of threshold criteria for [Formula: see text] , and estimates of the systematic uncertainties in the [Formula: see text]  measurements are presented.