Items 21-40 of 212

    • Journal Article

      Activity Correlations between Direction-Selective Retinal Ganglion Cells Synergistically Enhance Motion Decoding from Complex Visual Scenes 

      Kühn, Norma Krystyna; Gollisch, Tim
      Neuron 2019; 101(5): Art. 976.e7
      Neurons in sensory systems are often tuned to particular stimulus features. During complex naturalistic stimulation, however, multiple features may simultaneously affect neuronal responses, which complicates the readout of individual features. To investigate feature representation under complex stimulation, we studied how direction-selective ganglion cells in salamander retina respond to texture motion where direction, velocity, and spatial pattern inside the receptive field continuously change. We found that the cells preserve their direction preference under this stimulation, yet their direction encoding becomes ambiguous due to simultaneous activation by luminance changes. The ambiguities can be resolved by considering populations of direction-selective cells with different preferred directions. This gives rise to synergistic motion decoding, yielding more information from the population than the summed information from single-cell responses. Strong positive response correlations between cells with different preferred directions amplify this synergy. Our results show how correlated population activity can enhance feature extraction in complex visual scenes.
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    • Journal Article

      Using imaging photoplethysmography for heart rate estimation in non-human primates 

      Unakafov, Anton M.; Möller, Sebastian; Kagan, Igor; Gail, Alexander; Treue, Stefan; Wolf, Fred
      2018; 13(8) p.1-22: Art. e0202581
      For humans and for non-human primates heart rate is a reliable indicator of an individual’s current physiological state, with applications ranging from health checks to experimental studies of cognitive and emotional state. In humans, changes in the optical properties of the skin tissue correlated with cardiac cycles (imaging photoplethysmogram, iPPG) allow non-contact estimation of heart rate by its proxy, pulse rate. Yet, there is no established simple and non-invasive technique for pulse rate measurements in awake and behaving animals. Using iPPG, we here demonstrate that pulse rate in rhesus monkeys can be accurately estimated from facial videos. We computed iPPGs from eight color facial videos of four awake head-stabilized rhesus monkeys. Pulse rate estimated from iPPGs was in good agreement with reference data from a contact pulse-oximeter: the error of pulse rate estimation was below 5% of the individual average pulse rate in 83% of the epochs; the error was below 10% for 98% of the epochs. We conclude that iPPG allows non-invasive and non-contact estimation of pulse rate in non-human primates, which is useful for physiological studies and can be used toward welfare-assessment of non-human primates in research.
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    • Journal Article

      Can a time varying external drive give rise to apparent criticality in neural systems? 

      Priesemann, Viola; Shriki, Oren
      PLOS Computational Biology 2018; 14(5) p.1-29: Art. e1006081
      The finding of power law scaling in neural recordings lends support to the hypothesis of critical brain dynamics. However, power laws are not unique to critical systems and can arise from alternative mechanisms. Here, we investigate whether a common time-varying external drive to a set of Poisson units can give rise to neuronal avalanches and exhibit apparent criticality. To this end, we analytically derive the avalanche size and duration distributions, as well as additional measures, first for homogeneous Poisson activity, and then for slowly varying inhomogeneous Poisson activity. We show that homogeneous Poisson activity cannot give rise to power law distributions. Inhomogeneous activity can also not generate perfect power laws, but it can exhibit approximate power laws with cutoffs that are comparable to those typically observed in experiments. The mechanism of generating apparent criticality by time-varying external fields, forces or input may generalize to many other systems like dynamics of swarms, diseases or extinction cascades. Here, we illustrate the analytically derived effects for spike recordings in vivo and discuss approaches to distinguish true from apparent criticality. Ultimately, this requires causal interventions, which allow separating internal system properties from externally imposed ones.
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    • Journal Article

      Simple analytical model reveals the functional role of embodied sensorimotor interaction in hexapod gaits 

      Ambe, Yuichi; Aoi, Shinya; Nachstedt, Timo; Manoonpong, Poramate; Wörgötter, Florentin; Matsuno, Fumitoshi
      PLOS ONE 2018; 13(2) p.1-28: Art. e0192469
      Insects have various gaits with specific characteristics and can change their gaits smoothly in accordance with their speed. These gaits emerge from the embodied sensorimotor interactions that occur between the insect’s neural control and body dynamic systems through sensory feedback. Sensory feedback plays a critical role in coordinated movements such as locomotion, particularly in stick insects. While many previously developed insect models can generate different insect gaits, the functional role of embodied sensorimotor interactions in the interlimb coordination of insects remains unclear because of their complexity. In this study, we propose a simple physical model that is amenable to mathematical analysis to explain the functional role of these interactions clearly. We focus on a foot contact sensory feedback called phase resetting, which regulates leg retraction timing based on touchdown information. First, we used a hexapod robot to determine whether the distributed decoupled oscillators used for legs with the sensory feedback generate insect-like gaits through embodied sensorimotor interactions. The robot generated two different gaits and one had similar characteristics to insect gaits. Next, we proposed the simple model as a minimal model that allowed us to analyze and explain the gait mechanism through the embodied sensorimotor interactions. The simple model consists of a rigid body with massless springs acting as legs, where the legs are controlled using oscillator phases with phase resetting, and the governed equations are reduced such that they can be explained using only the oscillator phases with some approximations. This simplicity leads to analytical solutions for the hexapod gaits via perturbation analysis, despite the complexity of the embodied sensorimotor interactions. This is the first study to provide an analytical model for insect gaits under these interaction conditions. Our results clarified how this specific foot contact sensory feedback contributes to generation of insect-like ipsilateral interlimb coordination during hexapod locomotion.
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    • Journal Article

      Electrical stimulation of macaque lateral prefrontal cortex modulates oculomotor behavior indicative of a disruption of top-down attention 

      Schwedhelm, Philipp; Baldauf, Daniel; Treue, Stefan
      2017; 7(1)
      The lateral prefrontal cortex (lPFC) of primates is hypothesized to be heavily involved in decision-making and selective visual attention. Recent neurophysiological evidence suggests that information necessary for an orchestration of those high-level cognitive factors are indeed represented in the lPFC. However, we know little about the specific contribution of sub-networks within lPFC to the deployment of top-down influences that can be measured in extrastriate visual cortex. Here, we systematically applied electrical stimulations to areas 8Av and 45 of two macaque monkeys performing a concurrent goal-directed saccade task. Despite using currents well above saccadic thresholds of the directly adjacent Frontal Eye Fields (FEF), saccades were only rarely evoked by the stimulation. Instead, two types of behavioral effects were observed: Stimulations of caudal sites in 8Av (close to FEF) shortened or prolonged saccadic reaction times, depending on the task-instructed saccade, while rostral stimulations of 8Av/45 seem to affect the relative attentional weighting of saccade targets as well as saccadic reaction times. These results illuminate important differences in the causal involvement of different sub-networks within the lPFC and are most compatible with a stimulation-induced biasing of stimulus processing that accelerates the detection of saccade targets presented ipsilateral to stimulation through a disruption of contralaterally deployed top-down attention.
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    • Journal Article

      Quantitative optical nanophysiology of Ca2+ signaling at inner hair cell active zones 

      Neef, Jakob; Urban, Nicolai T.; Ohn, Tzu-Lun; Frank, Thomas; Jean, Philippe; Hell, Stefan W.; Willig, Katrin I.; Moser, Tobias
      2018; 9(1)
      Ca2+ influx triggers the release of synaptic vesicles at the presynaptic active zone (AZ). A quantitative characterization of presynaptic Ca2+ signaling is critical for understanding synaptic transmission. However, this has remained challenging to establish at the required resolution. Here, we employ confocal and stimulated emission depletion (STED) microscopy to quantify the number (20–330) and arrangement (mostly linear 70 nm × 100–600 nm clusters) of Ca2+ channels at AZs of mouse cochlear inner hair cells (IHCs). Establishing STED Ca2+ imaging, we analyze presynaptic Ca2+ signals at the nanometer scale and find confined elongated Ca2+ domains at normal IHC AZs, whereas Ca2+ domains are spatially spread out at the AZs of bassoon-deficient IHCs. Performing 2D-STED fluorescence lifetime analysis, we arrive at estimates of the Ca2+ concentrations at stimulated IHC AZs of on average 25 µM. We propose that IHCs form bassoon-dependent presynaptic Ca2+-channel clusters of similar density but scalable length, thereby varying the number of Ca2+ channels amongst individual AZs.
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    • Journal Article

      Saccade-synchronized rapid attention shifts in macaque visual cortical area MT 

      Yao, Tao; Treue, Stefan; Krishna, B. Suresh
      2018; 9(1)
      While making saccadic eye-movements to scan a visual scene, humans and monkeys are able to keep track of relevant visual stimuli by maintaining spatial attention on them. This ability requires a shift of attentional modulation from the neuronal population representing the relevant stimulus pre-saccadically to the one representing it post-saccadically. For optimal performance, this trans-saccadic attention shift should be rapid and saccade-synchronized. Whether this is so is not known. We trained two rhesus monkeys to make saccades while maintaining covert attention at a fixed spatial location. We show that the trans-saccadic attention shift in cortical visual medial temporal (MT) area is well synchronized to saccades. Attentional modulation crosses over from the pre-saccadic to the post-saccadic neuronal representation by about 50 ms after a saccade. Taking response latency into account, the trans-saccadic attention shift is well timed to maintain spatial attention on relevant stimuli, so that they can be optimally tracked and processed across saccades.
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    • Journal Article

      CKAMP44 modulates integration of visual inputs in the lateral geniculate nucleus 

      Chen, Xufeng; Aslam, Muhammad; Gollisch, Tim; Allen, Kevin; von Engelhardt, Jakob
      2018; 9(1)
      Relay neurons in the dorsal lateral geniculate nucleus (dLGN) receive excitatory inputs from retinal ganglion cells (RGCs). Retinogeniculate synapses are characterized by a prominent short-term depression of AMPA receptor (AMPAR)-mediated currents, but the underlying mechanisms and its function for visual integration are not known. Here we identify CKAMP44 as a crucial auxiliary subunit of AMPARs in dLGN relay neurons, where it increases AMPAR-mediated current amplitudes and modulates gating of AMPARs. Importantly, CKAMP44 is responsible for the distinctive short-term depression in retinogeniculate synapses by reducing the rate of recovery from desensitization of AMPARs. Genetic deletion of CKAMP44 strongly reduces synaptic short-term depression, which leads to increased spike probability of relay neurons when activated with high-frequency inputs from retinogeniculate synapses. Finally, in vivo recordings reveal augmented ON- and OFF-responses of dLGN neurons in CKAMP44 knockout (CKAMP44−/−) mice, demonstrating the importance of CKAMP44 for modulating synaptic short-term depression and visual input integration.
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    • Journal Article

      Medium- and high-intensity rTMS reduces psychomotor agitation with distinct neurobiologic mechanisms 

      Heath, Alesha; Lindberg, Daniel R.; Makowiecki, Kalina; Gray, Avalon; Asp, Anders J.; Rodger, Jennifer; Choi, Doo-Sup; Croarkin, Paul E.
      2018; 8(1)
      Definitive data are lacking on the mechanism of action and biomarkers of repetitive transcranial magnetic stimulation (rTMS) for the treatment of depression. Low-intensity rTMS (LI-rTMS) has demonstrated utility in preclinical models of rTMS treatments but the effects of LI-rTMS in murine models of depression are unknown. We examined the behavioral and neurobiologic changes in olfactory bulbectomy (OB) mice with medium-intensity rTMS (MI-rTMS) treatment and fluoxetine hydrochloride. We then compared 10-Hz rTMS sessions for 3 min at intensities (measured at the cortical surface) of 4 mT (LI-rTMS), 50 mT (medium-intensity rTMS [MI-rTMS]), or 1 T (high-intensity rTMS [HI-rTMS]) 5 days per week over 4 weeks in an OB model of agitated depression. Behavioral effects were assessed with forced swim test; neurobiologic effects were assessed with brain levels of 5-hydroxytryptamine, brain-derived neurotrophic factor (BDNF), and neurogenesis. Peripheral metabolomic changes induced by OB and rTMS were monitored through enzyme-linked immunosorbent assay and ultrapressure liquid chromatography-driven targeted metabolomics evaluated with ingenuity pathway analysis (IPA). MI-rTMS and HI-rTMS attenuated psychomotor agitation but only MI-rTMS increased BDNF and neurogenesis levels. HI-rTMS normalized the plasma concentration of α-amino-n-butyric acid and 3-methylhistidine. IPA revealed significant changes in glutamine processing and glutamate signaling in the OB model and following MI-rTMS and HI-rTMS treatment. The present findings suggest that MI-rTMS and HI-rTMS induce differential neurobiologic changes in a mouse model of agitated depression. Further, α-amino-n-butyric acid and 3-methylhistidine may have utility as biomarkers to objectively monitor the response to rTMS treatment of depression.
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    • Journal Article

      Propagation-based phase-contrast x-ray tomography of cochlea using a compact synchrotron source 

      Töpperwien, Mareike; Gradl, Regine; Keppeler, Daniel; Vassholz, Malte; Meyer, Alexander; Hessler, Roland; Achterhold, Klaus; Gleich, Bernhard; Dierolf, Martin; Pfeiffer, Franz; et al.
      Moser, TobiasSalditt, Tim
      2018; 8(1): Art. 4922
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    • Journal Article

      Precisely measured protein lifetimes in the mouse brain reveal differences across tissues and subcellular fractions. 

      Fornasiero, Eugenio F.; Mandad, Sunit; Wildhagen, Hanna; Alevra, Mihai; Rammner, Burkhard; Keihani, Sarva; Opazo, Felipe; Urban, Inga; Ischebeck, Till; Sakib, M. Sadman; et al.
      Fard, Maryam K.Kirli, KorayCenteno, Tonatiuh PenaVidal, Ramon O.Rahman, Raza-UrBenito, EvaFischer, AndréDennerlein, SvenRehling, PeterFeussner, IvoBonn, StefanSimons, MikaelUrlaub, HenningRizzoli, Silvio O.
      Nature Communications 2018; 9(1): Art. 4230
      The turnover of brain proteins is critical for organism survival, and its perturbations are linked to pathology. Nevertheless, protein lifetimes have been difficult to obtain in vivo. They are readily measured in vitro by feeding cells with isotopically labeled amino acids, followed by mass spectrometry analyses. In vivo proteins are generated from at least two sources: labeled amino acids from the diet, and non-labeled amino acids from the degradation of pre-existing proteins. This renders measurements difficult. Here we solved this problem rigorously with a workflow that combines mouse in vivo isotopic labeling, mass spectrometry, and mathematical modeling. We also established several independent approaches to test and validate the results. This enabled us to measure the accurate lifetimes of ~3500 brain proteins. The high precision of our data provided a large set of biologically significant observations, including pathway-, organelle-, organ-, or cell-specific effects, along with a comprehensive catalog of extremely long-lived proteins (ELLPs).
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    • Journal Article

      Attention decouples action potentials from the phase of local field potentials in macaque visual cortical area MT 

      Esghaei, Moein; Daliri, Mohammad R.; Treue, Stefan
      BMC Biology. 2018 Aug 06;16(1):86
      Background The timing of action potentials (“spikes”) of cortical neurons has been shown to be aligned to the phase of low-frequency (< 10 Hz) local field potentials (LFPs) in several cortical areas. However, across the areas, this alignment varies and the role of this spike-phase coupling (SPC) in cognitive functions is not well understood. Results Here, we propose a role in the coordination of neural activity by selective attention. After refining previous analytical methods for measuring SPC, we show that first, SPC is present along the dorsal processing pathway in macaque visual cortex (area MT); second, spikes occur in falling phases of the low-frequency LFP independent of the location of spatial attention; third, switching spatial attention into the receptive field (RF) of MT neurons decreases this coupling; and finally, the LFP phase causally influences the spikes. Conclusions Here, we show that spikes are coupled to the phase of low-frequency LFP along the dorsal visual pathway. Our data suggest that attention harnesses this spike-LFP coupling to de-synchronize neurons and thereby enhance the neural representation of the attended stimuli.
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    • Journal Article

      26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 

      Newton, Adam J. H.; Seidenstein, Alexandra H.; McDougal, Robert A.; Pérez-Cervera, Alberto; Huguet, Gemma; M-Seara, Tere; Haimerl, Caroline; Angulo-Garcia, David; Torcini, Alessandro; Cossart, Rosa; et al.
      Malvache, ArnaudSkiker, KaoutarMaouene, MounirRagognetti, GianmarcoLorusso, LetiziaViggiano, AndreaMarcelli, AngeloSenatore, RosaParziale, AntonioStramaglia, S.Pellicoro, M.Angelini, L.Amico, E.Aerts, H.Cortés, J.Laureys, S.Marinazzo, D.Stramaglia, S.Bassez, I.Faes, L.Almgren, HannesRazi, AdeelVan de Steen, FrederikKrebs, RuthAerts, HanneloreKanari, LidaDlotko, PawelScolamiero, MartinaLevi, RanShillcock, Juliande Kock, Christiaan P.Hess, KathrynMarkram, HenryLy, ChengMarsat, GaryGillespie, TomSandström, MalinAbrams, MathewGrethe, Jeffrey S.Martone, MaryannDe Gernier, RobinSolinas, SergioRössert, ChristianHaelterman, MarcMassar, SergePasquale, ValentinaPastore, Vito P.Martinoia, SergioMassobrio, PaoloCapone, CristianoTort-Colet, NúriaSanchez-Vives, Maria V.Mattia, MaurizioAlmasi, AliCloherty, Shaun L.Grayden, David B.Wong, Yan T.Ibbotson, Michael R.Meffin, HamishPrince, Luke Y.Tsaneva-Atanasova, KrasimiraMellor, Jack R.Mazzoni, AlbertoRosa, ManuelaCarpaneto, JacopoRomito, Luigi M.Priori, AlbertoMicera, SilvestroMigliore, RosannaLupascu, Carmen A.Franchina, FrancescoBologna, Luca L.Romani, ArmandoSaray, SáraVan Geit, WernerKáli, SzabolcsThomson, AlexMercer, AudreyLange, SigrunFalck, JoanneMuller, EilifSchürmann, FelixTodorov, DmitriiCapps, RobertBarnett, WilliamMolkov, YaroslavDevalle, FedericoPazó, DiegoMontbrió, ErnestMochol, GabrielaAzab, HabibaHayden, Benjamin Y.Moreno-Bote, RubénBalasubramani, Pragathi P.Chakravarthy, Srinivasa V.Muddapu, Vignayanandam R.Gheorghiu, Medorian D.Mimica, BartulWithlock, JonathanMureșan, Raul C.Zick, Jennifer L.Schultz, KelseyBlackman, Rachael K.Chafee, Matthew V.Netoff, Theoden I.Roberts, NicholasNagaraj, VivekLamperski, AndrewNetoff, Theoden I.Grado, Logan L.Johnson, Matthew D.Darrow, David P.Lonardoni, DavideAmin, HayderDi Marco, StefanoMaccione, AlessandroBerdondini, LucaNieus, ThierryStimberg, MarcelGoodman, Dan F. M.Nowotny, ThomasKoren, VeronikaDragoi, ValentinObermayer, KlausCastro, SamyFernandez, MarianoEl-Deredy, WaelXu, KeshengMaidana, Jean P.Orio, PatricioChen, WeiliangHepburn, IainCasalegno, FrancescoDevresse, AdrienOvcharenko, AleksandrPereira, FernandoDelalondre, FabienDe Schutter, ErikBratby, PeterGallimore, Andrew R.Klingbeil, GuidoZamora, CriseidaZang, YunliangCrotty, PatrickPalmerduca, EricAntonietti, AlbertoCasellato, ClaudiaErö, CsabaD’Angelo, EgidioGewaltig, Marc-OliverPedrocchi, AlessandraBytschok, IljaDold, DominikSchemmel, JohannesMeier, KarlheinzPetrovici, Mihai A.Shen, Hui-AnSurace, Simone C.Pfister, Jean-PascalLefebvre, BaptisteMarre, OlivierYger, PierrePapoutsi, AthanasiaPark, JiyoungAsh, RyanSmirnakis, SteliosPoirazi, PanayiotaFelix, Richard A.Dimitrov, Alexander G.Portfors, ChristineDaun, SilviaToth, Tibor I.Jędrzejewska-Szmek, JoannaKabbani, NadineBlackwel, Kim T.Moezzi, BaharSchaworonkow, NataliePlogmacher, LukasGoldsworthy, Mitchell R.Hordacre, BrentonMcDonnell, Mark D.Iannella, NicolangeloRidding, Michael C.Triesch, JochenMaex, ReinoudSafaryan, KarenSteuber, VolkerTang, RongxiangTang, Yi-YuanVerveyko, Darya V.Brazhe, Alexey R.Verisokin, Andrey Y.Postnov, Dmitry E.Günay, CengizPanuccio, GabriellaGiugliano, MichelePrinz, Astrid A.Varona, PabloRabinovich, Mikhail I.Denham, JackRanner, ThomasCohen, NettaReva, MariaRebola, NelsonKirizs, TeklaNusser, ZoltanDiGregorio, DavidMavritsaki, EiriniRentzelas, PanosUkani, Nikul H.Tomkins, AdamYeh, Chung-HengBruning, WesleyFenichel, Allison L.Zhou, YiyinHuang, Yu-ChiFlorescu, DorianOrtiz, Carlos L.Richmond, PaulLo, Chung-ChuanCoca, DanielChiang, Ann-ShynLazar, Aurel A.Moezzi, BaharCreaser, Jennifer L.Lin, CongpingAshwin, PeterBrown, Jonathan T.Ridler, ThomasLevenstein, DanielWatson, Brendon O.Buzsáki, GyörgyRinzel, JohnCurtu, RodicaNguyen, AnhAssadzadeh, SahandRobinson, Peter A.Sanz-Leon, PaulaForlim, Caroline G.de Almeida, Lírio O. B.Pinto, Reynaldo D.Rodríguez, Francisco B.Lareo, ÁngelForlim, Caroline G.Rodríguez, Francisco B.Montero, AaronMosqueiro, ThiagoHuerta, RamonRodriguez, Francisco B.Changoluisa, VinicioRodriguez, Francisco B.Cordeiro, Vinícius L.Ceballos, César C.Kamiji, Nilton L.Roque, Antonio C.Lytton, William W.Knox, AndrewRosenthal, Joshua J. C.Daun, SilviaPopovych, SvitlanaLiu, LiqingWang, Bin A.Tóth, Tibor I.Grefkes, ChristianFink, Gereon R.Rosjat, NilsPerez-Trujillo, AbrahamEspinal, AndresSotelo-Figueroa, Marco A.Cruz-Aceves, IvanRostro-Gonzalez, HoracioZapotocky, MartinHoskovcová, MartinaKopecká, JanaUlmanová, OlgaRůžička, EvženGärtner, MatthiasDuvarci, SevilRoeper, JochenSchneider, GabyAlbert, StefanSchmack, KatharinaRemme, MichielSchreiber, SusanneMigliore, MicheleLupascu, Carmen A.Bologna, Luca L.Antonel, Stefano M.Courcol, Jean-DenisSchürmann, FelixÇelikok, Sami U.Navarro-López, Eva M.Şengör, Neslihan S.Elibol, RahmiSengor, Neslihan S.Özdemir, Mustafa Y.Li, TianyiArleo, AngeloSheynikhovich, DenisNakamura, AkihiroShimono, MasanoriSong, YoungjoPark, SolChoi, IlhwanJeong, JaeseungShin, Hee-supSadeh, SadraGleeson, PadraigAngus Silver, R.Chatzikalymniou, Alexandra P.Skinner, Frances K.Sanchez-Rodriguez, Lazaro M.Sotero, Roberto C.Hertäg, LoreenMackwood, OwenSprekeler, HenningPuhlmann, SteffenWeber, Simon N.Higgins, DavidNaumann, Laura B.Weber, Simon N.Iyer, RamakrisnanMihalas, StefanTiccinelli, ValentinaStankovski, TomislavMcClintock, Peter V. E.Stefanovska, AnetaJanjić, PredragSolev, DimitarSeifert, GeraldKocarev, LjupčoSteinhäuser, ChristianSalmasi, MehrdadGlasauer, StefanStemmler, MartinZhang, DankeZhang, ChiStepanyants, ArmenGoncharenko, JuliaKros, LiekeDavey, Neilde Zeeuw, ChrisHoebeek, FreekSinha, AnkurAdams, RoderickSchmuker, MichaelPsarrou, MariaSchilstra, MariaTorben-Nielsen, BenjaminMetzner, ChristophSchweikard, AchimMäki-Marttunen, TuomoZurowski, BartoszMarinazzo, DanieleFaes, LucaStramaglia, SebastianoJordan, Henry O. C.Stringer, Simon M.Gajewska-Dendek, ElżbietaSuffczyński, PiotrTam, NicoladieZouridakis, GeorgePollonini, LucaTang, Yi-YuanAsl, Mojtaba M.Valizadeh, AlirezaTass, Peter A.Nold, AndreasFan, WeiKonrad, SaraEndle, HeikoVogt, JohannesTchumatchenko, TatjanaHerpich, JulianeTetzlaff, ChristianLuboeinski, JannikNachstedt, TimoCiba, ManuelBahmer, AndreasThielemann, ChristianeKuebler, Eric S.Tauskela, Joseph S.Thivierge, Jean-PhilippeBakker, RembrandtGarcía-Amado, MaríaEvangelio, MarianClascá, FranciscoTiesinga, PaulBuckley, Christopher L.Toyoizumi, TaroDubreuil, Alexis M.Monasson, RémiTreves, AlessandroSpalla, DavideRosay, SophieKleberg, Florence I.Wong, Willyde Oliveira Floriano, BrunoMatsuo, ToshihikoUchida, TetsuyaDibenedetto, DomenicaUludağ, KâmilGoodarzinick, AbdorrezaSchmidt, MaximilianHilgetag, Claus C.Diesmann, Markusvan Albada, Sacha J.Fauth, Michaelvan Rossum, MarkReyes-Sánchez, ManuelAmaducci, RodrigoMuñiz, CarlosVarona, PabloElices, IreneArroyo, DavidLevi, RafaelCohen, BenChow, CarsonVattikuti, ShashaankBertolotti, ElenaBurioni, Raffaelladi Volo, MatteoVezzani, AlessandroMenzat, BayarVogels, Tim P.Wagatsuma, NobuhikoSaha, SusmitaKapoor, ReenaKerr, RobertWagner, Johndel Molino, Luis C. G.Yang, Guangyu R.Mejias, Jorge F.Wang, Xiao-JingSong, HanbingGoodliffe, JosephLuebke, JenniferWeaver, Christina M.Thomas, JohnSinha, NishantShaju, NikhitaMaszczyk, TomaszJin, JingCash, Sydney S.Dauwels, JustinBrandon Westover, M.Karimian, MaryamMoerel, MichelleDe Weerd, PeterBurwick, ThomasWestra, Ronald L.Abeysuriya, RomeshHadida, JonathanSotiropoulos, StamatiosJbabdi, SaadWoolrich, MarkBensmail, ChamaWrobel, BorysZhou, XiaolongJi, ZilongLiu, XiaoXia, YanWu, SiWang, XiaoZhang, MingshaWu, SiOfer, NetanelShefi, OritYaari, GurCarnevale, TedMajumdar, AmitSivagnanam, SubhashiniYoshimoto, KennethSmirnova, Elena Y.Amakhin, Dmitry V.Malkin, Sergey L.Zaitsev, Aleksey V.Chizhov, Anton V.Zaleshina, MargaritaZaleshin, AlexanderBarranca, Victor J.Zhu, GeorgeSkilling, Quinton M.Maruyama, DanielOgnjanovski, NicoletteAton, Sara J.Zochowski, MichalWu, JiaxingAton, SaraRich, ScottBooth, VictoriaBudak, MaralDura-Bernal, SalvadorNeymotin, Samuel A.Suter, Benjamin A.Shepherd, Gordon M. G.Felton, Melvin A.Yu, Alfred B.Boothe, David L.Oie, Kelvin S.Franaszczuk, Piotr J.Shuvaev, Sergey A.Başerdem, BatuhanZador, AnthonyKoulakov, Alexei A.López-Madrona, Víctor J.Pereda, ErnestoMirasso, Claudio R.Canals, SantiagoMasoli, StefanoRongala, Udaya B.Mazzoni, AlbertoSpanne, AntonJorntell, HenrikOddo, Calogero M.Vartanov, Alexander V.Neklyudova, Anastasia K.Kozlovskiy, Stanislav A.Kiselnikov, Andrey A.Marakshina, Julia A.Teleńczuk, MariaTeleńczuk, BartoszDestexhe, AlainKuokkanen, Paula T.Kraemer, AnnaMcColgan, ThomasCarr, Catherine E.Kempter, Richard
      BMC Neuroscience. 2017 Aug 18;18(Suppl 1):60
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      Assessment of stress responses in rhesus macaques (Macaca mulatta) to daily routine procedures in system neuroscience based on salivary cortisol concentrations 

      Pfefferle, Dana; Plümer, Sina; Burchardt, Leonore; Treue, Stefan; Gail, Alexander
      PLOS ONE 2018; 13(1): Art. e0190190
      Non-human primates participating in neurophysiological research are exposed to potentially stressful experimental procedures, such as dietary control protocols, surgical implants and their maintenance, or social separation during training and experimental session. Here, we investigated the effect of controlled access to fluid, surgical implants, implant-related cleaning of skin margins, and behavioral training sessions on salivary cortisol levels of adult male rhesus macaques participating in neurophysiological research. The animals were trained to chew flavored cotton swabs to non-invasively collect saliva samples. Our data show no differences in cortisol levels between animals with and without implants, but both, controlled access to fluid and cleaning of implants individually increased salivary cortisol concentrations, while both together did not further increase the concentration. Specifically, before cleaning, individuals with controlled access to fluid had 55% higher cortisol concentrations than individuals with free access to fluid. Under free access to fluid, cortisol concentrations were 27% higher after cleaning while no effect of cleaning was found for individuals under controlled fluid access. Training sessions under controlled access to fluid also did not affect salivary cortisol concentrations. The observed changes in cortisol concentrations represent mild stress responses, as they are only a fraction of the range of the regular circadian changes in cortisol levels in rhesus monkeys. They also indicate that combinations of procedures do not necessarily lead to cumulative stress responses. Our results indicate that salivary cortisol levels of rhesus monkeys respond to neurophysiological experimental procedures and, hence, may be used to assess further refinements of such experimental methods.
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      Correlated microtiming deviations in jazz and rock music 

      Sogorski, Mathias; Geisel, Theo; Priesemann, Viola
      PLOS ONE 2018; 13(1): Art. e0186361
      Musical rhythms performed by humans typically show temporal fluctuations. While they have been characterized in simple rhythmic tasks, it is an open question what is the nature of temporal fluctuations, when several musicians perform music jointly in all its natural complexity. To study such fluctuations in over 100 original jazz and rock/pop recordings played with and without metronome we developed a semi-automated workflow allowing the extraction of cymbal beat onsets with millisecond precision. Analyzing the inter-beat interval (IBI) time series revealed evidence for two long-range correlated processes characterized by power laws in the IBI power spectral densities. One process dominates on short timescales (t < 8 beats) and reflects microtiming variability in the generation of single beats. The other dominates on longer timescales and reflects slow tempo variations. Whereas the latter did not show differences between musical genres (jazz vs. rock/pop), the process on short timescales showed higher variability for jazz recordings, indicating that jazz makes stronger use of microtiming fluctuations within a measure than rock/pop. Our results elucidate principles of rhythmic performance and can inspire algorithms for artificial music generation. By studying microtiming fluctuations in original music recordings, we bridge the gap between minimalistic tapping paradigms and expressive rhythmic performances.
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      Model-free inference of direct network interactions from nonlinear collective dynamics. 

      Casadiego, Jose; Nitzan, Mor; Hallerberg, Sarah; Timme, Marc
      Nature Communications 2017; 8(1): Art. 2192
      The topology of interactions in network dynamical systems fundamentally underlies their function. Accelerating technological progress creates massively available data about collective nonlinear dynamics in physical, biological, and technological systems. Detecting direct interaction patterns from those dynamics still constitutes a major open problem. In particular, current nonlinear dynamics approaches mostly require to know a priori a model of the (often high dimensional) system dynamics. Here we develop a model-independent framework for inferring direct interactions solely from recording the nonlinear collective dynamics generated. Introducing an explicit dependency matrix in combination with a block-orthogonal regression algorithm, the approach works reliably across many dynamical regimes, including transient dynamics toward steady states, periodic and non-periodic dynamics, and chaos. Together with its capabilities to reveal network (two point) as well as hypernetwork (e.g., three point) interactions, this framework may thus open up nonlinear dynamics options of inferring direct interaction patterns across systems where no model is known.
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      Neural and Response Correlations to Complex Natural Sounds in the Auditory Midbrain. 

      Lyzwa, Dominika; Wörgötter, Florentin
      Frontiers in neural circuits 2016; 10: Art. 89
      How natural communication sounds are spatially represented across the inferior colliculus, the main center of convergence for auditory information in the midbrain, is not known. The neural representation of the acoustic stimuli results from the interplay of locally differing input and the organization of spectral and temporal neural preferences that change gradually across the nucleus. This raises the question of how similar the neural representation of the communication sounds is across these gradients of neural preferences, and whether it also changes gradually. Analyzed neural recordings were multi-unit cluster spike trains from guinea pigs presented with a spectrotemporally rich set of eleven species-specific communication sounds. Using cross-correlation, we analyzed the response similarity of spiking activity across a broad frequency range for neurons of similar and different frequency tuning. Furthermore, we separated the contribution of the stimulus to the correlations to investigate whether similarity is only attributable to the stimulus, or, whether interactions exist between the multi-unit clusters that lead to neural correlations and whether these follow the same representation as the response correlations. We found that similarity of responses is dependent on the neurons' spatial distance for similarly and differently frequency-tuned neurons, and that similarity decreases gradually with spatial distance. Significant neural correlations exist, and contribute to the total response similarity. Our findings suggest that for multi-unit clusters in the mammalian inferior colliculus, the gradual response similarity with spatial distance to natural complex sounds is shaped by neural interactions and the gradual organization of neural preferences.
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      A Neurocomputational Model of Goal-Directed Navigation in Insect-Inspired Artificial Agents. 

      Goldschmidt, Dennis; Manoonpong, Poramate; Dasgupta, Sakyasingha
      Frontiers in neurorobotics 2017; 11: Art. 20
      Despite their small size, insect brains are able to produce robust and efficient navigation in complex environments. Specifically in social insects, such as ants and bees, these navigational capabilities are guided by orientation directing vectors generated by a process called path integration. During this process, they integrate compass and odometric cues to estimate their current location as a vector, called the home vector for guiding them back home on a straight path. They further acquire and retrieve path integration-based vector memories globally to the nest or based on visual landmarks. Although existing computational models reproduced similar behaviors, a neurocomputational model of vector navigation including the acquisition of vector representations has not been described before. Here we present a model of neural mechanisms in a modular closed-loop control-enabling vector navigation in artificial agents. The model consists of a path integration mechanism, reward-modulated global learning, random search, and action selection. The path integration mechanism integrates compass and odometric cues to compute a vectorial representation of the agent's current location as neural activity patterns in circular arrays. A reward-modulated learning rule enables the acquisition of vector memories by associating the local food reward with the path integration state. A motor output is computed based on the combination of vector memories and random exploration. In simulation, we show that the neural mechanisms enable robust homing and localization, even in the presence of external sensory noise. The proposed learning rules lead to goal-directed navigation and route formation performed under realistic conditions. Consequently, we provide a novel approach for vector learning and navigation in a simulated, situated agent linking behavioral observations to their possible underlying neural substrates.
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      Differential Effects of HCN Channel Block on On and Off Pathways in the Retina as a Potential Cause for Medication-Induced Phosphene Perception. 

      Bemme, Sebastian; Weick, Michael; Gollisch, Tim
      Investigative ophthalmology & visual science 2017-09-01; 58(11) p.4754-4767
      Purpose: Phosphene perception is a characteristic side effect of heart rate-reducing medication that acts on hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels. It is hypothesized that these phosphenes are caused by blocking HCN channels in photoreceptors and neurons of the retina, yet the underlying changes in visual signal processing in the retina caused by the HCN channel block are still unknown. Methods: We examined the effects of pharmacologic HCN channel block on the encoding of visual signals in retinal ganglion cells by recording ganglion cell spiking activity from isolated mouse retinas mounted on multielectrode arrays. Spontaneous activity and responses to various visual stimuli were measured before, during, and after administration of 3 μM ivabradine. Results: Retinal ganglion cells generally showed slower response kinetics and reduced sensitivity to high temporal frequencies under ivabradine. Moreover, ivabradine differentially affected the sensitivity of On and Off ganglion cells. On cells showed reduced response gain, whereas Off cells experienced an increase in response threshold. In line with these differential effects, Off cells, in contrast to On cells, also showed reduced baseline activity during visual stimulation and reduced spontaneous activity. Furthermore, Off cells, but not On cells, showed increased burst-like spiking activity in the presence of ivabradine. Conclusions: Our data suggest that pharmacologic HCN channel block in the retina leads to a shift in the relative activity of the On and Off pathways of the retina. We hypothesize that this imbalance may underlie the medication-induced perception of phosphenes.
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      Environmental enrichment accelerates ocular dominance plasticity in mouse visual cortex whereas transfer to standard cages resulted in a rapid loss of increased plasticity. 

      Kalogeraki, Evgenia; Pielecka-Fortuna, Justyna; Löwel, Siegrid
      PloS one 2017; 12(10): Art. e0186999
      In standard cage (SC) raised mice, experience-dependent ocular dominance (OD) plasticity in the primary visual cortex (V1) rapidly declines with age: in postnatal day 25-35 (critical period) mice, 4 days of monocular deprivation (MD) are sufficient to induce OD-shifts towards the open eye; thereafter, 7 days of MD are needed. Beyond postnatal day 110, even 14 days of MD failed to induce OD-plasticity in mouse V1. In contrast, mice raised in a so-called "enriched environment" (EE), exhibit lifelong OD-plasticity. EE-mice have more voluntary physical exercise (running wheels), and experience more social interactions (bigger housing groups) and more cognitive stimulation (regularly changed labyrinths or toys). Whether experience-dependent shifts of V1-activation happen faster in EE-mice and how long the plasticity promoting effect would persist after transferring EE-mice back to SCs has not yet been investigated. To this end, we used intrinsic signal optical imaging to visualize V1-activation i) before and after MD in EE-mice of different age groups (from 1-9 months), and ii) after transferring mice back to SCs after postnatal day 130. Already after 2 days of MD, and thus much faster than in SC-mice, EE-mice of all tested age groups displayed a significant OD-shift towards the open eye. Transfer of EE-mice to SCs immediately abolished OD-plasticity: already after 1 week of SC-housing and MD, OD-shifts could no longer be visualized. In an attempt to rescue abolished OD-plasticity of these mice, we either administered the anti-depressant fluoxetine (in drinking water) or supplied a running wheel in the SCs. OD-plasticity was only rescued for the running wheel- mice. Altogether our results show that raising mice in less deprived environments like large EE-cages strongly accelerates experience-dependent changes in V1-activation compared to the impoverished SC-raising. Furthermore, preventing voluntary physical exercise of EE-mice in adulthood immediately precludes OD-shifts in V1.
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