Complex Dynamics in Dedicated / Multifunctional Neural Networks and Chaotic Nonlinear Systems

We study complex behaviors arising in neuroscience and other nonlinear systems by combining dynamical systems analysis with modern computational approaches including GPU parallelization and unsupervised machine learning. To gain insights into the behaviors of brain networks and complex central pattern generators (CPGs), it is important to understand the dynamical principles regulating individual neurons as well as the basic structural and functional building blocks of neural networks. In the first section, we discuss how symbolic methods can help us analyze neural dynamics such as bursting, tonic spiking and chaotic mixed-mode oscillations in various models of individual neurons, the bifurcations that underlie transitions between activity types, as well as emergent network phenomena through synergistic interactions seen in realistic neural circuits, such as network bursting from non-intrinsic bursters. The second section is focused on the origin and coexistence of multistable rhythms in oscillatory neural networks of inhibitory coupled cells. We discuss how network connectivity and intrinsic properties of the cells affect the dynamics, and how even simple circuits can exhibit a variety of mono/multi-stable rhythms including pacemakers, half-center oscillators, multiple traveling-waves, fully synchronous states, as well as various chimeras. Our analyses can help generate verifiable hypotheses for neurophysiological experiments on central pattern generators. In the last section, we demonstrate the inter-disciplinary nature of this research through the applications of these techniques to identify the universal principles governing both simple and complex dynamics, and chaotic structure in diverse nonlinear systems. Using a classical example from nonlinear laser optics, we elaborate on the multiplicity and self-similarity of key organizing structures in 2D parameter space such as homoclinic and heteroclinic bifurcation curves, Bykov T-point spirals, and inclination flips. This is followed by detailed computational reconstructions of the spatial organization and 3D embedding of bifurcation surfaces, parametric saddles, and isolated closed curves (isolas). The generality of our modeling approaches could lead to novel methodologies and nonlinear science applications in biological, medical and engineering systems

Life in the Cold

Preface; First and Corresponding Author Contact Information; An Evolutionary Framework for Studies of Hibernation and Short-term Torpor -- Gordon C. Grigg; Was Adaptive Hypothermia a Prerequisite for the Colonization of Madagascar By Mammals? -- Barry G. Lovegrove; No Evidence for Torpor in a Small African Mainland Primate: The Lesser Bushbaby, Galago moholi -- Nomakwezi Mzilikazi, Barry G. Lovegrove, and Judith C. Masters; The Origin of Mammalian Heterothermy: A Case for Perpetual Youth? -- Michael B. Harris, Link E. Olson, and William K. Milsom; Passive Rewarming from Torpor in Mammals and Birds: Energetic, Ecological and Evolutionary Implications -- Fritz Geiser, Rebecca L. Drury, Gerhard Kortner, Christopher Turbill, Chris R. Pavey, and R. Mark Brigham; Solar Radiation and the Energetic Cost of Rewarming from Torpor -- Andrew M. McKechnie and Blair O. Wolf; The Role of α-Linolenic Acid (18:3) in Mammalian Torpor -- Craig L. Frank, Wendy R. Hood, and Mary C. Donnelly; Heat Transfer in Humans: Lessons from Large Hibernators -- Dennis Grahn and H. Craig Heller; Factors Influencing the Timing of Dormancy in the Pocket Mouse,Perognathus longimembris -- Alan R. French; The Energetic State-dependency of Autumn Immergence in Eastern Chipmunks -- Murray M. Humphries and Brandon Rodgers; Seasonal Timing of Reproduction and Hibernation in the Edible Dormouse (Glis glis) -- Claudia Bieber and Thomas Ruf; Reproduction and Hibernation in Females: A Comparison of Two Sympatric Ground-Dwelling Rodents -- Eva Millesi, Ilse E. Hoffmann, Anna Aschauer, and Claudia Franceschini; How the Photoperiod Times the Annual Reproductive and Hibernation Cycles -- P. Pevet, M. Saboureau, and P. Klosen; Behaviour, Body Temperature, and Hibernation in Tasmanian Echidnas (Tachyglossus aculeatus) -- Stewart Nicol, Christina Vedel-Smith, and Niels A. Andersen; Metabolic Diversity in Yellow-Bellied Marmots -- Kenneth B. Armitage; Metabolic Rate Reduction During Hibernation and Daily Torpor -- Fritz Geiser; How to Enter Torpor: Thermodynamic and Physiological Mechanisms of Metabolic Depression -- Gerhard Heldmaier and Ralf Elvert; Slow Loss of Protein Integrity During Torpor: A Cause for Arousal? -- Sandra L. Martin, Timothy Dahl, and L. Elaine Epperson; A Technique for Modelling Thermoregulatory Energy Expenditure in Free-ranging Endotherms -- Craig K. R. Willis, Jeffery E. Lane, Eric T. Liknes, David L. Swanson, and R. Mark Brigham; Sex Differences in the Response of Torpor to Exogenous Corticosterone During the Onset of the Migratory Season in Rufous Hummingbirds -- Sara M. Hiebert, John C. Wingfield, Marilyn Ramenofsky, Leah Deni, and Antoinette Grafin zu Elz; The Avian Enigma: “Hibernation” by Common Poorwills (Phalaenoptilus nuttalli) -- Christopher P. Woods and R. Mark Brigham; Shivering Thermogenesis in Birds and Mammals -- Esa Hohtola; The Impact of Social Interactions on Torpor Use in Hummingbirds -- Donald Powers; The Energetics of the Rewarming Phase of Avian Torpor -- Andrew E. McKechnie and Blair O. Wolf; Insect Cold-Hardiness: New Advances Using Gene Screening Technology -- Kenneth B. Storey and David C. McMullen; Advantages and Disadvantages of Freeze-Tolerance and Freeze-Avoidance Overwintering Strategies -- Karl Erick Zachariassen, Sindre Andre Pedersen, and Erlend Kristiansen; Live and Let Diapause: Cell Cycle Regulation During Insect Overwintering -- Savvas c. Pavlides, Kenneth A. Weir, and Steven P. Tammariello; Vertebrate Freeze Tolerance: Role of Freeze-Responsive Gene Expression -- Kenneth B. Storey; Ice, Antifreeze Proteins, and Antifreeze Genes in Polar Fishes -- Arthur L. DeVries; Overwintering in Submerged Turtles -- Donald C. Jackson; Environmental Physiology of Terrestrial Hibernation in Hatchling Turtles -- Patrick J. Baker, Jon P. Costanzo, and Richard E. Lee, Jr.; Overwintering in Tegu Lizards -- Denis V. Andrade, Colin Sanders, William K. Milsom, and Augusto S. Abe; Overwintering in Cold-Submerged Frogs -- Glenn J. Tattersall; Effect of Temperature on Regular and Modified Circannual Rhythms in the European Ground Squirrel Under Free-Running Conditions -- Radoslav K. Andjus, Marina Marjanovic, and Dragoslava Zivadinovic; The Role of the Suprachiasmatic Pacemaker (SCN) in Energy Expenditure During Hibernation of Golden-mantled Ground Squirrels -- Patricia J. DeCoursey; Does Hibernation Violate Biological Laws? -- Andre Malan; The Suprachiasmatic Nucleus Influences Energy Balance of Golden-mantled Ground Squirrels During Hibernation -- Norman E. Ruby; Pesticide Effects on Body Temperature of Torpid/Hibernating Rodents (Peromyscus leucopus and Spermophilus tridecemlineatus) -- Thomas E. Tomasi, Peta Elsken-Lacy, Jean A. Perry, and Kerry Withers; Steroidogenesis and the HPA Axis During Hibernation: Differential Expression of the StAR Protein -- Matthew T. Andrews, Meaghan M. Tredrea, and Aubie K. Shaw; A Quest for the Origin of Mammalian Uncoupling Proteins -- Marton Jastroch, Sigrid Stohr, Kerry Withers, and Martine Klingenspor; Brown-Fat-Derived and Thyroid-Hormone Thermogenesis: Mechanisms and Interactions -- Jan Nedergaard, Valeria Golozoubova, and Barbara Cannon; Alterations in Localization of Hippocampal Protein Kinase Cγ (PKCγ), but Not PKCα, -β1, or –β2, in European Ground Squirrels During Hibernation -- Eddy A. Van der Zee, Jens Stieler, Roelof A. Hut, Martin de Wilde, and Arjen M. Strijkstra; The Role of the Medial Septum in the Control of Hibernation -- Irina Yu. Popova and Yurii M. Kokoz; Proteolysis in Hibernators -- Frank can Breukelen; Post-genomic Approaches to the Mechanisms of Cold Response in Fish and Hibernating Small Mammals -- Daryl Williams, L. Elaine Epperson, Andrew R. Cossins, Jane Fraser, Weizhong Li, Sandra Martin, and Andrew Y. Gracey; Use of Suppression Subtractive Hybridization to Elucidate Novel Gene Products Related to Physiological Events in a Hibernator -- Gregory L. Florant, Chris Pittman, and Scott A. Summers; Clinical Applications and Limitations of Hypothermia -- Philip E. bickler; Hibernation in Mammals: A Model for Alzheimer-type Phosphorylation of the Microtubule-associated Protein Tau -- Thomas Arendt, Jens Stieler, Arjen M. Strijkstriam Roelof A. Hut, Eddy A. Van der Zee, max Holzer, and Woldfgang Hartig; Resistance of Livers to Cold Ischemia/Reperfusion Injury During Hibernation: Involvement of Matrix Metalloproteinase and Nitric Oxide Synthase -- Hannah V. Carey, Timothy M. Piazza, Sarah E. Davis, Susanne L. Lindell, Anna Durranis, Kieran Clarke, and James H. Southard; Anti-Proliferative Effects of Plasma from Hibernating Rodents -- Donna G. Sieckmann, Decheng Cai, Howard Jaffe, John Hallenbeck, and Richard M. McCarron; Antifreeze Proteins in Terrestrial Arthropods -- John G. Duman, Valerie A. Bennett, N. Li, L. Wang, L. Huang, T. Sformo, and B.M. Barnes; Cardiac Conduction and Resistance to Ventricular Fibrillation in Siberian Hibernator Ground Squirrel Citellus undulatus -- Vadim V. Fedorov, Rubin R. Aliev, Alexey V. Glukhov, Andrey V. Resnik, Andrey Anufriev, Irina A. Ivanova, Olga V. Nakipova, Stella G. Kolaeva, Leonid V. Rosenshtraukh, and Igor R. Efimov; The Correlation Between Akt Activity and Hibernation -- Decheng Cai, Richard M. McCarron, Donna Sieckmann, and John M. Hallenbeck; Protection from Traumatic Brain Injury During Hibernation -- Kelly L. Drew, Fang Zhou, Xiongwei Zhu, Rudy J. Castellani, and Mark A. Smith; δ-Opioid Agonists Protect the Rat Liver From Cold Storage and Ischemia/Reperfusion Injury -- Thomas L. Husted, Wen-Jian Chang, Alex B. Lentsch, Steven M. Rudich;Animal Adaptability to Oxidative Stress: Gastropod Estivation and Mammalian Hibernation -- Marcelo Hermes-Lima, Gabriella R. Ramos-Vasconcelos, Luciano A. Cardoso, Adrienne l. Orr, Patricia M. Rivera, and Kelly L. Drew

Deep Brain Stimulation (DBS) Applications

The issue is dedicated to applications of Deep Brain Stimulation and, in this issue, we would like to highlight the new developments that are taking place in the field. These include the application of new technology to existing indications, as well as ‘new’ indications. We would also like to highlight the most recent clinical evidence from international multicentre trials. The issue will include articles relating to movement disorders, pain, psychiatric indications, as well as emerging indications that are not yet accompanied by clinical evidence. We look forward to your expert contribution to this exciting issue

25th Annual Computational Neuroscience Meeting: CNS-2016

Abstracts of the 25th Annual Computational Neuroscience Meeting: CNS-2016 Seogwipo City, Jeju-do, South Korea. 2–7 July 201

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong