Long-Term Potentiation: One Kind or Many?

Do neurobiologists aim to discover natural kinds? I address this question in this chapter via a critical analysis of classification practices operative across the 43-year history of research on long-term potentiation (LTP). I argue that this 43-year history supports the idea that the structure of scientific practice surrounding LTP research has remained an obstacle to the discovery of natural kinds

State based model of long-term potentiation and synaptic tagging and capture

Recent data indicate that plasticity protocols have not only synapse-specific but also more widespread effects. In particular, in synaptic tagging and capture (STC), tagged synapses can capture plasticity-related proteins, synthesized in response to strong stimulation of other synapses. This leads to long-lasting modification of only weakly stimulated synapses. Here we present a biophysical model of synaptic plasticity in the hippocampus that incorporates several key results from experiments on STC. The model specifies a set of physical states in which a synapse can exist, together with transition rates that are affected by high- and low-frequency stimulation protocols. In contrast to most standard plasticity models, the model exhibits both early- and late-phase LTP/D, de-potentiation, and STC. As such, it provides a useful starting point for further theoretical work on the role of STC in learning and memory

Broadband random optoelectronic oscillator

[EN] Random scattering of light in transmission media has attracted a great deal of attention in the field of photonics over the past few decades. An optoelectronic oscillator (OEO) is a microwave photonic system offering unbeatable features for the generation of microwave oscillations with ultra-low phase noise. Here, we combine the unique features of random scattering and OEO technologies by proposing an OEO structure based on random distributed feedback. Thanks to the random distribution of Rayleigh scattering caused by inhomogeneities within the glass structure of the fiber, we demonstrate the generation of ultra-wideband (up to 40¿GHz from DC) random microwave signals in an open cavity OEO. The generated signals enjoy random characteristics, and their frequencies are not limited by a fixed cavity length figure. The proposed device has potential in many fields such as random bit generation, radar systems, electronic interference and countermeasures, and telecommunications.Thanks N. Shi and Y. Yang for comments and discussion. This work was supported by the National Key Research and Development Program of China under 2018YFB2201902 and the National Natural Science Foundation of China under 61925505. This work was also partly supported by the National Key Research and Development Program of China under 2018YFB2201901, 2018YFB2201903, and the National Natural Science Foundation of China under 61535012 and 61705217.Ge, Z.; Hao, T.; Capmany Francoy, J.; Li, W.; Zhu, N.; Li, M. (2020). Broadband random optoelectronic oscillator. Nature Communications. 11(1):1-8. https://doi.org/10.1038/s41467-020-19596-xS18111Feng, S., Kane, C., Lee, P. A. & Stone, A. D. Correlations and fluctuations of coherent wave transmission through disordered media. Phys. Rev. Lett. 61, 834 (1988).Wiersma, D. S. & Cavalieri, S. Light emission: a temperature-tunable random laser. Nature 414, 708 (2001).Wiersma, D. S. The physics and applications of random lasers. Nat. Phys. 4, 359 (2008).Turitsyn, S. K. et al. Random distributed feedback fibre laser. Nat. Photonics 4, 231–235 (2010).Babin, S. A., El-Taher, A. E., Harper, P., Podivilov, E. V. & Turitsyn, S. K. Tunable random fiber laser. Phys. Rev. A 84, 021805 (2011).Turitsyn, S. K. et al. Random distributed feedback fibre lasers. Phys. Rep. 542, 133–193 (2014).Barnoski, M., Rourke, M., Jensen, S. M. & Melville, R. T. Optical time domain reflectometer. Appl. Opt. 16, 2375–2379 (1977).Yao, X. S. & Maleki, L. Optoelectronic microwave oscillator. JOSA B 13, 1725–1735 (1996).Maleki, L. Sources: the optoelectronic oscillator. Nat. Photonics 5, 728 (2011).Yao, X. S. & Maleki, L. Multiloop optoelectronic oscillator. IEEE J. Quantum Electron 36, 79–84 (2000).Hao, T. et al. Breaking the limitation of mode building time in an optoelectronic oscillator. Nat. Commun. 9, 1839 (2018).Zhang, W. & Yao, J. Silicon photonic integrated optoelectronic oscillator for frequency-tunable microwave generation. J. Lightwave Technol. 36, 4655–4663 (2018).Hao, T. et al. Toward Monolithic Integration of OEOs: from systems to chips. J. Lightwave Technol. 36, 4565–4582 (2018).Zhang, J. & Yao, J. Parity-time–symmetric optoelectronic oscillator. Sci. Adv. 4, eaar6782 (2018).Liu, Y. et al. Observation of parity-time symmetry in microwave photonics. Light Sci. Appl. 7, 38 (2018).Nakazawa, M. Rayleigh backscattering theory for single-mode optical fibers. JOSA 73, 1175–1180 (1983).Hartog, A. & Gold, M. On the theory of backscattering in single-mode optical fibers. J. Lightwave Technol. 2, 76–82 (1984).Eickhoff, W., & Ulrich, R. Statistics of backscattering in single-mode fiber. In Optical Fiber Communication Conference. Optical Society of America (1981).Alekseev, A. E., Tezadov, Y. A. & Potapov, V. T. Statistical properties of backscattered semiconductor laser radiation with different degrees of coherence. Quantum Electron 42, 76–81 (2012).Gysel, P. & Staubli, R. K. Statistical properties of Rayleigh backscattering in single-mode fibers. J. Lightwave Technol. 8, 561–567 (1990).Staubli, R. K. & Gysel, P. Statistical properties of single-mode fiber rayleigh backscattered intensity and resulting detector current. IEEE Trans. Commun. 40, 1091–1097 (1992).Levy, E. C., Horowitz, M. & Menyuk, C. R. Modeling optoelectronic oscillators. JOSA B 26, 148–159 (2009).Yariv, A. Introduction to Optical Electronics 2nd edn. (Holt, Rinehart and Winston, New York, 1976).Aoki, Y., Tajima, K. & Mito, I. Input power limits of single-mode optical fibers due to stimulated Brillouin scattering in optical communication systems. J. Lightwave Technol. 6, 710–719 (1988).Song, H. J., Shimizu, N., Kukutsu, N., Nagatsuma, T. & Kado, Y. 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Broadband chaotic signals and breather oscillations in an optoelectronic oscillator incorporating a microwave photonic filter. J. Lightwave Technol. 32, 3933–3942 (2014)

The attachments of the anteromedial and posterolateral fibre bundles of the anterior cruciate ligament: Part 1: tibial attachment.

Accepted versio

Plasticity in the Olfactory System: Lessons for the Neurobiology of Memory

We are rapidly advancing toward an understanding of the molecular events underlying odor transduction, mechanisms of spatiotemporal central odor processing, and neural correlates of olfactory perception and cognition. A thread running through each of these broad components that define olfaction appears to be their dynamic nature. How odors are processed, at both the behavioral and neural level, is heavily dependent on past experience, current environmental context, and internal state. The neural plasticity that allows this dynamic processing is expressed nearly ubiquitously in the olfactory pathway, from olfactory receptor neurons to the higher-order cortex, and includes mechanisms ranging from changes in membrane excitability to changes in synaptic efficacy to neurogenesis and apoptosis. This review will describe recent findings regarding plasticity in the mammalian olfactory system that are believed to have general relevance for understanding the neurobiology of memory.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline