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Emily Kabeiseman, Riley T Paulsen, Brian D Burrell
The endocannabinoid system plays a critical role in modulating both peripheral and central nervous system function. Despite being present throughout the animal kingdom, there has been relatively little investigation of the endocannabinoid system beyond the traditional animal model systems. In this study, we report on the identification and characterization of a fatty acid aminohydrolase (FAAH) in the medicinal leech, Hirudo verbana . FAAH is the primary enzyme responsible for metabolizing the endocannabinoid signaling molecule arachidonoyl ethanolamide (anandamide or AEA) and therefore plays a critical role in regulating AEA levels in the nervous system...
April 18, 2024: Research Square
#2
JOURNAL ARTICLE
Zalina Dezhina, Jonathan Smallwood, Ting Xu, Federico E Turkheimer, Rosalyn J Moran, Karl J Friston, Robert Leech, Erik D Fagerholm
The definition of a brain state remains elusive, with varying interpretations across different sub-fields of neuroscience-from the level of wakefulness in anaesthesia, to activity of individual neurons, voltage in EEG, and blood flow in fMRI. This lack of consensus presents a significant challenge to the development of accurate models of neural dynamics. However, at the foundation of dynamical systems theory lies a definition of what constitutes the 'state' of a system-i.e., a specification of the system's future...
October 2023: PLoS Computational Biology
#3
JOURNAL ARTICLE
Jens-Steffen Scherer, Kevin Sandbote, Bjarne L Schultze, Jutta Kretzberg
Many neurons possess more than one spike initiation zone (SIZ), which adds to their computational power and functional flexibility. Integrating inputs from different origins is especially relevant for sensory neurons that rely on relative spike timing for encoding sensory information. Yet, it is poorly understood if and how the propagation of spikes generated at one SIZ in response to sensory stimulation is affected by synaptic inputs triggering activity of other SIZ, and by environmental factors like temperature...
2023: Frontiers in Cellular Neuroscience
#4
JOURNAL ARTICLE
Sonja Meiser, Jana Marie Sleeboom, Ihor Arkhypchuk, Kevin Sandbote, Jutta Kretzberg
Mechanosensory cells in the leech share several common features with mechanoreceptors in the human glabrous skin. Previous studies showed that the six T (touch) cells in each body segment of the leech are highly variable in their responses to somatic current injection and change their excitability over time. Here, we investigate three potential reasons for this variability in excitability by comparing the responses of T cells at two soma locations (T2 and T3): (1) Differential effects of time-dependent changes in excitability, (2) divergent synaptic input from the network, and (3) different anatomical structures...
2023: Frontiers in Cellular Neuroscience
#5
JOURNAL ARTICLE
Ricardo Erazo-Toscano, Mykhailo Fomenko, Samuel Core, Ronald L Calabrese, Gennady Cymbalyuk
Life-supporting rhythmic motor functions like heart-beating in invertebrates and breathing in vertebrates require an indefatigable generation of a robust rhythm by specialized oscillatory circuits, Central Pattern Generators (CPGs). These CPGs should be sufficiently flexible to adjust to environmental changes and behavioral goals. Continuous self-sustained operation of bursting neurons requires intracellular Na+ concentration to remain in a functional range and to have checks and balances of the Na+ fluxes met on a cycle-to-cycle basis during bursting...
July 10, 2023: ENeuro
#6
JOURNAL ARTICLE
Lidia Szczupak
Leeches display robust motor patterns and exhibit a relatively simple nervous system where neurons are unambiguously identified. This brief article focuses on Hirudo verbana and summarizes how research in this organism has contributed to insights in the field of motor control, where networks have been studied from population down to individual neuron perspectives.
July 6, 2023: Trends in Neurosciences
#7
JOURNAL ARTICLE
Hui-Ying Wang, Ke Yu, Zhe Yang, Guo Zhang, Shi-Qi Guo, Tao Wang, Dan-Dan Liu, Ruo-Nan Jia, Yu-Tong Zheng, Yan-Nan Su, Yi Lou, Klaudiusz R Weiss, Hai-Bo Zhou, Feng Liu, Elizabeth C Cropper, Quan Yu, Jian Jing
Locomotion in mollusc Aplysia is implemented by a pedal rolling wave, a type of axial locomotion. Well-studied examples of axial locomotion (pedal waves in Drosophila larvae and body waves in leech, lamprey, and fish) are generated in a segmented nervous system via activation of multiple coupled central pattern generators (CPGs). Pedal waves in molluscs, however, are generated by a single pedal ganglion, and it is unknown whether there are single or multiple CPGs that generate rhythmic activity and phase shifts between different body parts...
2023: Research: a science partner journal
#8
REVIEW
Erik D Fagerholm, Zalina Dezhina, Rosalyn J Moran, Federico E Turkheimer, Robert Leech
Entropy is not just a property of a system - it is a property of a system and an observer. Specifically, entropy is a measure of the amount of hidden information in a system that arises due to an observer's limitations. Here we provide an account of entropy from first principles in statistical mechanics with the aid of toy models of neural systems. Specifically, we describe the distinction between micro and macrostates in the context of simplified binary-state neurons and the characteristics of entropy required to capture an associated measure of hidden information...
February 1, 2023: Neuroscience and Biobehavioral Reviews
#9
REVIEW
Morgan N Collins, Karen A Mesce
This review article highlights the historical developments and current state of knowledge of an important neuromodulation technology: low-intensity focused ultrasound. Because compelling studies have shown that focused ultrasound can modulate neuronal activity non-invasively, especially in deep brain structures with high spatial specificity, there has been a renewed interest in attempting to understand the specific bioeffects of focused ultrasound at the cellular level. Such information is needed to facilitate the safe and effective use of focused ultrasound to treat a number of brain and nervous system disorders in humans...
2022: Frontiers in Physiology
#10
JOURNAL ARTICLE
Jun Aoki, Masako Isokawa, Michisato Toyoda
Space and time coherent mapping (STCM) is a technology developed in our laboratory for improved matrix-assisted laser desorption ionization (MALDI) time of flight (TOF) imaging mass spectrometry (IMS). STCM excels in high spatial resolutions, which probe-based scanning methods cannot attain in conventional MALDI IMS. By replacing a scanning probe with a large field laser beam, focusing ion optics, and position-sensitive detectors, STCM tracks the entire flight trajectories of individual ions throughout the ionization process and visualizes the ionization site on the sample surface with a subcellular scale of precision and a substantially short acquisition time...
October 26, 2022: Cells
#11
REVIEW
Jumana Ahmad, Claire Ellis, Robert Leech, Bradley Voytek, Pilar Garces, Emily Jones, Jan Buitelaar, Eva Loth, Francisco Páscoa Dos Santos, Adrián F Amil, Paul F M J Verschure, Declan Murphy, Grainne McAlonan
Brain function is a product of the balance between excitatory and inhibitory (E/I) brain activity. Variation in the regulation of this activity is thought to give rise to normal variation in human traits, and disruptions are thought to potentially underlie a spectrum of neuropsychiatric conditions (e.g., Autism, Schizophrenia, Downs' Syndrome, intellectual disability). Hypotheses related to E/I dysfunction have the potential to provide cross-diagnostic explanations and to combine genetic and neurological evidence that exists within and between psychiatric conditions...
November 8, 2022: Translational Psychiatry
#12
JOURNAL ARTICLE
Initial Variability and Time-Dependent Changes of Neuronal Response Features Are Cell-Type-Specific.
Jens-Steffen Scherer, Oda E Riedesel, Ihor Arkhypchuk, Sonja Meiser, Jutta Kretzberg
Different cell types are commonly defined by their distinct response features. But several studies proved substantial variability between cells of the same type, suggesting rather the appraisal of response feature distributions than a limitation to "typical" responses. Moreover, there is growing evidence that time-dependent changes of response features contribute to robust and functional network output in many neuronal systems. The individually characterized Touch (T), Pressure (P), and Retzius (Rz) cells in the medicinal leech allow for a rigid analysis of response features, elucidating differences between and variability within cell types, as well as their changes over time...
2022: Frontiers in Cellular Neuroscience
#13
JOURNAL ARTICLE
David A Weisblat
My goals in this chapter are to share my enthusiasm for studying the biology of leeches, to place this work in context by presenting my rationale for studying non-traditional biological models in general, and to sample just three of the questions that intrigue me in leech biology, namely segmentation, genome evolution and neuronal fate specification. I first became excited about the idea of using leeches as a subject of investigation as an undergraduate in 1970 and have been engaged in this work since I arrived at Berkeley as a postdoc in 1976, intending to study leech neurobiology...
2022: Current Topics in Developmental Biology
#14
JOURNAL ARTICLE
Aditya Athota, Blair Caccam, Ryan Kochis, Arjun Ray, Gert Cauwenberghs, Frederic D Broccard
In both invertebrate and vertebrate animals, small networks called central pattern generators (CPGs) form the building blocks of the neuronal circuits involved in locomotion. Most CPGs contain a simple half-center oscillator (HCO) motif which consists of two neurons, or populations of neurons, connected by reciprocal inhibition. CPGs and HCOs are well characterized neuronal networks and have been extensively modeled at different levels of abstraction. In the past two decades, hardware implementation of spiking CPG and HCO models in neuromorphic hardware has opened up new applications in mobile robotics, computational neuroscience, and neuroprosthetics...
November 2021: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#15
JOURNAL ARTICLE
Erik D Fagerholm, W M C Foulkes, Karl J Friston, Rosalyn J Moran, Robert Leech
The principle of stationary action is a cornerstone of modern physics, providing a powerful framework for investigating dynamical systems found in classical mechanics through to quantum field theory. However, computational neuroscience, despite its heavy reliance on concepts in physics, is anomalous in this regard as its main equations of motion are not compatible with a Lagrangian formulation and hence with the principle of stationary action. Taking the Dynamic Causal Modelling (DCM) neuronal state equation as an instructive archetype of the first-order linear differential equations commonly found in computational neuroscience, we show that it is possible to make certain modifications to this equation to render it compatible with the principle of stationary action...
August 12, 2021: Journal of Mathematical Neuroscience
#16
JOURNAL ARTICLE
Judith R Homberg, Roger A H Adan, Natalia Alenina, Antonis Asiminas, Michael Bader, Tom Beckers, Denovan P Begg, Arjan Blokland, Marilise E Burger, Gertjan van Dijk, Ulrich L M Eisel, Ype Elgersma, Bernhard Englitz, Antonio Fernandez-Ruiz, Carlos P Fitzsimons, Anne-Marie van Dam, Peter Gass, Joanes Grandjean, Robbert Havekes, Marloes J A G Henckens, Christiane Herden, Roelof A Hut, Wendy Jarrett, Kate Jeffrey, Daniela Jezova, Andries Kalsbeek, Maarten Kamermans, Martien J Kas, Nael Nadif Kasri, Amanda J Kiliaan, Sharon M Kolk, Aniko Korosi, S Mechiel Korte, Tamas Kozicz, Steven A Kushner, Kirk Leech, Klaus-Peter Lesch, Heidi Lesscher, Paul J Lucassen, Anita Luthi, Liya Ma, Anne S Mallien, Peter Meerlo, Jorge F Mejias, Frank J Meye, Anna S Mitchell, Joram D Mul, Umberto Olcese, Azahara Oliva González, Jocelien D A Olivier, Massimo Pasqualetti, Cyriel M A Pennartz, Piotr Popik, Jos Prickaerts, Liset M de la Prida, Sidarta Ribeiro, Benno Roozendaal, Janine I Rossato, Ali-Akbar Salari, Regien G Schoemaker, August B Smit, Louk J M J Vanderschuren, Tomonori Takeuchi, Rixt van der Veen, Marten P Smidt, Vladyslav V Vyazovskiy, Maximilian Wiesmann, Corette J Wierenga, Bella Williams, Ingo Willuhn, Markus Wöhr, Monique Wolvekamp, Eddy A van der Zee, Lisa Genzel
Policymakers aim to move toward animal-free alternatives for scientific research and have introduced very strict regulations for animal research. We argue that, for neuroscience research, until viable and translational alternatives become available and the value of these alternatives has been proven, the use of animals should not be compromised.
August 4, 2021: Neuron
#17
JOURNAL ARTICLE
Sergio Serrano, M Angeles Martínez, Roberto Barrio
Bursting phenomena and, in particular, square-wave or fold/hom bursting, are found in a wide variety of mathematical neuron models. These systems have different behavior regimes depending on the parameters, whether spiking, bursting, or chaotic. We study the topological structure of chaotic invariant sets present in square-wave bursting neuron models, first detailed using the Hindmarsh-Rose neuron model and later exemplary in the more realistic model of a leech heart neuron. We show that the unstable periodic orbits that form the skeleton of the chaotic invariant sets are deeply related to the spike-adding phenomena, typical from these models, and how there are specific symbolic sequences and a symbolic grammar that organize how and where the periodic orbits appear...
April 2021: Chaos
#18
JOURNAL ARTICLE
Parker J Ellingson, William H Barnett, Daniel Kueh, Alex Vargas, Ronald L Calabrese, Gennady S Cymbalyuk
Central pattern generators (CPGs), specialized oscillatory neuronal networks controlling rhythmic motor behaviors such as breathing and locomotion, must adjust their patterns of activity to a variable environment and changing behavioral goals. Neuromodulation adjusts these patterns by orchestrating changes in multiple ionic currents. In the medicinal leech, the endogenous neuromodulator myomodulin speeds up the heartbeat CPG by reducing the electrogenic Na+ /K+ pump current and increasing h-current in pairs of mutually inhibitory leech heart interneurons (HNs)which form half-center oscillators (HN HCOs)...
June 8, 2021: Journal of Neuroscience
#19
JOURNAL ARTICLE
Ricardo Javier Erazo Toscano, Parker J Ellingson, Ronald L Calabrese, Gennady S Cymbalyuk
The Na+ /K+ pump, often thought of as a background function in neuronal activity, contributes an outward current (Ipump) that responds to the internal concentration of Na+ ([Na+ ]i). In bursting neurons, such as those found in central pattern generator (CPG) neuronal networks that produce rhythmic movements, the [Na+ ]i and therefore the Ipump, can be expected to vary throughout the burst cycle. This responsiveness to electrical activity, combined with independence from membrane potential, endow Ipump with dynamical properties not common to channel-based currents (e...
May 9, 2021: Journal of Visualized Experiments: JoVE
#20
JOURNAL ARTICLE
Francisco F De-Miguel, Carolina Leon-Pinzon, Susana G Torres-Platas, Vanessa Del-Pozo, Guillermo A Hernández-Mendoza, Dilia Aguirre-Olivas, Bruno Méndez, Sharlen Moore, Celeste Sánchez-Sugía, Marco Antonio García-Aguilera, Alejandro Martínez-Valencia, Guillermo Ramírez-Santiago, J Miguel Rubí
Streams of action potentials or long depolarizations evoke a massive exocytosis of transmitters and peptides from the surface of dendrites, axons and cell bodies of different neuron types. Such mode of exocytosis is known as extrasynaptic for occurring without utilization of synaptic structures. Most transmitters and all peptides can be released extrasynaptically. Neurons may discharge their contents with relative independence from the axon, soma and dendrites. Extrasynaptic exocytosis takes fractions of a second in varicosities or minutes in the soma or dendrites, but its effects last from seconds to hours...
2021: Frontiers in Molecular Neuroscience
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