scholarly journals Viewpoint: What the Marine Mollusc Aplysia Can Tell the Neurologist About Behavioral Neurophysiology

1981 ◽  
Vol 8 (4) ◽  
pp. 275-280 ◽  
Author(s):  
Peter Ruben ◽  
Jeff Goldberg ◽  
Jon Edstrom ◽  
Karen Voshart ◽  
Ken Lukowiak
Keyword(s):  
Nervous System ◽  
Behavioral Plasticity ◽  
Systems Approach ◽  
Neural Substrates ◽  
Realistic Model ◽  
Model Systems ◽  
Neural Function ◽  
Experimental Conditions ◽  
Nervous Systems ◽  
Physical And Chemical

Only recently has man begun to regard himself as mundane and not divine. This conceptual liberation has allowed him to ask frank questions concerning the physical and chemical mechanisms which determine or affect his behavior. Unfortunately the answers to these questions have been slow in coming. The reasons for this are two-fold: Basic ethical considerations preclude the experiments necessary to investigate the neural substrates of human behavior in man. Further, man’s behavior and nervous system are both so enormously complex and subtle, it is therefore unlikely that much real fundamental knowledge could be gained from such experiments if performed. It is more expedient to study simple behavior in simpler organisms than man to understand how nervous systems operate in general and, it is hoped, to eventually gain a better understanding of the human in particular. This tactic is known as the “model systems” approach. By discovering the strategies adopted by less complex nervous systems to deal with simple situations one can devise a realistic model of the neural mechanisms that control more complex behavior in more advanced animals.Many animals have served as valuable sources of model systems. Among them the marine gastropod mollusc Aplysia has received considerable attention. In comparison to the human nervous system with approximately 50 billion neurons, the Aplysia nervous system contains relatively few neurons — about 20,000. Furthermore the study of the Aplysia nervous system has several other advantageous characteristics. A number of forms of behavioral plasticity that are found in all higher metazoans including man are also found in the Aplysia. These simple but non-trivial types of behavioral plasticity include habituation, sensitization and associative learning as well as easily defined qualities of neural function which we choose to call “behavioral states”. In addition the nervous system is composed of neurons which are large and, in many cases, easily identified by anatomical and physiological criteria so that the “same” cell can be studied in more than one animal under more than one set of experimental conditions. The cell bodies of the neurons in Aplysia, from which electrical recordings can be fairly easily obtained, are electrically close to their dendrites so that changes in postsynaptic potentials occurring during modifications of behavior can be monitored.

scholarly journals Neural shutdown under stress: an evolutionary perspective on spreading depolarization

2020 ◽  
Vol 123 (3) ◽  
pp. 885-895 ◽  
Author(s):  
R. Meldrum Robertson ◽  
Ken D. Dawson-Scully ◽  
R. David Andrew
Keyword(s):  
Systems Approach ◽  
Cellular Membrane ◽  
Membrane Potentials ◽  
Model Systems ◽  
Neural Function ◽  
Nervous Systems ◽  
Spreading Depolarization ◽  
Rapid Information Processing ◽  
Electrical Signaling ◽  
Open Question

Neural function depends on maintaining cellular membrane potentials as the basis for electrical signaling. Yet, in mammals and insects, neuronal and glial membrane potentials can reversibly depolarize to zero, shutting down neural function by the process of spreading depolarization (SD) that collapses the ion gradients across membranes. SD is not evident in all metazoan taxa with centralized nervous systems. We consider the occurrence and similarities of SD in different animals and suggest that it is an emergent property of nervous systems that have evolved to control complex behaviors requiring energetically expensive, rapid information processing in a tightly regulated extracellular environment. Whether SD is beneficial or not in mammals remains an open question. However, in insects, it is associated with the response to harsh environments and may provide an energetic advantage that improves the chances of survival. The remarkable similarity of SD in diverse taxa supports a model systems approach to understanding the mechanistic underpinning of human neuropathology associated with migraine, stroke, and traumatic brain injury.

Putting the Question in Perspective

2019 ◽  
pp. 3-12
Author(s):  
Dale Purves
Keyword(s):  
Nervous System ◽  
Scientific Progress ◽  
Operating Principle ◽  
Neural Function ◽  
Nervous Systems ◽  
The Brain ◽  
Human Nervous System

Basic to the question of whether or not the brain and the rest of the human nervous system have a simple operating principle are some central facts about biology and its relation to neuroscience. What nervous systems do is best appreciated in the context of what all organisms must accomplish in order to survive and prosper, with or without neural assistance. Although the author’s understanding of these issues is no more than that of any other student who pays a modicum of attention to the broader sweep of scientific progress, this chapter considers some points of consensus. The aim is to situate the quest for a principle of neural function in the context of biology writ large.

Brains as Engines of Association

2019 ◽  
Author(s):  
Dale Purves
Keyword(s):  
Neural Systems ◽  
Neural Function ◽  
Trial And Error ◽  
Nervous Systems ◽  
The Past ◽  
Sensing Systems ◽  
Lifetime Experience ◽  
Survival And Reproduction ◽  
Pros And Cons ◽  
And Behavior

Brains as Engines of Association seeks an operating principle of the human brain and is divided into four parts. The first part (“What Nervous Systems Do for Animals”) is intended to set the stage for understanding the emergence of neural systems as promoting what all organisms must accomplish: survival and reproduction. The second part (“Neural Systems as Engines of Association”) lays out the general argument that biological sensing systems face a daunting problem: they cannot measure the parameters of the world in the way physical instruments can. As a result, nervous systems must make and update associations (synaptic connections) on the basis of empirical success or failure over both evolutionary and individual time. The third part (“Evidence that Neural Systems Operate Empirically”) reviews evidence accumulated over the past 20 years that supports this interpretation in vision and audition, the sensory systems that have been most studied from this or any other perspective. Finally, the fourth part (“Alternative Concepts of Neural Function”) considers the pros and cons of other interpretations of how brains operate. The overarching theme is that the nervous systems of humans and every other animal operate on the basis associations between stimuli and behavior made by trial and error over species and lifetime experience.

scholarly journals Neurotoxicity in Marine Invertebrates: An Update

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 161
Author(s):  
Irene Deidda ◽  
Roberta Russo ◽  
Rosa Bonaventura ◽  
Caterina Costa ◽  
Francesca Zito ◽  
...  
Keyword(s):  
Nervous System ◽  
Marine Invertebrates ◽  
Marine Pollution ◽  
Marine Invertebrate ◽  
High Sensitivity ◽  
Model Systems ◽  
Neural Genes ◽  
Chemical Agents ◽  
Neurotoxic Effects ◽  
Invertebrate Model

Invertebrates represent about 95% of existing species, and most of them belong to aquatic ecosystems. Marine invertebrates are found at intermediate levels of the food chain and, therefore, they play a central role in the biodiversity of ecosystems. Furthermore, these organisms have a short life cycle, easy laboratory manipulation, and high sensitivity to marine pollution and, therefore, they are considered to be optimal bioindicators for assessing detrimental chemical agents that are related to the marine environment and with potential toxicity to human health, including neurotoxicity. In general, albeit simple, the nervous system of marine invertebrates is composed of neuronal and glial cells, and it exhibits biochemical and functional similarities with the vertebrate nervous system, including humans. In recent decades, new genetic and transcriptomic technologies have made the identification of many neural genes and transcription factors homologous to those in humans possible. Neuroinflammation, oxidative stress, and altered levels of neurotransmitters are some of the aspects of neurotoxic effects that can also occur in marine invertebrate organisms. The purpose of this review is to provide an overview of major marine pollutants, such as heavy metals, pesticides, and micro and nano-plastics, with a focus on their neurotoxic effects in marine invertebrate organisms. This review could be a stimulus to bio-research towards the use of invertebrate model systems other than traditional, ethically questionable, time-consuming, and highly expensive mammalian models.

scholarly journals Synapsin I (protein I), a nerve terminal-specific phosphoprotein. I. Its general distribution in synapses of the central and peripheral nervous system demonstrated by immunofluorescence in frozen and plastic sections.

1983 ◽  
Vol 96 (5) ◽  
pp. 1337-1354 ◽  
Author(s):  
P De Camilli ◽  
R Cameron ◽  
P Greengard
Keyword(s):  
Nervous System ◽  
Detailed Examination ◽  
Specific Protein ◽  
Nerve Cells ◽  
General Distribution ◽  
Synapsin I ◽  
Nervous Systems ◽  
Synaptic Region ◽  
Specific Localization ◽  
Peripheral Nervous Systems

Synapsin I (formerly referred to as protein I) is the collective name for two almost identical phosphoproteins, synapsin Ia and synapsin Ib (protein Ia and protein Ib), present in the nervous system. Synapsin I has previously been shown by immunoperoxidase studies (De Camilli, P., T. Ueda, F. E. Bloom, E. Battenberg, and P. Greengard, 1979, Proc. Natl. Acad. Sci. USA, 76:5977-5981; Bloom, F. E., T. Ueda, E. Battenberg, and P. Greengard, 1979, Proc. Natl. Acad. Sci. USA 76:5982-5986) to be a neuron-specific protein, present in both the central and peripheral nervous systems and concentrated in the synaptic region of nerve cells. In those preliminary studies, the occurrence of synapsin I could be demonstrated in only a portion of synapses. We have now carried out a detailed examination of the distribution of synapsin I immunoreactivity in the central and peripheral nervous systems. In this study we have attempted to maximize the level of resolution of immunohistochemical light microscopy images in order to estimate the proportion of immunoreactive synapses and to establish their precise distribution. Optimal results were obtained by the use of immunofluorescence in semithin sections (approximately 1 micron) prepared from Epon-embedded nonosmicated tissues after the Epon had been removed. Our results confirm the previous observations on the specific localization of synapsin I in nerve cells and synapses. In addition, the results strongly suggest that, with a few possible exceptions involving highly specialized neurons, all synapses contain synapsin I. Finally, immunocytochemical experiments indicate that synapsin I appearance in the various regions of the developing nervous system correlates topographically and temporally with the appearance of synapses. In two accompanying papers (De Camilli, P., S. M. Harris, Jr., W. B. Huttner, and P. Greengard, and Huttner, W. B., W. Schiebler, P. Greengard, and P. De Camilli, 1983, J. Cell Biol. 96:1355-1373 and 1374-1388, respectively), evidence is presented that synapsin I is specifically associated with synaptic vesicles in nerve endings.

scholarly journals Drosophila Stathmin: A Microtubule-destabilizing Factor Involved in Nervous System Formation

2002 ◽  
Vol 13 (2) ◽  
pp. 698-710 ◽  
Author(s):  
Sylvie Ozon ◽  
Antoine Guichet ◽  
Olivier Gavet ◽  
Siegfried Roth ◽  
André Sobel
Keyword(s):  
Nervous System ◽  
System Development ◽  
Nervous System Development ◽  
Microtubule Assembly ◽  
Nervous Systems ◽  
Germ Cell Migration ◽  
Numerous Cell ◽  
First Time

Stathmin is a ubiquitous regulatory phosphoprotein, the generic element of a family of neural phosphoproteins in vertebrates that possess the capacity to bind tubulin and interfere with microtubule dynamics. Although stathmin and the other proteins of the family have been associated with numerous cell regulations, their biological roles remain elusive, as in particular inactivation of the stathmin gene in the mouse resulted in no clear deleterious phenotype. We identified stathmin phosphoproteins inDrosophila, encoded by a unique gene sharing the intron/exon structure of the vertebrate stathmin andstathmin family genes. They interfere with microtubule assembly in vitro, and in vivo when expressed in HeLa cells. Drosophila stathmin expression is regulated during embryogenesis: it is high in the migrating germ cells and in the central and peripheral nervous systems, a pattern resembling that of mammalian stathmin. Furthermore, RNA interference inactivation ofDrosophila stathmin expression resulted in germ cell migration arrest at stage 14. It also induced important anomalies in nervous system development, such as loss of commissures and longitudinal connectives in the ventral cord, or abnormal chordotonal neuron organization. In conclusion, a single Drosophilagene encodes phosphoproteins homologous to the entire vertebrate stathmin family. We demonstrate for the first time their direct involvement in major biological processes such as development of the reproductive and nervous systems.

Tai Chi and meditation-plus-exercise benefit neural substrates of executive function: a cross-sectional, controlled study

2014 ◽  
Vol 11 (4) ◽  
Author(s):  
Teresa D. Hawkes ◽  
Wayne Manselle ◽  
Marjorie H. Woollacott
Keyword(s):  
Executive Function ◽  
Aerobic Exercise ◽  
Tai Chi ◽  
Neural Substrates ◽  
Event Related Potential ◽  
Controlled Study ◽  
Neural Function ◽  
Cross Sectional ◽  
P300 Event Related Potential

Abstract: We report the first controlled study of Tai Chi effects on the P300 event-related potential, a neuroelectric index of human executive function. Tai Chi is a form of exercise and moving meditation. Exercise and meditation have been associated with enhanced executive function. This cross-sectional, controlled study utilized the P300 event-related potential (ERP) to compare executive network neural function between self-selected long-term Tai Chi, meditation, aerobic fitness, and sedentary groups. We hypothesized that because Tai Chi requires moderate aerobic and mental exertion, this group would show similar or better executive neural function compared to meditation and aerobic exercise groups. We predicted all health training groups would outperform sedentary controls.: Fifty-four volunteers (Tai Chi, n=10; meditation, n=16; aerobic exercise, n=16; sedentary, n=12) were tested with the Rockport 1-mile walk (estimated VO: Only Tai Chi and meditation plus exercise groups demonstrated larger P3b ERP switch trial amplitudes compared to sedentary controls.: Our results suggest long-term Tai Chi practice, and meditation plus exercise may benefit the neural substrates of executive function.

scholarly journals The life history of Hepatozoon leptodactyli (Lesage, 1908) Pessoa, 1970: a parasite of the common laboratory animal: the frog of the genus Leptodactylus

1973 ◽  
Vol 71 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Sylvio Celso Goncalves da Costa ◽  
Samuel B. Pessoa ◽  
Neize de Moura Pereira ◽  
Tania Colombo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Life History ◽  
Laboratory Animal ◽  
Peripheral Circulation ◽  
Experimental Conditions ◽  
History Of ◽  
The Central Nervous System ◽  
The Common ◽  
Common Laboratory

The main object of the present paper is to furnish a brief account to the knowledgement of Protozoa parasitic in common Brazilian frog of the genus Leptodactylus for general students in Zoology and for investigators that use this frog as a laboratory animal. Hepatozoon leptodactyli (Haemogregarina leptodactyli) was found in two species of frogs - Leptodactylus ocellatus and L. pentadactylus - in which develop schizogony whereas sporogony occurs in the leech Haementeria lutzi as was obtainded in experimental conditions. Intracellular forms have been found in peripheral circulation, chiefly in erythrocytes, but we have found them in leukocytes too. Tissue stages were found in frog, liver, lungs, spleen, gut, brain and heart. The occurence of hemogregarine in the Central Nervous System was recorded by Costa & al,(13) and Ball (2). Some cytochemical methods were employed in attempt to differentiate gametocytes from trophozoites in the peripheral blood and to characterize the cystic membrane as well. The speorogonic cycle was developed in only one specie of leech. A brief description of the parasite is given.

scholarly journals The Photocatalytic Activity of Cement in Reducing Air Pollutants

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1422-1424
Keyword(s):  
Climate Change ◽  
Air Pollution ◽  
Global Warming ◽  
Photocatalytic Activity ◽  
Ion Chromatography ◽  
Air Pollutants ◽  
Experimental Conditions ◽  
Open Environment ◽  
Physical And Chemical ◽  
The Ideal

Air pollution is the major concern in the recent years because of causing imbalance to the ecosystem and also increases global warming and climate change. This paper, tries to investigate the applicability of photo catalytic cement in removing the pollutants under partially controlled and simpler experimental conditions such that it mimics the ideal state of its use, that is the natural open environment where it always is susceptible to complex physical and chemical interactions. It also gives an overview of the concentrations of the contaminants reduced not limiting to NOx residues alone, by employing Ion Chromatography instead of NOx analyzers.

scholarly journals Neuropeptides and Behaviors: How Small Peptides Regulate Nervous System Function and Behavioral Outputs

2021 ◽  
Vol 14 ◽  
Author(s):  
Umer Saleem Bhat ◽  
Navneet Shahi ◽  
Siju Surendran ◽  
Kavita Babu
Keyword(s):  
Nervous System ◽  
Behavioral Plasticity ◽  
Environmental Changes ◽  
Sensory Information ◽  
Synaptic Activity ◽  
Small Peptides ◽  
C Elegans ◽  
Wide Range ◽  
Nervous System Function ◽  
Insight Into

One of the reasons that most multicellular animals survive and thrive is because of the adaptable and plastic nature of their nervous systems. For an organism to survive, it is essential for the animal to respond and adapt to environmental changes. This is achieved by sensing external cues and translating them into behaviors through changes in synaptic activity. The nervous system plays a crucial role in constantly evaluating environmental cues and allowing for behavioral plasticity in the organism. Multiple neurotransmitters and neuropeptides have been implicated as key players for integrating sensory information to produce the desired output. Because of its simple nervous system and well-established neuronal connectome, C. elegans acts as an excellent model to understand the mechanisms underlying behavioral plasticity. Here, we critically review how neuropeptides modulate a wide range of behaviors by allowing for changes in neuronal and synaptic signaling. This review will have a specific focus on feeding, mating, sleep, addiction, learning and locomotory behaviors in C. elegans. With a view to understand evolutionary relationships, we explore the functions and associated pathophysiology of C. elegans neuropeptides that are conserved across different phyla. Further, we discuss the mechanisms of neuropeptidergic signaling and how these signals are regulated in different behaviors. Finally, we attempt to provide insight into developing potential therapeutics for neuropeptide-related disorders.

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