Rhythmic changes in the serotonin content of the brain and eyestalk of crayfish during development

1999 ◽  
Vol 202 (20) ◽  
pp. 2823-2830 ◽  
Author(s):  
O. Castanon-Cervantes ◽  
B. Battelle ◽  
M.L. Fanjul-Moles

The present study investigated developmental circadian changes in the content of 5-hydroxytryptamine (5-HT) in two structures proposed to contain pacemakers in crayfish Procambarus clarkii: the cerebral ganglion and the eyestalks. Crayfish (N=260) from three developmental stages were divided into two groups: (1) animals subjected to 12 h:12 h light:dark cycles for 10 days and (2) animals treated as described above, then exposed to 72 h of continuous dim light. Crayfish from both groups were killed at different times of day, and the cerebral ganglion and the eyestalks of each were assayed for 5-HT by reversed-phase HPLC with electrochemical detection. In all stages of development, 5-HT content (expressed as (μ)g g(−)(1)wet mass tissue) showed circadian variations in both structures analyzed; rhythms continued to free-run under constant illumination, and total 5-HT content was higher in the brain (0.581+/−0.36 (μ)g g(−)(1); mean +/− s.e.m.) than in the eyestalks (0.299+/−0.15 (μ)g g(−)(1)). As development advances, the percentage of the rhythm that shows periods of 24 h diminishes, while the percentage of the rhythm that shows periods of 9 to 12 h increases. This seems to indicate that pulsatile variations in 5-HT content are superimposed in a circadian component. The relationship between the 5-HT rhythm and electroretinogram and motor activity rhythms during development is discussed.

2010 ◽  
Vol 2010 (1) ◽  
pp. 5-22
Author(s):  
Ralf Becker

The article examines the relationship between freedom, guilt and responsibility in Dostojewski’s and Sartre’s works. Both attribute a great measure of personal freedom to man. Therefore, they do not tolerate excuses. Whoever is free, carries responsibility and gets caught up in guilt. Dostojewski’s focus is mainly on guilt, Sartre’s is on responsibility. They share the conviction that we can delegate responsibility for our actions or our way of living neither to a whole, of which we are a part, like society (the ,milieu'), nor to a part, for which we are the whole, like the ,brain' or the ,genes'. In that sense, Dostojewski’s and Sartre’s attempts at an ethic of responsibility also offer convincing arguments against determinism.


Author(s):  
M.P. Sutunkova ◽  
B.A. Katsnelson ◽  
L.I. Privalova ◽  
S.N. Solovjeva ◽  
V.B. Gurvich ◽  
...  

We conducted a comparative assessment of the nickel oxide nanoparticles toxicity (NiO) of two sizes (11 and 25 nm) according to a number of indicators of the body state after repeated intraperitoneal injections of these particles suspensions. At equal mass doses, NiO nanoparticles have been found to cause various manifestations of systemic subchronic toxicity with a particularly pronounced effect on liver, kidney function, the body’s antioxidant system, lipid metabolism, white and red blood, redox metabolism, spleen damage, and some disorders of nervous activity allegedly related to the possibility of nickel penetration into the brain from the blood. The relationship between the diameter and toxicity of particles is ambiguous, which may be due to differences in toxicokinetics, which is controlled by both physiological mechanisms and direct penetration of nanoparticles through biological barriers and, finally, unequal solubility.


2020 ◽  
Vol 21 (9) ◽  
pp. 649-660
Author(s):  
Subashini Raman ◽  
Syed Mahmood ◽  
Ayah R. Hilles ◽  
Md Noushad Javed ◽  
Motia Azmana ◽  
...  

Background: Blood-brain barrier (BBB) plays a most hindering role in drug delivery to the brain. Recent research comes out with the nanoparticles approach, is continuously working towards improving the delivery to the brain. Currently, polymeric nanoparticle is extensively involved in many therapies for spatial and temporal targeted areas delivery. Methods: We did a non-systematic review, and the literature was searched in Google, Science Direct and PubMed. An overview is provided for the formulation of polymeric nanoparticles using different methods, effect of surface modification on the nanoparticle properties with types of polymeric nanoparticles and preparation methods. An account of different nanomedicine employed with therapeutic agent to cross the BBB alone with biodistribution of the drugs. Results: We found that various types of polymeric nanoparticle systems are available and they prosper in delivering the therapeutic amount of the drug to the targeted area. The effect of physicochemical properties on nanoformulation includes change in their size, shape, elasticity, surface charge and hydrophobicity. Surface modification of polymers or nanocarriers is also vital in the formulation of nanoparticles to enhance targeting efficiency to the brain. Conclusion: More standardized methods for the preparation of nanoparticles and to assess the relationship of surface modification on drug delivery. While the preparation and its output like drug loading, particle size, and charge, permeation is always conflicted, so it requires more attention for the acceptance of nanoparticles for brain delivery.


2010 ◽  
Vol 66 (1) ◽  
Author(s):  
Estelle Dannhauser

The article is a lengthy review of the book Jesus’ resurrection in Joseph’s garden by P.J.W. (Flip) Schutte. The book represents a quest to trace the relationship between Jesus’ resurrection, myth and canon. Schutte finds the origin of events underlying the biblical canon in proclamation. His focus in the book is the proclamation of the death and resurrection of Christ, which, in its developmental stages, hinged on the life and death of the historical Jesus. Proclamation developed into a mythical narrative that became the foundational myth for the Christ cult, validating its existence and rituals. With the growth and institutionalisation of the faith community (church), came an increased production of literature, causing the power-wielding orthodoxy to identify a body of literature containing the ‘truth’ and ‘correct teaching’, thus establishing the authoritative canon. In, through, behind and beyond Jesus of Nazareth, Schutte has perceived a canon behind the canon: a God of love. In Jesus, the man of myth with historical roots who has become to us the observable face of God, Schutte confesses the kerygma to open up before him. The proclamation therefore extends an invitation to join in a mythological experience and an encounter with God whose love is preached in the metaphor called Easter.


2021 ◽  
Vol 190 ◽  
pp. 553-559
Author(s):  
Irina K. Malashenkova ◽  
Vadim L. Ushakov ◽  
Sergey A. Krynskiy ◽  
Daniil P. Ogurtsov ◽  
Nikita A. Khailov ◽  
...  

Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S17.1-S17
Author(s):  
Haruo Nakayama ◽  
Yu Hiramoto ◽  
Yuriko Numata ◽  
Satoshi Fujita ◽  
Nozomi Hirai ◽  
...  

ObjectiveTo evaluate the relationship between functional anisotropy (FA) and neuropsychological evaluation in concussion.MethodsDiffusion tensor MRI included FA of the Brain and neuropsychological evaluation were conducted on 10 patients with concussion who were diagnosed from April 2017 to March 2018. FA was extracted from 2 regions of interest in Corpus callosum (CC) and corticospinal tract (CT). Detailed neuropsychological testing with an emphasis on Working memory (WM) and Processing speed (PS) was also conducted. The FA value in that 2 regions were compared between the 2 groups of 5 patients (group F) who failed either in WM or PS and 5 cases (group NF) who did not admit it.ResultsMean FA values in CC and CT in the Group F were 0.70 and 0.52. Mean FA values in CC and CT in the Group NF were 0.48 and 0.55.ConclusionsOur result suggests that the FA value of CC did not explain the significant fluctuation of the neuropsychological function. However, FA value in CT were shown to explain the fluctuation of WM and PS.


Author(s):  
James Deery

AbstractFor some, the states and processes involved in the realisation of phenomenal consciousness are not confined to within the organismic boundaries of the experiencing subject. Instead, the sub-personal basis of perceptual experience can, and does, extend beyond the brain and body to implicate environmental elements through one’s interaction with the world. These claims are met by proponents of predictive processing, who propose that perception and imagination should be understood as a product of the same internal mechanisms. On this view, as visually imagining is not considered to be world-involving, it is assumed that world-involvement must not be essential for perception, and thus internalism about the sub-personal basis is true. However, the argument for internalism from the unity of perception and imagination relies for its strength on a questionable conception of the relationship between the two experiential states. I argue that proponents of the predictive approach are guilty of harbouring an implicit commitment to the common kind assumption which does not follow trivially from their framework. That is, the assumption that perception and imagination are of the same fundamental kind of mental event. I will argue that there are plausible alternative ways of conceiving of this relationship without drawing internalist metaphysical conclusions from their psychological theory. Thus, the internalist owes the debate clarification of this relationship and further argumentation to secure their position.


2014 ◽  
Vol 67 (1) ◽  
Author(s):  
Farahwahida Mohd Yusof ◽  
Siti Norlina Muhamad ◽  
Arieff Salleh Rosman ◽  
Sarimah Noor Ahmad ◽  
Nor Farhah Razak ◽  
...  

This article discusses the phenomenon of sleep, with emphasized to its importance, sleeping times, sleeping positions and even the etiquette of sleeping, from the views of Islam and Science. The Quran and Science are inseparable and the relationship between the two is highly balanced. Scientists have said that the phenomena of sleep is a miracle that deserves to be analysed and studied in depth, as it is a complex phenomena. Glory and Praise to be Allah Almighty has decreed in the Quran of the importance of sleep in the day and night, and that sleep is one of the signs of Allah’s Almighty power and is a miracle to be studied by each individual. Islam places great importance on taking care of one’s body and sleep is one need that has to be fulfilled. Scientists have stressed that sleep is needed to rest the brain, improve memory, and increase one’s energy. This shows that Islam places great importance on having productivity and alertness in each individual’s deed. Many scientific facts that had been clearly stated in a fundamental manner in the Quran could only be analysed with the advanced technology of the 20th century. These facts were not known when they were first revealed and are proof that the Quran is the book of Allah Almighty. The view of Islam on the sleep phenomenon is in line with and is according to the findings of contemporary scien


1989 ◽  
Vol 1 (3) ◽  
pp. 201-222 ◽  
Author(s):  
Adam N. Mamelak ◽  
J. Allan Hobson

Bizarreness is a cognitive feature common to REM sleep dreams, which can be easily measured. Because bizarreness is highly specific to dreaming, we propose that it is most likely brought about by changes in neuronal activity that are specific to REM sleep. At the level of the dream plot, bizarreness can be defined as either discontinuity or incongruity. In addition, the dreamer's thoughts about the plot may be logically deficient. We propose that dream bizarreness is the cognitive concomitant of two kinds of changes in neuronal dynamics during REM sleep. One is the disinhibition of forebrain networks caused by the withdrawal of the modulatory influences of norepinephrine (NE) and serotonin (5HT) in REM sleep, secondary to cessation of firing of locus coeruleus and dorsal raphe neurons. This aminergic demodulation can be mathematically modeled as a shift toward increased error at the outputs from neural networks, and these errors might be represented cognitively as incongruities and/or discontinuities. We also consider the possibility that discontinuities are the cognitive concomitant of sudden bifurcations or “jumps” in the responses of forebrain neuronal networks. These bifurcations are caused by phasic discharge of pontogeniculooccipital (PGO) neurons during REM sleep, providing a source of cholinergic modulation to the forebrain which could evoke unpredictable network responses. When phasic PGO activity stops, the resultant activity in the brain may be wholly unrelated to patterns of activity dominant before such phasic stimulation began. Mathematically such sudden shifts from one pattern of activity to a second, unrelated one is called a bifurcation. We propose that the neuronal bifurcations brought about by PGO activity might be represented cognitively as bizarre discontinuities of dream plot. We regard these proposals as preliminary attempts to model the relationship between dream cognition and REM sleep neurophysiology. This neurophysiological model of dream bizarreness may also prove useful in understanding the contributions of REM sleep to the developmental and experiential plasticity of the cerebral cortex.


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