The microanatomy of the optic ganglia of Munida irrasa (Decapoda: Galatheidae)

1976 ◽  
Vol 54 (8) ◽  
pp. 1242-1255 ◽  
Author(s):  
Charles R. Bursey

The microanatomy of the optic ganglia of Munida irrasa was examined by reconstruction from stained serial sections. There are four optic ganglia arranged in a consecutive manner: a distal lamina ganglionaris followed by a medulla externis, medulla internis, and medulla terminalis. Two optic chiasmata are present. Typically, the major constituents of invertebrate ganglia are present: rind, neuropil, blood sinuses, hemocytes, and glia.Neurosecretory cells are found within each of the four ganglia. They are arranged at regular intervals throughout the proximal zone of the lamina ganglionaris. They are collected into ganglionic X organs in the other three ganglia. The medulla externis X organ sends its fiber tract into the lamina ganglionaris. The medulla internis X organ and the medulla terminalis X organ send their combined fiber tract into the sinus gland.The sinus gland is the only peripheral structure to receive axons from cells of the optic ganglia. The organ of Bellonci is wholly contained within the medulla terminalis. A cavity receptor organ is present in the periphery of the eyestalk; however, its nerve parallels the optic ganglia and enters the brain directly.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erica N. Grodin ◽  
Spencer Bujarski ◽  
Brandon Towns ◽  
Elizabeth Burnette ◽  
Steven Nieto ◽  
...  

AbstractIbudilast, a neuroimmune modulator which selectively inhibits phosphodiesterases (PDE)-3, -4, -10, and -11, and macrophage migration inhibitory factor (MIF), shows promise as a novel pharmacotherapy for alcohol use disorder (AUD). However, the mechanisms of action underlying ibudilast’s effects on the human brain remain largely unknown. Thus, the current study examined the efficacy of ibudilast to improve negative mood, reduce heavy drinking, and attenuate neural reward signals in individuals with AUD. Fifty-two nontreatment-seeking individuals with AUD were randomized to receive ibudilast (n = 24) or placebo (n = 28). Participants completed a 2-week daily diary study during which they filled out daily reports of their past day drinking, mood, and craving. Participants completed an functional magnetic resonance imaging (fMRI) alcohol cue-reactivity paradigm half-way through the study. Ibudilast did not have a significant effect on negative mood (β = −0.34, p = 0.62). However, ibudilast, relative to placebo, reduced the odds of heavy drinking across time by 45% (OR = 0.55, (95% CI: 0.30, 0.98)). Ibudilast also attenuated alcohol cue-elicited activation in the ventral striatum (VS) compared to placebo (F(1,44) = 7.36, p = 0.01). Alcohol cue-elicited activation in the VS predicted subsequent drinking in the ibudilast group (F(1,44) = 6.39, p = 0.02), such that individuals who had attenuated ventral striatal activation and took ibudilast had the fewest number of drinks per drinking day in the week following the scan. These findings extend preclinical and human laboratory studies of the utility of ibudilast to treat AUD and suggest a biobehavioral mechanism through which ibudilast acts, namely, by reducing the rewarding response to alcohol cues in the brain leading to a reduction in heavy drinking.


1998 ◽  
Vol 88 (4) ◽  
pp. 1036-1042 ◽  
Author(s):  
Sunil Eappen ◽  
Igor Kissin

Background Subarachnoid bupivacaine blockade has been reported to reduce thiopental and midazolam hypnotic requirements in patients. The purpose of this study was to examine if local anesthetically induced lumbar intrathecal blockade would reduce thiopental requirements for blockade of motor responses to noxious and nonnoxious stimuli in rats. Methods After intrathecal and external jugular catheter placement, rats were assigned randomly to two groups in a crossover design study, with each rat to receive either 10 microl of 0.75% bupivacaine or 10 microl of normal saline intrathecally. The doses of intravenously administered thiopental required to ablate the eyelid reflex, to block the withdrawal reflex of a front limb digit, and to block the corneal reflex were compared. In two separate groups of animals, hemodynamic parameters and concentrations of thiopental in the brain were compared between intrathecally administered bupivacaine and saline. Results The thiopental dose required to block the described responses was decreased with intrathecally administered bupivacaine versus intrathecally administered saline from (mean +/- SD) 40 +/- 5 to 24 +/- 4 mg/kg (P < 0.001) for the eyelid reflex, from 51 +/- 6 to 29 +/- 6 mg/kg (P < 0.005) for front limb withdrawal, and from 67 +/- 8 to 46 +/- 8 mg/kg (P < 0.01) for the corneal reflex. The concentration of thiopental in the brain at the time of corneal reflex blockade for the group given bupivacaine was significantly lower than in the group given saline (24.1 vs. 35.8 microg/g, P = 0.02). Conclusion This study demonstrates that lumbar intrathecally administered local anesthetic blockade decreases anesthetic requirements for thiopental for a spectrum of end points tested. This effect is due neither to altered pharmacokinetics nor to a direct action of the local anesthetic on the brain; rather, it is most likely due to decreased afferent input.


Author(s):  
А.А. Грищенко ◽  
A.A. Grishchenko

Studying coupling between brain areas from its electromagnetic activity is one of the key approaches in epilepsy research now, since epileptic activity has been considered to be a result of pathological synchronization in the brain. Often, research is conducted on animal models, because this allows to perform intracranial measurement, and to get rid of interference caused by the skull and to receive signals from deeper regions of the brain such as thalamus or hippocampus. In this study, the intracranial recordings from the frontal and parietal areas of cortex are investigated with a nonlinear correlation coefficient and a mutual information function in a sliding time window. The coupling estimates obtained were subjected for statistical analysis for significance using surrogate data. The dynamics of connectivity between the frontal cortex and the parietal cortex was shown to vary from seizure to seizure and from animal to animal. Therefore, estimates of the significant change in connectivity associated with initiation of the absense seizure, found previously based on averaging over a large number of animals and a large number of seizures for an each animal, can be a result of contribution of a relatively small number of seizures (less than a half of considered), for which the changes are significant.


Part I. The Medulla Oblongata, And Its Variations Acoording To Diet And Feeding Habits In previous communications to this Society the relationship of the habits of feeding and diet to the form and pattern of the medulla oblongata has been described in the cyprinoids, clupeids, and gadoids (Evans, 1931, 1932, 1935). This research takes up a similar study of the brain of the Pleuronectidae. The expense has been borne by a grant from the Royal Society for which the author tenders his grateful thanks. It has seemed to be desirable to extend the observations to the fore- and mid-brain, as in some members of the family these present a very marked development. In order to elucidate some of the problems that arise I have also studied the brain of the eel, and some interesting conclusions have resulted. We find, as a result of examination by the naked eye and of serial sections, that we can divide the following species into four groups as follows: I. The sole, Solea vulgaris .


2020 ◽  
pp. 1-12 ◽  
Author(s):  
Erandi Hewawasam ◽  
Carmel T. Collins ◽  
Beverly S. Muhlhausler ◽  
Lisa N. Yelland ◽  
Lisa G. Smithers ◽  
...  

Abstract Infants born preterm miss out on the peak period of in utero DHA accretion to the brain during the last trimester of pregnancy which is hypothesised to contribute to the increased prevalence of neurodevelopmental deficits in this population. This study aimed to determine whether DHA supplementation in infants born preterm improves attention at 18 months’ corrected age. This is a follow-up of a subset of infants who participated in the N3RO randomised controlled trial. Infants were randomised to receive an enteral emulsion of high-dose DHA (60 mg/kg per d) or no DHA (soya oil – control) from within the first days of birth until 36 weeks’ post-menstrual age. The assessment of attention involved three tasks requiring the child to maintain attention on toy/s in either the presence or absence of competition or a distractor. The primary outcome was the child’s latency of distractibility when attention was focused on a toy. The primary outcome was available for seventy-three of the 120 infants that were eligible to participate. There was no evidence of a difference between groups in the latency of distractibility (adjusted mean difference: 0·08 s, 95 % CI –0·81, 0·97; P = 0·86). Enteral DHA supplementation did not result in improved attention in infants born preterm at 18 months’ corrected age.


Author(s):  
John David Adams

Historically, educators have taken a reticent and measured approach in engaging the affective domain in learning, particularly as it relates to human emotions. By default, the cognitive and psycho-motor domains have tended to receive a greater level of attention and care. The same imbalance, by and large, characterizes learning environments in church ministry, perhaps due to an overly cautious fear of crossing professional and ethical boundaries. Yet, emerging research and science on the brain reveal that the emotions play an essential role in the learning process. Through basic measures such as acknowledgment of the presence of emotions, the practice of empathy, and evoking emotion through story, educators in church ministry contexts can account for the vital contribution that emotions make to the process of learning and formation.


2020 ◽  
Author(s):  
Georg Hafner ◽  
Julien Guy ◽  
Mirko Witte ◽  
Pavel Truschow ◽  
Alina Rüppel ◽  
...  

Abstract The neocortex is composed of layers. Whether layers constitute an essential framework for the formation of functional circuits is not well understood. We investigated the brain-wide input connectivity of vasoactive intestinal polypeptide (VIP) expressing neurons in the reeler mouse. This mutant is characterized by a migration deficit of cortical neurons so that no layers are formed. Still, neurons retain their properties and reeler mice show little cognitive impairment. We focused on VIP neurons because they are known to receive strong long-range inputs and have a typical laminar bias toward upper layers. In reeler, these neurons are more dispersed across the cortex. We mapped the brain-wide inputs of VIP neurons in barrel cortex of wild-type and reeler mice with rabies virus tracing. Innervation by subcortical inputs was not altered in reeler, in contrast to the cortical circuitry. Numbers of long-range ipsilateral cortical inputs were reduced in reeler, while contralateral inputs were strongly increased. Reeler mice had more callosal projection neurons. Hence, the corpus callosum was larger in reeler as shown by structural imaging. We argue that, in the absence of cortical layers, circuits with subcortical structures are maintained but cortical neurons establish a different network that largely preserves cognitive functions.


2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S835-S835
Author(s):  
Charnae A Henry-Smith ◽  
Xianlin Han

Abstract Alzheimer’s disease is a progressive brain disease that slowly destroys memory and thinking skills. Alzheimer’s is characterized by an increase in Aβ plaques , and tau tangles. Neurons in the brain have axons covered in myelin sheath that connect microglia and astrocytes. The myelin sheath is composed of about 70% lipid composition; Sulfatide contributing to 30% overall. Sulfatide changes the morphology of primary microglia to their activated form. To study the role of microglia activation and sulfatide levels, three different mouse models were created: APP KI mice, CST Whole Body Ko mice, and cCST (conditional) KO. In order to create the genotype of the APP KI mice, a breeding mouse line was created. The APP KI gene had to be introduced in Plp1-Cre and cCST KO crossed mice to receive a working mouse model. During the duration of breeding for the APP KI mice, a preliminary experiment was performed on the CST KO mice. These mice were given the PLX3397 diet with the aim to remove the microglia and to see the effect of Aβ plaques. The PLX3397 will reduce the microglia targeting the CSF1R. After consuming the diet, the mice were harvested to collect tissues from the brain and spinal cord. Lipidomics and immunohistology were performed. In conclusion, we will continue the breeding of the CST flox/flox / Plp1-Cre / APP KI mice, and the drug dosage and treatment to be used in our APP KI mice will be based on preliminary data from our CST mice.


2006 ◽  
Vol 291 (6) ◽  
pp. E1188-E1196 ◽  
Author(s):  
Frederick P. Bellinger ◽  
Bradley K. Fox ◽  
Wing Yan Chan ◽  
Lori K. Davis ◽  
Marilou A. Andres ◽  
...  

Endocrine cells of the anterior pituitary are controlled by the central nervous system through hormonal interactions and are not believed to receive direct synaptic connections from the brain. Studies suggest that some pituitary cells may be modulated by the neurotransmitter glutamate ( 5 , 16 ). We investigated prolactin (PRL)-releasing cells of the anterior pituitary of a euryhaline fish, the tilapia ( Oreochromis mossambicus), for the presence of possible glutamate receptors (GluRs). Fura-2 imaging addressed the ability of glutamate to increase intracellular calcium. We observed a dose-dependent increase in intracellular calcium with transient perfusion (1–2 min) of glutamate (10 nM to 1 mM) in two-thirds of imaged cells. This increase was attenuated by the ionotropic GluR antagonist kynurenic acid (0.5–1.0 mM). The increase was also blocked or attenuated by antagonists of L-type voltage-gated calcium channels. The GluR agonist α-amino-3-hydroxy-5-methylisoxazole propionic acid (AMPA; 100 μM) produced intracellular calcium increases that were reversibly blocked by the selective AMPA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). In contrast, the selective agonist N-methyl-d-aspartate (NMDA; 100 μM to 1 mM in magnesium-free solution with 10 μM glycine) had no effect on intracellular calcium. Radioimmunoassays demonstrated that glutamate stimulated PRL release. CNQX but not the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid blocked this release. Antibodies for mammalian AMPA- and NMDA-type GluR produced a similar punctate immunoreactivity in the periphery of PRL cells. However, the NMDA antibody recognized a protein of a different molecular mass in PRL cells compared with brain cells. These results clearly indicate the presence of GluRs on tilapia PRL cells that can stimulate PRL release.


2020 ◽  
Vol 22 (7) ◽  
Author(s):  
Farzaneh Karami ◽  
Fateme Assarian ◽  
Fatemeh Sadat Ghoreishi ◽  
Mojtaba Sehat

Background: Methamphetamine dependence is a growing global problem. Currently, there are no approved pharmacotherapy options for the management of methamphetamine dependence. One of the alternatives to manage this addiction is the use of N acetylcysteine (NAC) due to its capacity to restore homeostasis in the brain glutamate systems disrupted in addiction and its ability to reduce craving and the risk of relapse. Methods: Methamphetamine‐dependent volunteers under methadone treatment (n = 38) were randomized to receive daily doses of 1200 mg of NAC, or placebo. The participants were followed for 12 weeks (two visits weekly). Craving and Beck Inventory Depression (BDI) was determined at the beginning of the study and also after one month, two months, and three months. Addiction severity index (ASI) was recorded at the beginning of the study and after three months. The data were analyzed via SPSS version 16.0 (SPSS Inc. Chicago, Illinios, USA) Results: The mean score of craving and BDI reduced after two months with NAC treatment. ASI (e.g., substance, familial, and psychiatric categories) was significantly reduced at the end of the study in the NAC group compared to placebo (P < 0.001). The success of the treatment in groups of NAC and placebo were 84% and 73%, respectively (P = 0.001). 63.2% of the NAC group patients avoided substance use for more than a month, but this was 10.5% in the placebo group (P = 0.001). Conclusions: The NAC showed good efficacy in suppressing methamphetamine craving, addiction severity index, and depression. It may be a useful pharmacological treatment for methamphetamine dependency.


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