Control of locomotion in marine mollusk Clione limacina. VIII. Cerebropedal neurons

1995 ◽  
Vol 73 (5) ◽  
pp. 1912-1923 ◽  
Author(s):  
Y. V. Panchin ◽  
L. B. Popova ◽  
T. G. Deliagina ◽  
G. N. Orlovsky ◽  
Y. I. Arshavsky

1. The pteropod mollusk Clione limacina swims by rhythmical oscillations of two wings, and its spatial orientation during locomotion is determined by tail movements. The majority of neurons responsible for generation of the wing and tail movements are located in the pedal ganglia. On the other hand, the majority of sensory inputs that affect wing and tail movements project to the cerebral ganglia. The goal of the present study was to identify and characterize cerebropedal neurons involved in the control of the swimming central generator or motor neurons of wing and tail muscles. Cerebropedal neurons affecting locomotion-controlling mechanisms are located in the rostromedial (CPA neurons), caudomedial (CPB neurons), and central (CPC neurons) zones of the cerebral ganglia. According to their morphology and effects on pedal mechanisms, 10 groups of the cerebropedal neurons can be distinguished. 2. CPA1 neurons project through the ipsilateral cerebropedal connective to both pedal ganglia. Activation of a CPA1 by current injection resulted in speeding up of the locomotor rhythm and intensification of the firing of the locomotor motor neurons. 3. CPA2 neurons send numerous thin fibers into the ipsi- and contralateral pedal and pleural ganglia through the cerebropedal and cerebropleural connectives. They strongly inhibit the wing muscle motor neurons and, to a lesser extent, slow down the locomotor rhythm. 4. CPB1 neurons project through the contralateral cerebropedal connective to both pedal ganglia. They activate the locomotor generator. 5. CPB2 neurons also project, through the contralateral cerebropedal connective, to both pedal ganglia. They affect wing muscle motor neurons. 6. CPB3 neurons have diverse morphology: they project to the pedal ganglia either through the ipsilateral cerebropedal connective, or through the contralateral one, or through both of them. They affect putative motor neurons of the tail muscles. 7. CPC1, CPC2, and CPC3 neurons project through the ipsilateral cerebropedal connective to both pedal ganglia. They activate the locomotor generator. 8. CPC4 and CPC5 neurons project through the contralateral cerebropedal connective to the contralateral pedal ganglia. They activate the locomotor generator. 9. Serotonergic neurons were mapped in the CNS of Clione by immunohistochemical methods. Location and size of cells in two groups of serotonin-immunoreactive neurons in the cerebral ganglia appeared to be similar to those of CPA1 and CPB1 neurons. This finding suggests a possible mechanism for serotonin's ability to exert a strong excitatory action on the locomotor generator of Clione. 10. The role of different groups of cerebropedal neurons is discussed in relation to different forms of Clione's behavior in which locomotor activity is involved.

2004 ◽  
Vol 91 (1) ◽  
pp. 336-345 ◽  
Author(s):  
R. Levi ◽  
P. Varona ◽  
Y. I. Arshavsky ◽  
M. I. Rabinovich ◽  
A. I. Selverston

In mollusks, statocyst receptor cells (SRCs) interact with each other forming a neural network; their activity is determined by both the animal's orientation in the gravitational field and multimodal inputs. These two facts suggest that the function of the statocysts is not limited to sensing the animal's orientation. We studied the role of the statocysts in the organization of search motion during hunting behavior in the marine mollusk, Clione limacina. When hunting, Clione swims along a complex trajectory including numerous twists and turns confined within a definite space. Search-like behavior could be evoked pharmacologically by physostigmine; application of physostigmine to the isolated CNS produced “fictive search behavior” monitored by recordings from wing and tail nerves. Both in behavioral and in vitro experiments, we found that the statocysts are necessary for search behavior. The motor program typical of searching could not be produced after removing the statocysts. Simultaneous recordings from single SRCs and motor nerves showed that there was a correlation between the SRCs activity and search episodes. This correlation occurred even though the preparation was fixed and, therefore the sensory stimulus was constant. The excitation of individual SRCs could in some cases precede the beginning of search episodes. A biologically based model showed that, theoretically, the hunting search motor program could be generated by the statocyst receptor network due to its intrinsic dynamics. The results presented support for the idea that the statocysts are actively involved in the production of the motor program underlying search movements during hunting behavior.


1996 ◽  
Vol 75 (2) ◽  
pp. 538-546 ◽  
Author(s):  
T. P. Norekian ◽  
R. A. Satterlie

1. A pair of serotonin-immunoreactive neurons has been identified in the cerebral ganglia of the pteropod mollusk Clione limacina, which produce coordinated, excitatory/inhibitory effects on neurons controlling two incompatible behaviors, swimming and whole body withdrawal. These cells were designated cerebral serotonergic ventral (Cr-SV) neurons. 2. Activation of Cr-SV neurons produces a prominent inhibition of the pleural withdrawal neurons, which have been previously shown to induce whole body withdrawal in Clione. In addition, the cerebral neurons produce weak excitatory inputs to swim motor neurons, pedal serotonergic neurons involved in the peripheral modulation of swimming, and to the serotonergic heart excitor neuron. 3. Inhibitory and excitatory effects appear to be produced by serotonin because they are mimicked by exogenous serotonin and are blocked by the serotonin antagonist mianserin. 4. All serotonergic neurons identified thus far in the CNS of Clione appear to function in a coordinated manner, altering a variety of neural centers all directed toward the activation of swimming behavior.


1995 ◽  
Vol 73 (5) ◽  
pp. 1924-1937 ◽  
Author(s):  
Y. V. Panchin ◽  
Y. I. Arshavsky ◽  
T. G. Deliagina ◽  
L. B. Popova ◽  
G. N. Orlovsky

1. When swimming freely, the pteropod mollusk Clione limacina actively maintains a vertical orientation, with its head up. Any deflection from the vertical position causes a correcting motor response, i.e., bending of the tail in the opposite direction, and an additional activation of the locomotor system. Clione can stabilize not only the vertical orientation with its head up, but also the posture with its head down. The latter is observed at higher water temperature, as well as at a certain stage of hunting behavior. The postural control is absent in some forms of behavior (vertical migrations, defensive reactions, "looping" when hunting). The postural reflexes are driven by input from the statocysts. After removal of the statocysts, Clione was unable to maintain any definite spatial orientation. 2. Activity of the neuronal mechanisms controlling spatial orientation of Clione was studied in in vitro experiments, with the use of a preparation consisting of the CNS and statocysts. Natural stimulation (tilt of the preparation up to 90 degrees) was used to characterize responses in the statocyst receptor cells (SRCs). It was found that the SRCs depolarized and fired (10-20 Hz) when, during a tilt, they were in a position on the bottom part of the statocyst, under the statolith. Intracellular staining has shown that the SRC axons terminate in the medial area of the cerebral ganglia. Electrical connections have been found between some of the symmetrical SRCs of the left and right statocysts. 3. Gravistatic reflexes were studied by using both natural stimulation (tilt of the preparation) and electrical stimulation of SRCs. The reflex consisted of three components: 1) activation of the locomotor rhythm generator located in the pedal ganglia; this effect of SRCs is mediated by previously identified CPA1 and CPB1 interneurons that are located in the cerebral ganglia and send axons to the pedal ganglia; 2) bending the tail evoked by differential excitation and inhibition of different groups of tail muscle motor neurons; this effect is mediated by CPB3 interneurons; and 3) modification of wing movements by differential excitation and inhibition of different groups of wing motor neurons; this effect is mediated by CPB2 interneurons. 4. Gravistatic reflexes in the tail motor neurons were inhibited or reversed at a higher water temperature. 5. The SRCs are not "pure" gravitation sensory organs because they are subjected to strong influences from the CNS. In particular, CPC1 interneurons, participating in coordination of different aspects of the hunting behavior, exert an excitatory action on some of the SRCs, and inhibitory actions on others.(ABSTRACT TRUNCATED AT 400 WORDS)


1995 ◽  
Vol 74 (05) ◽  
pp. 1271-1275 ◽  
Author(s):  
C M A Henkens ◽  
V J J Bom ◽  
W van der Schaaf ◽  
P M Pelsma ◽  
C Th Smit Sibinga ◽  
...  

SummaryWe measured total and free protein S (PS), protein C (PC) and factor X (FX) in 393 healthy blood donors to assess differences in relation to sex, hormonal state and age. All measured proteins were lower in women as compared to men, as were levels in premenopausal women as compared to postmenopausal women. Multiple regression analysis showed that both age and subgroup (men, pre- and postmenopausal women) were of significance for the levels of total and free PS and PC, the subgroup effect being caused by the differences between the premenopausal women and the other groups. This indicates a role of sex-hormones, most likely estrogens, in the regulation of levels of pro- and anticoagulant factors under physiologic conditions. These differences should be taken into account in daily clinical practice and may necessitate different normal ranges for men, pre- and postmenopausal women.


1998 ◽  
pp. 61-62
Author(s):  
N. S. Jurtueva

In the XIV century. centripetal tendencies began to appear in the Moscow principality. Inside the Russian church, several areas were distinguished. Part of the clergy supported the specificobar form. The other understood the need for transformations in society. As a result, this led to a split in the Russian church in the 15th century for "non-possessors" and "Josephites". The former linked the fate of the future with the ideology of hesychasm and its moral transformation, while the latter sought support in alliance with a strong secular power.


2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.


Moreana ◽  
2017 ◽  
Vol 54 (Number 207) (1) ◽  
pp. 36-56
Author(s):  
Gerard Wegemer

After establishing a context of More's lifelong engagement with the “calculus” of pleasure, this essay shows how the section devoted to the Utopians' pleasure philosophy is structured around five formulations of a “rule” to calculate “true and honest [honesta]” pleasure in ways that playfully imitate and echo the “rule” Cicero formulates several times in De officiis to discern one's duty when there seems to be a conflict between honestas et utilitas. When followed, the Utopian pleasure calculus shows the necessary role of societas, officii, iustitia, caritas, and the other aspects of human nature, most importantly friendship, that Cicero stresses in his rule and that he argued Epicurus ignored. Much of the irony and humor of this section depends on seeing the predominance of Ciceronian vocabulary in Raphael's unusual defense [patrocinium] of pleasure, rather than a Ciceronian defense of duty rooted in honestas. Throughout, however, this essay also shows how More goes beyond Cicero by including Augustinian and biblical allusions to suggest ways that our final end is not as Epicurus or the Stoics or Cicero claim; the language and allusions of this section point to a level of good cheer and care for neighbors and for God in ways quite different from any classical thinker.


1973 ◽  
Vol 74 (4) ◽  
pp. 769-774 ◽  
Author(s):  
Akira Yokoyama ◽  
Hiroshi Tomogane ◽  
Katuaki Ôta
Keyword(s):  

ABSTRACT A non-steroidal oestrogen antagonist, MER-25, was administered to cycling rats for elucidating the role of oestrogen in the surge of prolactin observed on the afternoon of pro-oestrus (POe). In animals injected with 20 mg of MER-25 intramuscularly on the afternoon (16.30 h) of the first day of dioestrus (D-1), the surge of prolactin was blocked while the level of prolactin on the afternoon of POe of these animals was significantly higher than that of the corresponding controls injected with oil. Ovulation was also blocked in these animals treated with the drug on the afternoon of D-l. On the other hand, treatment on the morning (10.30 h) of the 2nd day of dioestrus failed to prevent not only the surge of prolactin but also ovulation. These observations provide strong evidence for the view that oestrogen is responsible for the surge of prolactin on the afternoon of POe, and that the surge is accompanied by that of LH.


1960 ◽  
Vol XXXIV (III) ◽  
pp. 411-429 ◽  
Author(s):  
Melvin J. Fregly ◽  
Kenneth M. Cook

ABSTRACT The anti-thyroid drugs, thiouracil, propylthiouracil, and methimazole, prevented both development of elevated blood pressure and cardiac hypertrophy usually accompanying kidney encapsulation with latex envelopes. These drugs also reduced elevated blood pressure of rats with hypertension of 13 to 40 weeks' duration prior to drug administration. Addition of desiccated thyroid powder to diet containing an anti-thyroid drug overcame the anti-hypertensive effect of the latter. Withdrawal of thyroid powder only was followed by return of blood pressure to previous low level within 3 weeks. The results suggest that the anti-hypertensive effect of these drugs is related directly to the hypothyroidism produced rather than to extrathyroidal effects of the drugs. Comparison of potencies of the 3 drugs in terms of anti-hypertensive effect, inhibition of growth rate, increase in testicular size, and increase in thyroid size suggests that propylthiouracil and methimazole are equally potent per unit weight of drug. Thiouracil has approximately half the potency of the other two.


2017 ◽  
Vol 4 (1) ◽  
pp. 189-215
Author(s):  
Yoiz Shofwa Shafrani

Perkembangan dunia perbankan syariah tidak lepas dari peran para nasabah yang memberikan kepercayaan terhadap pihak perbankan untuk penyimpanan asset keuangannya. Faktanya banyak kelompok nasabah yang memutuskan untuk menjadi nasabah di perbankan syariah karena faktor religiusitasnya. Faktor lain yang dapat ikut mempengaruhi keputusan nasabah adalah kualitas produk. Di mana kualitas produk merupakan karakteristik yang melekat dari suatu produk. Kemungkinan yang terjadi bahwa kebanyakan nasabah pada perbankan syariah juga masih merupakan nasabah perbankan konvensional.Tujuan yang ingin dicapai dalam penelitian ini adalah untuk mengetahui pengaruh kualitas produk dan tingkat religiusitas nasabah terhadap keputusan nasabah untuk menyimpan dananya atau tidak di BSM Cabang Purwokerto. Alat analisis yang digunakan adalah analisis regresi linier berganda, dengan jumlah sampel 100 nasabah. Diperoleh hasil Y = 5,046 + 0,101X1 + 0,218X2. Berdasarkan uji F yang sudah dilakukan maka dapat diketahui bahwa variabel kualitas produk dan religiusitas secara bersama – sama berpengaruh terhadap keputusan nasabah untuk menyimpan dananya di BSM Cabang Purwokerto. Berdasarkan uji t yang sudah dilakukan dapat diketahui bahwa secara partial baik variabel kualitas produk maupun variabel religiusitas berpengaruh terhadap keputusan nasabah untuk menyimpan dananya di BSM Cabang Purwokerto. The progress of the Islamic bank cannot be separated from the role of its customers who give trust to the bank to deposit their financial assets. It is a fact many groups of customers decide to be the customers of the Islamic bank because of their religiosity. The other influences factor of a customer’s decision is the quality of the product. The aim of this research was to determine the effect of product quality and level of customers’ religiosity towards customers’ decision whether to keep their funds in Syariah Mandiri Bank, Branch of Purwokerto, or not. The analytical tool used was multiple linear regression analysis, with a sample of 100 customers. The results indicate Y = 5,046 + 0,101X1 + 0,218X2. Based on F, it can be seen that both variables of product quality and religiosity simultanously affect the customers’ decision to keep theirfunds in BSM Branch of Purwokerto. Based on t test, it can be seen that independently, either variable of product quality or variables of religiosityinfluences the customers’ decision to keep their funds in BSM Branch of Purwokerto.


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