scholarly journals Determining the function of zebrafish epithalamic asymmetry

2008 ◽  
Vol 364 (1519) ◽  
pp. 1021-1032 ◽  
Author(s):  
Lucilla Facchin ◽  
Harold A Burgess ◽  
Mahmud Siddiqi ◽  
Michael Granato ◽  
Marnie E Halpern

As in many fishes, amphibians and reptiles, the epithalamus of the zebrafish, Danio rerio , develops with pronounced left–right (L–R) asymmetry. For example, in more than 95 per cent of zebrafish larvae, the parapineal, an accessory to the pineal organ, forms on the left side of the brain and the adjacent left habenular nucleus is larger than the right. Disruption of Nodal signalling affects this bias, producing equal numbers of larvae with the parapineal on the left or the right side and corresponding habenular reversals. Pre-selection of live larvae using fluorescent transgenic reporters provides a useful substrate for studying the effects of neuroanatomical asymmetry on behaviour. Previous studies had suggested that epithalamic directionality is correlated with lateralized behaviours such as L–R eye preference. We find that the randomization of epithalamic asymmetry, through perturbation of the nodal -related gene southpaw , does not alter a variety of motor behaviours, including responses to lateralized stimuli. However, we discovered significant deficits in swimming initiation and in the total distance navigated by larvae with parapineal reversals. We discuss these findings with respect to previous studies and recent work linking the habenular region with control of the motivation/reward pathway of the vertebrate brain.

Author(s):  
Malcolm A. MacIver ◽  
Barbara L. Finlay

The water-to-land transition in vertebrate evolution offers an unusual opportunity to consider computational affordances of a new ecology for the brain. All sensory modalities are changed, particularly a greatly enlarged visual sensorium owing to air versus water as a medium, and expanded by mobile eyes and neck. The multiplication of limbs, as evolved to exploit aspects of life on land, is a comparable computational challenge. As the total mass of living organisms on land is a hundredfold larger than the mass underwater, computational improvements promise great rewards. In water, the midbrain tectum coordinates approach/avoid decisions, contextualized by water flow and by the animal’s body state and learning. On land, the relative motions of sensory surfaces and effectors must be resolved, adding on computational architectures from the dorsal pallium, such as the parietal cortex. For the large-brained and long-living denizens of land, making the right decision when the wrong one means death may be the basis of planning, which allows animals to learn from hypothetical experience before enactment. Integration of value-weighted, memorized panoramas in basal ganglia/frontal cortex circuitry, with allocentric cognitive maps of the hippocampus and its associated cortices becomes a cognitive habit-to-plan transition as substantial as the change in ecology. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.


2012 ◽  
Vol 71 (3) ◽  
pp. 390-400 ◽  
Author(s):  
Hans-Rudolf Berthoud ◽  
Heike Münzberg ◽  
Brenda K. Richards ◽  
Christopher D. Morrison

There is considerable disagreement regarding what constitutes a healthy diet. Ever since the influential work of Cannon and Richter, it was debated whether the ‘wisdom of the body’ will automatically direct us to the foods we need for healthy lives or whether we must carefully learn to eat the right foods, particularly in an environment of plenty. Although it is clear that strong mechanisms have evolved to prevent consumption of foods that have previously made us sick, it is less clear whether reciprocal mechanisms exist that reinforce the consumption of healthy diets. Here, we review recent progress in providing behavioural evidence for the regulation of intake and selection of proteins, carbohydrates and fats. We examine new developments in sensory physiology enabling recognition of macronutrients both pre- and post-ingestively. Finally, we propose a general model for central neural processing of nutrient-specific appetites. We suggest that the same basic neural circuitry responsible for the homoeostatic regulation of total energy intake is also used to control consumption of specific macro- and micronutrients. Similar to salt appetite, specific appetites for other micro- and macronutrients may be encoded by unique molecular changes in the hypothalamus. Gratification of such specific appetites is then accomplished by engaging the brain motivational system to assign the highest reward prediction to exteroceptive cues previously associated with consuming the missing ingredient. A better understanding of these nutrient-specific neural processes could help design drugs and behavioural strategies that promote healthier eating.


Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5101-5112 ◽  
Author(s):  
J.O. Liang ◽  
A. Etheridge ◽  
L. Hantsoo ◽  
A.L. Rubinstein ◽  
S.J. Nowak ◽  
...  

The vertebrate brain develops from a bilaterally symmetric neural tube but later displays profound anatomical and functional asymmetries. Despite considerable progress in deciphering mechanisms of visceral organ laterality, the genetic pathways regulating brain asymmetries are unknown. In zebrafish, genes implicated in laterality of the viscera (cyclops/nodal, antivin/lefty and pitx2) are coexpressed on the left side of the embryonic dorsal diencephalon, within a region corresponding to the presumptive epiphysis or pineal organ. Asymmetric gene expression in the brain requires an intact midline and Nodal-related factors. RNA-mediated rescue of mutants defective in Nodal signaling corrects tissue patterning at gastrulation, but fails to restore left-sided gene expression in the diencephalon. Such embryos develop into viable adults with seemingly normal brain morphology. However, the pineal organ, which typically emanates at a left-to-medial site from the dorsal diencephalic roof, becomes displaced in position. Thus, a conserved signaling pathway regulating visceral laterality also underlies an anatomical asymmetry of the zebrafish forebrain.


Author(s):  
Fay E. Clark ◽  
Stan A. Kuczaj II

Behavior is lateralized when it is performed preferentially by one side of the body, and this phenomenon is seen across a wide range of vertebrate taxa. Furthermore the brain and body are contralateral in many animals, meaning that the left brain hemisphere most dominantly controls the right side of the body and vice versa. Lateralized behavior in humans and nonhuman primates reveals a population right-hand bias. Recent studies in primates have also begun to link differences in lateralized behavior to task complexity, and responses to novel versus familiar stimuli. Parallel research on cetaceans is sparse although evidence accrued over the last decade suggests captive dolphins have a preference for swimming counter-clockwise, a right-eye advantage in spatio-cognitive tasks and a right-eye preference for viewing novel objects, although this is the reverse of the general vertebrate pattern. Lateralized behavior was examined in a group of six male bottlenose dolphins (Tursiops truncatus) in response to a novel underwater maze, and compared to behavior during a baseline condition (no maze present). Dolphins were significantly more likely to swim counter-clockwise round their pool during both the baseline and maze condition, interpreted as a right eye bias. Swimming rotation was also weaker in dolphins during the maze condition, suggesting that the maze may have disrupted routine circular swimming behavior. There was no clear preference for using the left or right side of the maze, except in two high- using subjects with a strong right preference. Modifications and extensions to the methods are discussed.


Abjadia ◽  
2016 ◽  
Vol 1 (1) ◽  
pp. 51
Author(s):  
Danial Hilmi

<p>يتطلب من تعليم اللغة العربية توفير أحوال عقول الدارسين في قبول الدروس وتعبيرها بالقدرة اللغوية. في الواقع أن هناك مشكلات في تحقيقه حيث كانت كفاءتهم الشفهية كالكفاءة الأساسية للغة لا تجري جيدا خاصة في ضوء العلوم العصبية النفسية. هذه الأمور يؤدي إليها إعداد الأهداف والمواد التي لا تراعي احتياجات عقولهم. اختيار طرائق وأساليب تعليمها يفيد الجانب الأيسر من الدماغ كثيرا ولو تقع اللغة فيه، ولكن إذا كان الجانب الأيمن لا يستفاد جيدا فيكون التعليم من متطلبه الاختراعي فيه لا يجري جيدا.</p><p>The demand of learning Arabic fundamentally requires the optimization of the condition of brain’s learners in receiving and expressing language skills. In reality, problems can be found in the process of implementation in which the speaking competenceas a core language skill cannot be well realized, when particularly inspected through Neuropsychology perspective.  This is because the designs of purpose and material do not consider the brain needs of the learners. In addition, selection of instruction methods and strategies tend to reflect the optimization of left brain even though language lies in the left brain. In contrary, if the brain is not well maximized and balanced, then the language learning requiring the creativity embodied in the right brain cannot be well activated too.</p>


Author(s):  
M. Sato ◽  
Y. Ogawa ◽  
M. Sasaki ◽  
T. Matsuo

A virgin female of the noctuid moth, a kind of noctuidae that eats cucumis, etc. performs calling at a fixed time of each day, depending on the length of a day. The photoreceptors that induce this calling are located around the neurosecretory cells (NSC) in the central portion of the protocerebrum. Besides, it is considered that the female’s biological clock is located also in the cerebral lobe. In order to elucidate the calling and the function of the biological clock, it is necessary to clarify the basic structure of the brain. The observation results of 12 or 30 day-old noctuid moths showed that their brains are basically composed of an outer and an inner portion-neural lamella (about 2.5 μm) of collagen fibril and perineurium cells. Furthermore, nerve cells surround the cerebral lobes, in which NSCs, mushroom bodies, and central nerve cells, etc. are observed. The NSCs are large-sized (20 to 30 μm dia.) cells, which are located in the pons intercerebralis of the head section and at the rear of the mushroom body (two each on the right and left). Furthermore, the cells were classified into two types: one having many free ribosoms 15 to 20 nm in dia. and the other having granules 150 to 350 nm in dia. (Fig. 1).


Author(s):  
Яна Валерьевна Самиулина

В настоящей статье предпринята попытка исследовать отдельные проблемные аспекты института потерпевшего в российском уголовном процессе. В этих целях подвергнуты анализу правовые нормы, регламентирующие его процессуальный статус. Раскрываются отдельные пробелы уголовно-процессуального законодательства в сфере защиты законных прав и интересов потерпевшего. Автор акцентирует внимание на том, что совершенствование уголовно-процессуального законодательства в части расширения правомочий потерпевшего по отстаиванию своих нарушенных преступлением прав следует продолжить. На основании проведенного исследования действующего законодательства в части регламентации прав потерпевшего от преступления предлагается расширить перечень получаемых им копий постановлений, указанных в п. 13 ч. 2 ст. 42 УПК РФ. Автор предлагает включить в перечень указанной законодательной нормы право получения потерпевшим копии постановления об избрании конкретного вида меры пресечения, избранного в отношении подозреваемого (обвиняемого). Для создания действенного механизма защиты интересов потерпевших от преступления юридических лиц предлагаем ч. 9 ст. 42 УПК РФ изложить в следующей редакции: «в случае признания потерпевшим юридического лица его процессуальное право в уголовном процессе осуществляет представляющий его профессиональный адвокат». This article attempts to investigate certain problematic aspects of the institution of the victim in the Russian criminal process. For this purpose, analyzed the individual norms governing his procedural status. Separate gaps of the criminal procedure legislation in the sphere of protection of the legal rights and interests of the victim are disclosed. The author emphasizes that the improvement of the criminal procedure legislation in terms of the extension of the victim’s authority to defend his rights violated by the crime should be continued. On the basis of the study of the current legislation regarding the regulation of the rights of the victim of a crime, it is proposed to expand the list of decisions received by him, referred to in paragraph 13, part 2 of article 42 Code of Criminal Procedure. The author proposes to include in the list of the indicated legislative norm the right to receive the victim a copy of the decision on the selection of a specific type of preventive measure, selected in relation to the suspect (accused). To create an effective mechanism for protecting the interests of legal entities victims of a crime, we offer part 9 of art. 42 of the Code of Criminal Procedure of the Russian Federation shall be reworded as follows: «if a legal entity is recognized as a victim, his procedural right in criminal proceedings is exercised by the professional lawyer representing him».


2020 ◽  
Vol 17 (2) ◽  
pp. 110-120
Author(s):  
N.D. Sorokina ◽  
◽  
L.R. Shahalieva ◽  
S.S. Pertsov ◽  
L.V. Polma ◽  
...  

One of the most common causes of chronic pain in the facial region, including in the trigeminal nerve link, which is not associated with dental diseases, is pain dysfunction of the temporomandibular joint. At the same time, there is evidence in the literature that there are relationships between pain dysfunction of the temporomandibular joint, abnormal occlusion, cervical-muscular tonic phenomena, postural disorders, dysfunction of the Autonomous nervous system and cochleovestibular manifestations. At the same time, neurophysiological indicators of functional disorders in the maxillofacial region and intersystem interactions in pain dysfunction of the temporomandibular joint are insufficiently studied.Goal. The aim of the work is to evaluate the neurophysiological features of trigeminal afferentation in terms of trigeminal somatosensory evoked potentials (TSWP) and the auditory conducting system of the brain in terms of acoustic stem evoked potentials (ASVP) in distal occlusion of the dentition with pain dysfunction of the temporomandibular joint (TMJ) in comparison with physiological occlusion in students 18-21 years old. Material and methods. The main study included 41 students with distal occlusion (21 girls and 20 boys), (grade II Engl, symmetrically right and left in 14 people, and grade II Engl on the left and grade I on the right in 12 people, grade I on the left and grade II on the right in 15 people). All respondents with distal occlusion and who were practically healthy signed an informed consent to participate in the study. We used complex orthodontic methods of examination, subjective degree of severity and intensity of pain in the TMJ, assessment of the Autonomous nervous system (samples and tests), and neurophysiological methods for assessing TSVP and ASVP. Results. Significant differences in ASEP parameters were found in the group of respondents with distal occlusion in the form of a decrease in the latency period of peak I, III, and V compared to physiological occlusion, that correlated with the subjective assessment (in points) of cochleovestibular disorders. According to the TSVP study, a decrease in the duration of latent periods was found, which indicates an increased excitability of non-specific brain stem structures at the medullo-ponto-mesencephalic level compared to the control group. Conclusions. The results obtained are supposed to be used for differential diagnostics, including such dental diseases as TMJ pain dysfunction, occlusion abnormalities accompanied by pain syndrome. Additional functional diagnostics of multi-modal VP of the brain (acoustic evoked potentials, trigeminal evoked potentials) can be performed in conjunction with indicators of autonomic nervous system dysfunction, with parameters of severity of clinical symptoms of cochleovestibular disorders, musculoskeletal dysfunction the maxillofacial area, with indicators of pain, which will determine the tactics and effectiveness of subsequent treatment.


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