Symmetrically Organized Dorsal Unpaired Median (Dum) Neurones and Flash Control in the Male Firefly, Photuris Versicolor

1981 ◽  
Vol 93 (1) ◽  
pp. 133-147
Author(s):  
THOMAS A. CHRISTENSEN ◽  
ALBERT D. CARLSON
Keyword(s):  
Nervous System ◽  
Lucifer Yellow ◽  
Dorsal Surface ◽  
Complex Behaviour ◽  
Neural Organization ◽  
Courtship Signal ◽  
The Central Nervous System ◽  
Spontaneous Action ◽  
Neural Anatomy ◽  
Dorsal Unpaired Median

1. Male fireflies of the species Photuris versicolor produce a species-typical triple-pulsed flash which is used as a courtship signal. The neural anatomy was examined to determine if this complex behaviour could be attributed to the organization within the central nervous system. 2. The lantern is innervated primarily by the two most posterior abdominal ganglia. Bilateral roots from these ganglia form a symmetrical pattern of innervation to both sides of the lantern tissue. With minor exceptions, this pattern is similar to that described for other firefly species. 3. The neural organization within the lantern ganglia was determined by back-filling the roots with cobalt or Lucifer Yellow CH, and then examining the ganglia in whole mount. Clusters of three or four large dorsal unpaired median (DUM) neurone somata, each sending bilateral processes out of the lantern roots, were found in both lantern ganglia. 4. The DUM neurone axons bifurcate several times and ramify throughout the dorsal surface of the lantern tissue. More than one DUM neurone may innervate a particular region of photogenic tissue. 5. When dye was back-filled into peripheral branches of the lantern roots that do not innervate photogenic tissue, no DUM somata were stained. Instead, the fibres that filled carried the dye anteriorly up the nerve cord through the ipsilateral connective. No fibres were observed to cross the ganglion midline or exit from the contralateral root, nor were any fibres stained in the contralateral connectives. 6. DUM neurones within the lantern ganglia have resting potentials between 30 and 45 mv and they exhibit multiple, as well as single-peaked spontaneous action potentials. The presence of multiple spikes might reflect the special bilateral morphology of these neurones. 7. The lantern nervous system is organized in an arrangement capable of synchronizing the excitation of all the lantern photocytes. This neural organization could aid in the control of the complex flash pattern displayed by male Photuris versicolor fireflies.

Memoirs: The Innervation of the Heart of Crustacea

1934 ◽  
Vol s2-76 (304) ◽  
pp. 511-548
Author(s):  
J. S. ALEXANDROWICZ
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Dorsal Surface ◽  
Local System ◽  
Dorsal Side ◽  
The Other ◽  
Muscle Fibres ◽  
Cardiac Nerve ◽  
The Central Nervous System ◽  
Dorsal Nerves

1. The three systems of nerves, viz. the local system, the regulator nerves, and the nerves of the arterial valves, which were previously described by the writer as innervating the heart of the Decapod Crustacea, have also been found in Squilla mantis. 2. The local system consists of not less than fourteen neurons. Their cells are situated in a nerve-trunk running alongside the dorsal surface of the heart, and, with the exception of the three anterior elements, lie at regular intervals each behind a pair of the ostial orifices. The cells give off the following processes: (a) the axons which form the chief part of the fibres in the ganglionic trunk and which after sending off many branches end on the muscle-fibres of the myocardium; (b) the dendrites--short arborescent branches arising both from cell-bodies and axons, and ending in the neighbourhood of the trunk on themuscle-fibres too; (c) short collaterals ending in fine networks of fibrils in the ganglionic trunk. 3. The system of regulator nerves connecting the local system with the central nervous system, in the Decapoda consisting of one pair of nerves, is represented in the Stomatopoda by three paired nerves which in our description have been termed Nervi cardiaci dorsales. For the designation of each of them the letters α,β, and γ have been used. Their course indicates that they originate in the large thoracic ganglionic mass. After passing on the dorsal side of the extensor muscles these nerves approach the heart from its dorsal side, and enter its ganglionic trunk in the region of the fourth body-segment. The nerve a is made up of one thick fibre only, the nerves β and γ contain one thick and several thinner fibres each. In the ganglionic trunk two sets of fibres given off by the dorsal nerves can be distinguished: one of them, termed System I, is made up of thicker fibres whose branches give synapses with the cells, collaterals, and dendrites of the local neurons; the other, called System II, consists of thinner fibres accompanying the long branches of the axons which pass to the muscles. 4. The system of nerves supplying the arterial valves is made up of (a) the anterior cardiac nerve running to the valve of the anterior aorta; and (b) the segmental nerves of the heart passing in each metamere to the valves of the paired arteries. There are, in all, fifteen pairs of these nerves. The last pair supplies the valves of the fifteenth pair of arteries and the valve of the posterior aorta. Each segmental nerve sends off anastomotic branches to the contralateral nerve, but does not show any connexions with the nerves of the neighbouring segments. In this respect these nerves in Squilla differ from those in the Decapods since in the latter they are all interconnected by anastomosing fibres. On the other hand, in Squilla as well as in Decapods the anterior cardiac nerve has no connexion with the segmental nerves of the heart. 5. With regard to the function of the nerve-elements enumerated above, the local system is to be considered as an autonomic apparatus which rules the beat of the heart, whereas the dorsal nerves convey the inhibitory and accelerator impulses from the central nervous system. The first of the dorsal nerves, α, has been found carrying the inhibitory impulses. The stimulation of the two following nerves, β and γ, quickens the beat of the heart, but this effect of the physiological experiment does not exclude the possibility that the nerves β and γ contain both inhibitory and accelerator fibres. The two sets of fibres in the ganglionic trunk which have been termed Systems I and II are probably concerned the former with the inhibitory and the latter with the accelerator action. The function of the nerves of the arterial valves probably consists in the maintaining of a tonic contraction of the muscles of the valves.

Convulsive Seizures Following Subdural Application of Fibrin Sealant Containing Tranexamic Acid in a Rat Model

Neurosurgery ◽  
2000 ◽  
Vol 47 (6) ◽  
pp. 1463-1467 ◽  
Author(s):  
Michael G. Schlag ◽  
Rudolf Hopf ◽  
Heinz Redl
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Tranexamic Acid ◽  
Rat Model ◽  
Fibrin Sealant ◽  
Dorsal Surface ◽  
Behavioral Observations ◽  
The Central Nervous System ◽  
Convulsive Seizures ◽  
Phosphate Buffered Saline

ABSTRACT OBJECTIVES Tranexamic acid (t-AMCA) has been shown to cause severe convulsions in humans and cats when applied topically to the central nervous system. We wanted to determine whether pure t-AMCA or fibrin sealant (FS) containing t-AMCA would induce similar effects when applied to the spinal cord in a rat model. METHODS Following low-thoracic laminectomy, the dura was incised to expose the dorsal surface of the lumbar enlargement. Rats were allocated to one of the following treatments: 1) t-AMCA (10 mg/ml), 2) vehicle (phosphate buffered saline), 3) FS containing t-AMCA, 4) FS containing aprotinin. The response of the rats was evaluated based on neurological and behavioral observations. Additionally, motor function was scored in the rats that had received FS. RESULTS Application of either 10 mg/ml t-AMCA or FS containing t-AMCA caused severe hind limb spasms that developed into spontaneous generalized convulsions. Two of the three rats that had received FS containing t-AMCA died of respiratory failure. In contrast, application of vehicle or FS containing aprotinin did not cause any abnormal conditions of the animals. CONCLUSION Tranexamic acid may cause severe complications when used in the central nervous system. Thus, fibrin sealants containing t-AMCA should not be used in neurosurgery.

Analyzing the brain

2000 ◽  
Vol 23 (4) ◽  
pp. 540-541
Author(s):  
Peter Gouras
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Modeling ◽  
Neural Function ◽  
Link Structure ◽  
Neural Organization ◽  
On Line ◽  
The Central Nervous System ◽  
The Brain ◽  
Combining Information

Neural organization describes an approach to analyzing neural function in anatomically defined subsystems in the brain, the hippocampus, cerebellum, sensory systems, thalamus, basal ganglia, and cerebral cortex, combining information on neurocircuitry with mathematical models that link structure with function. It is an up-to-date source on the major schemes and background for neural modeling of the central nervous system and is combined with a Web site that includes tutorials and on-line modeling possibilities.

scholarly journals ABNORMALITIES PRODUCED IN THE CENTRAL NERVOUS SYSTEM BY ELECTRICAL INJURIES

1930 ◽  
Vol 51 (6) ◽  
pp. 943-964 ◽  
Author(s):  
Orthello R. Langworthy
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Dorsal Surface ◽  
Nerve Cells ◽  
Histological Structure ◽  
Dorsal Nucleus ◽  
Different Types ◽  
Group A ◽  
The Central Nervous System ◽  
Circuit Group

The alternating and continuous circuits produced different types of lesions in the central nervous system. Hemorrhages were common after alternating current shocks and few hemorrhages were observed in the continuous circuit group. With both types of circuits at 1000 and 500 volts potential, severe abnormalities in the nerve cells were observed. These were more marked in the continuous circuit group. A uniformly staining, shrunken, pyknotic nucleus was taken as a criterion of nerve cell death. The Purkinje cells of the cerebellum were most susceptible to the current. Injured cells were studied in the dorsal nucleus of the vagus, in the somatic motor group, among the primary sensory neurones and in the olives. Changes in the histological structure of the cells in reference to recovery have been discussed. Injury to the cerebral and cerebellar cortices occurred on the dorsal surface close to the head electrode. Small cavities were produced, particularly in the cerebral cortex, as the result of the circuit contact. With the continuous and alternating circuits at 110 and 220 volts potential less severe changes were observed in the nerve cells although hemorrhages were common in the alternating circuit group. It must be assumed in these cases that death was due to respiratory block rather than actual death of the cells.

Effects of Hyperoxia on Lung Utrastructure

1970 ◽  
Vol 28 ◽  
pp. 26-27
Author(s):  
Gladys Harrison
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Light Microscopy ◽  
Oxygen Effects ◽  
Age Dependent ◽  
The Central Nervous System ◽  
The Subject ◽  
Space Age ◽  
Alveolar Septa ◽  
Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

Emigration of neutrophils in the central nervous system

1983 ◽  
Vol 41 ◽  
pp. 788-789
Author(s):  
John L.Beggs ◽  
John D. Waggener ◽  
Wanda Miller ◽  
Jane Watkins
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Osmium Tetroxide ◽  
White Blood Cells ◽  
Arterial Perfusion ◽  
E Coli ◽  
Intracisternal Injection ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
Interendothelial Junctions

Studies using mesenteric and ear chamber preparations have shown that interendothelial junctions provide the route for neutrophil emigration during inflammation. The term emigration refers to the passage of white blood cells across the endothelium from the vascular lumen. Although the precise pathway of transendo- thelial emigration in the central nervous system (CNS) has not been resolved, the presence of different physiological and morphological (tight junctions) properties of CNS endothelium may dictate alternate emigration pathways.To study neutrophil emigration in the CNS, we induced meningitis in guinea pigs by intracisternal injection of E. coli bacteria.In this model, leptomeningeal inflammation is well developed by 3 hr. After 3 1/2 hr, animals were sacrificed by arterial perfusion with 3% phosphate buffered glutaraldehyde. Tissues from brain and spinal cord were post-fixed in 1% osmium tetroxide, dehydrated in alcohols and propylene oxide, and embedded in Epon. Thin serial sections were cut with diamond knives and examined in a Philips 300 electron microscope.

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