scholarly journals The effect of ventral nerve cord cutoff between the third thoracic and the first abdominal segments on oviposition in female imagines of the American cockroach, Periplaneta americana

2000 ◽  
Vol 51 (4) ◽  
pp. 269-273
Author(s):  
Xingfu XIAN
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Periplaneta Americana ◽  
American Cockroach ◽  
The Third

Organization of the Giant Axons of the Cockroach Periplaneta Americana

1969 ◽  
Vol 50 (3) ◽  
pp. 615-627
Author(s):  
M. E. SPIRA ◽  
I. PARNAS ◽  
F. BERGMANN
Keyword(s):  
Nerve Cord ◽  
Periplaneta Americana ◽  
Thoracic Ganglion ◽  
American Cockroach ◽  
Abdominal Ganglion ◽  
Common Pathway ◽  
Average Delay ◽  
Giant Axons ◽  
Stimulation Of

1. Stimulation of the connectives between the suboesophageal and prothoracic ganglia of the American cockroach induced ipsilateral descending spikes in the abdominal giant axons with an average delay of 0·6 msec, per thoracic ganglion. 2. Nicotine at 5 µg./ml. had no effect on conduction in the abdomen but blocked ascending responses sequentially at the 6th abdominal ganglion then at the levels of T1; T2, and T3. 3. Simultaneous descending and ascending impulses resulted in mutual extinction along the nerve cord with the point of collision depending on the interval between stimuli. 4. It is suggested that a common pathway subserves ascending and descending giant impulses and models for bi-directional conduction are discussed.

Electrical stimulation—Effects on the protein in the ventral nerve cord of cockroach,Periplaneta americana

1985 ◽  
Vol 94 (4) ◽  
pp. 407-411 ◽  
Author(s):  
S L Maheswari ◽  
K Balasundaram ◽  
V R Selvarajan
Keyword(s):  
Electrical Stimulation ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Periplaneta Americana

scholarly journals Evolutionary Trends in the Ventral Nerve Cord of the Stingless Bees ( Meliponini)

2017 ◽  
Vol 9 (1) ◽  
pp. 117-129
Author(s):  
Alvaro Wille
Keyword(s):  
Nerve Cord ◽  
Abdominal Segment ◽  
Stingless Bees ◽  
Ventral Nerve Cord ◽  
Evolutionary Trends ◽  
The Third ◽  
Starting Point ◽  
Primitive Forms ◽  
Trigona Fulviventris ◽  
Generalized Type

There are, in relation to the number of ganglia, three main types of ven­tral nerve cords in the adult stingless bees: 1) Those which have two ganglia in the thorax and five in the abdomen, 2) those which have two ganglia in the thorax and four in the abdomen, and 3) those which have three ganglia in the thorax and four in the abdomen. Intermediate types between those listed exist.The most generalized ventral nerve card was found in the workers of Trigona fulviventris, where each ganglion lies only one segment ahead from its respective segment (Fig. 1, A). When this generalized type of nerve cord is taken as a starting point, there are two major recognizable evolutionary trends almong the stingless bees (Fig. 1). One trend is toward the fusion of ganglion 7 with the preceding abdominal ganglion. This occurs independently in the several subgenera of Trigona, with a series of intermediate steps (Fig. 3, A to H). Among some of the species of Melipona there is also a tendency of fusion of ganglion 7 with ganglion 6 (Fig. 4, A to D ) but none of the species of Mélipona dissected was found with those ganglia completely fused.The second trend noted is toward cephalization of the nerve cord ( Fig. 2). This occurs only in Melipona. Here the abdominal ganglia migrate from two to four segments ahead from their respective segments. As a result, gan­glion 3, which in primitive forms was located in the second abdominal segment (first metasomal segment), has moved well inside the thorax. The presence of ganglion 3 in the thorax is characteristic of all the species of Melipona. The highest type of cephalization is found only in a few species, such as MeliPona flavipennis in which ganglia 4 and 5 have moved into the second abdominal segment, and ganglia 6 and 7 into the third. Therefore, in this type, the card extends in the abdomen only as far as the third abdominal segment (second metasomal segment, Fig. 2, E ) . There are, of course, intermediate types.

Visual and Multimodal Interneurones in the Ventral Nerve Cord of the Cockroach, Periplaneta Americana

1973 ◽  
Vol 59 (3) ◽  
pp. 675-696
Author(s):  
R. J. COOTER
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Tactile Stimulation ◽  
Periplaneta Americana ◽  
Compound Eye ◽  
Visual Stimulation ◽  
Contralateral Stimulation ◽  
Thoracic Nerve ◽  
General Properties ◽  
Stimulation Of

1. Visual and multimodal units were recorded from the thoracic nerve cord of the cockroach, Periplaneta americana, using glass microelectrodes. 2. Compound-eye units could be classified as ON-, OFF- or ON-OFF-units according to their response to visual stimulation. Some were multimodal, firing to both visual and tactile stimulation of the antennae. 3. Although some units were found to be either fired by ipsilateral or by contralateral stimulation only, others were fired by both types of stimulation, often in different ways. 4. Ocellar units were invariably OFF-units, mainly phasic, but one type showed tonic dark-firing in addition to the phasic OFF-burst. 5. The general properties of cockroach visual units are discussed and compared with those reported by other workers for different insects.

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