摘要:

AbstractThree groups of giant fibers are found in the cockroach ventral nerve cord. A latero‐dorsal group (dorsal GIs), a latero‐ventral group (ventral GIs) and a medio‐ventral group. The morphology of all three groups of fibers within the thoracic ganglia is described. The morphology of the dorsal and ventral GI pathways in the abdominal and suboesophageal ganglia is also described. The projection patterns of the neurons in each ganglion are remarkably similar which suggests a common function. When motorneurons 5rl (depressor) and 6Br4 (levator) are stained simultaneously with the dorsal and ventral GI groups, some branches from both motor and giant neurons converge. The branching of the remaining medio‐ventral group of fibers and their proximity to areas receiving motorneuronal input suggests that these are the small diameter axons described by Dagan and Parnas

ISSN:0022-3034    

DOI:10.1002/neu.480160402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe sensory arborizations of the femoral chordotonal organ (FECO), trochanteral campaniform sensilla (CS) and the trochanteral hairplate (THP) are restricted to the ipsilateral hemiganglion and possess large dendritic fields in the dorsal and ventral neuropiles. The efferent projections of the fast (Df) and the slow (Ds) depressor motoneurons project into the same areas.Three groups of trichoid sensilla located on the coxal and trochanteral cuticular walls have central contralateral projections and in one case intersegmental projections. All sensory projections terminate either just lateral of or in the Ventral Association Centre (VAC).Comparisons with the mechanoreceptors of other insects reveal similar projection patterns for some proprioceptors and non‐homologous central configurations for other

ISSN:0022-3034    

DOI:10.1002/neu.480160403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTwelve segments of ventral nerve cord (VNC) from donor earthworms,Eisenia foetida, were transplanted into recipient worms from which a comparable length of VNC had been removed. Within the first few days after transplantation, bud‐like formations, containing outgrowths of the giant nerve fibers, were evident at the ends of transplanted and recipient VNC. Morphological and electrophysiological evidence indicated that by 4–10 days after transplantation, medial (MGF) and lateral (LGF) giant fibers within the transplanted VNC formed cell‐specific connections with their counterparts in the recipient VNC. Although the diameters of the giant fiber connections in the transplant‐recipient junctions were often larger than normal, spike conduction across the junction was initially slow (approximately 1.0 m/s) but gradually increased over the next 2–3 weeks. Within the transplant, giant fibers were initially normal in appearance, but spike conduction was slow (1–2 m/s). During the next few weeks velocities increased by as much as fourfold and then stabilized for the next several months. However, by 4–5 weeks after transplantation, giant fiber morphology within the transplant was altered significantly, as indicated by the formation of numerous branch‐like extensions along the length of each giant fiber. By 9–10 months there were further morphological changes in the transplant, as indicated by decreased branching of the giant fibers and altered neuropile. Despite these morphological changes, through‐conduction of giant fiber spike

ISSN:0022-3034    

DOI:10.1002/neu.480160404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTwelve segments of earthworm ventral nerve cord (VNC) were excised from either segments 10–22 (i.e., within the MGF sensory field) or segments 75–87 (i.e., within the LGF sensory field) in donor worms and heterotopically, or homotopically, transplanted into recipient animals. Morphological evidence indicated that by four days after transplantation, peripheral connections were formed between the transplanted VNC and the body wall of the recipient, many of these connections involving novel pathways projecting ventrally from the transplant. Restoration of giant fiber touch sensitivity in the transplant occurred from 4–14 days after transplantation. Regardless of the site of transplantation, the restored sensitivity (i.e., MGF versus LGF sensory field) always reflected the origin of the donor VNC. Restoration of MGF‐mediated motor activity in the transplant occurred approximately 17–22 days after transplantation. In the case of heterotopic transplants (i.e., anterior VNC into posterior segments), the restored MGF‐mediated muscle potentials were facilitating, indicating at least some tendency for persistance of this feature after transplantation. Behavioral observations suggested that reconnections involving other reflex pathways (e.g., those controlling setal movements and peristaltic locomotion) were made within the transplant region and that properties of the restored reflexes reflected those of the donor VNC. The rapid restoration of sensory and motor connections, despite heterotopic placement, indicates a significant capacity for peripheral regeneration by the transplanted VNC. On the other hand, the maintenance of various properties of reflex function, despite heterotopic transplantation, suggests a limited capacity for rearrangement of established central connections in the trans

ISSN:0022-3034    

DOI:10.1002/neu.480160405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe innervation of the accessory flexor muscle of the limbs of several decapod crustaceans was studied by means of vital staining, with methylene blue and electron microscopy. Three patterns of innervation were found. In the first pattern, the distal (DAFM) and proximal (PAFM) heads of the accessory flexor muscle were supplied by two axons (a thick and a thin) which travel in a private nerve along the length of the merus. This pattern was found in the crab (Cancer) and the lobster (Homarus), and conforms to the classical pattern established in the literature. In the second pattern, the nerve to the DAFM is made up of conjoined branches of the flexor and accessory flexor nerves. Consequently, the DAFM receives at least five axons in the portunid crabs,Carcinus, Callinectes, andOvalipes, and occasionally six axons inOvalipes. The PAFM in those portunids receives the usual two axons. In the third pattern, based on preliminary observations on the grapsid crab,Pachygrapsus, “super‐innervation” of the accessory flexor muscle appears to include not only five axons to the DAFM but also at least three to the PAFM. In all species, methylene blue staining of the axon terminations revealed a regular pattern of blebs which are thought to correspond to synaptic terminals as revealed by electron micro

ISSN:0022-3034    

DOI:10.1002/neu.480160406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractUltrastructural examination of the IIN1b nerve to the dorsal longitudinal flight muscle ofManduca sextaL. verified the presence of neurosecretory processes. Subspherical and irregular vesicles were found where the nerve enters the muscle, while spherical vesicles were found in the proximal region only. A dorsal unpaired median (DUM) cell, the median nervous system, and two or more peripheral cells are the sources of these neurosecretory inclusions.Light the electron microscopy CoCl2backfills of the transverse nerve produced intensification of a peripheral neuron (#1) and processes in nerves IIN1a and IIN1b. Similar backfills of nerve IIN1b produced intensification of a DUM cell, a second peripheral neuron (#2), and processes in the transverse nerve and nerve IIN1a. Neuron #1 contained large spherical electron‐dense vesicles while neuron #2 contained smaller subspherical vesicles. These cells were situated upon the link and/or transverse nerves.Based on these results, we suspect central and peripheral neurosecretory processes reach nerve IIN1b as follows: the link nerve projects prothoracic median nervous system and neuron #2 processes, nerve IIN1a projects neuron #1 processes, and nerve IIN1 projects mesothoracic DUM cell processes, although this latter pathway was less clea

ISSN:0022-3034    

DOI:10.1002/neu.480160407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480160408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480160401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY