摘要:

AbstractMongrel dogs were anesthetized intraperitoneally with pentobar‐bitol. One cc of cerebrospinal fluid was drawn through a needle inserted into the cisterna magna and mixed with 1 cc (4–9 million viable BCG organisms) of freeze‐dried bacillus Calmette‐Guerin. One minute later this mixture was injected by the same needle into the cisterna magna. At 1 and 12 days postinjection, experimental animals were perfused with buffered aldehydes. Samples of the leptomeninges were post‐fixed in OsO4 and routinely prepared for scanning and transmission electron microscopy. Leptomeningeal samples of untreated, control animals were similarly prepared.Scanning and transmission microscopy confirm that free cells resting on the sub‐arachnoid linings and within the subpial connective tissue space of control animals possess the morphology of macrophages (Malloy and Low, 1976). Viable BCG in the subarachnoid space produces a 3‐fold increase in the free cell population of the leptomeninges in 24 hours and a 10‐fold increase in 12 days. These cells tend to form associations varying from loose aggregates to tight clusters. Approximately 80% of these free cells express macrophage morphology, with abundant plasma‐lemmal microappendages and cytoplasmic vacuoles. Transmission electron microscopy of the free cell population of BCG‐stimulated animals reveals at least two other members of the leukocyte series on the lep

ISSN:0092-7317    

DOI:10.1002/cne.901720302

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn locusts a single‐celled stretch receptor (SR) neurone at the base of each wing monitors wing elevation and contributes to the control of the flight motor output. The central projections of these neurones are very complex but consistent in detail in the three species studied(Chortoicetes, LocustaandSchistocerca). The hindwing SR projects to the second and third thoracic ganglia, the forewing SR to the first, second and third thoracic ganglia. Both send fine axons into the abdominal connective.Within the ganglia each SR forms an extensive arborization, entirely ipsilateral and mainly in the dorsal neuropile, divided intomedial, mediolateral, andlateralbranches. The projections of the two ipsilateral SR neurones overlap almost completely in the second and third ganglia. There are recurrent loops between branches of a single neurone both within and between ganglia.Light microscope analysis shows apparent contacts between the SR neurones and flight motor neurones and other wing sensory afferents, as well as long inter‐neurones, other motor neurones and two types of multiaxonal neurones of unknown function. There are three groups of contacts between each SR and a flight motor neurone: laterally on the main branches, medially with the terminal twigs; and in theanterior dorsorriedial glomerulus, where the interganglionic recurrent branch also terminates. All contacts are ipsilateral except for those with the contralateral branches of the dorsal longitudinal muscle motor neurones.We suggest that the SR neurones are multifunctional. Differential information transfer could result both from the spatial distribution of synaptic connections with the motor neurones from filtering caused by low safety factors at branch junctions. Information in the lateral branching could be used for general excitation and control of firing frequency of the motor neurones; that in the medial branch for wing control and coordinat

ISSN:0092-7317    

DOI:10.1002/cne.901720303

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe central arborizations of the stretch receptor (SR) neurones are very consistent from one individual to another. Superimposition of normalized neurones from eight individuals ofLocustashow very little variation even in the detailed branching pattern. There is, however, a commonly foundalternativecourse for the main medial branch in the metathoracic ganglion. Rare, radical departures from the normal branching pattern are termed“mistakes.” Only three have been found, all in the forewing SR projection, one with an extra branch and two with missing branches.Terminals of twigs in the alternative region of the medial branch occupy consistent positions in the neuropile, although these are reached by different routes. Mistakes have terminals in areas normally containing SR endings. Both these findings suggest that there may be labelled sites in the neuropile which the growing tips of the SR neurones seek

ISSN:0092-7317    

DOI:10.1002/cne.901720304

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

年代:1977

数据来源: WILEY

摘要:

AbstractCats were trained pre‐ and/or postoperatively on flux and pattern discriminations, and were examined in a series of visuomotor tests which measured attention and orientation to, and following and localization of stationary and moving stimuli, in a free situation and in a perimetry test.Cortical lesions were placed in areas 17 and 18, or in the middle and posterior suprasylvian gyri and sulci–areas 19, 20, 21, 7 and lateral suprasylvian cortex (LSA), as delineated by cyto‐ and myeloarchitecture, and by electrophysiological mapping.After removal of all of area 17 and up to 90‐95% of 18, postoperative learning of flux and pattern discriminations is at a high level, although in some cases slowed. Visuomotor behavior is normal. Such lesions result in severe atrophy only of laminae A, AI and C in the lateral geniculate nuclear complex (LGNd).The neuronal systems for perceiving and discriminating simple, large planime triepat terns and forms, and for mediating visually guided behavior characteristic of this species lie outside of areas 17‐18. The cortices primarily responsible for form discrimination in the cat include those in the suprasylvian gyri and sulci.After lesions which removed areas 19, 20, 21 and LSA, sparing most of 37‐18, form discriminations based on orientation or shape were prolonged or absent. Although these animals showed slow tracking and poor depth judgment, the visual fields were full and they had good sensory and perceptive capacity as seen in normal flux and near normal pattern (gratings) discrimination. Such lesions result in severe atrophy in lateral and inferior pulvinar complex. Although these nuclei receive visual input primarily from the superficial laminae of the superior colliculus and certain nuclei of the pretectum, both areas 19 and LSA receive a dual input from pulvinar and parts of LGNd.Whether these marked deficits in form discrimination after suprasylvian lesions are due to involvement of certain crucial areas of this extensive cortex, or whether all are involved in some integrated fashion, is not yet completely clear. Removal of 19, 21 and parts of LSA are followed by similar (but somewhat less marked) deficits of both retention and learning. Lesion in area 20 alone (cortical target of the lateral pulvinar) leaves retention of preoperatively learned discriminations intact but results in prolonged initial learning.Previous work by the present authors has shown similar deficits in form discrimination in the cat after lesions in the pretectumsuperior colliculus. These data, together with the present findings appear to support the hypothesis that the midbrainpulvinarcortieal pathways provide the first stage in simple, coarse form perception and discrimination in t

ISSN:0092-7317    

DOI:10.1002/cne.901720305

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

年代:1977

数据来源: WILEY

摘要:

AbstractEight of nineteen chemotactic mutants of the nematodeCaenorhabditis eleganshave morphological defects in the sensory endings of neurons at the tip of the head. The mutants were obtained as worms swimming away from attractant or found amongst male potency mutants or mutants exhibiting erratic behavior. The nineteen mutants fall into at least twelve complementation groups. Mutants E1034 and E1035, alleles ofche‐1, show morphological alterations in the sensory endings of amphidial neurons and inner labial type 2 neurons, both prospective chemosensory neurons. Both mutants contain noncomplementing ts sterile mutations linked to the chemosensory mutation. E1066 shows abnormalities in all the sheath cells associated with the sensory neurons and in the bundling pattern of the amphidial neurons. El 126 is structurally abnormal only in the sensory endings of inner labial type 2 neurons, supporting a chemosensory role for these neurons. E1033(cke‐2)and El 124(cke‐3)cause defects in the ciliary structure of all but one type of ciliated sensory neuron in the head. E1062 is grossly defective in head structure and the structure of the male copulatory organ, suggesting these opposite ends of the nematode rich in sensory structures share gene functions in embryogenesis. Our study illustrates the possibilities for genetic dissection of the development of a small set of nerves in a simple org

ISSN:0092-7317    

DOI:10.1002/cne.901720306

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

年代:1977

数据来源: WILEY

摘要:

AbstractExtensive terminal branchings of fine fibers in the substantia gelatinosa of Golgi‐Kopsch preparations of the adult cat spinal cord were subjected to a semi‐quantitative analysis. Transverse sections suggest that these fibers are probably unmyelinated primary afferent elements of dorsal root origin. In transverse sections these elements pass medially and ventrally and shortly disappear due to a change in orientation. Similar thin fibers in sagittal sections can be followed for several hundred microns as they give rise to side branches that also run mainly in a longitudinal direction. The side branches divide in turn to produce preterminal axon arborizations. The arborizations were distributed in 150 μ wide zones in the dorsal horn region corresponding to Rexed's lamina II. The end terminals are large bulbs, usually preceded by two to three equally large en passant enlargements. Seven to eight terminals stem from each side branch. The terminals and enlargements are arranged in narrow (16‐26μ m thick) sagittal sheets. The terminals of several side branches often converge upon a common region so that clusters of ter minals occur within the sagittal sheet. It is proposed that these observations are consistent with the substantia gelatinosa (lamina II) as the termination of unmyelinated (C) primary afferent fibers and that the latter are the only type of primary fibers ending in this portion of the spin

ISSN:0092-7317    

DOI:10.1002/cne.901720307

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe tract of Lissauer receives small caliber dorsal root fibers in addition to axons arising from dorsal horn neurons. The termination of Lissauer's tract and dorsal root fibers was examined in the C7 segment of the rhesus monkey spinal cord. The distribution of normal dorsal root afferents was mapped by labelling the C7 dorsal root ganglion with tritiated amino acids, and then compared with the degeneration of C7 dorsal root fibers following an intradural dorsal rhizotomy. To focus on the distribution of the small afferents, the degeneration following a Lissau er tractotomy was compared with the degeneration following dorsal rhizotomy and following selected lesions involving the large afferents. The survival times following the lesions and rhizotomies were varied to facilitate identification of groups of fibers and terminals which might degenerate at different rates.Both large and small diameter dorsal root afferents were found to exhibit the same rostrocaudal topography within the dorsal horn. The C7 root axons and terminals distribute throughout the mid‐C7 dorsal horn grey. Proceeding rostrally through C6, the majority of the C7 root fibers ending in laminae I‐IV shift to a lateral position. Proceeding caudally through C8, the C7 root fibers shift medially. Few of the small diameter C7 afferents entering via Lissauer's tract extend above C6 or below C8. Large diameter C7 afferents, arising as dorsal column collaterals, can extend several segments above and below C7.Autoradiography revealed label in all dorsal horn laminae, the heaviest always occurring in the substantia gelatinosa. After one day, label was absent over dorsal column and Lissauer's tract axons, suggesting that the label was mainly associated with fine axonal branches or possibly terminals. After six to ten days many axons were labelled and could be traced into the dorsal and ventral horn.Degeneration from the rhizotomies and lesions, as demonstrated with Fink‐Heimer and Nauta methods, depended on the survival time. No degeneration products were present before three days. The large afferents begin to degenerate within the dorsal horn after three to four days and mainly terminate in laminae IV‐VI; by 12 days they can also be traced into the intermediate and ventral grey. The small afferents, which include those serving pain and temperature sensibility, arise from the tract of Lissauer and distribute to laminae I, II and III.The tract of Lissauer consists of two populations, each containing small afferents. One population degenerates at three to five days and distributes mainly to laminae II and III (substantia gelatinosa); the other degenerates around 12 days and distributes mainly to lamina I and the outer zone of II. It is suggested that the exclusive termination of the small afferents to laminae I, II and III may be correlated with certain unique histochemical properties (e.g., high substance P and high opiate receptor binding levels) of these same dorsal horn areas. In addition the early degeneration may involve non‐myelinated C afferents and the later degeneration may involve the small myelinated A delta

ISSN:0092-7317    

DOI:10.1002/cne.901720308

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

年代:1977

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901720301

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

年代:1977

数据来源: WILEY