摘要:

AbstractAlthough retrograde and anterograde degeneration studies have provided important information concerning brain stem afferents to the fastigial nuclues (FN), these data may be incomplete and should be confirmed by axonal transport methods. Attempts were made to inject horseradish peroxidase (HRP) unilaterally into the FN in a series of adult cats. Animals were perfused with dextran and a fixative solution of paraformaldehyde and glutaraldehyde in 0.1 M phospate buffer. Representataive sections were treated by the Graham and Karnovsky (1966) method.Selective HRp injections in one FN resulted in retrograde transport of the marker of Purkinje cells of the ipsilateral vermis and distinctive appendages of the contralateral medial accessory olivary (MAO) nucleus (nucleus β and the dorso‐medial cell column). Retrograde transport of the label was found bilaterally in cells of the medial (MVN) and inferior (IVN) vestibular nuclei, in cell group x and in the nucleus prepositus (PP). Labeled vestibular neurons, most numerous in MVN, were identified in dorsal, caudal and lateral regions, with a slight ipsilateral preponderance. Only a few neurons in caudal, dorsal and lateral regions of th IVN were labeled and none of these included cells of group f. Labeled cells in the caudal third of PP were greatest ipsilaterally. Rostral and caudal injections of FN labeled smaller numbers of cells in MVN, IVN, cell group x and PP.HRP injections of FN and portions of lobules VIII and IX resulted in bilateral retrograde lableing of larger numbers of cells in MVN, IVN and cell group x, and ipsilateral labeling of cells in group y and the interstitial nucleus of the vestibular nerve. Injections of HRP into basal folia of lobules V and VI resulted in retrograde transport of the marker to cells of the medial and dorsal accessory olivary nuclei contralaterally, and to cells of the ipsilateral accessory cuneate nucleus. Transport of label injected into portions of the pyramis was detected in parts of the contralateral MAO and bilaterally in parts of the pontine and reticulotegmental nucleiThis study suggests that the principal afferents of the fastigial nucleus arise from: (1) Purkinje cells of the ipsilateral vermis, (2) restricted portions of the contralateral MAO (nucleus ß and dorsomedial cell column), (3) portions of the MVN and IVN (bilaterally) and (4) caudala parts of the PP. Secondary vestibular inputs to the fastigial nucleus probably are relayed mainly by cells in the cerebellar cor

ISSN:0092-7317    

DOI:10.1002/cne.901720202

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe visual fields of 18 cats were measured before and after various lesions. Preoperatively, all cats had identical fields. With both eyes open, they saw from 90° left to 90° right; with one eye, from 90° ipsilateral to 45° contralateral. Thus the field for nasal retina extends from 90° ipsilateral through to the midline; for temporal retina, from the midline through to 45° contralateralIn summary, postoperative testing led to two major conclusions. (1) Large occipito‐temporal cortical lesions produce a stable field blindness, but the blindness is alleviated by a transection of the commissure of th superior colliculus (or a unilateral collicular ablation). This transaction yields the same result whether it occurs in an operation before, during, or after the cortical lesion. These data confirm and extend the Sprague effect. (2) Cats made dependent upon retinotectal pathways due to cortical ablations responded much better to stimulatian of nasal retina than to stimulation of temporal retina. This presumably is related to the preponderance of nasal retina as a source of the retinotectal pathway. Since even smaller cortical lesions limited to areas 17, 18, and 19 produce this nasal/temporal retinal difference, it is concluded that integrity of the geniculocorticl pathways is necessary for good temporal retinal vision as determined by these

ISSN:0092-7317    

DOI:10.1002/cne.901720203

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe visual fields of seven cats raised with binocular lid suture were measured before and after various neural lesions. Each of the cats preoperatively responded with each eye to stimuli from 90° ipsilateral through to the midline. A transection of the optic chiasm rendered one cat bline on the visual field tests. Large bilateral occipito‐temporal cortical ablations (4 cats) did not measurably affect orienting responses or the extent of visual field. Unilateral occipito‐temporal cortical ablations (2 cats) also had no affect on the visual fields, but subsequent ablations of the contralateral superior colliculus produced permanent blindness in the hemifield contralateral to the ablated tectum. These two cats also were apparently blind with the eye contralateral to the ablated tectum; but with the other eye, the cats retained their preoperative orienting responses. These data are consistent with the hypothesis that, with early binocular deprivation, cats develop dependence upon retinotectal and not thalamocortical pathways for visually guided orienting beha

ISSN:0092-7317    

DOI:10.1002/cne.901720204

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe cell populations of the occipital cortex were examined in young rats subjected to different sensory experiences. In one series recently weaned animals were reared in enriched, impoverished or control environments. The enriched environment was obtained by keeping the animals among “toys” and other rats; the impoverished environment, by rearing the animals one pr cage in a darkened, quiet room; and the control environment, by housing the animals three per cage under animal room conditions. Six recently weaned rats were kept ini each environment for 30 days and ten, for 80 days. In a second series suckling rats for 15 minutes per day during the first ten days after birth; twelve rats were studied, six handled and six unhandled controls. In the two series, the animals were sacrificed under anesthesia by perfusion with mixed aldehydes. Semithin epon sections of occipital cortex ere stained with toluidine blue; neurons and the three main types of glia were enumerated. In addition, the thickness of the cortex was measured and the glial cells of corpus callosum counted in the animals exposed to the three environments for 80 days.Under the influence of theenriched environment, the occipital cortex enlarged, the number of oligodendrocytes increased over the controls by 27‐33% in the 30‐ and 80‐day groups and the number of astrocytes, by 13% in the 80‐day grup. Within the cortex, only certain layers showed the increase in glial numbers. In the corpus callosum, however, the numbers of glial cells did not differ from those in controls. In the animals exposed to theimpoverished environment, neither the size of the cortex nor the number of oligodendrocytes and astrocytes differed from controls.The animals subjected tohandlingalso showed evidence of cortical enlargement, but the only significant change in glial cells was a 12% increase in astrocytes.It is concluded that handling and enrichment produce changes in anatomical indices of neural function including depth of cortex and numbers of glial cells. The glial response was specific to the type of manipulation since astrocytes were predominantly affected by handling and oligodendrocytes, by enrichment. The effect of handling on astrocytes may be attributed to the stimulation being applied at a time of astrocyte proliferation, whereas the effect of the enriched environment on oligodendrocytes occurred at a time of active production of these cells. The differences in cell numbers were explained by changes in the rate of cell population growth; since the impoverished did not differ from the control animals, the changes probably consisted of growth acceleration in the enriched animals rather than dimiution in the impove

ISSN:0092-7317    

DOI:10.1002/cne.901720205

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe effects of visual deprivation upon dorsal lateral geniculate (DLG) cell size were compared for seven kittens reared with monocular lid‐suture (MD), seven with binocular lid‐suture (BD), and six with one eye lid‐sutured and the other eye enucleated soon after birth (MD‐E). Six additional kittens were reared normally for comparison. For each kitten the cross‐sectional areas of 300 cells were measured in one or both nuclei. Measurements were taken from the binocular segment of laminae A and A1 and th monocular segment of lamina A.In agreement with previous studies, cells in th binocular segment of the deprived laminae of MD cats were smaller (33‐34%) than those in the non‐deprived laminae. Comparisons with normal animals indicated that this difference was due to an increase (10‐15%) in size of cells in the non‐deprived laminae as well as a decrease (23‐25%) in size of cells in the deprived laminae. Cells in the monocular segment also were affected by deprivation in MD cats, and this effect increased with the age (and duration of the deprivation) of the animal. However, it was always smaller than the decrease in sell size in the binocular portion of the DLG.In BD kittns, DLG cells were smaller (7‐12%) than normal in all portions of the nucleus, including both the binocular and monocular segments. Direct comparisons between the deprived laminae of MD and BD kittens indicated that the decrease in cell size was greater for MD kittens in the binocular segment, but tended to be greater for BD kittens in the monocular segment. IN MD‐E kittens, DLG cells in the deprived laminae were smaller (11‐17%) than normal in all portions of the nucleus, including both the binocular and monocular segments. Thus, the effects of deprivation were similar to those in BD kittens, even though inputs from the deprived eye had been placed a competitive advantage in MD‐E kittens. These results indicate that two factors may affect cell size in the DLG of visually deprived cats: deprivationper seand abnormal binocular competition.Finally, separate analyses for the ten largest and the ten smallest cells in each lamina of each cat were carried out in an attempt to determine if the changes in cell size were limited to the largest cells. In every case, differences observed for the total sample of cells were paralleled by differences from normal of both the largest cells present and the smallest cells present in the deprived laminae. Since at least two alternative interpretations can account for this finding, the question of whether the large cells are selectively affected by visual deprivation re

ISSN:0092-7317    

DOI:10.1002/cne.901720206

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

年代:1977

数据来源: WILEY

摘要:

AbstractStructurally diverse sensory regions occur in the otolith organs of the goldfish inner ear. Scanning electron microscopy reveals regional distinctions based on thre criteria. (1) Hair cells have difference sizes of apical bundles, based on thickness. In all three maculae, two central regions have hair cells with bundles significantly thicker than those in surrounding regions. (2) Hair cell population density varies, with regional aggregations present. The central regions with thick bundles have two to three times the density of surrounding regions with thin bundles, and contain 40‐80% of the total hair cell number in each macula. (3) Hair cell orientation maps show that each macula has two oppositely oriented cell populations that can be separated completely, not by a zone of interspersion, but apparently by a single unbroken lineThe lagena is like the utricle in having hair cells with the kinocilium on the side of the cell toward the opposition line, but in the saccule the kinocilia face away from the line, and the small macula neglecta consists of two completely separate, oppositely oriented patches. The opposition line does not divide each macula simply down its midline; instead, the line divides the regions with thick bundles into narly equal opposing aras, except for a remarkably abrupt large loop in the line in the anterior part of the sacculeThe regional structural diversity in these organs may relate to localized functional diversity of responses to tilt, vibration and soun

ISSN:0092-7317    

DOI:10.1002/cne.901720207

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

年代:1977

数据来源: WILEY

摘要:

AbstractDegeneration experiments reveal that the vestibular nerve of the adult opossum distributes to an extensive and diverse area of the brainstem and, as in placental mammals, the traditionally named nuclei do not receive a uniform distribution of primary afferent fibers. Nevertheless, such nuclei as well as other nearby cell groups have been considered as vestibular since they share other mutual connections. Except for subgroups. “1”, “g” and the nucleus suprvestibularis all of the vestibular subdivisions generally recognized in more specialized placentals (e.g., the cat) have been identified in the marsupial opossum.Each of the vestibular nuclei and “extra‐nuclear” cell stations are described as to their boundaries, cytoarchitecture and dendritic domain. Whenever possible we have employed a terminology consistent with that used for the cat. In several instances we have used results from experimental degeneration material to identify nuclear boundaries and divisions which are not apparnt in routine Nissl, Golgi or silver

ISSN:0092-7317    

DOI:10.1002/cne.901720208

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

年代:1977

数据来源: WILEY

摘要:

AbstractWe have demonstrated the connectivity of the opossum's vestibular nuclei using degeneration, autoradiographic and horseradish peroxidase techniques and have found it to be generally comparable to that reported for the cat. Apart from the primary input described in Part I of our study, the cerebellum provides the major source of afferent connections to the vestibular complex. Axons from the cerebellar cortex distribute mainly to vestibular areas which receive no primary afferent projections, e.g., the dorsal part of the lateral vestibular nucleus, the dorsolateral margin of the inferior vestibular nucleus as well as cell groups comparable to “f” and “x” In contrast, fastigial fibers show considerable overlap with primary vestibular input, particularly in the ventral part of the lateral nucleus, the central part of the inferior nucleus and the medial nucleus. Axons of fastigial origin also distribute to the superior vestibular nucleus, to subnuclei “f” and “x” and to the parasolitary region. Although spinal fibers are diffuse within the main vestibular nuclei, they ramify quite densely within subnucleus “x”. Most of th spinovestibular projection appears to arise in the cervical spinal cord of the opossum.Ipsilateral connections from the interstitial nucleus of Cajal and surrounding aras end predominantly, but not exclusively, in the medial vestibular nucleus. A crossed midbrain projection has been verified from the red nucleus to cell group “x” and the lateral part of the inferior nuclues, as well as to an area possibly comparable to cell group “z,” as described for the cat.In Part I of our study we have shown that the major targets of primary vestibular fibers are the central part of the superior nuclues, a portion of parabrachial complex possibly comparabale to subnuclues “y,” the ventral part of th lateral nucleus and the medial nucleus. All of these primary zones give rise to fibers supplying extraocular nuclei and surrounding areas (present study). The ascending midbrain fibers from the superior nucleus end mainly ipsilaterally, whereas those from the putative subnucleus “y” and the medial vestibular nucleus distribute contralaterally for the most part.Although the dorsal part of the lateral vestibular nucleus has no primary vestibular input, it does receive a major projection from the cerebellar cortex. This same region of the lateral nuclues projects to the spinal cord, but not to extraocular nuclei. The ventral part of the lateral nucleus, and perhaps the medial nucleus, also relay to the spinal cord. Additional projections from all vestibular nuclei can potentially affect multiple systems, including those innervating the spinal cord. Finally, commissural vestibular connections of the opossum are shown to

ISSN:0092-7317    

DOI:10.1002/cne.901720209

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

年代:1977

数据来源: WILEY

摘要:

AbstractSubstantial portions of the dorsal, and almost the entire posteroventral and anteroventral (Av) cochlear nuclei were aspirated unilaterally in a chimpanzee. Axonal degeneration was studied by the Fink‐Heimer method. The greatest amount of degeneration was followed medially from the region of Av into the lateral part of the trapezoid body. Degeneration also coursed around the superior surface of the restiform body and was traced into the dorsal and intermediate acoustic striae.Within the superior olivary complex, degeneration was distributed to: the ipsilateral lateral superior olive; laterally and medially oriented dendrites of the ipsilateral and contralateral medial superior olivary nuclei respectively (some periosomatic degeneration also was present bilaterally); the contralateral medial trapezoid nucleus; retro‐olivary and preolivary cell groups bilaterally. Abundunt degeneration passed into the contralateral lateral lemniscus and was distributed largely to its ventral nucleus. The contralateral central nucleus of the inferior colliculus was a major site of termination of ascending second order auditory fibers. The caudal tip of the ipsilateral ventral nucleus of the lateral lemniscus received abundant degeneration, but this diminished rostrally. The ipsilateral inferior colliculus contained a moderate amount of degeneration.A fair number of degenerated second order auditory fibers ascended in the contralateral brachium of the inferior colliculus and were distributed both to the principal and magnocellular divisions of the medial geniculate body. This pathway appears to represent a phylogenetic advance in the brain of the great

ISSN:0092-7317    

DOI:10.1002/cne.901720210

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

年代:1977

数据来源: WILEY

摘要:

AbstractBased on one adult chimpanze monocularly injected with radioactive proline, retinofugal fibers were found to terminate bilaterally in the suprachiasmatic, prgeniculate, lateral geniculate, olivary, pretectal and lateral terminal nuclei, and the superior colliculi; the existence of a dorsal terminal nucleus of the accessory optic system is in doubt. In the ipsilateral geniculat nucleus, the fibers terminat in layers 2, 3 and 5; in the contralateral nucleus, they end in layers 1, 4, and 6. Miday throuh the geniculate nucleus, 3 and 4 split medially into two daughter layers 3 and 4 split medially into two daughter layers each. In the superior colliculi, most of the retinal terminals are aggregated superficially in a band located in the stratum griseum superficiale. The contralateral band is interrupted by gaps; the ipsilateral band has fewer gaps, is slightly thicker and located more deeply. There is a limited second tier of terminals in the contralateral superficial gray.

ISSN:0092-7317    

DOI:10.1002/cne.901720211

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

年代:1977

数据来源: WILEY