摘要:

AbstractThe visual cortex was studied in the mouse (C57 Black/6J strain) by recording from single units, and a topographic map of the visual field was constructed. Forty‐five percent of the neurons in striate cortex responded best to oriented line stimuli moving over their receptive fields; they were classified as simple (17%), complex (25%) and hypercomplex (3%). Of all preferred orientations horizontal was most common. Fifty‐five percent of receptive fields were cicularly symmetric: these were on‐center (25%), off‐center (7%) and homogeneous on‐off in type (23%). Optimal stimulus velocities were much higher than those reported in the cat, mostly varying between 20° and 300°/sec. The field of vision common to the two eyes projected to more than one‐third of the striate cortex. Although the contralateral eye provided the dominating influence on cells in this binocular area, more than two‐thirds of cells could also be driven through the ipsilateral eye. The topography of area 17 was similar to that found in other mammals: the upper visual field projected posteriorly, the most nasal part mapped onto the lateral border. Here the projection did not end at the vertical meridian passing through the animal's long axis, but proceeded for at least 10° into the ipsilateral hemifield of vision, so that at least 20° of visual field were represented in both hemispheres. The magnification in area 17 was rather uniform throughout the visual field. In an area latral to area 17 (18a) the fields were projected in condensed mirror image fashion with respect to the arrangement of area 17. Medial to area 17 a third visual area (area 18) was again related to 17 as a conde

ISSN:0092-7317    

DOI:10.1002/cne.901600302

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

年代:1975

数据来源: WILEY

摘要:

AbstractWe located the corresponding barrel in Layer IV of the mouse Sml cortex in eleven cerebral hemispheres sectioned in a plane tangential to the pia overlying Sml and in one sectioned in a plane normal to the pia. All of the brains were serially sectioned and prepared by a combined Golgi‐Nissl method. In the section in which barrel C‐1 could be optimally visualized each neuronal soma was outlined with a camera lucida and the cross‐sectional area measured with the aid of a small computer.In all, nearly 7,000 neurons were measured. We estimate that on average barrel C‐1 contains about 2,000 neurons. The mean cross‐sectional area of the perikarya is 62.51 μ2(S.D. ± 14.51 μ2) and the size distribution of the neurons is unimodal and positively skewed. There is no segregation of cells within the barrel on the basis of size. The spatial distribution of cells in the barrel is fairly constant, from specimen to specimen, and the characteristic cytoarchitectonic appearance of the barrel can be related to regional neuronal packing density sicne there are at least 1.6 as many neurons in the sides of the barrel as the hollow.The constancy of the cellular composition of the barrels indicates that the mechanisms responsible for the development of the mouse SmI cortex are fairly rigidly determined, and that the barrel field should lend itself well to further quantitative, developmental and physiologi

ISSN:0092-7317    

DOI:10.1002/cne.901600303

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe randomness of the impregnation of layer IV cortical neurons by the Golgi‐Cox method (Van der Loos, 1956) has been assessed directly in Barrel C‐1 of the mouse SmI. All Golgi‐Cox impregnated neurons and unimpregnated neurons which were revealed with Nissl counterstain were counted and measured in ten cerebral hemispheres cut tangential to the pia overlying the barrel field. The percentage of Golgi stained neurons varied considerably in different preparations from 0.73% to 2.26% with an average of 1.29%. The size distributions of both the Golgi impregnated and Nissl stained cells are similar but the difference of the means is statistically significant. However, if the means are eqated there is no statistical difference in the two populations. When the Golgi precipitate is removed and the cells re‐measured following Nissl staining there is a systematic reduction of the perikaryal cross‐sectional area which is compatible with the differences in the means observed for the two populations as a whole. Finally, the frequency with which Golgi impregnated neurons are found in the barrel sides and hollows parallels the frequency with which Nissl stained neurons are observed in these two locations. We conclude that this variant of the Golgi method impregnates barrel neurons randomly. The value of this information for quantitative studies of cerebral cortex is discussed as is the potential of the system for elucidating some of the mechanisms responsible for Golgi imp

ISSN:0092-7317    

DOI:10.1002/cne.901600304

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe complete structure of the anterior sensory nervous system of the small nematode C.eleganshas been determined by reconstruction from serial section electronmicrographs. There are 58 neurons in the tip of the head. Fifty‐two of these are arranged in sensilla. These include six inner labial sensilla, six outer labial sensilla, four cephalic sensilla and two amphids. Each sensillum consists of ciliated sensory neurons ending in a channel enclosed by two nonneuronal cells, the sheath and socket cells. The amphidial channel opens to the outside as does that of the inner labial sensilla so that these probably contain chemoreceptive neurons. The endings of the other sensilla are embedded in the cuticle and may be mechanoreceptive. The cell bodies of all the neurons lie near the nerve ring and their axons project into the ring or into ventral ganglia. One of the ciliated sensory neurons in each of the six inner labial sensilla makes direct chemical synapses onto a muscle making these sensory‐motor neurons. The anatomy of four isogenic animals was compared in detail and found to be largely invariant. The anatomy of juveniles is nearly identical to that of the adult, but males have four additional neuron proces

ISSN:0092-7317    

DOI:10.1002/cne.901600305

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

年代:1975

数据来源: WILEY

摘要:

AbstractWe studied and compared the ipsilateral afferents of the superficial and deep layers of the superior colliculus of the rhesus monkey. Using a stereptaxic method, microelectrodes were inserted through the contralateral hemisphere in order to make electrolytic lesions of the superior colliculus. Large lesions involved all layers of the superior colliculus, while smaler lesions involved either the superficial or the deep layers of the superior colliculus. Following various survival times, the brains were prepared with the Fink‐Heimer technique (1967). Following lesions of the superficial layers of the superior colliculus, definite degenerated axonal endings were found in the dorsal and ventral lateral genuculate nuclei, inferior pulvinar, centrontermediate nucleus, magnocellular dorsomedial nucleus, anterior pretectal nucleus and pretectal refion. Sparse degenerated axonal endings were found in the limitans nucleus, lateral posterior nucleus and some intralaminar nuclei following lesions of the superficial layers in the rostral portion of the superior colliculus. Following lesions of the deep layers of the superior colliculus, degenerated axonal endings were found in the central gray, magnocellular medial geniculate nucleus, suprageniculatre nucleus, limations nucleus, lateral posterior nulceus, medial and oral pulvinarm nucleus of athe accessory optic tract, zona incerta, subdivisions of the ventral lateral and ventral posterior lateral nuclei, ventral posterior inferior nulceus, densocellular and mulriform dorsomedial nuclei, all intralaminar nucleim inferior coliculus, parabigeminal nucleus, olivary nucleus, reunions nucleus, Forel's Field H and an undefined midbrain nucleus. In general the projections were topographically organized in that the caudal portions of thalamic nuclei. All the degeneration patterns seen after lesions of the superficial and dep layers were accoundted for by large lesions which involved all layers of the superior colliculus. It is conclude that the superficial and deep layers of the rhesus monkey superior colliculus have different ascending projections. The findings are related to the organization of visual and multimodal thalamocortical system in primates and other mammal

ISSN:0092-7317    

DOI:10.1002/cne.901600306

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe organization of cerebellar corticovestibular fibers was studied in a prosimian primate (Galago senegalensis) using the Fink and Heimer (1967) method. The vestibular complex ofGalagois larger than in other mammals and some higher primates. Vermis lobule IX contributes the largest number of fibers to the ipsilateral vestibular complex. Lobules VI and VIII give rise to lesser, but similar, numbers of fibers which also pass into the ipsilateral vestibular nuclei. Vermis lobule VII and the paravermal and lateral cortices contribute extremely sparse numbers of fibers to the dorsal area of the ipsilateral vestibular complex. All degenerated fibers enter the vestibular nuclei through a large diffusely organized juxtarestiform body.Fibers from vermis lobule VII and the paravermal and lateral cortices terminate in dorsal areas of the ipsilateral vestibular nuclei. Vermis lobule VI projects into dorsal and lateral regions of the ipsilateral SVN, LVN and SpVN. Vermis lobules VIII and IX project into the dorsal and into progressively more central and medial regions of the ipsilateral SVN, LVN and SpVN. This gives the clear impression of a rostro‐caudal origin of fibers from the posterior lobe vermis which terminate in an overlapping lateral to medial sequence in the vestibular nuclei, lesions of vermis lobule IX also elicit degeneration in dorsal areas of the ipsilateral medullary reticular formation and in the ipsilateral parabrachial nucle

ISSN:0092-7317    

DOI:10.1002/cne.901600307

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe central projections of the trigeminal, facial and anterior lateral line nerves were studied in the carp (Cyprinus carpio) by the Nauta and Fink‐Heimer silver techniques following rhizotomy.Degenerating trigeminal fibers were found projecting on the nucleus of the descending trigeminal root and on the medial funicular nucleus. The former can be subdivided in five portions lying dorsal to the various cranial motor nuclei. The afferent facial fibers could be traced into the facial, glossopharyngeal and vagal lobes, while the anterior lateral line nerve projects on rostral, medial and caudal parts of the medial nucleus and on the eminetia granularis. The anterior lateral line nerve can be divided into a dorsal and a ventral root, each following the same course. The role trigeminal and facial nerves play in proprioception of respiratory muscles is discusse

ISSN:0092-7317    

DOI:10.1002/cne.901600308

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

年代:1975

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901600301

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

年代:1975

数据来源: WILEY