bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypothalamo‐hypophyseal system in the minnow, Phoxinus phoxinus L. with a note on the effects of hypophysectomy
Authors: Bhargava H. N. 
Published: December 2004

AbstractThe developmental differentiation of the hypothalamo‐hypophyseal system and its disposition in the adult normal minnow is described. Neurosecretory stainable material is present either as granules or droplets in the nucleus preopticus and it is suggested that they are related with one another and follow a sequence in their developmental appearance. This differentiation of the neuorsecretory material and its distribution along the preoptico‐hypophyseal tract suggests a strong basis in support of the “transport‐hypothesis” of Bargmann and Scharrer ('51). The presences of the Herring bodies and peripheral movement of the neurosecretory material along the axon is suggestive of the functional role performed by the tract in the process of storage and release of hormone into the circulation.The presence of intrathalamic branches of the optic nerve and their close association with neurosecretory fibers of the tract seem to be of significance in the important problem of retina‐pituitary relationship.Injections of synthetic oxytocin, synthetic lysine vasopressin and a suspension of acetone‐dried hypothalmus containing nucleus preopticus and the neurosecretory material have no effect on the color response in the minnow.The effect of hypophysectomy clearly confirms that the axons of the nucleus preopticus pass down to the neurohypophysis. After severe operational interruptions of the fibers, their trophic centers (the cell bodies of the nucleus preopticus) degenerate. The accumulation of the neurosecretory material in the stalk region after hypophysectomy supports the “transport‐hypothesis.”
Electron microscopic study on gliosome formation in postnatal development of spinal cord in the cat
Authors: Hashimoto Paulo H. 
Published: December 2004

AbstractThe CNS of cats including newly‐born, 2 day‐, 4 day‐, 10 day‐, 18 day‐, 3 week‐, 6 week‐ and 3 month‐old kittens and adults, were fixed by perfusion from the aorta with 1% osmium tetroxide in acetate‐veronal buffer, or with 2.5 to 3% glutaraldehyde or 4% formaldehyde in phosphate buffer and retreatment with osmium tetroxide after removal. The astrocytes in the intermediolateral horn of the thoracic spinal cord and in the neighboring lateral funiculus were examined under the electron microscope. The astrocytic mitochondria are larger than the neuronal ones at birth. They have a finely granular matrix and dispersed cristae mitochondriales. During the first 4 to 10 days after birth many of the astrocytic mitochondria enlarge, with an increase in the amount of matrix material and its crystallization into a filamentous array, forming “gliosomes.” Within two to three weeks, a bundle of crystalline filaments with a regular periodicity are formed in the matrix. The rough surfaced endoplasmic reticulum seems to be closely associated with the processes of gliosome formation. Namely, cisterane of the rough endoplasmic reticulum first accompany the growing mitochondria, then lose ribosomes on their proximal membranes, and finally change into vesicles of the smooth endoplasmic reticulum around the gliosomes and gliofilaments. The possible significance of these structural changes is discussed.
The cortical projection of the pulvinar in the cat
Authors: de. V. Clüver P. F. , Campos‐Ortega J. A. 
Published: December 2004

AbstractThe cortical projection from the pulvinar has been studied in the cat with the help of stereotaxic coagulation and silver impregnation methods. The pulvinar of the cat projects fundamentally into the gyri suprasylvius posterior and medius, lateral bank of the posterior lateral sulcus, middle ectosylvian and anterior sylvian gyri. The projection to the gyrus suprasylvius is topologically organized overlapping with the projection of the n. lateralis posterior. The question of the ending of degenerated fibers in the parasplenial gyri is discussed.The thalamic degenerated fibers are present in the deeper layers of the cortex. There are however regions in the posterior suprasylvian gyrus in which degenerated fibers are present in the molecular layer as well as in the deeper layers. This different topographic distribution of the endings of the thalamic fibers is discussed with relation to the problem of the “sustaining” and “essential” thalamo‐cortical projections.
Spinal cord representation of the micturition reflex
Authors: Oliver John E. , Bradley William E. , Fletcher Thomas F. 
Published: December 2004

AbstractThe spinal cord origin and peripheral pathways of the sensory and motor nerves to the urinary bladder were delineated in the cat by stimulating the appropriate nerves near the urinary bladder and recording from the dorsal and ventral rootlets near the spinal cord.The parasympathetic preganglionic neurons originated in the sacral segments of the spinal cord and reached the bladder by way of the pelvic nerve. The preganglionic parasympathetic perikarya to the urinary bladder were distributed over a length of approximately 1.5 segments, centered near the junction of segments S‐2 and S‐3 in cats with a median arrangement of the lumbosacral plexus. Conduction velocities in preganglionic parasympathetic fibers to the bladder ranged from 46 to 2 M/sec with a mean maximal velocity of 18.2 M/sec.The major sympathetic pathway to the bladder was in the hypogastric nerve. Preganglionic sympathetic fibers originated in the lumbar spinal cord and traveled through the caudal mesenteric ganglion and hypogastric nerve to the urinary bladder. There were both ipsilateral and contralateral preganglionic and afferent fibers in this pathway. The preganglionic sympathetic neurons originated in segments L‐2 and L‐5. They were usually distributed over approximately 2 full segments centered near the junction of L‐3 and L‐4 in cats with a median arrangement of the lumbosacral plexus.Neurons involved in the micturition reflex may extend from the rostral end of the L‐2 segment to the caudal end of the S‐3 segment. The sympathetic preganglionic neurons were usually separated from the somatic and parasympathetic columns by segments L‐5 to L‐7.
On the direct cortical connections of the nucleus centrum medianum thalami
Authors: Totibadze Nana K. , Moniava E. S. 
Published: December 2004

AbstractThe center median nucleus of the cat was damaged electrolytically by a horizontally introduced electrode through the cerebellum. After a postoperative survival of ten days to a month degenerated fibers were studied by a modified Nauta method. Direct connections of the center median nucleus of diffuse character were found terminating bilaterally in V–VI layers of the neocortex. Another cortical projection from the center median nucleus terminating in layers III–IV was limited to the anterior and middle regions of the lateral and suprasylvian gyri, the anterior ectosylvian and sylvian gyri and the cornal gyrus. Fibers to the contralateral cortex were found to pass through the corpus callosum.Threshold stimulation of the center median nucleus evoked recruiting response (with a short latency) only in the limited area of the cortex whose direct connections terminate in III–IV layers. Diffuse recruiting response was obtained only with the stronger stimulation. Following lesion of the center median nucleus, diffuse recruiting response, evoked by stimulation of other nonspecific nuclei, was not obtained in the area of the cortex whose III–IV layers recieve connections from the center median nucleus. This supports the view that diffuse recruiting response during stimulation of one nonspecific nucleus is evoked by intrathalamic sprading of impulses to other nonspecific nuclei.
Localization of sound after section of the brachium of the inferior colliculus
Authors: Strominger Norman L. , Oesterreich Roger E. 
Published: December 2004

AbstractNine adult cats were trained on a discrimination requiring localization of sound in space. Localization was tested at successively decreasing discrimination angles, and thresholds were determined. The brachium of the inferior colliculus was sectioned bilaterally either in a single operation or in two stages with intervening behavioral tests. Large transient losses in localizing ability were found in three animals with complete unilateral brachium lesions. While performance improved with protracted retraining, two of these animals had some permanent impairment. Following complete bilateral lesions of the acoustic brachium, animals were not able to localize sound as tested by the present methods. In a single animal, extensive but bilaterally incomplete destruction of the brachium was without effect on localization.
The rubro‐spinal tract of the opossum (Didelphis virginiana)
Authors: Martin George F. , Dom Richard 
Published: December 2004

AbstractThe course, caudal extent and termination of the opossum rubro‐spinal tract were determined by employing the Nauta‐Gygax and Fink‐Heimer techniques on the spinal cords of animals with lesions either within the red nucleus or within the descending fibers emanating from that nucleus. Prior to placement of the lesion, the area at the tip of the electrode was stimulated and the concomitant movements of skeletal muscles were palpated.The rubro‐spinal tract traversed the entire length of the spinal cord and was located within the dorsolateral portion of the lateral funiculus. The tract was partially separated from the surface throughout cervical and thoracic levels by fibers of the dorsal spino‐cerebellar tract. More caudally the rubro‐spinal tract coursed immediately beneath the cord surface.At cervical levels, rubro‐spinal fibers ended extensively within the lateral portion of laminae V and VI (Rexed, '52) and minimally within the medial portions of the same laminae. Fascicles also ended within lamina VII. At thoracic levels, lamina VI disappeared and rubro‐spinal fibers terminated within the lateral and, to a lesser extent, the medial portions of laminae V and VII. Lamina VI was present at lumbar and rostral sacral levels and the majority of rubro‐spinal fibers ended within the lateral part of that lamina. However, a few fibers terminated within laminae V and VII at such levels. At caudal sacral and coccygeal levels lamina VI disappeared and rubro‐spinal bundles ended within laminae V and VII.Stimulation of the caudal red nucleus initiated contraction of the flexor musculature of the contralateral forelimb, and to a lesser degree, the contralateral hindlimb. Contraction of the contralateral paraxial musculature was also noted at cervical and thoracic levels during such experiments. Stimulation of the rubro‐spinal tract and adjacent tegmentum immediately caudal to the red nucleus resulted in similar movements, but they were essentially limited to the side of the stimulation.
Monoamine‐containing neurons in planaria
Authors: Welsh John H. , Williams Lois D. 
Published: December 2004

AbstractThe Falck and Hillarp fluorescence method was used in a study of the identification and distribution of monoamine‐containing neurons in three species of planarians, with principal attention given to Phagocata oregonensis. Nerve cells containing 5‐hydroxytryptamine (5HT) and others containing a primary catecholamine (CA) were found in the cerebral ganglia and ventral nerve cords; also in the peripheral plexus and pharynx. The fluorescing components of the peripheral plexus are mostly CA‐containing in dorsal regions and 5 HT‐containing in ventral regions. Some 5HT cells have processes that penetrate the ventral epidermis. These may be sensory or they may have a cilio‐regulatory role. A typical nerve net of multipolar CA cells was found in the pharynx; also a deeper layer of 5HT cells. The occurrence of other types of neurons (cholinergic and neurosecretory) in planarians is discussed. The early evolution of various common chemical types of nerve cells is indicated.
The development of the human motor trigeminal complex and accessory facial nucleus and their topographic relations with the facial and abducens nuclei
Authors: Jacobs Miriam J. 
Published: December 2004

AbstractThe development of the motor trigeminal complex and accessory facial nucleus was traced in 23 human fetuses (seven and one‐half to 21 weeks, menstrual age; 20.7–p177.5 mm CR length) and a 75‐day infant both by graphic reconstructions and cytologic methods. Positional relationships with the facial and abducens nuclei were determined.Differentiation begins at the junction of the posterior trigeminal and accessory facial nuclei (level of pontine flexure) and proceeds rostralward in the motor trigeminal complex and caudalward in the facial complex. The neurons that differentiate earliest complete their migration first and migrate the least from their original position. Thus the posterior trigeminal nucleus is most dorsally and the accessory facial cell groups are most medially located. Migration of the trigeminal complex is completed by eitht weeks and of the facial complex by ten to ten and one‐half weeks.Correlations are made between the differentiation of the motor neurons of the trigeminal and facial nerves and: (1) the development of the muscles that they have been postulated to supply; (2) the known function of these muscles; (3) the development of reflex activity in these muscles; (4) the mammalian experimental and human pathologic evidence for their innervation. These correlations support the view that the posterior trigeminal nucleus supplies the anterior belly and the accessory facial nucleus the posterior belly of the digastric muscle and that the posterodorsal part of the motor trigeminal nucleus innervates the mylohyoid muscle. Furthermore, the sequence of differentiation of the trigeminal complex indicates that the ventral trigeminal muscles (floor of the mouth) are represented primarily dorsally and posteriorly in the trigeminal complex and the progressively more dorsal muscles increasingly farther ventrally and anteriorly.The three subdivisions of the motor trigeminal nucleus are probably related to the three major embryonic muscle masses that they supply early in development. Because the inconstant subgroups in the three subdivisions appear when the complixity of reflex activity increases, perhaps they represent functional units rather than single muscles.The position of the abducens nucleus varies widely and no consistent migration cephalad occurs. It may reach caudal motor trigeminal nuclear levels early in fetal life or remain at caudal levels of the facial nucleus postnatally. No accessory abducens nucleus was identified. The neurons in the location allocated to it in some mammals develop from the common cell column between the motor trigeminal nucleus and the facial nucleus and constitute the accessory facial nucleus. Possible explanations for the widely different number of cells in the posterior trigeminal and accessory facial nuclei are discussed.
Comparisons in structure of tendon organs in the rat, cat and man
Authors: Bridgman Charles F. 
Published: December 2004

AbstractGolgi tendon organs from human, cat and rat extensor digitorum brevis muscles are compared in structural design. Microscopic studies reveal that these receptors appear to be very similar in structure, suggesting close functional similarities even though they are largest in man, intermediate size in cats and smallest in rats. This contrasts with similar observations on the structure of muscle spindles which show strong differences in respect to the insertion of intrafusal muscle fibers thereby implying species specialization of response characteristics to intramuscular tensions and pressures.Reconstructive drawings of human tendon organs from serial sections suggest how sensory endings may be affected by tensions at the musculotendinous junctions due to stretch or contraction of motor units. Finely divided collagen bundles appear to compress and distort nerve endings lying between them, thus inducing the generation of spike discharges.
Topical projection of the olivocerebellar system in the cat: An electrophysiological study
Authors: VanGilder John C. , O'Leary James L. 
Published: December 2004

AbstractUsing electrophysiological recording, topical aspects of the olivocerebellar projection were studied in the locally anesthetized cat immobilized with Flaxedil. Transcortical evoked potentials were recorded simultaneously from eight electrodes distributed over the cerebellar surface, and averaged with a LINC computer. Precautions were taken to eliminate virtual potentials from this volume conductor situation. The evoked potentials consisted of a 4–6 msec positive spike, latency 4.5–7 msec, followed by a 15–30 msec slow negative deflection. Each was recorded from one or two folia contralateral in distribution. Medial and dorsal accessory nuclei project largely to cerebellar vermis. A rostrocaudal relationship was found between posterior vermis and medial accessory nucleus, and vermal anterior lobe received its projection from the caudal and midportions of medial and dorsal accessory components. A dense representation of accessory nucleus responses was present over the declive as compared with other cerebellar areas. Paravermal responses of anterior lobe derived from rostral dorsal accessory olive, and principal olive connected to the hemispheral region. The ventral lamella of principal olive projected to Crus II, dorsal lamella to Crus I. These lobules are represented rostrally in the principal nucleus, whereas the source for paramedial lobules was situated more caudally. The results correlate well with the retrograde degeneration studies of Brodal ('40, '54) but differ in the detail of some projections.
Thalamotelencephalic projections in the turtle (Pseudemys scripta)
Authors: Hall William C. , Ebner Ford F. 
Published: December 2004

AbstractThe telencephalic projections of the turtle thalamus were studied using the Fink‐Heimer ('67) technique for staining degenerated axons and their terminals. Large thalamic lesions produced terminal degeneration in the basal telencephalic nuclei, the core of the dorsal ventricular ridge and the outer half of layer I in general cortex. A variety of control lesions confirmed that these projections arise in the thalamus. Circumscribed thalamic lesions revealed first, that there is some degree of spatial organization in the turtle's thalamocortical projection system and second, that at least one sensory relay nucleus, the dorsal lateral geniculate, projects to general cortex. Detailed comparisons of the turtle's thalamotelencephalic projections with those present in two primitive mammalian species, the hedgehog and the opossum, provided a basis for identifying probable homologies in the forebrains of reptiles and mammals.
Subcortical projections, cortical associations, and some intrinsic interlaminar connections of the striate cortex in the squirrel monkey (Saimiri)
Authors: Spatz W. B. , Tigges J. , Tigges Margarete 
Published: December 2004

AbstractLaminar lesions made by the thermocoagulation in the lateral striate cortex of Saimiri reveal details of three distinct groups of descending fibers: interlaminar, cortico‐cortical, and cortico‐subcortical. The two most massive connections originate mainly from layer III. These are the interlaminar fibers terminating in the underlying layer V, and the systematically arranged projection upon area 18. Another cortical projection upon a narrow region in the superior temporal sulcus originates mainly from the infragranular layers, from which originate also the fibers passing to three subcortical structures, viz. the colliculus superior, the medial pulvinar and the griseum pontis. These subcortical projections are sparse compared to the interlaminar and cortico‐cortical connections. In particular, no evidence was obtained that the lateral geniculate nucleus receives fibers from the lateral striate cortex. Lesions injuring the white matter, however, produced, in addition, anterograde degeneration in the nucleus praetectalis, three pulvinar nuclei, the lateral geniculate nucleus and the pregeniculate nucleus. This degeneration must have resulted from the interruption of fibers originating in areas other than the lateral striate cortex, and passing beneath the site of the lesion.The origin of the interlaminar fibers and of the association fibers upon area 18 provided strong evidence that, in Saimiri's striate cortex, the two sublayers traditionally referred to as sublayers IVa and IVb, actually form part of the conspicuously enlarged layer III which thus is subdivided into three distinct sublayers.
Electron microscopic studies of Wallerian degeneration in rat optic nerves. II. Astrocytes, oligodendrocytes and adventitial cells
Authors: Vaughn James E. , Pease Daniel C. 
Published: December 2004

AbstractFibrous astrocytes, oligodendrocytes and adventitial cells have been studied in rat optic nerves undergoing Wallerian degeneration. Postoperative survival times ranged from five hours to 250 days. Fibrous astrocytes fill the spaces made available by the removal of degenerating nerve fibers. In addition, some astrocytes apparently become phagocytic and engulf degenerating myelin fragments. This reaction is small in comparison to that of multipotential glia (Vaughn), Hinds and Skoff, '70, and it appears to be secondary to the role of astrocytes in scar formation. There is no evidence from this study suggesting that oligodendrocytes engulf degenerating nerve fibers. Indeed, they do not exhibit dramatic changes during fiber degeneration beyond forming aberrant myelin sheaths during the late postoperative stage. Similarly, adventitial cells generally remain unaltered although a few adventitial cells containing numerous inclusions are encountered in degenerating tissue. Adventitial cells are always located within the perivascular space and neither they nor leukocytes have been observed in transit from blood vessels into the neural parenchyma. Finally, an attempt is made to reconcile some of the diverse results concerning the origin of CNS phagocytes. It is suggested that in most pathological situations there is contribution of phagocytes from several different sources and the relative importance of each source is determined by the extent of degeneration and the degreed of inflammation.
Cells of origin of sympathetic pre‐ and postganglionic cardioacceleratory fibers in the pigeon
Authors: Macdonald Robert L. , Cohen David H. 
Published: December 2004

AbstractThe pre‐ and postganglionic cardioacceleratory innervation is described in the pigeon. The peripheral course of the postganglionic cardiac nerves has been determined using microdissection and electrical stimulation. Using these techniques and retrograde degeneration methods, the distribution within the sympathetic ganglia of the cells of origin of these fibers has been localized to the three right caudal cervical ganglia (12, 13 and 14). It has also been shown on the basis of electrical stimulation combined with selective ablation of the right sympathetic chain that cardioaccelerator preganglionic fibers probably arise from the most caudal cervical segment of the spinal cord (14), always arise from the upper two thoracic segments (15 and 16), and occasionally arise from a mid‐thoracic segment (17). The left sympathetic chain was shown to have an inconsistent influence on heart rate. On the basis of retrograde degeneration, the cells of origin of sympathetic preganglionic fibers have been localized to a welldefined cell column dorsal to the central canal (column of Terni).