bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cortical connections of the caudal subdivision of the dorsolateral area (V4) in monkeys
Authors: Steele G. E. , Weller R. E. , Cusick C. G. 
Published: January 2005

AbstractEvidence suggests that all primates have rostral and caudal subdivisions in the region of visual cortex identified as the dorsolateral area (DL) or V4. However, the connections of DL/V4 have not been examined in terms of these subdivisions. To determine the cortical connections of the caudal subdivision of DL (DLc) in squirrel monkeys, injections of the neuroanatomical tracers wheat germ agglutinin conjugated to horseradish peroxidase, Diamidino Yellow, and Fluoro‐Gold were made in cortex rostral to V II. To aid in delineating the borders of DLC, cortex was also evaluated architectonically.Based on similar patterns of connections, DLC extends from dorsolateral to ventrolateral cortex. DLC receives strong, feedforward input from V II and projects in a feedforward fashion to the rostral subdivision of DL (DLR) and caudal inferior temporal (IT) cortex, including a separate location in the inferior temporal sulcus. DLC has weaker connections with V I, the middle temporal area (MT), cortex rostral to MT in the location of the fundal superior temporal area (FST), cortex dorsal to DLC, ventral cortex‐rostral to V II, and cortex in the frontal lobe, lateral to the inferior arcuate sulcus. Only lateral DLC has connections with V I, and only dorsolateral DLC has connections with cortex dorsal to DLC. The topographic organization of DLC was inferred from its connections with V II. Thus, dorsolateral DLC represents the lower field, lateral DLC represents central vision, and ventrolateral DLC represents the upper field.Limited observations were made on DLR. Confirming earlier observations (Cusick and Kaas: Visual Neurosci. 1:211, 1988), DLR is paler than DLC myeloarchitectonically. DLR receives only sparse feedforward input from V II, but stronger input from DLC. DLR has strong connections with cortex just rostral to dorsal V II, ventral posterior parietal cortex in the sylvian fissure, MT, the medial superior temporal area, FST, and the inferior temporal sulcus. DLR also shares connections with IT cortex. Thus, while both DLC and DLR are involved in the pathway relaying visual information to IT cortex, an area specialized for object vision, DLR also projects densely to areas such as MT involved in the pathway relaying to posterior parietal cortex, a region specialized for spatial localization and motion perception.
Activity‐dependent changes in eye influence during monocular blockade: Increases in the effects of visual stimulation on 2‐DG uptake in the adult rat geniculostriate system
Authors: Thurlow G. A. , Cooper R. M. 
Published: January 2005

AbstractWe examined the effects of loss of monocular retinal activity 2‐deoxyglucose (2‐DG) uptake in the adult rat geniculostriate system. Of particular interest was whether the influence of the normally functioning eye changed during long‐term contralateral retinal silence. Group 1 rats were subjected to short‐term (24 hours) and group 2 rats to long‐term (21–90 days) monocular tetrodotoxin (TTX) blockade, and metabolic activity was assessed during exposure to square‐wave gratings. Group 1 rats exhibited patterns of cortical glucose utilization commensurate with complete monocular loss of retinal activity: minimal 2‐DG uptake in contralateral monocular area 17 and dorsal lateral geniculate nucleus (LGN), and a bilateral depression in the binocular regions; 2‐DG uptake was highest in the monocular regions fed by the stimulated normal eye (in both area 17 and the LGN) and these regions appeared unaffected by the monocular blockade. After repeated injections of TTX (group 2), metabolic activity in binocular area 17 and binocular LGN increased bilaterally relative to the metabolically active monocular regions contralateral to the normal eye. Group 3 rats were monocularly TTX‐injected for 30 or 60 days, and, 24 hours before 2‐DG, all retinal activity was eliminated by means of binocular TTX injections or binocular enucleation. Glucose utilization in the binocular regions of both area 17 and the LGN in these rats was depressed to levels seen in monocular area 17 after complete and recent loss of activity from the contralateral eye, indicating that the metabolic increase which occurred in the binocular regions during long‐term monocular retinal blockade was dependent upon the neuronal processing of retinal information from the non‐TTX eye. We conclude that, in the adult rat, an activity‐dependent, physiologically based shift in ocular influence occurred in the binocular geniculostriate system during long‐term monocular retinal inactivation.
Gonadotropin hormone‐releasing hormone (GnRH) immunoreactivity in the mesencephalon of sharks and rays
Authors: Wright Douglas E. , Demski Leo S. 
Published: January 2005

AbstractOther than association with the terminal nerve (TN), little is known concerning the distribution of gonadotropin hormone‐releasing hormone (GnRH) in elasmobranchs. The purpose of this study was to identify GnRH immunoreactivity in the brains of three elasmobranch species with special regard to the mesencephalon. The round stingray (Urolophus halleri), thornback guitarfish (Platyrhinoidis triseriata), and leopard shark (Triakis semifasciatus) were used und immunocytochemistry was performed with antisera to both salmon and mammalian GnRH. A large GnRH‐immunoreactive (ir) nucleus extends rostrocaudally for approximately 1.5 mm along and adjacent to the midline of the midbrain near the area of the oculomotor nerve. GnRH‐ir fibers surround the nucleus and are found diffusely throughout the mesencephalon; some of the fibers may contact the ventricle. The medulla and spinal cord contain ir fibers that most likely originate from the midbrain nucleus. Mesencephalic GnRH‐ir cell groups have been reported in representatives of all vertebrate classes with the exception of agnathans and mammals. Such a well‐developed cell group in elasmobranchs may aid in understanding the evolution of GnRH systems with regard to the mesencephalon as well as providing insight to the functional significance of this cell group. Possible homologies to mesencephalic GnRH systems reported in other vertebrates is discussed as well.
Lateral asymmetries and testosterone‐induced changes in the gross morphology of the hypoglossal nucleus in adult canaries
Authors: DeVoogd Timothy J. , Pyskaty D. James , Nottebohm Fernando 
Published: January 2005

AbstractThe caudal portion of the hypoglossal nucleus (tracheosyringeal, nXIIts) contains the motor neurons that innervate the syrinx in songbirds. It receives projections from telencephalic and midbrain nuclei that are necessary for song production. Its neurons concentrate androgens. The present study assesses the gross morphology of the hypoglossal nucleus in canaries. In this species song is more frequent, elaborate, and stereotyped in males than in females. Adult females respond to testosterone by developing a stereotyped song that is sung frequently. Song in male canaries is much more disrupted by damage on the left side of the song system than by damage on the right. We find anatomical correlates for each of these attributes in the nXIIts. This nucleus is 83% larger in males than in females. This is caused primarily by a sex difference in neuropil volume as there is no significant sex difference in the number of neurons in nXIIts. nXIIts grows by 34% in females given testosterone as adults. It is about 8% larger on the left than on the right in males, females, and females treated with testosterone. Sex differences are also found in the rostral (lingualis) portion of nXIIts which controls muscles of the tongue, but there is no effect here of adult treatment with testosterone. Comparisons of these data with earlier measures of synaptic density and morphology in nXIIts suggest that the testosterone acts on this nucleus by inducing a modest increase in synapse numbers and by altering the efficacy of synapses in nXIIts. This contrasts with the effects of testosterone on n. robustus archistriatalis, a telencephalic component of the song system in which testosterone induces massive amounts of synaptogenesis.
Origin and distribution of neuropeptide‐FF‐like immunoreactivity in the spinal cord of rats
Authors: Kivipelto Leena , Panula Pertti 
Published: January 2005

AbstractNeuropeptide FF, or F8Famide (Phe‐Leu‐Phe‐Gln‐Pro‐Gln‐Arg‐Phe‐NH2; “morphine‐modulating peptide”), isolated from bovine brain, is an FMRF‐NH2‐like peptide with morphine‐modulating effects. Neuropeptide FF (NFF) is highly concentrated in spinal cords of various mammalian species. There is evidence that NFF participates in the modulation of nociceptive mechanisms.The present study was aimed at describing the distribution and origin of the neuropeptide‐FF‐like immunoreactivity (LI) in the rat spinal cord. For distribution studies spinal cord sections from colchicine‐treated animals were processed according to the indirect immunofluorescence method. Retrograde fluorescent tracer was injected in the lumbar dorsal spinal cord to study descending NFF‐LI‐containing spinal pathways.NFF‐immunoreactive (ir) cell bodies were detected in the substantia gelatinosa, marginal zone, laminae III, IV, and X at all levels of the spinal cord, and the dorsolateral funiculus, and dorsal gray commissure of the lumbosacral transition zone. NFF‐ir fibers and terminals were identified in laminae I‐IV and X, dorsolateral funiculus, intermediolateral cell column, dorsal gray commissure, sacral parasympathetic nucleus, and ventral horn. A spinal NFF‐LI‐containing descending pathway originating in the lamina X neurons was observed, but a supraspinal origin of descending NFF‐ir fibers was not identified.According to this study the NFF‐LI of the spinal cord is of intrinsic spinal origin. The anatomical distribution supports the concept that the NFF‐like peptides have a role in the nociception. They may also be involved in sensory‐visceral reflex arcs.
Descending projections to the rat sacrocaudal spinal cord
Authors: Masson Robert L. , Sparkes Mary L. , Ritz Louis A. 
Published: January 2005

AbstractDescending supraspinal and propriospinal neurons projecting to the female rat sacrocaudal spinal cord, the portion of the spinal cord that innervates the tail, were identified following injection of Fluoro‐Gold into the S1‐Ca2, spinal cord segments. This study attempted to determine anatomical substrates for propriospinal and supraspinal control of the tail.Propriospinal neurons were identified throughout laminae V‐VIII and X at all levels of the spinal cord. The greatest density of labeling was in the lumbar enlargement, followed by the cervical enlargement, with least in the thoracic spinal cord. Within a given cord level, labeling was greatest within the intermediate zone. In addition, other prominent spinal cord collections included neurons in (1) lamina V of the lumbar enlargement, (2) dorsal lamina X of the cervical enlargement, and (3) the lateral spinal nucleus within the cervical enlargement.Supraspinal cells were identified within raphe nuclei, reticular formation nuclei, dorsal column nuclei, vestibular nuclei, noradrenergic groups, the red nucleus, the periaqueductal gray, the hypothalamus, and the motor cortex.These data indicate that there are significant descending projections to the sacrocaudal spinal cord, with distributions similar to those of other cord levels. Functionally, important supraspinal and propriospinal influences on tail, pelvic viscera and limbs, such as with locomotion, balance, defense, micturition, defecation, and sexual functions, may be mediated by these connections.
Activity‐dependent regulation of glutamic acid decarboxylase in the rat barrel cortex: Effects of neonatal versus adult sensory deprivation
Authors: Akhtar N. D. , Land P. W. 
Published: January 2005

AbstractImmunocytochemical techniques were used to study the effects of tactual deprivation on glutamic acid decarboxylase (GAD) containing neurons in rat somatosensory barrel cortex. In normal rats GAD immunoreactive neurons and puncta are present in all laminae, with dense patches of GAD immunoreactive puncta centered on the barrels in lamina IV. Trimming whiskers of adult rats leads to a reversible decrease of GAD immunoreactivity in barrels corresponding to trimmed hairs. Intensity of GAD staining also is reversibly altered in supragranular laminae of nondeprived barrel columns flanked by deprived barrels. This indicates that GAD levels in the barrel cortex ordinarily fluctuate with changes in sensory input. By contrast, animals whose whiskers are trimmed from birth have normal GAD staining in both deprived and nondeprived barrels. Moreover, if trimmed whiskers of neonatally deprived animals are allowed to grow to normal lengths and are retrimmed later in adulthood GAD staining is not affected. Thus early tactual deprivation disrupts mechanisms that permit modulation of transmitter enzyme levels in cortical neurons following changes in sensory experience.
The calcium binding protein calbindin‐D 28K reveals subpopulations of projection and interneurons in the cat superior colliculus
Authors: Mize R. Ranney , Jeon Chang‐Jin , Butler Grace D. , Luo Qian , Emson Piers C. 
Published: January 2005

AbstractThe calcium binding protein calbindin‐D 28K (CaBP) has been localized in the cat superior colliculus (SC). Four important features of SC organization have been revealed by using CaBP immunocytochemistry. 1) CaBP neurons formed three laminar tiers in SC, one within the upper one half of the superficial gray layer (SGL), the second bridging the deep optic (OL) and intermediate gray layers (IGL), and the third within the deep gray layer (DGL). 2) CaBP labeled several classes of interneuron in SC. In the upper CaBP tier, the labeled neurons were all small, but they varied in morphology and included horizontal, pyriform, and stellate neurons. A unique class of interneuron was labeled by anti‐CaBP in the OL‐IGL tier. This cell was stellate‐like with highly varicose dendrites and broad dendritic trees. Other labeled neurons in the intermediate and deep tiers included nonvaricose stellate neurons and rare large neurons in the DGL. 3) A few anti‐CaBP neurons were projection neurons. Virtually no CaBP neurons were retrogradely labeled after injections of HRP into the predorsal bundle and dorsolateral midbrain tegmentum or into the lateral posterior nucleus. However, 2.4% of anti‐CaBP neurons were retrogradely labeled after HRP injections into the dorsal and ventral lateral geniculate nuclei. These represented 14.7% of all neurons projecting to the LGN complex. 4) A small percentage of CaBP neurons co‐localized GABA. A two‐chromagen double‐labeling technique showed that about 4.0% of labeled neurons were labeled by both antibodies. In summary, antibodies to CaBP densely labeled subpopulations of neurons in the cat SC, most of which were interneurons, some of which projected to the LGN, and a few of which co‐localized GABA.
Entorhinal cortex of the monkey: V. Projections to the dentate gyrus, hippocampus, and subicular complex
Authors: Witter Menno P. , Amaral David G. 
Published: January 2005

AbstractThe topographic and laminar organization of entorhinal projections to the dentate gyrus, hippocampus, and subicular complex was investigated in the Macaca, fascicularis monkey. Injections of 3H‐amino acids were placed at various positions within the entorhinal cortex and the distribution of anterogradely labeled fibers and terminals within the other fields of the hippocampal formation was determined. Injections of the retrograde tracers Fast blue, Diamidino yellow, and wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) were also placed into the dentate gyrus, hippocampus, and subicular complex, and the distribution of retrogradely labeled cells in the entorhinal cortex was plotted using a computer‐aided digitizing system. The entorhinal cortex gave rise to projections that terminated in the subiculum, in the CA1, CA2, and CA3 fields of the hippocampus, and in the dentate gyrus. Projections to the dentate gyrus, and fields CA3 and CA2 of the hippocampus, originated preferentially in layers II and VI of the entorhinal cortex whereas projections to CA1 and to the subiculum originated mainly in layers III and V. Anterograde tracing experiments demonstrated that all regions of the entorhinal cortex project to the outer two‐thirds of the molecular layer of the dentate gyrus and to much of the radial extent of the stratum lacunosum‐moleculare of CA3 and CA2. While the terminal distributions of entorhinal projections to the dentate gyrus, CA3, and CA2 were not as clearly laminated as in the rat, projections from rostral levels of the entorhinal cortex preferentially innervated the outer portion of the molecular layer and stratum lacunosum‐moleculare, whereas more caudal levels of the entorhinal cortex projected relatively more heavily to the deeper portions of the entorhinal terminal zones. The entorhinal projection to the CA1 field of the hippocampus and to the subiculum followed a transverse rather than radial gradient of distribution. Rostral levels of the entorhinal cortex terminated most heavily at the border of CA1 and the subiculum. More caudal levels of the entorhinal cortex projected to progressively more distal portions of the subiculum (towards the presubiculum) and more proximal portions of CA1 (towards CA2). Lateral portions of the entorhinal cortex projected to caudal levels of the recipient fields and more medial parts of the entorhinal cortex projected to progressively more rostral portions of the fields.
Growth cones and axon trajectories of a sensory pathway in the amphibian spinal cord
Authors: Nordlander Ruth H. , Gazzerro John W. , Cook Holly 
Published: January 2005

AbstractCentral axons of sensory ganglion (SG) neurons of the Xenopus tail enter the spinal cord via the ventral roots and travel dorsally and rostrally following a diagonal course within the lateral marginal zone (LMZ) to reach the dorsolateral fasciculus (DLF) (Nordlander et al.: Brain Res., 440:391–395, 1988). Axons are dispersed as they cross the cord. At the DLF they turn and travel together rostrally, sharing the fascicle with axons of primary sensory neurons (Rohon‐Beard cells) already present in the tract. In this paper we analyze the growth patterns of the central projections of SG axons in the tail by using HRP applied to proximal branches of tail spinal nerves. Growth cones of the diagonal route are variable in configuration, often bearing processes that spread within the LMZ. Once in the DLF, growth cones change shape, becoming distinctly linear. While growth cones navigating the diagonal part of the route never contact or fasciculate with other diagonal SG axons, SG growth cones and axons of the DLF are more closely associated with their fellows. Measurements of the slopes of SG axons in the diagonal route indicated a limited range with a mean of 23° with respect to the cord axis. On the basis of these observations, we conclude that 1) navigational patterns for growth cones of this pathway differ for the diagonal versus the DLF part of its course, and 2) fasciculation is not a mechanism used by SG axons to reach the DLF, but that instead, each axon is able to find its way independently.
Primate supplementary eye field. II. Comparative aspects of connections with the thalamus, corpus striatum, and related forebrain nuclei
Authors: Shook B. L. , Schlag‐Rey M. , Schlag J. 
Published: January 2005

AbstractThe supplementary eye field (SEF) was defined electrophysiologically in behaving monkeys to study its connections with the diencephalon and corpus striatum. The specificity of SEF pathways was determined with horseradish peroxidase (HRP) histochemistry to compare its connections with those of the arcuate frontal eye field (FEF), contiguous dorsocaudal area 6 (6DC), and primary motor cortex (M1, arm/hand region). Results indicate that patterns of SEF connectivity were similar to the FEF and markedly different from areas GDC and Ml. Primary reciprocal thalamic pathways of the SEF were with the magnocellular ventral anterior (VA) nucleus, medial parvicellular VA, medial area X, and paralaminar medialis dorsalis (multi‐formis and parvicellularis). FEF showed similar connections but its most robust pathway was with MD rather than VA. In contrast, area 6DC showed the most extensive reciprocal connections with lateral VApc and lateral area X with only sparse connections with paralaminar MD. Area 6DC also exhibited reciprocal connections with the ventral lateral (VL) complex and the ventral posterior lateral nucleus, pars oralis (VPLo). M1 showed dense bidirectional connections with VPLo, and to a lesser extent, with VL. M1 pathways with the medial dorsal nucleus were negligible. All areas exhibited connections with the paracentral and central lateral nuclei and only M1 lacked connections with the central superior lateral nucleus.SEF and FEF exhibited similar efferent projections to the caudate and putamen. In the caudate, terminal fields were restricted to a central longitudinal core while those from area 6DC were more widely distributed. Eye field efferents were restricted to the putamen's face region while 6DC projections were more exuberant. The arm/hand region of Ml projected to the arm/hand region of the putamen.Pathways are discussed with respect to their significance in oculomotor control.
Neuroglial arrangements in the olfactory glomeruli of the hedgehog
Authors: Valverde Facundo , Lopez‐Mascaraque Laura 
Published: January 2005

AbstractThe olfactory glomeruli represent morphological and functional units in which olfactory information is processed in specialized synaptic arrangements established between the central processes of sensory neurons, whose cell bodies are located in the olfactory epithelium, and the terminal (intraglomerular) portions of the dendrites of periglomerular, tufted, and mitral cells. The olfactory glomeruli are surrounded by distinctive glial formations in which the peripheral glia interacts with the central glia. We have studied the morphology and organization of neuroglial cells in the layer of olfactory nerves and the glomerular layer of the olfactory bulb in the insectivorous hedgehog (Erinaceus europaeus) with the electron microscope, Golgi method, and immunohistochemistry by using antibodies to glial fibrillary acidic protein (GFAP) and “rip,” a monoclonal antibody that stains oligodendrocytes and their processes in the rat (Friedman et al.: Glia 2:380–390, 1989).The peripheral glia is represented by a special category of cells that are closely related to astrocytes and known as sheathing cells. They accompany olfactory axons to their entrance in the glomeruli where they interact with the central glia, represented by astrocytes and oligodendrocytes. The sheathing cells typically display indented nuclei and protoplasmic expansions forming laminar processes wrapping several axons together. Astrocytes surrounding the glomerular neuropil belong to the velate type. They display numerous sheet‐like processes enveloping dendritic segments and periglomerular cell bodies. Oligodendrocytes were found surrounding the glomeruli and at the interstices separating different glomeruli. Myelinated dendritic segments and cell bodies were found surrounding the olfactory glomeruli. These myelin coverings probably derive from oligodendrocytes. Together with the astrocytic lamellar expansions, they provide a rigid structural support that contributes to the segregation of groups of different cells while remaining relatively isolated from other influences at the periphery of the glomeruli.