bluuebunny/crossref_metadata_2025 huggingface dataset:
Cortical connections of inferior temporal area TEO in macaque monkeys
Authors: Distler C. , Boussaoud D. , Desimone R. , Ungerleider Leslie G.
Published: January 2005

In macaque monkeys, lesions involving the posterior portion of the inferior temporal cortex, cytoarchitectonic area TEO, produce a severe impairment in visual pattern discrimination. Recently, this area has been shown to contain a complete, though coarse, representation of the contralateral visual field (Boussaoud, Desimone, and Ungerleider: J. Comp. Neurol. 306:554–575, '91). Because the inputs and outputs of area TEO have not yet been fully described, we injected a variety of retrograde and anterograde tracers into 11 physiologically identified sites within TEO of seven rhesus monkeys and analyzed the areal and laminar distribution of its cortical connections.

Our results show that TEO receives feedforward, topographically organized inputs from prestriate areas V2, V3, and V4. Additional sparser feedforward inputs arise from areas V3A, V4t, and MT. Each of these inputs is reciprocated by a feedback projection from TEO. TEO was also found to have reciprocal intermediate‐type connections with the fundus of the superior temporal area (area FST), cortex in the most posteromedial portion of the superior temporal sulcus (the posterior parietal sulcal zone [area PP]), cortex in the intraparietal sulcus (including the lateral intraparietal area [area LIP]), the frontal eye field, and area TF on the parahippocampal gyrus. The connections with V3A, V4t, and PP were found only after injections in the peripheral field representations of TEO. Finally, TEO was found to project in a feedforward pattern to area TE and to areas anterior to FST on the lateral bank and floor of the superior temporal sulcus (areas TEm, TEa, and IPa, Seltzer and Pandya: Brain Res. 149:1–24, '78), all of which send feedback projections to TEO. Feedback projections also arise from parahippocampal area TH, and areas TG, 36, and possibly 35. These are complemented by only sparse feedforward projections to TG from central field representations in TEO and to TH from peripheral field representations.

The results thus indicate that TEO forms an important link in the occipitotemporal pathway for object recognition, sending visual information forward from V1 and prestriate relays in V2–V4 to anterior inferior temporal area TE. © 1993 Wiley‐Liss, Inc.

This article is a US Goveriiment work and, as such, is in the public domain in the United States of America.
Evidence that transmitter‐containing dystrophic neurites precede paired helical filament and Alz‐50 formation within senile plaques in the amygdala of nondemented elderly and patients with Alzheimer's disease
Authors: Benzing William C. , Ikonomovic Milos D. , Brady Daniel R. , Mufson Elliott J. , Armstrong David M.
Published: January 2005

Immunocytochemical techniques were employed to examine the temporal ordering whereby amyloid β‐protein (AβP) and neuronal elements collectively come together to form senile plaques in Alzheimer's disease (AD). Specifically, we addressed three questions: (1) whether AβP deposition precedes or follows neuritic changes; (2) whether paired helical filament (PHF) formation is an early or late event in the genesis of the dystrophic neurites which participate in plaque formation; and (3) whether the density of senile plaques displays any relationship with the prevalence of PHF or Alz‐50 containing neurons. To address these questions we studied the amygdala from a group of patients with AD, a group of nondemented age‐matched individuals exhibiting a sufficient number of senile plaques to be classified by neuropathological criteria as AD, and a group of age‐matched controls without AD pathology. Amyloid‐bearing plaques were demonstrated by AβP immunolabeling and thioflavine‐S staining. Neuritic changes in the form of dystrophic neurites were observed with the aid of antibodies against PHF, Alz‐50, as well as antibodies against several neuropeptides (i.e., substance P, somatostatin, and neurotensin) and the acetylcholine biosynthetic enzyme, choline acetyltransferase.

By using a graded range of pathologic changes both within and across the patient population to provide us with a means of evaluating plaque deposition from its earliest to most advanced stages of development, we observed in patients and/or regions of the amygdala displaying a mild degree of pathologic change AβP deposition in the absence of any neuritic changes. With increasing density of AβP, however, we began to observe dystrophic neurites within plaques. In regions of relatively few plaques, the dystrophic neurites were immunolabeled only with antibodies against the various neurotransmitters and they lacked evidence of cytoskeletal pathology (i.e., Alz‐50 or PHF). Only as the density of AβP increased further within a region, were dystrophic neurites observed that exhibited Alz‐50 or PHF. In no instance did we observe a relationship between the density of AβP deposition and the density of Alz‐50 or PHF‐immunoreactive neurons. Collectively, our data suggest that the deposition of AβP is an early pathologic event in senile plaque formation. Thereafter, swollen neurites can be seen in the vicinity of AβP. This early neuritic response, which can first be visualized by immunolabeling for one or another transmitter substance, is followed by alterations in the cytoskeleton as recognized initially by antibodies to Alz‐50 and subsequently by the presence of PHF. © 1993 Wiley‐Liss, Inc.
Distribution of luteinizing hormone‐releasing hormones I and II (LHRH‐I and ‐II) in the quail and chicken brain as demonstrated with antibodies directed against synthetic peptides
Authors: van Gils Jelle , Absil Philippe , Grauwels Luc , Moons Lieve , Vandesande Frans , Balthazart Jacques
Published: January 2005

Polyclonal antibodies were raised in rabbits against polypeptides corresponding to the N‐terminal part (heptapeptides) of the two avian gonadotropin‐releasing hormones, chicken (c) LHRH‐I and ‐II. These peptides, which were synthesized by the continuous‐flow technique, were selected because they contained the smallest number of common amino acid residues. The pGlu‐His‐Trp‐Ser sequence at the C‐terminal was suppressed to avoid possible cross‐reactions between the antisera. The antisera generated in this way were tested for specificity by solid and liquid phase absorption as well as by antigen spot tests. The antiserum raised against cLHRH‐I recognized this peptide preferentially though not exclusively. Some cross‐reaction with cLHRH‐II was observed in the absorption test, although spotting tests suggested a total specificity. The anti cLHRH‐II appeared to be completely specific in all tests. These two antibodies were then used to study the distribution of cLHRH‐I and ‐II immunoreactive structures in the quail and chicken brain. cLHRH‐I immunoreactive perikarya were observed in a fairly wide area covering the preoptic‐anterior hypothalamic and septal region. By contrast, cLHRH‐II cells were confined to a single group located in the dorsal aspects of the occulomotor nuclei, at the junction of the di‐ and mesencephalon. A sex difference in the number of cLHRH‐I cells was detected in the anterior lateral preoptic region of the quail. Fibers immunoreactive for either cLHRH‐I or cLHRH‐II were widely distributed in the telencephalon, diencephalon, and mesencephalon but showed a specific pattern of anatomical localization. In particular, a high density of cLHRH‐I fibers were seen in the external layer of the median eminence, while cLHRH‐II fibers were less prominent at this level. Contrary to previous reports, a significant amount of cLHRH‐II fibers were however seen throughout the median einence (mostly external layer). The extensive distribution of both cLHRH‐I and ‐II fibers in the quail and chicken brain is consistent with the potential role played by these peptides in the gonadotropin secretion and in the control of reproductive behavior. The specific role of cLHRH‐II remains however elusive at present. © 1993 Wiley‐Liss, Inc.
Expression of neuronal and glial polypeptides during histogenesis of the human cerebellar cortex including observations on the dentate nucleus
Authors: Yachnis Anthony T. , Rorke Lucy B. , Lee Virginia M.‐Y. , Trojanowski John Q.
Published: January 2005

In order to gain a more complete understanding of the sequential pattern of gene expression during neurogenesis and gliogenesis in humans, we followed the expression of well‐characterized, developmentally regulated polypeptides in the cerebellar cortex and dentate nucleus by immunohistochemistry using monoclonal antibodies of highly defined specificity. At 8–10 weeks gestational age (GA), progenitor cells and their immediate progeny in the rhombencephalic ventricular zone expressed vimentin and nestin and, to a lesser extent, microtubule‐associated protein 5 (MAP5) and glial fibrillary acidic protein (GFAP), but not the low affinity nerve growth factor receptor (NGFR). In contrast, postmitotic, migrating immature neurons in the intermediate zone gave strong reactions for MAP2, tau, and a nonphosphorylated form of middle molecular weight neurofilament (NF) protein (NF‐M) and weak reactivity for NGFR. At 15 weeks GA, proliferating cells of the superficial part of the cerebellar external granular layer stained only for NGFR, while more deeply situated cells of the external granular layer stained positively for NGFR, MAP2, MAP5, tau, and chromogranin A, which correlates with the early outgrowth of parallel fibers. All phosphoisoforms of NF‐M as well as the low (NF‐L) and high (NF‐H) molecular weight NF proteins and alpha‐internexin were expressed in the somatodendritic domain of Purkinje cells and dentate nucleus neurons from about 20 weeks GA with a gradual compartmentalization of highly phosphorylated forms of NF‐M and NF‐H into axons by the end of gestation. Alpha‐internexin was also expressed strongly in axons of the deep white matter from 20 weeks GA to adulthood. MAP2, synaptophysin, and NGFR showed early, transient expression in the somatodendritic domain of Purkinje cells followed by the appearance of a 220 kDa nestin‐like peptide that continued to be expressed in adult Purkinje cells. Notably, developing dentate nucleus neurons expressed many of these proteins in a similar temporal sequence. Early in the developing cerebellar cortex, the expression of NF protein and synaptophysin occurred in discrete patches or columns similar to those described for other antigens (i.e., zebrins). Finally, radial glia were positive for vimentin, GFAP, and nestin from 8 weeks GA to 8 months postnatal. This study describes the distinct molecular programs of lineage commitment in cerebellar progenitor cells and in differentiating neurons and astrocytes of the human cerebellum. The acquisition of a mature molecular neuronal phenotype correlates with the establishment of structural polarity in cerebellar neurons. © 1993 Wiley‐Liss, Inc.
A quantitative study of the lateral spread of Müller cell responses to retinal lesions in the rabbit
Authors: Humphrey M. F. , Constable I. J. , Chu Y. , Wiffen S.
Published: January 2005

A wide variety of retinal pathology is associated with an increase in Müller glial cell expression of glial fibrillary acidic protein (GFAP). In this study the time course and spatial spread of the Müller cell GFAP response following argon laser photocoagulation lesions was examined in wholemounted rabbit retina.

At 24 hours single focal lesions were surrounded by GFAP positive Müller cell end feet which declined in density with distance but extended as far as 2–3 mm from the lesion. The Müller cell reaction reached a maximal spread of 4–5 mm at 14 to 21 days and had started to contract by 30 days, leaving a core of GFAP positive processes immediately around the lesion site at 60 days. This zone of spread was much larger than the area of disrupted pigment epithelium. Isodensity plots did not reveal any correlation with the trajectory of retinal ganglion cell axons. The spread of reaction was more confined for lesions within the visual streak than in the dorsal or ventral retinal periphery.

Multiple lesions within a focal region of retina resulted in a greater density of GFAP reactive end feet with a corresponding greater spread. However, when five to ten lesions were made in a horizontal row, the Müller cells over the entire retina became GFAP immunoreactive. This pan‐retinal reaction took several days to spread, peaked at 7–14 days, and contracted back to the primary lesion sites by 2 months.

This spread of Müller cell reactivity may be triggered by the diffusion of substances released by injury or it may be due to direct cellular communication. The extensive indirect effect on Müller cells of laser irradiation might be an important component of the clinical effect of laser photocoagulation and indicates a long distance communication mechanism between retinal glia which is poorly understood. This study also shows the importance of the time at which the Müller cell response is assessed. © 1993 Wiley‐Liss, Inc.
Substance P‐ and tyrosine hydroxylase‐ containing neurom in the human dorsal motor nucleus of the vagus nerve
Authors: Huang Xu‐Feng , Paxinos George , Halasz Paul , McRitchie Deborah , Törk Istvan
Published: January 2005

The aim of this study was to provide a comprehensive account of the topography, morphology, and frequencies of the substance P‐ and tyrosine hydroxylase‐containing neurons in the human dorsal motor nucleus of the vagus nerve. The morphology of immunoreactive neurons was studied and llie varialions of Lhe cell distrihulions were presented hy three‐dimensional Computer reconstructions. Three types of substance P‐like immunoreactive neurons were identified. They were predominantly located in the dorsointermediate, centrointermediate, caudointermediate, and caudal division of the dorsal motor nucleus of the vagus nerve. The morphology of substance P‐like immunoreactive neurons varied according to the subnuclei in which they were found. Three types oftyrosine hydroxylase‐like immunoreactive neurons were identified, mainly in the periphery ofthe dorsal motor nucleus ofthe vagus nerve, including the medial fringe, ventrointermediate, and dorsointermediate subnuclei of the 10. Many cells throughout the ventrointermediate subnucleus of the dorsal motor nucleus of the vagus nerve are seen ventrally to intermingle with the tyrosine hydroxylase neurons of the intermediate reticular zone.

Computer reconstructions provided a three‐dimensional view ofthe positions of substance P‐ and tyrosine hydroxylase‐like immunoreactive neurons within the subdivisions ofthe dorsal motor nucleus of the vagus nerve. The uneven distribution of substance P‐ and tyrosine hydroxylase‐like immunoreaetive neurons within the subdivisions suggests an involvement of these substances in some, but not all, autonornic functions of the dorsal motor nucleus of the vagus nerve. © 1993 Wiley‐Liss, Inc.
Comparative brain ontogeny of the crayfish and clawed lobster: Implications of direct and larval development
Authors: Helluy Simone , Sandeman Renate , Beltz Barbara , Sandeman David
Published: January 2005

The freshwater crayfish Cherax destructor and the lobster Homarus americanus have many similarities including life style, body form, and neural organization. However, the ontogenic history is very different in the two species. The development of Cherax is short and direct whereas the development of Homarus comprises three pelagic larval stages and takes more than twice as long from extrusion to benthic stages at constant temperature. In order to determine the progression of maturation of the nervous system in each species and the potential implications of pelagic forms on brain structure, the timing of appearance of 22 general and neural developmental events clearly identifiable in both species was compared. The onset of serotonin antigenicity in the different parts of the brain was chosen as one marker of neural development.

During the first month of embryogenesis the timing of morphological, physiological, and neural events is similar in the two species. Morphological development is then accelerated in the crayfish near hatching time and over the two postembryonic stages before the advent of the independent benthic stage. Such heterochronic processes can at least partly account for the different developmental patterns in the two decapods.

Among the characters showing similar timing in the two species is the formation of glomeruli (presumptive zones of synaptic contact) in the olfactory lobes of the deutocerebrum, although this event is embryonic in Homarus but postembryonic in Cherax. In contrast, glomerular formation in the accessory lobes is heterochronic: in both species, the glomeruli of the accessory lobes are acquired postembryonically, that is, 3 to 4 months earlier in Cherax than in Homarus. These data suggest that the development of the glomeruli in the olfactory lobes may depend primarily on internal developmental signals, whereas the triggering of glomerular formation in the accessory lobes may depend on external cues. The fact that, in Homarus, only the postlarval stages show mature accessory glomeruli may be a reflection of the functional requirements of benthic life. © 1993 Wiley‐Liss, Inc.
Tonotopic organization, architectonic fields, and connections of auditory cortex in macaque monkeys
Authors: Morel A. , Garraghty P. E. , Kaas J. H.
Published: January 2005

Microelectrode recordings were used to investigate the tonotopic organization of auditory cortex of macaque monkeys and guide the placement of injections of wheat germ agglutininhorse radish peroxidase (WGA‐HRP) and fluorescent dyes. Anatomical and physiological results were later related to histological distinctions in the same brains after sections were processed for cytoarchitecture, myeloarchitecture, acetylcholinesterase (AchE), or cytochrome oxidase (CO). The experiments produced serveral major findings. (1) Neurons throughout a broad expanse of cortex were highly responsive to pure tones, and best frequencies could be determined for neurons in arrays of recording sites. (2) The microelectrode recordings revealed two systematic representations of tone frequencies, the primary area (AI) and a primary‐like rostral field (R) as previously described. The representation of high to low frequency tones in A1 was largely caudorostral along the plane of the sulcus. A reversal of the order of representation of frequencies occurred in R. (3) AI and R together were coextensive with a koniocellular, densely myelinated zone that expressed high levels of AchE and CO. These architectonic features were somewhat less pronounced in R than AI, but a clear border between the two areas was not apparent. (4) Cortex bordering AI and R was less responsive to tones, but when best frequencies for neurons could be determined, they matched those for adjoining parts of AI and R. (5) Architectonically distinct regions were apparent within some of the cortex bordering AI and R. (6) The major ipsilateral cortical connections of AI were with R and cortex immediately lateral and medial to AI. (7) Callosal connections of AI were predominately with matched locations in the opposite AI, but they also included adjoining fields. (8) Neurons in the ventral (MGV), medial (MGM), and dorsal (MGD) nuclei of the medial geniculate complex projected to AI and cortex lateral to AI. (9) Injections in cortex responsive to high frequency tones labeled more dorsal parts of MGV than injections in cortex responsive to low frequency tones. © 1993 Wiley‐Liss, Inc.
Connections of the olfactory bulb in the gymnotiform fish, Apteronotus leptorhynchus
Authors: Sas Emilia , Maler Leonard , Weld Madeline
Published: January 2005

This work examines the connectivity of the olfactory bulb in the gymnotiform fish Apteronotus leptorhynchus. Wheat germ agglutinin conjugated horseradish peroxidase was iontophoresed in different areas and depths of the bulb in order to define its efferent and afferent connections. The olfactory bulb projects bilaterally via the medial (medial and centromedial fascicles) and lateral olfactory (lateral and centrolateral fascicles) tracts. The nervus terminalis courses through the ventromedial aspect of the bulb to terminate in parts of the medial subpallium and hypothalamus. Its telencephalic component could be identified by a nonpreadsorbable substance P‐like immunoreactivity. Fibers within the medial olfactory tract form four telencephalic terminal fields: peduncular, medial, intermediate and posterior fields. The diencephalic terminal fields in the habenula, preoptic, and hypothalamic areas appear to correspond to some of the nervus terminalis fibers (von Bartheld and Meyer [1986] Cell Tissue Res. 245: 143‐158, Krishna et al. [1992] Gen. Comp. Endocrinol. 85:111‐117), and to axons of telencephalic bulbopetal cells of area dorsalis posterior. The terminal fields of the medial olfactory tract and nervus terminalis partially overlap in the ventral telencephalic areas partes ventralis, supracommissuralis, and rostral preoptic region. The lateral olfactory tract forms a lateral terminal field and contributes to the intermediate and posterior terminal fields. Olfactory fibers cross in the interbulbar, anterior, and habenular commissures and tuberal decussation. Consistent differnces were noted between the medial and lateral olfactory bulb, with respect to their cytoarchitectonics, immunohistochemistry, and connections. In addition to the olfactory nerve, bulbar afferents are predominantly ipsilateral, with minor inputs originating from the contralateral bulb and telencephalic area dorsalis posterior, nucleus raphe centralis, and locus ceruleus. © 1993 Wiley‐Liss, Inc.
Galanin immunoreactivity within the primate basal forebrain: Evolutionary change between monkeys and apes
Authors: Benzing William C. , Kordower Jeffrey H. , Mufson Elliott J.
Published: January 2005

Galanin immunoreactivity (GAL‐ir) is differentially expressed within the basal forebrain of monkeys and humans. Most monkey magnocellular basal forebrain neurons colocalize GAL‐ir. In contrast, virtually no human magnocellular basal forebrain neurons express GAL‐ir. Rather, an extrinsic galaninergic fiber plexus innervates these neurons in humans. The present study examined the expression of GAL‐ir within the basal forebrain of apes to establish the phylogenetic level at which this transformation occurs. The staining patterns of GAL‐ir within the basal forebrain of both lesser (gibbons) and great (chimpanzee and gorilla) apes were compared to that previously observed within monkeys and humans. All apes displayed a pattern of basal forebrain GAL‐ir indistinguishable from humans. GAL‐ir was not expressed within ape basal forebrain magnocellular neurons as seen in monkeys. Rather like humans, a dense collection of GAL‐ir fibers was seen in close apposition to magnocellular perikarya. In addition, a few GAL‐ir parvicellular neurons were scattered within the ape basal forebrain. These data indicate that the evolutionary change in the expression of GAL‐ir within the primate basal forebrain occurs at the branch point of monkeys and apes. © 1993 Wiley‐Liss, Inc.
Quantitative analyses of intracellularly characterized and labeled thalamocortical projection neurons in the ventrobasal complex of primates
Authors: Havton L. A. , Ohara P. T.
Published: January 2005

This study describes the architecture of neurons and individual dendritic arbors of thirteen intracellularly labeled thalamocortical projection neurons that respond to non‐noxious stimuli from the primate (Macaca fascicularis or Macaca mulatta) ventrobasal complex (VB). The neurons compose a homogeneous morphological class with total dendritic lengths from 10,169 μm to 21,711 μm (mean 17,615 μm ± 3,705). The labeled neurons were remarkably similar in most measured parameters including the number of dendrites (7.5 ± 1.2), percentage of dichotomous branching (89.8% ± 3.4), and contribution of terminal branches to total dendritic length (88.4% ± 2.0).

The individual dendrites ranged in total length from 443 μm to 7,657 μm with a mean of 2,346 μm (±137, n = 98). There was a positive correlation between stem dendrite diameter and total dendrite length, making it possible to estimate the total size of an individual dendrite by measuring the stem dendrite diameter. There was only a small increase in mean path distance with increasing dendritic size at the whole neuron and individual dendritic levels, so that for individual dendrites the mean path distance of a dendrite consisting of only two segments was 199 μ, while the mean path distance for a dendrite with eight segments was only 45 μm longer. Analysis of dendrite diameter, segment order, and path distance shows that dendritic diameter is not reliable for determining the location of synaptic contacts viewed by electron microscopy onto dendritic trees. The small variation of measured parameters between these neurons presents a powerful tool for future developmental, plasticity and comparative studies of VB neurons. © 1993 Wiley‐Liss, Inc.
Subpopulations of GABA neurons containing somatostatin, neuropeptide Y, and parvalbumin in the dorsomedial cortex of the lizard Psammodromus algirus
Authors: Dávila Josée Carlos , Megías Manuel , de la Calle Adelaida , Guirado Salvador
Published: January 2005

Different subpopulations of GABA neurons containing the neuropeptides somatostatin and neuropeptide Y, and the calcium binding protein parvalbumin were studied by immunocytochemistry using light and electron microscopy in the dorsomedial cortex of the lizard Psammodromus algirus to investigate the connectivity of different subsets of GABA neurons in the lizard dorsomedial cortical circuitry and to compare cortical regions of reptiles and mammals. GABA neurons were classified into different subsets by using the peroxidase anti‐peroxidase immunohistochemical method on adjacent Araldite‐embedded semithin sections. GABA neurons in the dorsomedial cortex fall into three major subsets: (1) neurons with somatostatin (and neuropeptide Y), which accounted for about 44% of the GABA population; (2) neurons with parvalbumin, which accounted for about 13% of the GABA neurons; and (3) neurons without parvalbumin or neuropeptides, which represented 40% of all GABA cells. This division of GABA neurons in non‐overlapping subpopulations of neuropeptide‐ and parvalbumin‐containing cells is similar to that found in the mammalian hippocampal formation. On the basis of the nerve terminal fields, somatostatin‐ and parvalbumin‐immunoreactive neuronal populations appear to be functionally different, acting on different portions of the projection neurons. Parvalbumin‐immunoreactive neurons inhibit the pyramidal neurons at the cell body level, whereas somatostatin‐immunoreactive neurons inhibit them on distal dendrites. The results of the present study add more similarities between the lizard dorsomedial cortex and parts of the mammalian hippocampus. © 1993 Wiley‐Liss, Inc.
The inhibitory motoneurons of crayfish thoracic limbs: Identification, structures, and homology with insect common inhibitors
Authors: Wiens T. J. , Wolf H.
Published: January 2005

The three inhibitory motoneurons supplying crayfish thoracic limbs were identified, stained, and compared structurally. The inhibitors to the walking leg muscles (in Orconectes) were identified anatomically by a combination of immunocytochemical staining for gammaaminobutyric acid (GABA) or glutamate decarboxylase and differential backfill staining with nickel and cobalt ions. The cheliped inhibitors were identified intracellularly and injected with Lucifer Yellow (Pucifustucus) or cobalt (Procumbarus). The common inhibitor (CI) in each thoracic segment has a medial or slightly contralateral soma near the ganglion's posterior boundary, a gently curving primary neurite, an extensive ipsilateral dendritic tree, and an axon emerging through the anterior root. The stretcher‐closer inhibitor (SI) has a soma slightly anterior and ipsilateral to the CI's, a sharply bent proximal neurite, a smaller dendritic tree, and an axon in the posterior root. The opener inhibitor (OI) lies more laterally and often posterior to the CI; its diagonally directed neurite enters the posterior root. The inhibitors' structures were related to major neuroanatomical landmarks within the ganglion, to soma positions of excitatory motoneurons revealed by backfilling, and to soma locations of inhibitory interneurons revealed by GABA‐like immunoreactivity.

In their peripheral distributions to the leg muscles and in their central structures, these crayfish limb inhibitors show striking similarities with those of the locust. Crayfish and locust thoracic ganglia also show more general neuroanatomical similarities. These observations suggest that the crayfish CI, SI, and 01 are, respectively, homologous with the locust CI1 CI2, and CI3. The implications of such a homology for arthropod phylogeny are discussed. © 1993 Wiley‐Liss, Inc.
Glutamatergic and cholinergic projections to the pontine inhibitory area identified with horseradish peroxidase retrograde transport and immunohistochemistry
Authors: Lai Y. Y. , Clements J. R. , Siegel J. M.
Published: January 2005

Previous studies in our laboratory have shown that microinjection of acetylcholine and non‐N‐methyl‐D‐aspartate (NMDA) glutamate agonists into the pontine inhibitory area (PIA) induce muscle atonia. The present experiment was designed to identify the PIA afferents that could be responsible for these effects, by use of retrograde transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA‐HRP), glutamate immunohistochemistry and NADPH‐diaphorase staining techniques. Experiments were performed in both decerebrate and intact cats. Dense retrograde WGA‐HRP labelling was found in neurons in the periaqueductal gray (PAG) and mesencephalic reticular formation (MRF) at the red nucleus (RN) level, ventral portion of paralemniscal tegmental field (VFTP), retrorubral nucleus (RRN), contralateral side of PIA (CPIA), pontis reticularis centralis caudalis (PoC), and most rostral portion of the nucleus parvicellularis (NPV) and nucleus praepositus hypoglossi (PH) at the level of the pontomedullary junction; moderate labelling was seen in pedunculopontine nucleus, pars compacta (PPNc), laterodorsal tegmental nucleus (LDT), superior colliculus (SC), MRF and PAG at the level caudal to RN, medial and superior vestibular nuclei, and principle sensory trigeminal nucleus (5P); and light labelling was seen in dorsal raphe (DR) and locus coeruleus complex (LCC). The projection neurons were predominantly ipsilateral to the injection site, except for both vFTP and RRN, which had more projection cells on the contralateral side. Double labelled WGA‐HRP/NADPH‐d neurons could be found in PPNc and LDT. Double labelled WGA‐HRP/glutamatergic neurons could be seen at high densities in MRF, RRN, vFTP, and cPIA, moderate densities in SC, LDT, PPNc, PoC, and NPV, and low densities in PH, 5P, DR, LCC, and PAG. No cells in LDT and PPNc were triple labelled with NADPH‐d, glutamate antibody and WGA‐HRP. The mesopontine efferents identified here may mediate the suppression of muscle tone in REM sleep and coordinate muscle tone during head and neck movements. © 1993 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Differential action of the albino mutation on two components of the rat's uncrossed retinofugal pathway
Authors: Chan S. O. , Baker Gary E. , Guillery R. W.
Published: January 2005

The development of the uncrossed retinofugal pathways in normally pigmented and albinorats, aged from embryonic day (E) 14.5 to E18.5, was investigated. Dil was placed into one optic tract and the retinal origin of the uncrossed component, as well as its course in the optic stalk, was studied. The results show that, as in the mouse, the uncrossed retinal projection has two components. The first component is seen at E15.5 in normally pigmented animals. It develops exclusively in the central parts of the retina and is normal in albino littermates. The second component, which arises from the peripheral parts of the ventrotemporal retina, is seen two days later at E17.5 in all animals but is significantly smaller in albinos than in their pigmented littermates.

Studies of axons in the optic stalk labelled retrogradely with DiI placed in the optic tract indicate that the uncrossed axons have no preference for any position in the stalk except when they approach the chiasm, where they tend to accumulate at the caudal region of the stalk. The uncrossed axons intermingle with the crossed axons along the entire length of the stalk. In albino embryos, no obvious difference in the prechiasmatic course of uncrossed axons was seen at any age examined.

It is concluded that the albino mutation in rats affects the late ventrotemporal component of the uncrossed pathway selectively. It does not act on the early central component. Further, the intermingling of crossed and uncrossed axons in the stalk and the apparently unaffected prechiasmatic course of uncrossed axons in albinos indicate that the albino gene has its primary action in the retina. © 1993 Wiley‐Liss, Inc.
Light and electron microscopic immunocytochemical localization of PKCδ immunoreactivity in the rat central nervous system
Authors: Merchenthaler István , Liposits Zsolt , Reid Joanne J. , Wetsel William C.
Published: January 2005

Protein kinase C (PKC) is one of the major cellular signal transduction systems. Since at least nine different PKC isoenzymes have been described, the purpose of the present studies was to identify the regional, cellular, and subcellular distributions of PKCδ in the rat central nervous system (CNS) by light and electron microscopic immunocytochemistry. We have found that PKCδ immunoreactivity is present in all major subdivisions of the rat CNS. Within each of the subdivisions, PKCδ immunoreactivity is localized to perikarya that monitor sensory and motor functions. More specifically, PKCδ is found in the olfactory bulb, cerebral cortex, lateral septum, thalamus, vestibular and cochlear nuclei, inferior olive, nucleus of the solitary tract, cerebellum, and superficial layers of the dorsal horn in the spinal cord. In most cases, the distribution of this isoenzyme is distinct from that of the conventional isoforms. Within the CNS, PKCδ is localized primarily in neurons; however, neurons of the same type are not uniformly labeled. This is most evident in the cerebellum, where alternating columns of Purkinje cells are immunostained. While PKCδ is prominent in perikarya, occasional immunostaining is seen in dendrites, fibers or axons, and nerve terminals. Electron microscopic analysis of the posterolateral nucleus of the thalamus reveals that the cell nucleus, the rough endoplasmic reticulum, and the plasma membrane are all immunopositive. Since each of the PKC subspecies may have different substrate, lipid, and other co‐factor requirements, the regional, cellular, and subcellular distribution of each of these isoforms should help to define their functional environments. © 1993 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Branching projections from mesopontine nuclei to the nucleus reticularis and related thalamic nuclei: A double labelling study in the rat
Authors: Spreafico R. , Amadeo A. , Angoscini P. , Panzica F. , Battaglia G.
Published: January 2005

Branching projections from pedunculopontine and laterodorsal tegmental nuclei to different thalamic targets were studied by means of a double retrograde tracing technique. The results show a topographic distribution of mesopontine neurons projecting to different thalamic targets. In addition, the present data demonstrate that a small percentage (≤ 5%) of mesopontine neurons projecting to the intralaminar nuclei or to the rostral pole of the reticular nucleus innervate both these areas by means of branching axons. By contrast, a large number of mesopontine neurons projecting to the sensorimotor thalamic nuclei send axon collaterals to the caudal part of the reticular nucleus. The present findings support the hypothesis of an inhomogeneity of different sectors of the thalamic reticular nucleus. Thus, this nucleus can be differentiated into two functional areas, in accordance with their connections with functionally different cortical fields and thalamic districts. The possibility that these two areas of the thalamic reticular nucleus subserve different mechanisms during sleep phenomena is discussed. © 1993 Wiley‐Liss, Inc.
Transient neovascularisation of the frog retina during optic nerve regeneration
Authors: Tennant M. , Moore S. R. , Beazley L. D.
Published: January 2005

In conditions such as diabetic retinopathy, degenerative events in the retina are associated with neovascularisation. It is well established that a proportion of retinal ganglion cells die during optic nerve regeneration in the frog. The present study has determined whether neovascularisation takes place during this regenerative process.

To do so, the pattern of blood vessels overlying the retinal ganglion cell layer was analysed in the frog Litoria (Hyla) moorei. We examined normal animals and those undergoing optic nerve regeneration following nerve crush. Blood vessels were visualised by perfusion with Indian ink and retinae were prepared as wholemounts.

In normal animals, the vascular tree was found to lie superficial to the nerve fibre layer and was more complex in regions overlying the area centralis and visual streak. After nerve crush, abnormal blood vessels transiently formed between the existing branches of the vascular tree. The new vessels were concentrated as an annulus centred on the optic nerve head and over the area centralis in midtemporal retina. The neovascularisation became most extensive between 6 and 10 weeks postcrush and disappeared by 12 weeks. The spatiotemporal sequence of neovascularisation suggests that it is triggered by accumulations of degenerating material formed as a proportion ofthe ganglion cells die during optic nerve regeneration. © 1993 Wiley‐Liss, Inc.
Optic nerve degeneration induces the expression of MHC antigens in the rat visual system
Authors: Rao Kanchan , Lund Raymond D.
Published: January 2005

The brain has long been considered to be an immunologically privileged site. However, privilege is not absolute, as has been shown by the inability of foreign tissue grafts to survive indefinitely in the brain. The rejection of this tissue is accompanied by the upregulation of major histocompatibility complex (MHC) antigen expression. Therefore it is essential to define conditions that influence the expression of these antigens in the brain, especially since such a definition may further the understanding of disease processes that lead to the autoimmune destruction of the central nervous system. Here we show that both MHC class l and class II antigens are expressed within 1 or 2 days of eye removal by cells showing the morphological characteristics of microglia. Expression is seen along the optic pathway and within the brainstem centers to which optic axons project. In the early stages of the reaction, MHC class I antigen expression is seen throughout the optic pathway, including the terminal distribution areas of the subcortical visual centers, while MHC cells class II are localised mainly to degenerating myelinated fiber systems. These changes are not accompanied by any alteration in the integrity ofthe blood‐brain barrier. During the second week postlesion, class l positive cells are found beyond the confines of the degenerating pathways, while class II positive cells are seen within regions such as the stratum griseum superficiale of the superior colliculus, where few myelinated axons are present. There is subsequent diminution of MHC positive cells, but a small number of cells are still seen 60 days post‐lesion.

Focal lesions within the eye show that at early survival times, while class l MHC positive cells are distributed throughout the nerve, class II positive cells are largely absent from the unmyelinated segment of the nerve. Retrograde changes in the retina after nerve section are accompanied only by MHC class l antigen expression. These observations show that neural degeneration is accompanied by a rigid sequence of events involving expression of MHC antigens by microglia. If foreign antigens were present in the brain while these events were taking place, it is possible that such antigens would be recognised and destroyed by the host immune system. © 1993 Wiley‐Liss, Inc.
Prenatal exposure to ethanol alters the postnatal development and transformation of radial glia to astrocytes in the cortex
Authors: Miller Michael W. , Robertson Shirley
Published: January 2005

Postmitotic neurons migrate from a zone(s) near the ventricles to the neocortex. During this migration, neurons associate with radial glia. After serving their role as guides for neuronal migration, the radial glia transform into astrocytes. Prenatal exposure to ethanol causes abnormal neuronal migration. We examined the effects of gestational exposure to ethanol on radial glia and astrocytes. Radial glia were stained immunohistochemically with the antibody RAT‐401, and astrocytes were labeled with an antibody directed against glial‐fibrillary acidic protein (GFAP). The subjects were the offspring of rats fed an ethanol‐containing liquid. diet (Et), pair‐fed a liquid control diet (Ct), or fed chow and water (Ch). During the first postnatal week, radial glial fibers (in Et‐treated rats and controls) stretched from the ventricular surface through the developing. cerebral wall to the pial surface. In the Et‐treated rats, the radial processes were less dense and more poorly fasciculated than they were in the Ch‐and Ct‐treated rats. Moreover, by postnatal day (P) 5, there was a significant reduction in RAT‐401 immunostaining in the Et‐treated rats, particularly in the superficial cortex. A similar reduction in control rats did not begin until P10. In all three treatment groups, GFAP‐immunoreactive astrocytes were in the cortex throughout the period from P1 to P45. In neonates, GFAP‐positive cells were distributed in the marginal zone (layer I) and the intermediate zone (the white matter). The number of GFAP‐positive cells in the cortical plate increased steadily with time so that, by P26, GFAP‐immunoreactive astrocytes were distributed evenly through all cortical laminae. Interestingly, between P5 and P12, the number of astrocytes was significantly greater in Et‐treated rats than in controls.

Thus prenatal exposure to ethanol induces the premature loss of RAT‐401‐positive processes and the precocious increase in GFAP immunostaining. These ethanol‐induced changes in glial development indicate that ethanol accelerates the transformation of radial glia into astrocytes. Moreover, the ethanol‐induced premature degradation of the network of radial glial fibers may underlie the migration of late‐generated neurons to ectopic sites. © 1993 Wiley‐Liss, Inc.
The A‐1 antigen: A novel marker in experimental peripheral nerve injury
Authors: Azzarelli Biagio , Woodburn Robert , Olivelle Suman , Kimbro Sean , Siakotos Aristotle , Taylor Milton , Lee Chao‐Hung , Yen Margaret , Paulsrud John
Published: January 2005

Expression of the Schwann cell phenotype is regulated by signals from the adjoining axon. After axotomy, the Schwann cell ceases the production and maintenance of the myelin sheath and assumes phagocytic properties necessary to digest its own myelin. The molecular mechanisms responsible for this behavior remain unclear. A monoclonal antibody termed BIKS was produced after the immunization of mice with guinea pig lymphoid tissue. This antibody recognizes a cytoplasmic vesicle‐associated molecule (A‐1 antigen) which is abundant in all tissue macrophages but is also expressed in small amounts in normal Schwann cells. Following axotomy, the A‐1 antigen appears to be translocated from a perinuclear site to accumulate in large quantities around myelin ovoids in Schwann cells, as well at the nodes of Ranvier‐sites where Wallerian degeneration is known to commence. The level of the antigen remains high when axons are prevented from regeneration. During repair of crush injury, however, the level of antigen drops concomitant with the ingrowth of regenerating axons, suggesting axonal control of A‐1 antigen expression. © 1993 Wiley‐Liss, Inc.
The innervation of the mystacial pad of the rat as revealed by PGP 9.5 immunofluorescence
Authors: Rice Frank L. , Kinnman Erik , Aldskogius Håkan , Johansson Olle , Arvidsson Jan
Published: January 2005

The innervation of the mystacial pad in the rat was investigated with the aid of antihuman protein gene product (PGP) 9.5 immunofluorescence. PGP 9.5 is ubiquitin carboxyl‐terminal hydrolase, which is distributed throughout neuronal cytoplasm. This technique revealed all previously known innervation as well as a wide variety of small‐caliber axons and some endings of large‐caliber afferents that had not been observed before. Newly revealed innervation affiliated with vibrissal‐follicle sinus complexes included (1) fine‐caliber, radially oriented processes in the epidermal rete ridge collar; (2) a loose network of fine‐caliber, circumferentially arrayed processes in the centrifugal part of the mesenchymal sheath at the level of the ring sinus; (3) a loose haphazard network of fine‐caliber and medium‐caliber processes in the mesenchymal sheath and among the trabeculae of the cavernous sinus; (4) a loose network of circumferentially arrayed processes within the mesenchymal sheath of the cavernous sinus and in close proximity to the basement membrane; (5) a dense network of reticular‐like endings provided by large‐caliber afferents to the mesenchymal sheath in the upper part of the cavernous sinus; and (6) fine‐caliber innervation to the dermal papilla at the base of all vibrissal shafts. In the intervibrissal skin, a dense distribution of fine‐caliber individual and clustered profiles was detected in the epidermis. In addition to previously known innervation, Merkel endings were consistently observed in the epidermis at the mouths of guard hairs, loose networks of fine‐caliber axons were found around the necks of occasional guard hairs, and fine‐caliber profiles were frequently affiliated with vellus hairs. Vascular profiles were heavily innervated throughout the dermis. Axons and motor end plates of the facial nerve innervation to papillary muscles also were labeled. Transection of the infraorbital nerve eliminated all but the facial nerve innervation. Unilateral removal of the superior cervical ganglion eliminated the innervation to the dermal papillae but caused no other noticeable reduction. PGP 9.5‐like immunofluorescence was also moderately expressed in apparent Schwann cells, in Merkel cells only in the external root sheath of vibrissal follicles, and in apparent dendritic and/or Langerhans cells usually located in the epidermis and occasionally in the follicles. PGP 9.5‐like immunofluorescence persisted in highly vacuolated profiles along the usual courses of medium to large‐caliber axons 2 weeks after nerve transection. The possible functional role of the newly discovered innervation is considered along with that of previously identified afferents. © 1993 Wiley‐Liss, Inc.