bluuebunny/crossref_metadata_2025 huggingface dataset:
Small‐field neurons associated with oculomotor and optomotor control in muscoid flies: Functional organization
Authors: Gilbert Cole , Strausfeld Nicholas J.
Published: January 2005

In fleshflies, Sarcophaga bullata, intracellular recording and Lucifer yellow dye‐filling have revealed small‐field elements of sexually isomorphic retinotopic arrays in the lobula and lobula plate, the axons of which project to premotor channels in the deutocerebrum that supply head‐turning and flight‐steering motor neurons. The dendrites of the small‐field elements visit very restricted oval areas of the retinotopic mosaic, comprising fields that are typically 6–8 input columns wide and 12–20 high. Their physiologically determined receptive fields are also small, typically 20° or less in diameter. The neurons are hyperpolarized in stationary illumination and are transiently depolarized by light OFF and to a lesser degree by light ON. Motion of a striped grating elicits a periodic excitation at the fundamental or second harmonic of the stimulus temporal contrast frequency. The arrangement of these elements in retinotopic arrays with their small receptive fields and flicker‐sensitive dynamic properties make these neurons well suited for the position‐dependent, direction‐insensitive detection of small objects in the fly's visual field, which, is known to drive fixation and tracking.
Organization of inferior olivary projections to the flocculus and ventral paraflocculus of the rat cerebellum
Authors: Ruigrok T. J. H. , Osse R.‐J. , Voogd J.
Published: January 2005

The climbing fiber projection to the rat flocculus and adjacent ventral paraflocculus was investigated by using Phaseolus vulgaris‐leucoagglutinin as an anterograde and horseradish peroxidase as a retrograde tracer.

Large injections of horseradish peroxidase in the flocculus and ventral paraflocculus indicated that the climbing fibers to this region are derived exclusively from any of the following contralateral olivary regions: the dorsal cap of Kooy, the ventrolateral outgrowth, the caudal half of the ventral leaf of the principal olive near its lateral bend, and the rostral pole of the medial accessory olive. Subsequent anterograde and retrograde studies with small injections demonstrated that the latter area projects to the C2 zone, which runs caudally in the ventral paraflocculus and enters the caudalmost aspect of the flocculus. The ventral leaf of the principal olive is connected to a D zone in the cerebellar hemisphere and paraflocculus, which, upon entering the ventral paraflocculus, divides into a caudal and rostral strip, termed FD and FD′, respectively. The dorsal cap and the ventrolateral outgrowth each project to two distinct zones in the flocculus and part of the ventral paraflocculus. Two floccular zones, which are continuous with the parafloccular FD and FD′ zones, receive their climbing fibers from the ventrolateral outgrowth. Two other zones, (FE and FE′) receive their climbing fibers from the dorsal cap. The FE′ zone is found at the rostral pole of the flocculus and is followed caudalwards by the FD′, FE, FD, and C2 zones, respectively. The rostromedial part of the dorsal cap is connected to the continuation of the FE zone into the ventral paraflocculus.

The observation that the dorsal cap and the Ventrolateral outgrowth are both connected to a set of two alternating zones of floccular/ventral parafloccular Purkinje cells is in agreement with recent studies in the rabbit, and suggests that these zones reflect functionally distinct and discrete units related to specific aspects of visuomotor control.
Repetitive firing properties in subpopulations of the chick Edinger Westphal nucleus
Authors: Fujii Joanne T.
Published: January 2005

The avian Edinger Westphal nucleus, through the ciliary ganglion, controls accommodation, iris constriction, and blood flow through the choroid. In live brainstem slices, the nucleus is easily identifiable as an olive‐shaped cluster of neurons dorsal to the oculomotor nerve and nucleus. Intracellular recordings from neurons in the nucleus identified two classes of responses to sustained (300 to 500 ms) injections of depolarizing current. One set of cells fired action potentials for the duration of the pulse while a second set of cells fired action potentials only transiently, during the first 50 to 100 ms, after which they remained silent regardless of the size of the depolarization.

Intracellular recordings followed by injections of the fluorescent dye lucifer yellow revealed that repetitively firing cells were located in the lateral half of the nucleus while non‐repetitively or transiently firing cells were located in the medial half. These locations correspond to different Edinger Westphal subdivisions which have distinct inputs and target populations. The varying firing patterns are discussed with reference to the known functions of the subdivisions in which they occur.

Replacement of calcium by magnesium in the extracellular medium had no effect on the number of action potentials fired by non‐repetitively firing cells, suggesting that a calcium‐activated potassium current is not responsible for suppressing repetitive firing in these cells. In contrast, in repetitively firing cells removal of extracellular calcium increased the frequency of action potential discharge and decreased the amplitude of afterhyperpolarizations following single action potentials. Addition of cadmium to the bath medium had similar effects. This suggests the presence of a significant calcium‐activated potassium current and involvement of this current in regulating the frequency of action potential discharge.
Distribution of substance P‐immunoreactive elements in the preoptic area and the hypothalamus of the rat
Authors: Larsen Philip J.
Published: January 2005

The localization and morphology of neurons, processes, and neuronal groups in the rat preoptic area and hypothalamus containing substance P‐like immunoreactivity were studied with a highly selective antiserum raised against synthetic substance P. The antiserum was thoroughly characterized by immunoblotting; only substance P was recognized by the antiserum. Absorption of the antiserum with synthetic substance P abolished immunostaining while addition of other hypothalamic neuropeptides had no effect on the immunostaining. The specificity of the observed immunohistochemical staining pattern was further confirmed with a monoclonal substance P antiserum.

The distribution of substance P immunoreactive perikarya was investigated in colchicinetreated animals, whereas the distribution of immunoreactive nerve fibers and terminals was described in brains from untreated animals. In colchicine‐treated rats, immunoreactive cells were reliably detected throughout the preoptic area and the hypothalamus. In the preoptic region, labeled cells were found in the anteroventral periventricular and the anteroventral preoptic nuclei and the medial and lateral preoptic areas. Within the hypothalamus, immunoreactive cells were found in the suprachiasmatic, paraventricular, supraoptic, ventromedial, dorsomedial, supramammillary, and premammillary nuclei, the retrochiasmatic, medial hypothalamic, and lateral hypothalamic areas, and the tuber cinereum. The immunoreactive cell groups were usually continuous with adjacent cell groups.

Because of the highly variable effect of the colchicine treatment, it was not possible to determine the actual number of immunoreactive cells. Mean soma size varied considerably from one cell group to another. Cells in the magnocellular subnuclei of the paraventricular and supraoptic nuclei were among the largest, with a diameter of about 25 μm, while cells in the supramammillary and suprachiasmatic nuclei were among the smallest, with a diameter of about 12 μm.

Immunoreactive nerve fibers were found in all areas of the preoptic area and the hypothalamus. The morphology, size, density, and number of terminals varied considerably from region to region. Thus, some areas contained single immunoreactive fibers, while others were innervated with such a density that individual nerve fibers were hardly discernible.

During the last decade, knowledge about neural organization of rodent hypothalamic areas and mammalian tachykinin biochemistry has increased substantially. In the light of these new insights, the present study gives comprehensive morphological evidence that substance P may be centrally involved in a wide variety of hypothalamic functions. Among these could be sexual behavior, pituitary hormone release, and water homeostasis.
A projection from the parabigeminal nucleus to the pulvinar nucleus in Galago
Authors: Diamond Irving T. , Fitzpatrick David , Conley Michael
Published: January 2005

A projection from the parabigeminal nucleus (Pbg) to the striate‐recipient zone of the pulvinar nucleus in the prosimian Galago was identified by anterograde and retrograde transport methods. In addition to the pulvinar nucleus, Pbg projections were found to terminate in layers 4 and 5 of the dorsal lateral geniculate nucleus and the central lateral nucleus. All three of these structures project to the superficial layers of the striate cortex. Similarities between the Pbg in mammals and the nucleus isthmi in nonmammals in connections and neurochemistry reinforce the idea that these two nuclei are homologous.
Metabolic correlates of optokinetic stimulation in the central visual system of the frog, Rana pipiens
Authors: Fite Katherine V. , Bengston Lynn , Taggert Gregory , Montgomery Neil , Tyler Christopher
Published: January 2005

The [14C]2‐deoxyglucose (2‐DG) method was used to identify those structures in the central visual system of Rana pipiens showing increased metabolic activity during binocular and monocular optokinetic stimulation at two pattern velocities (2 deg/sec and 9 deg/sec). Analysis of autoradiograms made with computer‐assisted microdensitometry and pseudocolor image‐enhancement techniques revealed that the greatest uptake of 2‐DG occurred in the pretectal region, which included the large‐celled nucleus lentiformis mesencephali (nLM), nucleus pretectalis, and pretectal gray. Both temporal‐to‐nasal (T‐N) and nasal‐to‐temporal (N‐T) directions of pattern motion were correlated with high levels of 2‐DG uptake. However, the nucleus of the basal optic root (nBOR) showed the greatest uptake of 2‐DG for the N‐T direction, which evokes little or no optokinetic (OKN) response in this species. These results suggest that the major efferent projection from nBOR to nLM may exert its greatest effect upon the ipsilateral pretectuni during N‐T stimulation.

Other regions showing substantial 2‐DG uptake included a large region of the ventral thalamus, for all stimulus conditions tested, including those cell groups associated with the retinorecipient neuropil, corpus geniculatum. The pattern of uptake was less closely associated with specific parameters of optokinetic stimulation than was observed in the pretectum and accessory optic nucleus. Like nBOR, the auricular lobe of the cerebellum also showed greatest uptake of 2‐DG for the N‐T, monocular stimulus condition. The neural circuitry that underlies OKN and its directional asymmetry during monocular stimulation appears to involve a number of structures whose functional interrelationships are yet to be described.
Alpha and gamma motoneurons in the peroneal nuclei of the cat spinal cord: An ultrastructural study
Authors: Destombes J. , Horcholle‐Bossavit G. , Thiesson D. , Jami L.
Published: January 2005

The aim of the present study was to investigate whether ultrastructural features can be used as a guide to identify α‐ and γ‐motoneurons among the intermediate‐size neurons of the peroneal motor nuclei. The peroneus brevis and peroneus tertius muscles of adult cats were injected with horseradish peroxidase, and motoneurons labeled by retrograde axonal transport were examined by electron microscopy. In both nuclei, the distributions of cell‐body diameters, measured in the light microscope, were bimodal covering the range of 28–84 μm, with a trough around 50 μm. The sample of 25 motoneurons selected for the ultrastructural study included not only large (presumed α) and small (presumed γ) neurons but also intermediate‐size cell bodies with diameters in the 40–60 μm range. For each motoneuron, 2–5 profiles were reconstructed from ultrathin sections taken at 6–8 μm intervals. Synaptic boutons were counted and their lengths of apposition were measured. On the basis of three criteria, namely: (1) bouton types present on the membrane, (2) percentage of membrane length covered by synapses, and (3) the aspect of the nucleolus, all the examined motoneurons, including those with intermediate sizes, fell into one of two categories. Fourteen motoneurons, with cell‐body diameters in a range of 55–84 μm, were contacted by all types of boutons (mainly S‐type with spherical vesicles, F‐type with flattened vesicles, and C‐type with subsynaptic cistern); the synaptic covering of the somatic membrane was over 40% and the nucleus contained a vacuolated nucleolus. These were considered α‐motoneurons. Eleven motoneurons, with only S and F boutons, a synaptic covering under 30%, a compact nucleolus and a cell‐body diameter ranging between 28 and 50 μm, were considered γ‐motoneurons. No other combination of the three criteria was observed. These results show that unequivocal distinction of α‐ and γ‐motoneurons is possible in the peroneal nuclei, on the basis of morphological differences independent of cell‐body size.
Ontogeny of gene expression of adenosine A2 receptor in the striatum: Early localization in the patch compartment
Authors: Schiffmann S. N. , Vanderhaeghen J.‐J.
Published: January 2005

The ontogeny of adenosine A2 receptor mRNA and adenosine A2, binding sites distributions was studied by in situ hybridization histochemistry and receptor autoradiography in pre‐ and post‐natal rat striatum, postnatal dog striatum, and a human fetus striatum and compared to that of dopamine D1 and μ opiate receptors. The early postnatal striatum demonstrated heterogeneous distributions of adenosine A2 receptor mRNA and adenosine A2 binding sites with patches of dense labeling corresponding to dopamine D1 and μ opiate receptors enriched zones. This patchy pattern evolved to the homogeneous distribution observed in the adult. The higher intensity of adenosine A2 receptor mRNA enriched patches correspond at the microscopical level to a higher density of labeled neurons in the patches areas and also to a higher level expression per labeled patches neuron than in the matrix ones. This demonstrates for the first time that differences in patch/matrix receptor density is at least partly linked to different levels of receptor gene expression.
Ontogeny of somatostatin immunoreactivity in the cat retina
Authors: White C. A. , Chalupa L. M.
Published: January 2005

In the ganglion cell layer of the adult cat retina, subgroups of displaced amacrine cells and alpha ganglion cells are immunoreactive for somatostatin or a somatostatinlike substance. Both types of immunoreactive cells are found preferentially in inferior retina. We studied the development of somatostatin immunoreactivity in the prenatal and postnatal cat retina to determine how such unusual distributions of immunoreactive cells arise. Somatostatin‐immunoreactive profiles were first observed at embryonic day (E) 30, within the inner retina in a central region that included the optic disk and the area centralis. By E36, immunoreactivity had virtually disappeared from the central retina but was present throughout the periphery. The immunoreactive profiles could not be classified morphologically because of their immaturity but were most likely retinal ganglion cells, the earliest born cells of the inner retina.

Of the two types of immunoreactive cell observed in the adult, the first to be recognized morphologically was the displaced amacrine cell, at E45. These cells were virtually adultlike in morphology and number by E51, two weeks before birth. In contrast, immunoreactive alpha ganglion cells were not apparent until five days after birth and did not achieve their mature numbers and immunoreactive staining characteristics until more than a month later. From the time they could initially be recognized, both immunoreactive displaced amacrine cells and alpha cells were distributed mainly in the inferior retina. A third type of somatostatin‐immunoreactive cell was transiently observed in the superior and inferior retina during prenatal and early postnatal development. These cells were characterized by granular staining in irregular shapes and few, if any, faintly stained processes. Injections of retrograde tracers into retinorecipient targets revealed that many of these cells were retinal ganglion cells. They disappeared by postnatal day 38.

Our results indicate that somatostatin immunoreactivity initially follows a central‐to‐peripheral pattern of development, as is typical of other developmental events in the mammalian retina. They also indicate that the two types of somatostatin‐immunoreactive neurons present in the adult cat retina (displaced amacrine and alpha ganglion cells) attain their mature immunocytochemical properties with very different timecourses. Finally, the observation that somatostatin immunoreactivity appears transiently in the granular‐staining ganglion cells, distributed throughout the superior and inferior retina, suggests that the peptide may play a regulatory role in the development of the retina and/or retinofugal pathways.
Distribution of neurons expressing neurokinin B in the rat brain: Immunohistochemistry and in situ hybridization
Authors: Marksteiner Josef , Sperk Günther , Krause James E.
Published: January 2005

Neurokinin B (NKB) belongs to the family of neuropeptides named tachykinins. Members of this family such as substance P or neurokinin A have been proposed to function as neurotransmitters or neuromodulators. Searching for possible sites of action of NKB in the central nervous system, we have now investigated its distribution within the rat brain by immunohistochemical techniques and in situ hybridization. For immunohistology two different antisera directed against amino acid sequences within preprotachykinin B were used. One antiserum had been raised against a synthetic derivative of NKB; the other one was directed towards the amino acids 50–79 of preprotachykinin B, which are referred to as peptide 2.

Essentially the same distribution of immunoreactive perikarya was obtained with both antisera and it closely corresponded to the cellular localization of preprotachykinin B mRNA. Neurons containing NKB immunoreactivity and mRNA were present in many areas including cerebral cortex, hippocampal formation, amygdaloid complex, bed nucleus of the stria terminalis, ventral pallidum, habenula, medial preoptic area, arcuate nucleus, and lateral mammillary bodies. Dense immunoreactive fibers were observed in various parts of the brain and were most prominent in the olfactory bulb and tubercle, the lateral olfactory tract, medial hypothalamus, around blood vessels of the median eminence and interpeduncular nucleus, amygdaloid nuclei, stria terminalis, subbrachial nucleus, and medial geniculate nucleus. Fibers of less intense staining were seen among other brain areas in the substantia nigra, the reticular formation, and the area of the nucleus of the solitary tract. Surgical lesion of the fasciculus retroflexus revealed that the dense fiber network observed in the interpeduncular nucleus originates from the ventral and dorsal parts of the medial habenula. Our data suggest a widespread and distinct distribution of neurons expressing NKB within the central nervous system, suggesting possible neuromodulatory roles of this neuropeptide for various brain functions.
Immunocytochemical localization of androgen receptors in the male songbird and quail brain
Authors: Balthazart Jacques , Foidart Agnes , Wilson Elizabeth M. , Ball Gregory F.
Published: January 2005

The distribution of androgen receptors was studied in the brain of the Japanese quail (Coturnix japonica), the zebra finch (Taeniopygia guttata), and the canary (Serinus canaria) by immunocytochemistry with a polyclonal antibody (AR32) raised in rabbit against a synthetic peptide corresponding to a sequence located at the N‐terminus of the androgen receptor molecule. In quail, androgen receptor‐immunoreactive cells were observed in the nucleus intercollicularis and in various nuclei of the preoptic‐hypothalamic complex, namely, the nucleus preopticus medialis, the ventral part of the nucleus anterior medialis hypothalami, the nucleus paraventricularis magnocellularis, the nucleus ventromedialis hypothalami, and the tuberal hypothalamus. In the two songbird species, labeled cells were also observed in various nuclei in the preoptic‐hypothalamic region, in the nucleus taeniae, and in the nucleus intercollicularis. Additional androgen receptor‐immunoreactive cells were present in the androgen‐sensitive telencephalic nuclei that are part of the song control system. These immunoreactive sells filled and outlined the boundaries of the hyperstriatum ventrale, pars caudalis, nucleus magnocellularis neostriatalis anterioris (both in the lateral and medial subdivisions), and nucleus robustus archistriatalis. The immunoreactive material was primarily present in cell nuclei but a low level of immunoreactivity was also clearly detected in cytoplasm in some brain areas. These studies demonstrate, for the first time, that androgen receptors can be detected by immunocytochemistry in the avian brain and the results are in general agreement with the binding data obtained by autoradiography with tritiated dihydrotestosterone. Immunocytochemical methods offer several advantages over autoradiography and their use for the study of the androgen receptor will greatly facilitate the analysis of steroid‐sensitive systems in the avian brain.
Distribution of nigrothalamic projections in the dog
Authors: Sakai Sharleen T. , Smith André
Published: January 2005

The distribution of nigrothalamic projections was studied in the dog by using the autoradiographic tracing method. On the basis of a systematic series of tritiated amino acid injections into different portions of the substantia nigra, we found that the rostral three‐fourths of the substantia nigra pars reticulata (SNr) gives rise to widespread thalamic projections. The nigrothalamic label, occupied a longitudinal band extending from rostral ventral anterior nucleus (VA) through to caudal mediodorsal nucleus (MD). In the dog, VA is histochemically identified as an acetylthiocholinesterase (AChE)‐negative region and is distinct from the adjacent ventral lateral nuclei which stain positively for AChE. In rostral thalamus, the dense autoradiographic label was observed in rostral VA within the AchE‐negative region lying alongside the mammillothalamic tract (MT). The adjacent AChE‐positive ventral lateral nuclei did not contain autoradiographic label. In addition, homogeneously distributed silver grains were observed throughout the ventromedial nucleus (VM) bilaterally. More caudally, as the ventral lateral thalamic compartment emerges, label was also observed within the internal medullary lamina region, including the paralaminar portion of VA, the central lateral nucleus (CL), and the paralaminar portion of MD. Finally, in caudal thalamus, the central portion of MD, as well as the parafascicular nucleus (Pf), contained autoradiographic label. The overall nigrothalamic distribution observed in the dog was similar to the distribution of nigrothalamic projections in monkeys with one exception. Unlike that of primates, the distribution of nigral efferents is to the whole extent of VM in the dog as in other non‐primate species. Overall, we found that nigral efferents primarily project to three main thalamic targets: the VA/MD region, VM, and the internal medullary lamina region, which includes dorsal CL and paralaminar VA and MD. We propose that these three nigrothalamic territories may constitute critical links subserving different functional channels.
Differential cholinergic innervation within functional subdivisions of the human cerebral cortex: A choline acetyltransferase study
Authors: Mesulam M.‐Marsel , Hersh Louis B. , Mash Deborah C. , Geula Changiz
Published: January 2005

The distribution of cholinergic fibers in the human brain was investigated with choline acetyltransferase immunocytochemistry in 35 cytoarchitectonic subdivisions of the cerebral cortex. All cortical areas and all cell layers contained cholinergic axons. These fibers displayed numerous varicosities and, on occasion, complex preterminal profiles arranged in the form of dense clusters. The density of cholinergic axons tended to be higher in the more superficial layers of the cerebral cortex. Several distinct patterns of lamination were identified. There were also major differences in the overall density of cholinergic axons from one cytoarchitectonic area to another. The cholinergic innervation of primary sensory, unimodal, and heteromodal association areas was lighter than that of paralimbic and limbic areas. Within unimodal association areas, the density of cholinergic axons and varicosities was significantly lower in the upstream (parasensory) sectors than in the downstream sectors. Within paralimbic regions, the non‐isocortical sectors had a higher density of cholinergic innervation than the isocortical sectors. The highest density of cholinergic axons was encountered in core limbic structures such as the hippocampus and amygdala. These observations show that the cholinergic innervation of the human cerebral cortex displays regional variations that closely follow the organization of information processing systems.
Distribution of neuropeptide Y, substance P, and Choline acetyltransferase in the developing visual system of the pigeon and effects of unilateral retina removal
Authors: Bagnoli Paola , Fontanesi Gigliola , Alesci Roberto , Erichsen Jonathan T.
Published: January 2005

The distribution of three neuroactive substances, neuropeptide Y, substance P, and choline acetyltransferase, was studied by immunocytochemical methods in central visual regions of adult, developing, and ablated pigeon brains. In normal adult brains, neuropeptide Y‐positive cells and processes were present in the nucleus pretectalis, the nucleus of the basal optic root, the nucleus of the marginal optic tract, and the visual Wulst. Substance P‐positive cells and processes were found in the optic tectum and in the visual Wulst. Stained fibers and terminal‐like processes, but no cells, were also observed in several visual thalamic nuclei. Choline acetyltransferase‐positive cells and processes were located in the optic tectum, visual Wulst, the nucleus isthmo opticus, nucleus isthmi and certain visual thalamic nuclei. Cholinergic fibers and processes, but no cells, were present in the nucleus principalis precommissuralis, the supraoptic decussation, and the nucleus lentiformis mesencephali, pars magnocellularis. In the course of development, the distribution of immunoreactivity for all three substances was found to vary. These changes often involved either progressive increases or decreases in the density of labeled cells, neuropil and/or terminal‐like profiles. Experiments with retina ablated pigeons clearly demonstrated that changes in the normal pattern of immunoreactivity distribution only occurred if the retina was removed immediately after hatching, i.e., before retinofugal connections have been established. The adult pattern of immunoreactivity for all three substances appears to be reached at about the same time that the anatomical and functional maturation of the pigeon visual system is completed. The present results suggest that this temporal correlation reflects the important role that retinal afferents play in the development of these putative peptidergic and cholinergic systems.
Parvalbumin‐containing nonpyramidal neurons in intracortical transplants of rat hippocampal and neocortical tissue: A light and electron microscopic immunocytochemical study
Authors: Plaschke Martina , Nitsch Robert , Wenzel Jürgen , Frotscher Michael
Published: January 2005

Previous immunocytochemical studies have shown that GABAergic nonpyramidal neurons of the rat hippocampus survive in intracerebral transplants. However, information is still lacking about the dendritic organization and the input synapses of these cells as well as their capacity to express the calcium‐binding protein parvalbumin (PARV) under transplant conditions.

In the present study, a monoclonal antibody against PARV was used to examine the dendritic morphology and the synaptic organization of parvalbumin‐containing GABAergic neurons in hippocampal and dentate transplants. In addition, parvalbumin‐containing nonpyramidal neurons were studied in neocortical transplants to compare the differentiation of grafted allocortical and neocortical nonpyramidal neurons.

Tissue blocks of hippocampus and fascia dentata and of the parietal neocortex were taken from late embryonic rats (E 21 and E 16, respectively) and were transplanted into a cavity in the somatosensory cortex of young adult rats. After 3.5 or 7 months survival, the recipient brains were fixed by perfusion and immunostained for PARV. As in the hippocampal formation in situ, PARV‐containing neurons in the hippocampal transplants were observed within and in the vicinity of the pyramidal and granule cell layer. In neocortical transplants, PARV‐immunoreactive cells were distributed in all parts of the transplant with dendrites extending in various directions. In both hippocampal and neocortical transplants, immunoreactive dendrites were smooth and displayed the characteristic regular varicosities known from in situ studies of these cells. Numerous unlabeled terminals as well as a few immunoreactive boutons established synapses on the immunoreactive dendrites. PARV‐positive terminals formed the typical pericellular baskets around the immunoreactive cell bodies of pyramidal neurons and granule cells in the transplants. They established symmetric synapses with cell bodies and proximal dendrites. Synapses on axon initial segments were absent or rare.

Our results demonstrate that allocortical as well as neocortical nonpyramidal neurons transplanted to the neocortex of adult recipients survive transplantation, express the calcium‐binding protein parvalbumin, and develop a cell‐specific morphology. © 1992 Wiley‐Liss, Inc.
The localization of nerve growth factor‐like immunoreactivity in the adult rat basal forebrain and hippocampal formation
Authors: Conner J. M. , Muir D. , Varon S. , Hagg T. , Manthorpe M.
Published: January 2005

The role of nerve growth factor (NGF) as a target derived neurotrophic agent for specific cell populations in the peripheral nervous system has been well documented and much evidence suggests that NGF may serve a similar neurotrophic role in the CNS supporting the cholinergic neurons of the basal forebrain. Previous attempts to localize NGF by immunocytochemical methods, however, have not yielded evidence confirming the regional distribution expected based upon reported levels of extractable NGF. In the present study, affinity purified polyclonal antibodies to β‐NGF and a modified immunohistochemical protocol were used to demonstrate specific NGF‐like immunoreactivity in the adult rat hippocampal formation and basal forebrain. In the hippocampal formation, NGF‐like immunoreactivity was localized primarily within the hilus of the dentate gyrus and within stratum lucidum of the CA3 and CA2 hippocampal subfields. Staining appeared to be associated with cell processes and was similar to the reported distribution of mossy fibers suggesting that granule cells may either serve as a primary source of hippocampal NGF or that mossy fibers selectively accumulate NGF produced by other cell populations. In the basal forebrain, NGF‐like immunoreactivity was localized within neuronal cell bodies of the medial septum, diagonal band, and nucleus basalis of Meynert and was further demonstrated to colocalize exclusively with LNGF‐R positive neurons. These findings demonstrate the presence of an NGF‐like antigen in association with cholinergic neurons of the basal forebrain and strongly support the hypothesis that NGF may serve as an endogenous trophic factor for this adult neuronal population. © 1992 Wiley‐Liss, Inc.
Galanin immunoreactivity in the primate central nervous system
Authors: Kordower Jeffrey H. , Le Hieu K. , Mufson Elliott J.
Published: January 2005

Galanin‐immunoreactive profiles were localized within the monkey and human central nervous system. In the monkey telencephalon, galanin‐immunoreactive perikarya were seen within the anterior olfactory nucleus, basal forebrain, endopiriform nucleus, hippocampus, and bed nucleus of the stria terminalis. The caudate nucleus and putamen contained galanin‐immunoreactive perikarya whereas the nucleus accumbens displayed only galanin‐immunoreactive fibers. In the diencephalon, galanin‐immunoreactive profiles were seen within the medial preoptic area, periventricular, suprachiasmatic, paraventricular, and arcuate nuclei as well as the lateral hypothalamic area. Within the thalamus, only galanin‐immunoreactive fibers were seen within the midline paraventricular, reuniens, and rhomboid nuclei. In the mesencephalon, scattered galanin‐immunoreactive fibers were seen in the periaquaductal gray, ventral tegmental area, and midbrain reticular formation. In the metencephalon, galanin‐immunoreactive neurons were observed in the medial vestibular nucleus and nucleus prepositus. In the myelencephalon, galanin‐immunoreactive perikarya were seen within the nucleus of the tractus solitarius and hypoglossal nucleus. Dense collections of galanin‐immunoreactive fibers were found in the spinal descending tract of V, nucleus of the tractus solitarius, and dorsal motor nucleus of X. Galanin immunoreactivity was also observed within all circumventricular organs. Spinal anterior horn neurons expressed galanin immunoreactivity, and immunopositive fibers were seen within the tract of Lissauer and the substantia gelatinosa. Although the distribution of galanin immunoreactivity was generally similar between monkeys and humans, there were a few striking exceptions. The human supraoptic nucleus contained galanin‐immunoreactive neurons, whereas the monkey supraoptic nucleus displayed only immunopositive fibers. Similarly, galanin‐immunoreactive perikarya and fibers were seen in the human locus coeruleus and subcoeruleus, whereas in monkeys these regions contained only fibers. These data demonstrate a widespread distribution of galanin‐containing profiles in primates, suggesting that galanin may modulate cognitive, sensory, motor, and autonomic processes. © 1992 Wiley‐Liss, Inc.
Development of catecholaminergic, Indoleamine‐accumulating and NADPH‐diaphorase amacrine cells in rabbit retinae
Authors: Mitrofanis John , Robinson Stephen R. , Ashwell Ken
Published: January 2005

We have investigated the ontogeny of four classes of amacrine cells in the rabbit retina. In particular, the distribution, number, soma diameter, dendritic field diameter, and pattern of dendritic stratification were studied in catecholaminergic (CA) and indoleamine‐accumulating (IA) amacrines and in two classes of nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase amacrine cells. The first CA and IA cells are observed on the 27th postconceptional day (27PCD) and the first NADPH‐diaphorase cells on 28PCD. These first cells are concentrated in the central part of the visual streak, and at subsequent ages, cells in this part of the streak have larger somata and more mature dendritic fields than those elsewhere, supporting the notion that the peak density region is a developmentally advanced part of the retina.

Throughout development, amacrine cells of all classes are concentrated in the visual streak, with their density reaching minima at the superior and inferior retinal margins. As their total number increases, the difference in cell density between the streak and the periphery decreases, presumably because proportionately more cells are added at the periphery. Their total number peaks around 42PCD, followed by a decline of 12–31% to adult values. Once the peak number of cells has been reached, the difference in cell density between the streak and periphery begins to increase. The rate of this increase is closely correlated with the increase in retinal area. This redistribution of amacrine cells, as well as a greater expansion of their dendritic fields in peripheral retina, is almost certainly the product of nonuniform retinal expansion. © 1992 Wiley‐Liss, Inc.
A unique morphological subtype of horizontal cell in the rabbit retina with orientation‐sensitive response properties
Authors: Bloomfield Stewart A.
Published: January 2005

Intracellular recordings were obtained from horizontal cells in the rabbit retina to assess the orientation sensitivity of their visual responses to moving and stationary rectangular slits of light. Cells were subsequently labeled with horseradish peroxidase (HRP) for morphological identification. The responses of A‐type horizontal cells and those of the somatic and axon terminal endings of B‐type horizontal cells (with the exception of one cell) were found to be insensitive to the orientation of light stimuli. However, 20 horizontal cells encountered within or just superior to the visual streak displayed clear orientation‐sensitive response properties. These cells were divided into two groups: the majority (70%) showed preference for light stimuli oriented parallel to the visual streak, whereas the remainder preferred stimuli oriented orthogonal to the visual streak. Analysis of the shape of the receptive fields of these cells by means of a narrow, displaced slit of light revealed an anisotropy with the major or elongated axis of the receptive field of each cell aligned along the same angle as its physiological preferred orientation.

Morphologically, the orientation‐sensitive horizontal cells formed a homogeneous group with an architecture corresponding to that of elongated A‐type or Ae‐type horizontal cells reported previously in the rabbit retina. These cells showed a marked elongation of their dendritic arbors with the major axes oriented either parallel or orthogonal to the visual streak. Furthermore, the orientation of the dendritic arbor of each cell matched that of its physiological preferred orientation. The present results, then, suggest strongly that the orientation sensitivity of Ae‐type horizontal cells results directly from the asymmetry in their dendritic arbors. The spatial location and specialized physiology of Ae‐type horizontal cells suggest that they play a role in the formation of orientation‐sensitive properties exhibited by more proximal neurons in the rabbit retina.
Inhibitory synaptic input to identified rubrospinal neurons in Macaca fascicularis: An electron microscopic study using a combined immuno‐GABA‐gold technique and the retrograde transport of WGA‐HRP
Authors: Ralston Diane Daly , Milroy Antonia M.
Published: January 2005

Rubrospinal neurons of the magnocellular division of the red nucleus of Macaca fascicularis were retrogradely labeled following spinal cord microinjections of wheat germ agglutinin‐horseradish peroxidase, as demonstrated by the chromagen tetramethylbenzidine, identifying the mesencephalic cells of origin of this descending motor pathway. The tissue was processed for electron microscopy and subsequently tested on the electron microscope grid for immunoreactivity of gamma aminobutyric acid (GABA) in presumed local circuit neuronal somata, in dendrites, and in axonal terminals. Results demonstrate the presence of retrogradely labeled rubrospinal neurons of medium and large diameters (30–90 μm) and immunoreactive neurons of small size (> 20 μm in diameter) within the nucleus. In addition, there are substantial numbers of GABAergic, presumably inhibitory, synaptic structures contacting somata and primary, medium, and small sized dendrites, as well as spineheads of rubrospinal neurons. The immunoreactive presynaptic profiles exhibit two different morphological appearances: one axonal and the other dendritic. Axonal terminals contain densely packed pleomorphic to flattened vesicles and form primarily symmetrical synapses with somata and all regions of the dendritic arbor. GABAergic profiles resembling presynaptic dendrites (PSDs) are also present. These profiles possess scattered flattened to pleomorphic synaptic vesicles in a translucent cytoplasm and are often postsynaptic to axonal terminals of unknown origin, or to GABAergic profiles. GABAergic local circuit neurons (LCNs), the neurites of which remain within the confines of the nucleus, appear to be contacted primarily by cortical and cerebellar afferents. These LCNs may or may not possess axons and thus may represent both the source of the GABAergic axonal terminals as well as that of the PSDs. Inhibitory afferents from other sources, such as the mesencephalic reticular formation, may also account for GABAergic terminals involved in this inhibition. We propose that the level of excitability of rubrospinal neurons and their subsequent activation of spinal motor neurons and interneurons is significantly regulated by the local circuit GABAergic inhibitory interneuronal population of the nucleus proper and probably by axons entering the nucleus from an extranuclear source.
Distribution of buccalin‐like immunoreactivity in the central nervous system and peripheral tissues of Aplysia californica
Authors: Miller M. W. , Alevizos A. , Cropper E. C. , Kupfermann I. , Weiss K. R.
Published: January 2005

The neuropeptide buccalin A was originally purified and sequenced from a nerve‐muscle system used in feeding‐related behaviors of Aplysia californica in which it has been proposed that it acts as a modulatory cotransmitter. The distribution of buccalin‐like immunoreactivity in the central ganglia and in peripheral tissues of Aplysia californica was examined by whole mount immunohistochemical techniques. Immunoreactive material was located in specific cell bodies and clusters of neurons in each of the ganglia. Immunoreactive fibers were present in each of the connectives between ganglia, in tracts coursing through the ganglia, and in the majority of the peripheral nervos. Most fibers were smooth in contour, but some had regularly spaced swellings. Varicosities containing immunoreactive material were located on specific neuronal somata and on certain tissues associated with the feeding, circulatory, digestive, and reproductive systems. The specific and widespread distribution of buccalin‐like immunoreactivity supports the hypothesis that members of the buccalin peptide family act as neuromodulators or neurotransmitters in a variety of central and peripheral circuits in Aplysia.
Differential calbindin‐like immunoreactivity in the brain stem auditory system of the chinchilla
Authors: Kelley Peggy E. , Frisina Robert D. , Zettel Martha L. , Walton Joseph P.
Published: January 2005

Calbindin is a 28 kD calcium‐binding protein found in neural tissue. Although its functional role in neurons is unknown, it has been proposed that calbindin is involved in intracellular buffering and could therefore influence temporal precision of neuronal firing. In the barn owl, calbindin‐like immunoreactivity was found to be selectively present in brain stem auditory pathways used to process interaural time differences, but was absent from the interaural intensity pathway. The present study demonstrates calbindin immunoreactivity in the auditory brain stem of the chinchilla, a rodent with exceptionally good low‐frequency hearing. In the superior olivary complex and periolivary areas, immunoreactivity was divided between neuropil labeling in the lateral and medial superior olives and dorsomedial periolivary nucleus, and labeling of the somata of the medial and ventral nuclei of the trapezoid body and anterolateral periolivary nucleus. Strong immunoreactivity was observed in the ventral and dorsal divisions of the ventral nucleus of lateral lemniscus somata and the vental division's columnarly organized fiber plexus. The dorsal nucleus of the lateral lemniscus was void of immunoreactivity. Virtually all principal neurons of the sagulum showed darkly labeled somata surrounded by a densely labeled fiber plexus. Immunoreactivity in the inferior colliculus was primarily limited to the paracentral nuclei, with only an occasional labeled cell in the central nucleus. In conclusion, although selective labeling of calbindin in the mammalian auditory brain stem is impressive, no distinctive labeling of a functionally denned timing pathway was apparent as reported previously in the barn owl or electric fish.
Parvalbumin and calbindin immunocytochemistry reveal functionally distinct cell groups and vibrissa‐related patterns in the trigeminal brainstem complex of the adult rat
Authors: Bennett‐Clarke Carol A. , Chiaia Nicolas L. , Jacquin Mark F. , Rhoades Robert W.
Published: January 2005

Immunocytochemistry for calbindin (CA) and parvalbumin (PA) was combined with retrograde tracing from the thalamus, superior colliculus (SC), and cerebellum to define the ascending projections of neurons in the rat's trigeminal (V) brainstem complex that express immunoreactivity for these calcium binding proteins. Many PA‐immunoreactive neurons were observed in trigeminal nucleus principalis (PrV). Many of these cells projected to thalamus and a few sent axons to SC. In ventral PrV, PA‐immunoreactive neurons were arranged in a vibrissa‐related pattern. A very small number of large CA‐immunoreactive neurons were observed in dorsomedial PrV. None of these cells were labeled by our tracer deposits. Small neurons in V subnucleus oralis (SpO) were also immunoreactive for PA, but none were retrogradely labeled. A small percentage of the large neurons in SpO were CA‐immunoreactive; many of these were retrogradely labeled by tracer injections in the thalamus and/or SC. In V subnucleus interpolaris (SpI), many small to medium sized cells were PA‐positive and they were arrayed in a vibrissae‐like pattern. None of these neurons were retrogradely labeled from any of the above‐listed targets, but many were retrogradely labeled by tracer injections into ipsilateral PrV. SpI also contained many large CA‐immunoreactive cells. Many of these projected to the thalamus and/or SC and some were also retrogradely labeled by tracer injections into ipsilateral PrV. In V subnucleus caudalis (SpC), very dark PA‐immunoreactive neurons were located in the inner part of lamina II and less often in laminae I. Lightly labeled cells were located in the magnocellular laminae and formed vibrissa‐related aggregates. None of these neurons were retrogradely labeled by our tracer injections. CA‐immunoreactive cells were located throughout the depth of lamina II in SpC and smaller numbers were also visible in lamina I and layers III‐V. A small percentage of the CA‐positive cells in lamina I and in the magnocellular layers were retrogradely labeled from the thalamus.

These data indicate that PA and CA antisera identify two cell populations in whisker‐related regions of the V brainstem complex and that PA cells are somatotopically patterned in PrV, SpI, and SpC. These markers also distinguish two cell groups in superficial laminae of the medullary dorsal horn.