bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitric oxide synthase in the brain of the turtle Pseudemys scripta elegans
Authors: Brüning Gerold , Wiese Stephanie , Mayer Bernd
Published: January 2005

The distribution pattern of nitric oxide synthase (NOS) was investigated in the brain of the turtle by NADPH‐diaphorase histochemistry. The specificity of the histochemical staining was tested by immunocytochemical colocalization with an antiserum specific for NOS. In the forebrain, neurons staining intensely for nitric oxide synthase were localized in the olfactory tubercle, the basal ganglia complex, the basal amygdaloid nucleus, suprapeduncular nucleus, and the posterior hypothalamic area. Many positive fibers course in a tract connecting the basal amygdaloid nucleus with the hypothalamus, corresponding to the stria terminalis. Bundles of nitroxergic fibers were seen to course at the ventromedial edge of the optic tract and to cross in the supraoptic decussation, apparently consisting of tectothalamic and thalarnotectal fibers. In the midbrain, strongly NOS‐positive neurons were present in the substantia nigra, the nucleus profundus mesencephali, the periventricular grey of the optic tectum, the laminar nucleus of the torus semicircularis, and the nucleus of the lateral lemniscus. The area of the locus coeruleus harbored an accumulation of intensely stained neurons, which, as n mammals, might represent a cholinergic cell group of the reptilian brainstem. In the cerebellum, strong staining was confined to bundles of afferent fibers running in the lower molecular and in the Purkinje cell layer. These axons appeared to include ascending projections from the dorsal funicular nucleus or the spinal cord. NOS‐positive cells in the caudal Brainstem were found in the cerebellar nuclei, in the superior vestibular nucleus, in the reticular nuclei, ventrolateral to the nucleus of the solitary tract, in the perihypoglossal, and in the dorsal funicular nucleus. Taken together, these results suggest that nitric oxide acts as a messenger molecule in different areas of the reptilian brain and spinal cord. In certain areas, the pattern of expression of NOS appears to have evolved before radiation of present mammalian, avian, and reptilian species. © 1994 Wiley‐Liss, Inc.
Topography of developing thalamic and cortical pathways in the visual system of the cat
Authors: Kennedy H. , Salin P. , Bullier J. , Horsburgh G.
Published: January 2005

Adult patterns of connectivity could emerge during development by a process of selective elimination from an earlier, more widespread, connectivity. We have addressed this issue by examining the topography of developing projections to area 17 in the cat. At different postnatal ages, paired injections of the retrograde tracers diamidino yellow and fast blue were made in area 17. Interinjection separations were carefully controlled and the spatial distribution of the two populations of labelled neurones investigated.

Projections to the striate cortex from the lateral geniculate nucleus, area 18, as well as connections intrinsic to area 17 were analysed quantitatively with a graphic method that uses a two‐dimensional model of the projection. This allows two parameters of the projection to be calculated: the divergence (the spatial extent of area 17 contacted by an infinitely small region of an afferent structure) and the convergence (the extent of an afferent structure that projects to an infinitely small region of area 17).

During postnatal development, the bulk of the connections making up the geniculostriate and corticocortical pathways showed no variation either in their convergence and divergence. However, the projection of area 18 to area 17 and the intrinsic area 17 connections (but not the geniculostriate projection) in the 3–15‐day‐old kittens were each found to contain a small subpopulation of widely scattered neurones with widespread axonal trajectories.

These results, showing that many initially formed connections display a high degree of topographical order, are discussed in terms of the control mechanisms specifying axonal trajectories during development. © 1994 Wiley‐Liss, Inc.
Visual pontocerebellar projections in the macaque
Authors: Glickstein Mitchell , Gerrits Nico , Kralj‐Hans Ines , Mercier Barbara , Stein John , Voogd Jan
Published: January 2005

The cerebellum plays an important role in the visual guidance of movement. In order to understand the anatomical basis of visuomotor control, we studied the projection of pontine visual cells onto the cerebellar cortex of monkeys. Wheat germ agglutinin horseradish peroxidase was injected into the dorsolateral pons of two monkeys. Retrogradely labelled cells were mapped in the cerebral cortex and superior colliculus, and orthogradely labelled fibers in the cerebellar cortex. The largest number of retrogradely labelled cells in the cerebral cortex was in a group of medial extrastriate visual areas. The major cerebellar target of these dorsolateral pontine cells is the dorsal paraflocculus. There is a weaker projection to the uvula, paramedian lobe, and Crus II, and a sparse but definite projection to the ventral paraflocculus. There are virtually no projections to the flocculus. There are sparse ipsilateral pontocerebellar projections to these same regions of cerebellar cortex.

In nine monkeys, we made small injections of the tracer into the cerebellar cortex and studied the location of retrogradely filled cells in the pontine nuclei and inferior olive. Injections into the dorsal paraflocculus or rostral folia of the uvula retrogradely labelled large numbers of cells in the dorsolateral region of the contralateral pontine nuclei. Labelled cells were found ipsilaterally, but in reduced numbers. Injections outside of these areas in ventral paraflocculus or paramedian lobule labelled far fewer cells in this region of the pons. We conclude that the principal source of cerebral cortical visual information arises from a medial group of extrastriate visual areas and is relayed through cells in the dorsolateral pontine nuclei. The principal target of pontine visual cells is the dorsal paraflocculus. © 1994 Wiley‐Liss, Inc.
Implants of polymer‐encapsulated human NGF‐secreting cells in the nonhuman primate: Rescue and sprouting of degenerating cholinergic basal forebrain neurons
Authors: Emerich Dwaine F. , Winn Shelley R. , Harper James , Hammang Joseph P. , Baetge E. Edward , Kordower Jeffrey H.
Published: January 2005

Baby hamster kidney (BHK) cells were genetically modified to secrete high levels of human nerve growth factor (BHK‐hNGF). Following polymer encapsulation, these cells were implanted into the lateral ventricle of four cynomolgus monkeys immediately following a unilateral transection/aspiration of the fornix. Three control monkeys received identical implants, with the exception that the BHK cells were not genetically modified to secrete hNGF and thus differed only by the hNGF construct. One monkey received a fornix transection only. All monkeys displayed complete transections of the fornix as revealed by a comprehensive loss of acetylcholinesterase‐containing fibers within the hippocampus ipsilateral to the lesion. Control monkeys that were either unimplanted or received BHK‐control (non‐NGF secreting) cell implants did not differ from each other and displayed extensive losses of choline acetyltransferase and p75 NGF receptor (NGFr)‐immunoreactive neurons within the medial septum (MS; 53 and 54%, respectively) and vertical limb of the diagonal band (VLDB; 21 and 30%, respectively) ipsilateral to the lesion. In contrast, monkeys receiving implants of BHK‐hNGF cells exhibited a only a modest loss of cholinergic neurons within the septum (19 and 20%, respectively) and VLDB (7%). Furthermore, only implants of hNGF‐secreting cells induced a dense sprouting of cholinergic fibers within the septum, which ramified against the ependymal lining of the ventricle adjacent to the transplant site. Examination of the capsules retreived from monkeys just prior to their death revealed an abundance of cells that produced detectable levels of hNGF in a sufficient concentration to differentiate PC12A cells in culture. These findings support the use of polymer‐encapsulated cell therapy as a potential treatment for neurodegenerative diseases such as Alzheimer disease where basal forebrain degeneration is a consistent pathological feature. Moreover, this encapsulated xenogeneic system may provide therapeutically effective levels of a number of neurotrophic factors, alone or in combination, to select populations of neurons within the central nervous system. © 1994 Wiley‐Liss, Inc.
Analysis of gamma‐aminobutyric acidergic synaptic contacts in the thalamic reticular nucleus of the monkey
Authors: Williamson Andrew M. , Ohara Peter T. , Ralston Diane D. , Milroy Antonia M. , Ralston Henry J.
Published: January 2005

Gamma‐aminobutyric acidergic (GABAergic) neurons in the thalamic reticular nucleus (TRN) spontaneously generate a synchronous bursting rhythm during slow‐wave sleep in most mammals. A previous study at the electron microscopic level in cat anterior TRN has suggested that synchronous bursting activity could result from the large number of presumably GABAergic dendrodendritic synaptic contacts. However, little is known about the synaptology of the monkey thalamic reticular nucleus and whether it contains dendrodendritic contacts.

To address this issue, we examined tissue obtained from Macaca fascicularis that was prepared for electron microscopy using postembedding techniques to demonstrate GABA immunoreactivity. Examination of the anterior (motor) and posterior (somatosensory) portions of the TRN disclosed the following: The majority of synaptic contacts (87.5% of 958) were formed by axon terminals showing no GABA immunoreactivity and making asymmetric synaptic contacts on dendrites or cell bodies. A further 6.4% of synaptic contacts was composed of GABA‐immunoreactive presynaptic terminals making symmetric contacts with the dendrites of TRN neurons. The majority resembled the pleomorphic vesicle containing F‐terminals seen in the dorsal thalamus and known to originate from axons of TRN. A subset or possible second class did not resemble any previously described class of GABA‐immunoreactive terminals in the TRN. Both classes of these terminals making symmetric contacts may originate wholly or partially within the nucleus. There was one dendrodendritic synaptic contact and only a small number (3.2%) of axodendritic contacts with synaptic vesicles visible both pre‐ and postsynaptically.

We conclude that dendrodendritic contacts are probably not responsible for the synchronized bursting neuronal activity seen in the slow‐wave sleep of monkeys, and that, if TRN neurons are coupled synaptically, the most likely mechanism is through the synapses formed by recurrent axon collaterals of TRN neurons onto TRN dendrites. © 1994 Wiley‐Liss, Inc.
Projections of individual purkinje cells of identified zones in the ventral nodulus to the vestibular and cerebellar nuclei in the rabbit
Authors: Wylie D. R. , De Zeeuw C. I. , Digiorgi P. L. , Simpson J. I.
Published: January 2005

The projections of Purkinje cells from zones in the ventral nodulus of pigmented rabbits were studied with the use of extracellulary injected biocytin as an anterograde tracer. The zones were physiologically identified according to the complex spike modulation of Purkinje cells in response to optokinetic stimulation. Purkinje cells in the most medialzone do not respond to optokinetic stimulation; they project to the fastigial nucleus, the perifastigial white matter, the periinterposed white matter, and the medial vestibular nucleus. In the adjacent zone, Purkinje cells respond best to optokinetic stimulation about the vertical axis; they project to the periinterposed white matter and the medial vestibular nucleus. Purkinje cells in the next zone respond best to optokinetic stimulation about an axis approximately perpendicular to the ipsilateral anterior canal; they project to the periinterposed white matter, dorsal group y, the superior vestibular nucleus, and the medial vestibular nucleus. In the most lateral zone, Purkinje cells respond best to optokinetic stimulation about the vertical axis; they project to the periinterposed white matter, dorsal group y, and the medial vestibular nucleus. The majority of axons gave off collaterals and innervated more than one nucleus. Often, three or four different areas received terminals from a single Purkinje cell axon. The zonal projection pattern of the ventral nodulus is compared to that of the flocculus, which, with respect to the visual climbing fiber afferents, has similar zones. © 1994 Wiley‐Liss, Inc.
Overexpression of nerve growth factor in transgenic mice induces novel sympathetic projections to primary sensory neurons
Authors: Davis Brian M. , Albers Kathryn M. , Seroogy Kim B. , Katz David M.
Published: January 2005

Peripheral nerve crush induces novel projections from noradrenergic sympathetic neurons to sensory ganglia, and it has been suggested that these projections provide an anatomical substrate for chronic pain syndromes that occur after nerve injury. The present study demonstrates that novel sympathetic projections to sensory neurons are also induced in transgenic mice that overexpress nerve growth factor (NGF) in the skin. Specifically, a large proportion of trigeminal neurons in NGF transgenic mice were innervated by tyrosine hydroxylase (TH)‐positive pericellular arborizations that were seen only rarely in controls. Electron microscopic analysis of NGF transgenic mice revealed that trigeminal neurons were surrounded by numerous axonal varicosites containing synaptic specializations. Removal of the superior cervical ganglion abolished TH‐immunoreactive arborizations in the ipsilateral trigeminal ganglion confirming that these fibers were sympathetic axons. A two‐site enzymelinked immunosorbent assay revealed that transgenic ganglia contained a tenfold increase in NGF peptide compared to controls. However, reverse transcriptase polymerase chain reaction analysis showed no apparent expression of transgene mRNA in sensory ganglia, suggesting that the additional NGF was derived from increased NGF expression in the skin. These results indicate that NGF can induce novel sympathetic projections to sensory neurons in vivo and suggests a model in which increased NGF expression plays a role in the development of sympathetic hyperalgesia after nerve injury. © 1994 Wiley‐Liss, Inc.
Rapid expression and transport of embryonic N‐CAM in dentate gyrus following entorhinal cortex lesion: Ultrastructural analysis
Authors: Styren S. D. , Lagenaur C. F. , Miller P. D. , Dekosky S. T.
Published: January 2005

Neural cell adhesion molecules are known to be important in axon guidance and synapse formation in the developing brain. The embryonic form of neural cell adhesion molecule (eN‐CAM) is reexpressed in the outer molecular layer (OML) of the dentate gyrus following entorhinal cortex (ERC) lesion. Ultrastructural analysis revealed localization of eN‐CAM to the membrane of granule‐cell dendritic membranes and occasionally axons within the denervated zone. Because eN‐CAM is expressed rapidly (within 2 days) after ERC lesion, we were interested in the temporal sequence of expression. Denervated hippocampi (12, 15, 24, and 48 hours post‐ERC lesion) were stained with anti‐eN‐CAM and processed for immunoelectron microscopy. At 12 hours, there was no evidence of staining for eN‐CAM. By 15 hours after lesion, membranes of both dendrites and axons throughout the molecular layer exhibited moderate eN‐CAM staining, and dendritic cytoplasm was heavily labeled. Twenty‐four hours following lesion, plasma membrane staining of eN‐CAM on both axons and dendrites had increased in intensity within the OML, whereas membrane eN‐CAM staining was diminished in the inner molecular layer (IML), and the intradendritic cytoplasmic staining disappeared. By 48 hours after lesion, eN‐CAM staining had disappeared from the IML but remained intense and widely distributed in the OML. These findings suggest a rapid transport of de novo synthesized protein. A generalized reaction appears to occur immediately following denervation, and eN‐CAM is up‐regulated in the complete expanse of the dendritic membrane, despite the fact that only the OML is denervated. The newly up‐regulated eN‐CAM is rapidly withdrawn or disappears from the membrane in the (nondenervated) IML over the 24–48 hours postlesion. The brain rapidly responds to injury at the cellular level in the denervated zone in preparation for renervation by axon sprouting. © 1994 Wiley‐Liss, Inc.
Visual and somatosensory inputs to the avian song system via nucleus uvaeformis (Uva) and a comparison with the projections of a similar thalamic nucleus in a nonsongbird, columbia livia
Authors: Wild J. Martin
Published: January 2005

Nucleus uvaeformis (Uva), previously identified as a component of song control circuitry in songbirds, and nucleus dorsolateralis posterior thalami, pars caudalis (DLPc) in pigeon, were compared with respect to their relative positions in the dorsolateral part of the posterior thalamus, their cell types, and their afferent and efferent projections. Both nuclei are closely related to the habenulointerpeduncular tract, have similar cell types, and receive a dense projection from deep layers of the optic tectum, predominantly ipsilaterally, and a distinct projection from the dorsal column and external cuneate nuclei, predominantly contralaterally. Recordings of multiple unit activity evoked by visual and somatosensory stimuli were used to guide injections of tracer into either DLPc or Uva, and the projections to the telencephalon were charted. Both nuclei were found to have a major terminal field in the medial part of the ipsilateral neostriatum intermedium (NI), known as nucleus interfacialis (NIf) in songbirds, and a minor terminal field in the roof of the neostriatum caudale (NC). In pigeon, the DLPc terminations in NC were within a region known as neostriatum dorsale (Nd), and, in male songbirds, the Uva terminations were in the high vocal center (HVC). Recordings of visual and somatosensory evoked activity were then used to guide injections of tracer into NI, and the afferent and efferent projections were again compared in pigeon and songbirds. The projections from either DLPc or Uva were confirmed, and terminal fields were observed either in Nd in pigeon, the dorsolateral part of NC in female songbirds, or HVC in male songbirds. Injections of tracer into either Nd or HVC confirmed their sources of afferents in DLPc or Uva, respectively, and in NI, but there was incomplete overlap of the distribution of retrogradely labelled cells in NI and the terminal fields of DLPc or Uva.

It is concluded that DLPc and Uva are comparable nuclei having similar afferent and efferent projections relaying visual and somatosensory information to the telencephalon. The possible role of this information in vocal control is discussed. © 1994 Wiley‐Liss, Inc.
Size‐related colocalization of glycine and glutamate immunoreactivity in frog and rat vestibular afferents
Authors: Reichenberger I. , Dieringer N.
Published: January 2005

Presence and distribution of glutamate, glycine, GABA and β‐alanine in VIIIth nerves of frogs and rats were investigated with postembedding immunocytochemical methods on serial semithin sections.

In Scarpa's ganglion of the frog, all cell bodies were glutamate immunoreactive. About 17% of the cells per section were also glycine immunoreactive, but none were GABA or β‐alanine immunoreactive. The mean diameter of glycine‐positive cell bodies (26.7 ± 6.9 μm; N = 130) was significantly (P < 0.0001) larger than that of glycine‐negative cell bodies (15.7 ± 5.4 μm; N = 272). The intensity of glutamate immunostaining decreased with cell diameter, whereas the intensity of glycine immunostaining increased with cell diameter. As a result, the staining intensities for glutamate and glycine in a given cell were negatively correlated. Glycine immunoreactivity was also present in a size‐related manner in distal and proximal afferent fibers. The majority of thin fibers ( < 4 μm) was glycine negative, whereas most of the thick fibers ( > 10 μm) were glycine positive. Glycine‐positive fibers were observed in the sensory epithelia of all end organs in the inner ear. The saccular macula and its nerve, however, contained only few glycine immunoreactive structures.

In Scarpa's ganglion of the rat, all cells were immunoreactive for glutamate, about 12% for colocalized glycine, and none for GABA or β‐alanine. Glycine‐positive cell bodies were significantly (P < 0.0001) larger (32.2 ± 5.2 μm; N = 82) than glycine‐negative cell bodies (25.1 ± 5.3 μm; N = 274). Cell bodies in the spiral ganglion were only glutamate immunoreactive, whereas staining for glutamate, glycine, and GABA was dense in the ventral cochlear nucleus.

These results demonstrate that thicker vestibular afferent fibers represent a particular subpopulation that differs from the majority of thinner afferents due to their glycine immunoreactivity. © 1994 Wiley‐Liss, Inc.
Development of catecholamine systems in the brain of the lizard Gallotia galloti
Authors: Medina Loreta , Puelles Luis , Smeets Wilhelmus J. A. J.
Published: January 2005

For a better insight into general and derived traits of developmental aspects of catecholaminergic (CA) systems in amniotes, we have studied the development of these systems in the brain of a lizard, Gallotia galloti, with tyrosine hydroxylase (TH)‐ and dopamine (DA) immunohistochemical techniques. Two main groups of TH‐immunoreactive (THi) perikarya appear very early in development: one group in the midbrain which gives rise to the future ventral tegmental area, substantia nigra and retrorubral cell groups, and another group in the tuberomammillary hypothalamus. Somewhat later in development, TH/DA‐immunoreactive cells are observed in the thalamus, rostrodorsal hypothalamus and spinal cord, and, with another delay, in the suprachiasmatic nucleus, the periventricular organ, and the pretectal posterodorsal nucleus. CA cell groups that appear rather late in development include the cells in the olfactory bulb, the locus coeruleus and the caudal brainstem. As expected, the development of immunoreactive fibers stays behind that of the cell bodies, but reaches the adult‐like pattern just prior to hatching.

The present study revealed considerable variation in the relation between the state of cytodifferentiation and first expression of TH/DA immunoreactivity between CA cell groups. Catecholamine cells in the midbrain and tuberomammillary hypothalamus are still migrating, immature (absence of dendrites) and express only TH immunoreactivity at the time of first detection. Cells which appear at later developmental stages lie already further away from the ventricle, possess two or more dendritic prccesses, and generally express both TH‐ and DA immunoreactivity. © 1994 Wiley‐Liss. Inc.
Primate cingulostriatal projection: Limbic striatal versus sensorimotor striatal input
Authors: Kunishio Katsuzo , Haber Suzanne N.
Published: January 2005

The organization of the projections from the cingulate cortex to the striatum in the monkey was studied using the retrograde tracers Lucifer Yellow conjugated to dextran amines and horseradish peroxidase conjugated to wheat germ agglutinin. These tracers were injected into the different regions of the ventral (limbic) striatum and the dorsal (sensorimotor) striatum. The shell region of the nucleus accumbens was defined using calbindin‐D28K immunohistochemistry. Following injections into the ventral striatum, there are numerous retrogradely labeled neurons in the various regions of the primate cingulate cortex, most of which are derived from layer V. The cytoarchitectural subdivisions of cingulate cortex include the anterior cingulate cortex, areas 25, 24a–c, and 24a'–c', and the posterior cingulate cortex, areas 23a–c, 29, 30, and 31. There is a topographical organization of the projections from these different cingulate areas to the ventral and dorsal striatum. The medial ventral striatum receives input from the rostral part of the anterior cingulate cortex (areas 25 and 24a, b). The shell region of the nucleus accumbens receives fibers from areas 25, 24a,b, and 24a',b'. Projections to the central ventral striatum including the core of the nucleus accumbens are derived primarily from areas 25, 24a, 24b, and the medial part of area 24c. However, few labeled cells are detected in areas 24c and 24c'. The lateral ventral striatum receives input primarily from areas 24b, 24b' and 23b and medial portion of area 24c. The medial ventral striatum and the shell of the nucleus accumbens have a similar distribution of labeled cells, such that these regions derive their input almost entirely from the rostral anterior cingulate cortex. In contrast to the ventral striatum, the dorsal sensorimotor striatum receives projections from areas 24c, 24c' 23c and 31. These arise primarily from the lateral portion of lower bank and the fundus of the cingulate sulcus.

Our results demonstrate that areas 24c, 24c' and 23c, the lateral portion of the lower bank and the fundus of the cingulate sulcus project to the dorsal sensorimotor striatum. The medial portion of the lower bank of the cingulate cortex projects to the ventral striatum including the core of the nucleus accumbens. Different projections to striatum from discrete subdivisions of cingulate cortex indicate that these areas are heterogeneous and have different functions such that the fundus of the cingulate sulcus is related to skeletomotor function, whereas the medial portion of the lower bank of the cingulate sulcus is associated with the limbic‐related and association cortical function. The lateral portion of the lower bank may be a transition area and related to both motor and limbic functions.
Functional morphologies of retinal ganglion cells in the turtle
Authors: Kittila C. A. , Granda A. M.
Published: January 2005

Retinal ganglion cells in the turtle, Pseudemys scripta elegans, were examined by intracellular recording with a protocol of stationary and moving lights. Responses were apportioned among OFF, and ON, and ON‐OFF categories, and directional selectivity. Cells were injected with Neurobiotin, then later conjugated with avidin‐horseradish peroxidase in standard procedure. Morphological analysis of the stained cells included measurements of soma and dendritic field sizes, dendritic stratification, number of cell processes, dendritic branchings, and dendritic symmetry ratios.

ON and ON‐OFF cells are at least bistratified, sometimes tristratified, in both sublaminae A and B whether directionally selective or not. OFF cells, in contrast, are monostratified, or at least confined to sublamina A.

Morphological parameters of somal and dendritic field areas, branch point densities, and dendritic field asymmetries do not predict directional selectivity. Membrane polarization accompanying moving stimulation is discussed in terms of shunting inhibition and recording site. © 1994 Wiley‐Liss, Inc.
GABAergic and non‐GABAergic neurons in the nucleus of the optic tract project to the superior colliculus: An ultrastructural retrograde tracer and immunocytochemical study in the rabbit
Authors: Cardozo B. Nunes , Mize R. Ranney , van der Want J. J. L.
Published: January 2005

Both the nucleus of the optic tract (NOT) and the superior colliculus (SC) are thought to play important roles in the regulation of eye movements. The superior colliculus contributes to visual orientation and saccades, and the nucleus of the optic tract contributes to the detection of slow movements of the visual surround. Recently, a GABAergic projection has been described between these two nuclei in the cat, a species with frontal vision. The present study aimed at determining whether a similar GABAergic pathway exists in the rabbit, a species with lateral vision. To study this pathway we used the retrograde tracer cholera‐toxin (CTB) to identify NOT neurons projecting to the SC and GABA‐antibody immunostaining to identify GABA‐containing neurons and processes.

CTB injections into the superficial laminae of the SC showed that GABAergic and non‐GABAergic neurons in the NOT project to the SC. Both types of neurons have structural characteristics similar to other projection neurons in the NOT. In contrast to the NOT neurons projecting to the inferior olive (IO) which are mainly located in the rostral NOT, the GABAergic and non‐GABAergic NOT‐SC neurons are situated throughout the nucleus. The somata and principal dendrites of both neuron types receive numerous synaptic contacts from GABAergic terminals and only a few from retinal terminals. The NOT projection neurons to the SC thus establish prominent excitatory and inhibitory links between the two structures, suggesting the existence of separate circuits that could interact through a GABAergic and non‐GABAergic NOT‐SC projection. It is further suggested that these circuits may be involved in the regulation of saccades in the SC during optokinetic nystagmus. © 1994 Wiley‐Liss, Inc.
In situ hybridization analysis of CHOT1, a creatine transporter, in the rat central nervous system
Authors: Happe H. Kevin , Murrin L. Charles
Published: January 2005

A putative choline transporter (CHOT1) has been cloned from rat brain and is reported to express a high‐affinity, sodium‐dependent, hemicholinium‐3‐insensitive choline transporter in oocytes. A second transporter (OCCREATRA) cloned from rabbit brain is 98% homologous to CHOT1 and is reported to transport creatine. We examined the distribution of CHOT1 mRNA in rat brain by in situ hybridization, using a 48 base oligonucleotide probe. In adult rats, the hybridization signal was widespread, but with a distinct pattern. High levels of expression were detectedin the cerebellum (Purkinje and granule cell layers), choroid plexus, medial habenula, pontine nuclei, several brainstem, nuclei, and hippocampus (pyramidal cell layer). Moderate signal was detected in cortex, globus pallidus, corpus callosum, and most other white matter tracts. Very low levels were present in striatum, nucleus accumbens, hippocampus molecular layer, and cerebellar molecular layer. Emulsion autoradiography indicated cellular localization to both neurons and glia. CHOT1 mRNA was relatively abundant in some cholinergic regions, including the medial habenula, the medial septum, and several brainstem nuclei. However, the overall pattern was distinctly different from that expected for cholinergic markers and correlated well with the localization of creatine kinase. The widespread distribution and poor correlation with cholinergic markers indicates that the CHOT1 gene does not encode the classical choline transporter known to be associated with acetylcholine synthesis. It is possible that CHOT1 is associated with cholinergic neurotransmission in some brain regions. However, it appears to encode the rat creatine transporter, and its widespread and heterogeneous distribution suggests regions where creatine phosphate is an important energy source. © 1995 Willy‐Liss, Inc.
Dynorphin‐immunoreactive neurons in the rat nucleus accumbens: Ultrastructure and synaptic input from terminals containing substance P and/or dynorphin
Authors: van Bockstaele Elisabeth J. , Gracy K. Noelle , Pickel Virginia M.
Published: January 2005

The endogenous opioid peptide dynorphin is enriched in neurons in the nucleus accumbens, for which coexistence and synaptic interactions with substance P have been postulated. We examined the immunogold‐silver localization of dynorphin and immunoperoxidase labeling for substance P in single coronal sections through the core subregion of the nucleus accumbens of acrolein‐fixed rat brain tissue. Dynorphin‐immunoreactive somata were more prevalent than substance P‐containing neurons throughout the region sampled for ultrastructural analysis. Dynorphin‐labeled cells were spherical, contained unindented nuclei, and were closely apposed to other somata and dendrites, some of which also contained dynorphin immunoreactivity. The appositions were characterized by the absence of glial processes and contiguous contacts between the plasma membranes. Smooth endoplasmic reticulum and coated vesicles could also be identified in the cytoplasms on either side of the somatic or dendritic appositions. The dynorphin somata and dendrites received synaptic input from numerous unlabeled as well as dynorphin‐and/or substance P‐labeled axon terminals. Both types of terminals were morphologically similar in their content of small and large dense core vesicles and their formation of mainly symmetric synaptic specializations. In addition to dynorphin‐immunoreactive targets, numerous dynorphin‐and substance P‐labeled terminals also formed synapses with unlabeled somata and dendrites. In some cases, terminals separately labeled for dynorphin and substance P converged on common targets with or without detectable dynorphin immunoreactivity. Terminals colocalizing both peptides were also found to synapse on unlabeled or dynorphin‐labeled somata and dendrites. Additionally, presynaptic interactions were suggested by close appositions between dynorphin‐and/or substance P‐labeled terminals and other terminals that were unlabeled, dynorphin labeled, or substance P labeled. These results provide morphological data suggesting nonsynaptic communication between dynorphin‐immunoreactive neurons and other neurons possibly mediated through receptive sites or second messengers associated with smooth endoplasmic reticulum in the nucleus accumbens. They also indicate that, in this region, 1) the activity of dynorphin neurons may be dependent on activation of autoreceptors for dynorphin as well as substance P and 2) additional neurons lacking dynorphin immunoreactivity are most likely inhibited (symmetric junctions) by terminals containing either one or both peptides. The findings may have implications for motor and analgesic responses to aversive tonic pain transmitted through dynorphin and substance P pathways within the nucleus accumbens. © 1995 Willy‐Liss, Inc.
Dendritic reorganisation in the basal forebrain under degenerative conditions and its defects in Alzheimer's disease. I. Dendritic organisation of the normal human basal forebrain
Authors: Arendt Thomas , Marcova Lena , Bigl Volker , Brückner Martina K.
Published: January 2005

In the present study, the dendritic organisation of neurones in the normal human basal forebrain was analysed as a prerequisite for the evaluation of pathological changes occurring in Alzheimer's disease and related conditions (see other Arendt et al. papers in this issue).

Neurones in the basal nucleus of Meynert (NbM), the nucleus of the vertical limb of the diagonal band, and the medial septal nucleus were examined after Golgi impregnation. Cells were classified according to the dendritic branching pattern and soma shape as either reticular neurones or multipolar giant neurones. The reticular type of neurones constitutes more than 90% of neurones in the NbM. Cholinergic neurones also belong to this cell type. Reticular neurones were further subdivided into four subtypes. Morphological features and arrangement of reticular basal forebrain neurones were identical to those described for “reticular formation cells” or “isodendritic” neurones. Dendritic trees of reticular neurones show a spatial orientation perpendicular to passing fibres as well as a high degree of overlap, both of which are hallmarks of “open nuclei.”

The qualitative classification of Golgi‐impregnated basal forebrain neurones was substantiated by a computer‐based three‐dimensional analysis. Topologic and metric parameters of the dendritic tree were calculated for each type of neurone to characterise the degree of dendritic branching, the shape and orientation of the dendritic arborisation, the spatial extension of the dendritic tree, and soma size. The classification criteria were evaluated according to their power of discrimination between different cell types by means of a discriminant analysis. The quantitative approach applied in the present study not only provides an objective measure for the description and comparison of the structure of various types of neurones but also makes it possible to elucidate fine structural changes that might occur under pathologic conditions and that are not evident during qualitative studies alone. © 1995 Willy‐Liss, Inc.
NADPH‐diaphorase active and calbindin D‐28k‐immunoreactive neurons and fibers in the olfactory bulb of the hedgehog (Erinaceus europaeus)
Authors: Alonso J. R. , Arévalo R. , García‐Ojeda E. , Porteros A. , Briñón J. G. , Aijón J.
Published: January 2005

The hedgehog, a macrosomatic insectivore with an extraordinary development of the olfactory structures, has a crucial value for any phylogenetic or comparative study in mammals. The distribution pattern and morphology of NADPH‐diaphorase‐active and calbindin D‐28k‐immunoreactive neurons were studied in the main and accessory olfactory bulbs of the hedgehog. NADPH‐diaphorase (ND) staining was carried out by a direct histochemical method, and the calbindin D‐28k (CaBP) immunoreaction by using a monoclonal antibody and the avidin‐biotin‐immunoperoxidase method. The possible coexistence of both markers was determined by sequential histochemical‐immunohistochemical double labeling of the same sections. Specific neuronal populations were positive for both ND and CaBP markers. No cell colocalized both stains in the hedgehog olfactory bulb. A subpopulation of olfactory fibers, and a subpopulation of olfactory glomeruli, located on the medial side, were positive for ND. Surrounding both the ND‐positive and ND‐negative glomeruli, there were ND‐ and CaBP‐positive periglomerular cells, the latter group being much more abundant. A subpopulation of superficial short‐axon cells was CaBP positive but, contrary to what is observed in rodents, this neuronal type was always ND negative. In addition, three neuronal types were observed in the GL‐EPL border after CaBP immunostaining. These neuronal types have not been previously described either in the hedgehog or in the rodent olfactory bulb. Horizontal cells and vertical cells of Cajal were also observed after both ND and CaBP labeling. Distinct groups of ND‐ and CaBP‐positive cells, differing in size, shape, dendritic branching pattern, and staining intensity, were distinguished in the granule cell layer and in the white matter. The large and medium‐sized cells were identified as a very heterogeneous population of deep short‐axon cells, whereas a subpopulation of granule cells was ND positive. The accessory olfactory bulb showed ND staining in all vomeronasal fibers and glomeruli, and in subpopulations of periglomerular cells, granule cells, and deep short‐axon cells. The CaBP immunolabeling was more restricted and located in subpopulations of periglomerular cells and in deep short‐axon cells. These results indicate different and more complex ND and CaBP staining patterns in the hedgehog olfactory bulb than those previously described in rodents, including the presence of specific, chemically and morphologically defined new neuronal types. © 1995 Willy‐Liss, Inc.
Comparative localization of serotonin1A, 1C, and 2 receptor subtype mRNAs in rat brain
Authors: Wright D. E. , Seroogy K. B. , Lundgren K. H. , Davis B. M. , Jennes L.
Published: January 2005

Serotonin (5‐HT) mediates its effects on neurons in the central nervous system through a number of different receptor types. To gain better insight as to the localization of 5‐HT responsive cells, the distribution of cells expressing mRNAs encoding the three 5‐HT receptor subtypes 1A,1C, and 2 was examined in rat brain with in situ hybridization using cRNA probes. 5‐HT1A receptor mRNA labeling was most pronounced in the olfactory bulb, anterior hippocampal rudiment, septum, hippocampus (dentate gyrus and layers CAI‐3), entorhinal cortex, interpeduncular nucleus, and medullary raphe nuclei. 5‐HT 1C receptor mRNA labeling was the most abundant and widespread of the three 5‐HT receptor subtypes examined. Hybridization signal was denset in the choroid plexus, anterior olfactory nucleus, olfactory tubercle piriform cortex, septum, subiculum, entorhinal cortex, claustrum, accumbens nuclues, striatum, lateral amygdala, paratenial and paracentral thalamic nuclei, subthalamic nucleus, substantia nigra, and reticular cell groups. 5‐HT2 receptor mRNA was localized to the olfactory bulb, anteriorhippocampal rudiment, frontal cortex, piriform cortex, entorhinal cortex, claustrum, pontine nuclei, and cranial nerve motor nuclei including the oculomotor, trigeminal motor, facial, dorsal motor nucleus of the vagus, and hypoglossal nuclei. The distributions of mRNAs for the three different 5‐HT receptor subtypes overlap with regions that bind various 5‐HT receptor‐selective ligands and are present in nearly all areas known to receive serotonergic innervation. The results of this study demonstrate that nervous which express these 5‐HT receptor subtypes are very widespread in the central nervous system, yet possess unique distributions with in the rat brain. Moreover, previously unreported regions of 5‐HT receptor subtype expression were observed, particulary with the 5‐HT receptor riboprobe in the brainstem. Finally, several brain areas contain multiple 5‐HT receptor subtype mRNAs, which leads to the possibility that individual cells may express more than one 5‐HT receptor subtype. © 1995 Willy‐Liss, Inc.
Quantitative analysis of the columnar arrangement of neurons in the human cingulate cortex
Authors: Schlaug Gottfried , Schleicher Axel , Zilles Karl
Published: January 2005

The spatial organization of human cingulate (areas 24b, 23b, and 31) and pericingulate (areas 7 and 19) cortex was examined by using an image analyzer to measure characteristics of vertically oriented, translaminar columns of neurons in the cerebral cortex. Columns of 30–50 μm in diameter are hypothesized to be a general feature of cortical organization, but no quantitative analysis of different human cortical areas has been performed. Our results prove for the first time that a columnar organization was detectable in every area examined. The average width of cell columns was approximately 40 μm separated by a neuropil‐rich fascile of the same dimension. Because differences in the expression of a columnar organization were seen, the degree of columnization was subsequently expressed by a verticality index (VI) revealing specific changes in its dimension depending on the architectonic area. The VI was calculated by a linear combination of three variables derived from the measurement of cell density profiles in Nissl‐stained sections at right angles to vertically oriented cell columns. Variables included the amplitude of profile peaks, the standard deviation of the width of those profile peaks, and the standard deviation of the distances between profile peaks. The index of verticality describes the deviation of a distinct area and layer from the mean degree of vertical organization of all cortical areas and layers examined. Thus, different degrees of columnar organization can be quantitatively described by the verticality index and can be used as criteria to characterize architectonic areas. © 1995 Willy‐Liss, Inc.
Colocalization of somatostatin, neuropeptide Y, and NADPH‐diaphorase in the caudate‐putamen of the rat
Authors: Rushlow W. , Flumerfelt B. A. , Naus C. C. G.
Published: January 2005

Somatostatin, neuropeptide Y, and nicotinamide adenine dinucleotide phosphatediaphorase are colocalized within a small population of medium aspiny neurons in the caudate‐putamen of the rat. The extent of colocalization, however, appears to be in dispute. In order to examine the question of colocalization between these three neuroactive substances, a series of double‐labelling experiments was performed. This was accomplished by combining immunocytochemistry for somatostatin or neuropeptide Y or enzyme histochemistry for nicotinamide adenine dinucleotide phosphate‐diaphorase with in situ hybridization for somatostatin and/or neuropeptide Y mRNA. The results of such analysis indicate that nicotinamide adenine dinucleotide phosphate‐diaphorase and somatostatin mRNA are 100% colocalized throughout the caudate‐putamen, except for the area bordering the globus pallidus. All neurons that contain neuropeptide Y contain somatostatin message. Only 84% of the neurons that contain somatostatin mRNA, however, also contain neuropeptide Y. Neurons that contain somatostatin 28 but not neuropeptide Y are found throughout the caudate‐putamen. These results indicate that the somatostatin neuron population in the rat caudate‐putamen is not homogeneous. Instead, the medium aspiny neuron population is actually composed of several subpopulations based on the content of neuroactive substances. © 1995 Willy‐Liss, Inc.
Development of the catecholamine neurons in human embryos and fetuses, with special emphasis on the innervaton of the cerebral cortex
Authors: Zecevic Nada , Verney Catherine
Published: January 2005

The cathecholaminergic (CA) systems have been described as appearing early in the development of the mammalian central nervous system (CNS), but their exact distribution in humans has been studied only following gestational week (g.w.) 13. Furthermore, it is not known when CA fibers initially penetrate the developing cerebral cortex. In this study, the CA cells groups and fibers are described in the human central nervous system from 6 to 13 g.w. as revealed with immunocytochemical techniques, with antibodies raised against three synthetic enzymes of the catecholamine (CA) pathway: tyrosine hydroxylase (TH), dopamine‐β‐hydroxylase (DBH), and phenylethanolamine‐N‐methyltransferase (PNMT). At 6 g.w., TH‐like immunoreactive (TH‐IR) cell groups were widespread through the caudorostral extension of the CNS corresponding to the different dopaminergic mesencephalic and hypothalamic groups. Noradrenergic groups also were labeled in the medulla oblongata and in the locus coeruleus as well as in other areas in the pons. Additional TH‐IR cell groups might represent a transient developmental expression of TH similar to that observed in the rat. DBH immunoreactivity labeled primarily the noradrenergic pontic cell groups and, to a lesser extent, groups located in the medulla oblongata. Rare PNMT‐IR neurons were detected in the medulla oblongata only at 13 g.w. The main CA bundles described in the adult were also observed in human embryos and fetuses. At 6 g.w., TH‐IR pathways extended caudorostrally within the central tegmental tract and the dorsal tegmental bundle, the latter merging with the dopaminergic mesotelencephalic pathway giving rise to the medial forebrain bundle in the basal forebrain. At 7–8 g.w., TH‐IR fibers extended to the basal ganglia and the telencephalic wall. The first TH‐IR and, to a much lesser extent, DBH‐IR fibers penetrated the frontal lateral cortical anlage through the intermediate zone and sparsely through the marginal zone but not through the thin cortical plate. A second stream entered the telencephalic anlage frontomedially, ventral to the septal area. At 11 g.w., numerous TH‐IR fibers invaded the subplate layer, but they penetrated the cortical plate only at 13 g.w. At that time, TH‐IR and DBH‐IR fibers had reached the occipital cortex in a rostrocaudal gradient. The appearance of well‐organized CA system already in embryonic stages in humans could be of great importance for normal shaping of the nervous system as well as for development of cortical circuitry. © 1995 Willy‐Liss, Inc.