bluuebunny/crossref_metadata_2025 huggingface dataset:
Anatomy of the mushroom bodies in the honey bee brain: The neuronal connections of the alpha‐lobe
Authors: Rybak Jürgen , Menzel R.
Published: January 2005

Neural connections between the mushroom body (MB) and other protocerebral areas of the honeybee's brain were studied with the help of cobalt chloride and Golgi staining methods. Focal injections of cobalt ions into the α‐lobe neuropil of the MB reveal seven clusters of somata located in the protocerebrum and deutocerebrum of each brain hemisphere. These neurons connect the mushroom body neuropil with protocerebral areas and number approximately 400. They contact the layered organization of the α‐lobe at different locations. Some project not only into the α‐lobe, but also into the β‐lobe and pedunculus neuropils. Fifteen cell types which form intraprotocerebral circuits are morphologically described. They can be divided into three categories: (1) unilateral neurons, with projection fields restricted to the ipsilateral protocerebrum; these neurons connect the α‐lobe with areas in the protocerebral lobe and ramify with densely layered arborisations arranged perpendicularly to the longitudinal axis of the α‐lobe; (2) recurrent neurons, which interconnect subcompartments of the MB, forming loops at different leveles of the neuropil; their arborisations are mainly restricted to the α‐lobe, β‐lobe, pedunculus, and calyces of the ipsilateral MB; they also ramify sparsely around the neuropil of the α‐lobe; and (3) bilateral neurons, which either interconnect both α‐lobes or connect the ipsilateral α‐lobe and protocerebral lobe with the dorsolateral protocerebral lobe of the conntralateral hemisphere. The connections of different compartments of the MB with other parts of the protocerebrum as revealed in this study are discussed in the context of hypotheses about the functional role of MBs in the honeybee brain. © 1993 Wiley‐Liss, Inc.
Origin of serotoninergic afferents to the hypoglossal nucleus in the rat
Authors: Manaker Scott , Tischler Laura J.
Published: January 2005

The hypoglossal nucleus contains serotonin and several different serotonin receptors, and serotonin is present in fibers and terminals contacting hypoglossal motoneurons. Serotonin alters the excitability of hypoglossal motoneurons, and may influence hypoglossal motoneuron activity in a variety of physiological processes. Since the hypoglossal nucleus contains no serotoninergic somata, the present study sought to identify the sources of serotoninergic afferents to the hypoglossal nucleus. Fluorogold was injected into the hypoglossal nucleus and serotoninergic immunofluorescence was utilized in a dual‐fluorescence technique to identify the sources of serotoninergic afferents to the hypoglossal nucleus. The results demonstrate that most serotoninergic afferents to the hypoglossal nucleus originate from the nuclei raphe pallidus and obscrus, while fewer originate from the nucleus raphe magnus and the parapyramidal region. Other regions of the medial tegmental field and the pons that contain both serotoninergic neurons and neuronal afferents to the hypoglossal nucleus contain no double‐labeled neurons. © 1993 Wiley‐Liss, Inc.
The dorsomedial visual area of owl monkeys: Connections, myeloarchitecture, and homologies in other primates
Authors: Krubitzer Leah A. , Kaas Jon H.
Published: January 2005

Cortical connections of the dorsomedial visual area (DM) of owl monkeys were revealed with injections of the bidirectional tracer, wheatgerm agglutinin conjugated with horseradish peroxidase (WGA‐HRP), or the retrograde fluorescent tracer, diamidino yellow. Microelectrode recordings in two cases identified DM as a systematic representation of the visual hemifield in a densely myelinated rectangle of cortex just rostral to the dorsomedial portion of the second visual area (V–II, or area 18). Cortex was flattened and cut parallel to the surface in all cases so that the myeloarchitectonic borders of DM and other areas such as the primary visual area (V‐I or area 17), V‐II or area 18, and the middle temporal visual area (MT) could be readily determined, and the surface view patterns of connections could be directly appreciated. The ipsilateral pattern of connections of DM were dense and visuotopically congruent with area 17, area 18, and MT, and moderate to dense connections were with the medial visual area (M), the rostral division of the dorsolateral visual area, the dorsointermediate area, the ventral posterior area, the caudal division of inferotemporal cortex (ITc), the ventral posterior parietal area, and visuomotor cortex of the frontal lobe. The connections of DM were concentrated in the cytochrome oxidase (CO)‐dense blobs of area 17, the CO‐dense bands of area 18, and the CO‐dense regions of MT. Callosal connections of DM were with matched locations in DM in the opposite hemisphere, and with VPP.

The ipsilateral connections of DM with area 17 were confirmed by injecting WGA‐HRP into area 17 in one owl monkey. In addition to labelled cells and terminals in area 18 and MT, bidirectionally transported tracer was also apparent in DM. Evidence for the existence of DM in other primates was obtained by injecting area 17 and examining the areal patterns of connections and myeloarchitecture in three species of Old World monkeys, two additional species of New World monkeys, and prosimian galagos. In all of these primates, one of three major targets of area 17 was a densely myelinated zone of cortex just rostral to dorsomedial area 18, in the location of DM in owl monkeys. Thus, it seems likely that DM is a visual area common to all primates. © 1993 Wiley‐Liss, Inc.
Central retinal area is not the site where ganglion cells are generated first
Authors: Rager Ute , Rager Günter , Frei Bernard
Published: January 2005

The development of retinal ganglion cells (RGC) was studied in the chick from stage 18 to adulthood. Our main objectives were to identify the retinal site where the first RGCs differentiate, to locate this site relative to the optically defined central retinal area, and to map the spatial arrangement of the RGC field at different stages in development. The eyes of the experimental animals were fixed and serially sectioned. The borders of RGC fields were determined from the presence of either ganglion cell perikarya or ganglion cell axons. In seven cases between stages 21 and 26, the borders of the RGC fields were confirmed electron microscopically. The serial sections together with the RGC fields were then reconstructed in three dimensions. The reconstructed retinae were projected onto a plane by using the radially equidistant polar azimuthal projection.

First, RGCs appear dorsal to the apex of the optic fissure. Ganglion cell development then initially spreads out symmetrically with respect to the optic fissure. However, from stage 29 on, the nasal half of the retina expands much more than the temporal half. This asymmetrical growth entails that the optic fissure is eventually located in the temporal half of the retina in the mature animal.

The RGC fields of the embryonic stages were superimposed on the retina of a visually active animal according to their real size and position. It turned out that the central retinal area was at least 2 mm away from the site where the first RGCs were generated. It is not before stage 28 that the prospective central retinal area is included into the expanding ganglion cell field. The fact that RGCs at the central retinal area are generated 2.5 days later than first RGCs near the apex of the optic fissure has important implications for the formation of the retinotectal projection. © 1993 Wiley‐Liss, Inc.
Immunohistochemical localization of a ligand‐binding and a structural subunit of nicotinic acetylcholine receptors in the central nervous system of Drosophila melanogaster
Authors: Schuster Renate , Phannavong Bounpheng , Schröder Christiane , Gundelfinger Eckart D.
Published: January 2005

The distribution of two subunits of nicotinic acetylcholine receptors in the developing and the differentiated central nervous system of Drosophila melanogaster was studied. With subunit‐specific antibodies raised against the ligand‐binding α‐like subunit ALS and the putative non‐ligand‐binding subunit ARD, we find both ALS‐like and ARD‐like immunoreactivity widely distributed in most neuropiles of the optic lobes, the protocerebrum, the deutocerebrum and the thoracic ganglion of the adult fly. With a single exception, namely in the lamina of the visual system, the antigens recognized by the two types of antibodies are colocalized. This observation is consistent with previous immunoprecipitation data indicating that the ALS and ARD proteins are integral components of the same hetero‐oligomeric receptor that binds the nicotinic antagonist α‐bungarotoxin with high affinity. During embryonic development ARD‐like immunoreactivity is first detectable in ≈︁ 10 hour old embryos. Both subunits are consistently detected in the central nervous system ofthe late embryo, the three larval stages, and all prepupal and pupal stages. During metamorphosis the optic stalk is transiently immunoreactive with anti‐ARD, but not with anti‐ALS antiserum. Although in larvae and adults, immunoreactivity with both types of antibodies is most abundant in synaptic regions, in embryos and pupae strong staining of cortical cell body layers is observed, in particular with anti‐ARD antisera. As these developmental periods coincide with strong accumulation of ARD transcripts, the cell body staining may reflect newly synthesized and assembled receptors, while the functional ARD‐ and ALS‐containing receptor may be destined for synapses. © 1993 Wiley‐Liss, Inc.
Synapses between slowly adapting lung stretch receptor afferents and inspiratory beta‐neurons in the nucleus of the solitary tract of cats: A light and electron microscopic analysis
Authors: Anders Klaus , Ohndorf Wolfgang , Dermietzel Rolf , Richter Diethelm W.
Published: January 2005

Previous neuroanatomic and physiologic studies indicated that afferent fibres from slowly adapting pulmonary stretch receptors (SAR) project to the nuclei of the solitary tract and terminate on inspiratory beta‐neurons. In the present study we combined electrophysiologic and morphologic approaches to verify the presumed monosynaptic connections between SARs and beta‐neurons.

Single identified beta‐neurons and single identified SAR afferent fibres were labelled intrasomally and intraaxonally, respectively, with horseradish peroxidase (HRP) in the same anesthetized cats. Under the light microscope, we analyzed the morphology of beta‐neurons and their dendritic fields and of the terminal projection pattern of fibres from SARs and identified potential synaptic connections between boutons of SAR afferent fibres and the soma and dendrites of beta‐neurons. The identified tissue was then processed further for electron microscopic analysis.

On average, beta‐neurons had 6 primary dendrites that bifurcated 3–8 times. The dendritic trees extended 1.5 mm both rostrocaudally in the ventrolateral nucleus of the solitary tract and medially into the intermediate subnucleus. Axons of beta‐neurons curved toward the midline and no collateral branches were evident over its stained length (2.5–3.4 mm).

Axodendritic synaptic contacts between SAR fibres and beta‐neurons were identified electron microscopically in four of six tissue samples chosen by light microscopy. In addition, we located 2 axodendritic and 2 axosomatic synaptic contacts that were not observed under light microscopic screening. The boutons of SAR fibres contained clear, round vesicles and formed asymmetrical synapses with beta‐neurons. Multiple synaptic connections were found between collaterals of a single SAR and single beta‐neurons, indicating a dense terminal projection of single SAR afferent fibres onto beta‐neurons. These morphologic data prove monosynaptic connections between electrophysiologically identified SAR afferent fibres and beta‐neurons. © 1993 Wiley‐Liss, Inc.
Correlations between the receptive field properties and morphology of neurons in the deep layers of the hamster's superior colliculus
Authors: Mooney Richard D. , Nikoletseas Michael M. , King Tod D. , Savage Steven V. , Huang Xiaoguang
Published: January 2005

Extracellular and intracellular recording, receptive field mapping, and intracellular HRP injection techniques were used to define the morphological classes of cells in the deep laminae of the hamster's superior colliculus and to determine whether there are any correlations between the structural and functional characteristics of these neurons. A total of 110 neurons were characterized and reconstructed. Of these, 23.6% (N = 26) were visual, 60% (N = 66) were somatosensory, 0.9% (N = 1) were bimodal (visual‐somatosensory), and 15.4% (N = 17) were unresponsive. Of the somatosensory neurons, 72.7% (N = 48) were low threshold, 4.5% (N = 3) had a wide dynamic range, 9.1% (N = 6) responded only to noxious stimulation, and 13.6% (N = 9) had complex somatosensory receptive fields.

Deep layer cells were divided into eight morphological classes. These classes were multipolar cells (26.4%, N = 29), bipolar cells (9.1%, N = 10), widefield vertical cells (7.3%, N = 8), horizontal cells (13.6%, N = 15), stellate cells (10.9%, N = 12), ventrally directed cells (5.5%, N = 6), sparse radial cells (17.3%, N = 19), and small sparse radial cells (6.4%, N = 7). Four cells (3.6%) did not fit into this classification scheme. Univariate and multivariate analyses of variance of properties such as soma area, number of branch points, total dendritic length, and volume and orientation of dendritic arbor indicated that these classes were significantly different. However, X2 analysis and multivariate analysis of variance indicated no significant relationships between morphological class and either laminar location or receptive field type. There was a significant positive relationship between the possession of dendrites that extended into the superficial laminae and visual responsivity. © 1993 Wiley‐Liss, Inc.
Expiratory neurons of the bötzinger complex in the rat: A morphological study following intracellular labeling with biocytin
Authors: Bryant Thomas H. , Yoshida Shigetaka , de Castro Denis , Lipski J.
Published: January 2005

The term “Bötzinger Complex” (BOT) refers to a distinct group of neurons, located near the rostral portion of the nucleus ambiguus, which are known to play an important role in the control of respiratory movements. Previous studies conducted in cats have demonstrated that most of these neurons are active during expiration, exerting a monosynaptic inhibitory action on several subpopulations of inspiratory neurons in the medulla and spinal cord. The aim of this study was to examine morphological properties and possible synaptic targets of BOT neurons in the rat. Forty‐one expiratory neurons were labeled intracellularly with biocytin; 12 were interneurons (BOT neurons) and 29 were motoneurons. The latter could not be antidromically activated following stimulation of the superior laryngeal or vagal nerves. BOT neurons showed extensive axonal arborisations in the ipsilateral medulla, with some projections to the contralateral side. Bouton‐like axon varicosities mainly clustered in two areas: near the parent cell bodies, and in the area corresponding to the rostral part of the ventral respiratory group (VRG). In five pairs of labeled neurons, each consisting of one BOT neuron and one inspiratory neuron in the rostral VRG, no appositions were identified at the light microscopic level between axons of BOT neurons and dendrites or cell bodies of inspiratory neurons. These results demonstrate that some features of BOT expiratory neurons in the rat are similar to those previously described in cats. The differences include their more ventral location in relation to the compact formation of nucleus ambiguus (retrofacial nucleus), and the relative paucity in the rat of neurons displaying an augmenting pattern of activity and of neurons with spinally projecting axons. In addition, we were unable to find morphological evidence for contacts between labeled BOT neurons and ipsilateral inspiratory neurons near the obex level, a finding not consistent with previous electrophysiological studies in the cat in which such synaptic connections have been identified. © 1993 Wiley‐Liss, Inc.
Nerve growth factor receptor (p75)‐immunoreactivity in the normal adult feline trigeminal system and following retrogasserian rhizotomy
Authors: Henry Michael A. , Westrum Lesnick E. , Bothwell Mark , Johnson Lonnie R.
Published: January 2005

The 75 kDa protein nerve growth factor receptor [NGFr(p75)] is a neurotrophin receptor that is able to bind different members of the neurotrophin family of molecules implicated in affecting neruronal survival. Here we describe the light microscopic distribution of NGFr(p75)‐immunoreactivity (IR) within the feline trigeminal brainstem sensory nuclear complex and trigeminal ganglion of normal adult subjects and in subjects 10 and 30 days following retrogasserian rhizotomy. Within the trigeminal ganglion of normal subjects, numerous fibers and most of the neuronal cell bodies showed NGFr(p75)‐IR that varied in intensity, while cells and fibers with NGFr(p75)‐IR were less numerous within the mesencephalic trigeminal nucleus. Within the main sensory and spinal trigeminal nuclei, NGFr(p75)‐IR formed a reproducible pattern that varied between the different subnuclei. The NGFr(p75)‐IR consisted both of dense pockets and a low level NGFr(p75)‐IR that was selective to the trigeminal neuropil. Following rhizotomy, most of the NGFr(p75)‐IR was lost from the main sensory and spinal trigeminal nuclei, except in regions where the upper cervical roots and cranial nerves VII, IX, and X project. In contrast, examination of the central root that was still attached to the trigeminal ganglion showed increased NGFr(p75)‐IR in fibers and supporting cells, as did the motor root within the peripheral mandibular division. These results indicate that the majority of the NGFr(p75)‐IR within the main sensory and spinal trigeminal nuclei originates from primary trigeminal afferents and that retrogasserian rhizotomy leads to an up‐regulation of NGFr(p75)‐IR in the part of the central root that is contiguous with the ganglion. © 1993 Wiley‐Liss, Inc.
Retrograde labeling of neurons in the spinal cord that project directly to the amygdala or the orbital cortex in the rat
Authors: Burstein Rami , Potrebic Sonja
Published: January 2005

The amygdala and orbital cotex are thought to play an important role in the regulation of autonomic functions, hormonal secretion, and behavioral expression in response to sensory stimulation. The responsiveness of neurons in these regions to stimulation of cutaneous and visceral organs indicates that sensory information reaches the amygdala and orbital cortex. In the past, a large number of studies have thoroughly documented multiple neural pathways by which sensory information can reach these regions via relay nuclei in the brainstem and diencephalon. Recent studies reported that the amygdala and orbital cortex also receive direct input from the spinal cord. The aim of this study was to determine the magnitude and the origin of these projections in the rat.

Injections of the retrograde tracer Fluoro‐Gold (FG), restricted to the amygdala, labeled several hundred neurons bilaterally (60% contralateral) throughout the length of the spinal cord. More than 60% of labeled neurons were found in the lateral reticulated area of the deep dorsal horn and the gray matter surrounding the central canal. Many neurons were also found in the lateral spinal nucleus. Labeled neurons were concentrated in upper lumbar and upper cervical segments.

Injections of Fluoro‐Gold that were centered in the orbital cortex labeled only a small number of neurons (73% contralateral) within the spinal cord. Most labeled neurons were found in the lateral reticulated area. Neurons located in the intermediate zone and the gray matter surrounding the central canal were found mainly in upper lumbar and upper cervical segments.

These findings, together with the anterograde tracing observations, provide evidence for direct projections of spinal cord neurons to the amygdala and orbital cortex. Their laminar distribution in the spinal cord and the involvement of the amygdala and orbital cortex in limbic functions suggest that these pathways may play a role in neuronal circuits that enable somatosensory information, including pain, to affect autonomic, endocrine and behavioral functions. © 1993 Wiley‐Liss, Inc.
Fate of abdominal ventral unpaired median cells during metamorphosis of the hawkmoth, Manduca sexta
Authors: Pflüger H. J. , Witten J. L. , Levine Richard. B.
Published: January 2005

Each of the unfused abdominal ganglia in the larval, pupal, and adult stages of the hawkmoth, Manduca sexta, has two large ventral median neurons with axons that bifurcate to innervate targets on both sides of the abdomen. Although the dendritic structures of the two neurons are similar, their axons branch to innervate distinct sets of target muscles. During metamorphosis both neurons undergo dendritic regression, followed by growth of new arborizations during adult development. The neurons must innervate different targets in the larva and adult, since many larval muscles degenerate and are replaced during metamorphosis. Both neurons were reactive with an antibody to the neuromodulatory compound, octopamine, in the larval and adult stages. Pairwise intracellular recordings in isolated nerve cords revealed spontaneous excitatory synaptic potentials that occurred in the ventral median neurons of each ganglion in an anterior‐to‐posterior sequence. The synaptic potentials were eliminated when the interganglionic connective was interrupted posterior to the subesophageal ganglion. The ventral median neurons were also excited by tactile stimulation of the body surface in larvae, pupae and adults. © 1993 Wiley‐Liss, Inc.
Nitric oxide synthase‐like immunoreactivity in lumbar dorsal root ganglia and spinal cord of rat and monkey and effect of peripheral axotomy
Authors: Zhang Xu , Verge Valerie , Wiesenfeld‐Hallin Zsuzsanna , Ju Gong , Bredt David , Snyder Solomon H. , Hökfelt Tomas
Published: January 2005

With the immunofluorescence technique, nitric oxide synthase (NOS)‐like immunoreactivity (LI) was found in a few medium‐sized and small sensory neurons in lumbar (L) 4 and L5 dorsal root ganglia (DRG) of normal rat, and in most of these neurons, NOS‐LI coexisted with calcitonin gene‐related peptide and sometimes with substance P and galanin. NOS‐immunoreactive nerve fibers, terminals and small neurons were also located in the dorsal horn of the segments 4 and 5 of the rat lumbar spinal cord with the highest density in inner lamina II. Many NOS‐positive neurons and fibers were seen in the area around the central canal. A sparse network of NOS‐immunoreactive nerve fibers was found in the ventral horn. After unilateral sciatic nerve cut in the rat, the number of NOS‐positive neurons increased in the ipsilateral L4 and L5 DRGs, mainly in medium and small neurons, but also in some large neurons and very small neurons. NOS‐LI could now also be seen in the ipsilateral dorsal roots, and in an increased number of fibers and terminals in both outer and inner lamina II of the ipsilateral dorsal horn. The number of NOS‐immunoreactive neurons in lamina II of the ipsilateral dorsal horn was reduced. In the monkey L4 and L5 DRGs, many small neurons were NOS‐immunoreactive, but only a few weakly stained nerve fibers and terminals were found in laminae I‐IV of the dorsal horn at L4 and L5 lumbar levels. A few NOS‐positive neurons were present in lamina X. The number of NOS‐immunoreactive neurons was somewhat reduced in DRGs 14 days after peripheral axotomy, but no certain effect was seen in the dorsal horn. These results, together with earlier in situ hybridization studies, demonstrate that axotomy in rat induces a marked upregulation of NOS synthesis in primary sensory neurons, thus suggesting a role for NO in lesioned sensory neurons. In contrast, no such effect was recorded in monkey, perhaps indicating distinct species differences. © 1993 Wiley‐Liss, Inc.
Tanycytes in the sunfish brain: NADPH‐diaphorase histochemistry and regional distribution
Authors: Ma Pokay M.
Published: January 2005

NADPH‐diaphorase histochemistry has been shown to be a useful method for identifying cells that synthesize and release nitric oxide, which is implicated in the modulation of a variety of neural functions, including synaptic transmission, cerebral blood flow, and excitotoxicity. In the sunfish brain, NADPH‐diaphorase histochemistry stains tanycytes specifically and almost exclusively, allowing for a thorough examination of the morphology and distribution of this type of cell. Tanycytes are nonciliated, process‐bearing ependymal and extraependymal cells that contact the ventricular surface via apical processes, and the pial surface via basal processes. Ependymal tanycytes are located at the ventricular surface, and project basal processes into the parenchyma of the brain. Extraependymal tanycytes are found away from the ventricular matrix. Some extraependymal tanycytes are small, bipolar, and tend to be associated with bundles of basal processes. Isolated extraependymal tanycytes are larger, darkly stained, and multipolar. Their basal processes terminate in specialized endfeet on blood vessels, neuronal somata, or the pial surface. Specialized types of tanycytes are found in the optic tectum, the epineurial septum between axonal bundles along the midline in the medulla, and in restricted regions on the pial surface in the medulla. The only NADPH‐diaphorase‐positive neurons are found in the commissural nucleus of area ventralis telencephali. Injection of horseradish peroxidase into the ventricles shows that tanycytes lining the third and fourth ventricles are capable of taking up the tracer and transporting it into their basal processes.

Tanycytes are unevenly distributed in the brain. There is a rough rostrocaudal gradient of cell density: tanycytes are sparse in the telencephalon and dense in the isthmus and medulla, although cell density is low in the spinal cord. Not all ventricular linings contain tanycytes: cell density is low in the medial ventricle of the telencephalon and in the infundibular recess, and high along the fourth ventricle.

The function of tanycytes in the sunfish is not known. The association of tanycytes with both the ventricles and blood vessels raises the possibility that they play some role in sampling the biochemical constituents of both compartments and communicating the information to neural elements. It is proposed that tanycytes react to the biochemical composition in the ventrile and plasma by increasing or decreasing nitric oxide synthesis and release, which in turn influence neuronal activity or cerebral blood flow. © 1993 Wiley‐Liss, Inc.
Neurophysin‐containing pathway from the paraventricular nucleus of the hypothalamus to a sexually dimorphic motor nucleus in lumbar spinal cord
Authors: Wagner Christine K. , Clemens Lynwood G.
Published: January 2005

A model that has been widely used in the study of steroid sensitive neurons, the spinal nucleus of the bulbocavernosus (SNB) is a sexually dimorphic motor nucleus in the lower lumbar spinal cord that innervates the striated bulbocavernosus (BC) muscle. The BC is responsible for penile reflexes in the male rat, which are important in ensuring pregnancy in females. The characterization of afferents to the SNB aids in the understanding of the neural circuitry involved in reproductive behavior. We have recently identified the paraventricular nucleus (PVN) as a possible source of afferents to the SNB. Because the PVN is the major source of oxytocin/vasopressin within the central nervous system (CNS), the purpose of the present study was to examine and characterize a neurophysin (NP)‐containing pathway from the PVN to the SNB. The results demonstrate that neurons of the lateral parvicellular subnucleus of PVN, which project to levels of spinal cord containing SNB motoneurons, contain NP, the coproduct of oxytocin and vasopressin. NP‐containing fibers and putative terminals were found in the region of the SNB and appear to contact the soma and proximal dendrites of SNB motoneurons which were retrogradely identified as BC‐innervating. Electrolytic lesions, which destroy the lateral parvicellular subnucleus of PVN, abolish NP‐containing fibers in the region of the SNB, suggesting that the PVN is the source of these NP fibers. The results of this study indicate a NP‐containing projection from the hypothalamus directly to SNB motoneurons. It is suggested that this pathway may play a role in the integration of penile reflexes with other aspects of male copulatory behavior that are under hypothalamic control. © 1993 Wiley‐Liss, Inc.
NGF Augmentation rescues trigeminal ganglion and principalis neurons, but not brainstem or cortical whisker patterns, after infraorbital nerve injury at birth
Authors: Henderson Theodore A. , Rhoades Robert W. , Bennett‐Clarke Carol A. , Osborne Pat A. , Johnson Eugene M. , Jacquin Mark F.
Published: January 2005

Prior studies indicate that neonatal nerve injury kills many trigeminal (V) first‐ and second‐order cells, and interrupts pattern formation in the brainstem and cerebral cortex. Yet it is not known whether effects upon cell survival and pattern formation are causally related. To determine whether axotomized V ganglion cells can be rescued by an exogenous trophic agent, rats received 5 mg/kg of nerve growth factor (NGF) prior to, and every day after, infraorbital nerve section on the day of birth until sacrifice on postnatal day (PND) 1, 3, 5, 7, or 14. Other animals received identical lesions without NGF. Ganglion cell numbers were significantly reduced by PNDl in pups not given NGF, while NGF‐treated rats displayed no significant cell loss through PND7. However, NGF did not permanently rescue V neurons because ganglion cell numbers were reliably reduced by PND14.

Cell numbers in V nucleus principalis were reduced by PNDl in pups not given NGF, while NGF‐treated animals displayed no cell loss through PND14. NGF's rescue of second‐order cells is probably an indirect effect of NGF actions upon V ganglion cells because, in other newborns, NGF failed to maintain principalis cells after direct lesion of the left V ganglion.

To determine whether preventing cell death permits whisker‐related pattern formation, other rats also received NGF prior to and after infraorbital nerve section at birth. After 3–14 days, patterns were assessed in the brainstem and cortex with cytochrome oxidase histochemistry and serotonin immunocytochemistry. Whisker‐related patterns failed to develop as in cases not given NGF.

These data indicate that communication with the periphery is necessary for the maintenance of central whisker‐related patterns. They also suggest that V ganglion cells can be rescued, albeit temporarily, from rapid injury‐induced death by NGF, thereby delaying injury‐induced cell death in nucleus principalis. However, the mechanism(s) responsible for injury‐induced pattern alterations in the developing V system remains to be elucidated. © 1993 Wiley‐Liss, Inc.
Origins of cerebellar mossy and climbing fibers immunoreactive for corticotropin‐releasing factor in the rabbit
Authors: Errico P. , Barmack N. H.
Published: January 2005

Corticotropin‐releasing factor (CRF) has been implicated by both anatomical and physiological techniques as a potential cerebellar transmitter or modulator. In the present experiment, with the aid of immunohistochemistry, we have described specific cerebellar afferent pathways in the rabbit in which CRF is located. CRF‐immunoreactive climbing fibers were present in the molecular layer throughout the cerebellum, but especially in lobules 8–9a. All inferior olivary neurons were CRF‐immunoreactive.

In lobules 8–9a, CRF‐immunoreactive mossy fibers were organized in sagittal bands. The highest density of CRF‐immunoreactive mossy fiber terminals was observed in the granule cell layer of lobules 8–9a and the flocculus. No CRF‐immunoreactive perikarya were located in rabbit cerebellum. The brainstem origin of CRF‐immunoreactive mossy fiber terminals was suggested by numerous CRF‐immunoreactive perikarya located in the medial, lateral and descending vestibular nuclei, nucleus prepositus hypoglossi, nucleus x, paramedian reticular nucleus, gigantocellular reticular nucleus, lateral reticular nucleus, and raphe nuclei.

Using double label experiments, we investigated the specific CRF afferent projection to the flocculus and posterior vermis. Horseradish peroxidase (HRP) injections into the posterior vermis double labeled CRF‐immunoreactive neurons in the caudal medial and descending vestibular nuclei and nucleus prepositus hypoglossi. HRP injections into the flocculus double labeled more CRF‐immunoreactive neurons in the nucleus prepositus hypoglossi than in the vestibular nuclei. HRP injections into either the posterior vermis or flocculus double labeled CRF‐immunoreactive neurons in the paramedian reticular nucleus, nucleus reticularis gigantocellularis, and raphe nuclei. These data suggest that CRF may play an important role in vestibularly related functions of the cerebellum. © 1993 Wiley‐Liss, Inc.
Parvalbumin‐containing neurons in the cerebral cortex of the lizard Podarcis hispanica: Morphology, ultrastructure, and coexistence with GABA, somatostatin, and neuropeptide Y
Authors: Martínez‐Guijarro F. J. , Soriano E. , Del Río J. A. , Blasco‐Ibáñez J. M. , López‐Garcia C.
Published: January 2005

The morphology, fine structure, and degree of colocalization with GABA, somatostatin, and neuropeptide Y of parvalbumin‐containing cells were studied with immunocytochemistry in the cerebral cortex of the lizard Podarcis hispanica. Parvalbumin‐containing cells make up a morphologically heterogeneous population of spine‐free neurons, displaying the morphological features of nonprincipal cells previously described in Golgi studies. Electron microscopically, parvalbumin‐immunoreactive cell bodies are similar in all cortical areas and layers. The perisomatic input is moderate in number, and boutons with either round clear vesicles or flattened vesicles were observed making asymmetric or symmetric synaptic contacts, respectively. Parvalbumin‐immunoreactive dendrites are smooth and almost completely covered with synaptic boutons of different types, most of which establish asymmetric contacts. Parvalbumin‐immunoreactive boutons are concentrated around cell bodies of principal cells. They are large, containing abundant mitochondria and small pleomorphic vesicles, and establishing symmetric synaptic contacts with somata, proximal dendritic shafts, and axon initial segments of principal cells. Colocalization studies revealed that all the parvalbumin‐containing cells are GABA‐immunoreactive, representing only a fraction of the GABA‐immunopositive cell population, and that parvalbumin‐ and peptide‐ (somatostatin and neuropeptide Y) containing cells show a negligible overlap.

These results demonstrate that in the cerebral cortex of the lizard Podarcis hispanica, parvalbumin‐containing cells represent a subset of nonprincipal GABAergic neurons largely involved in perisomatic inhibition, which are different from the peptide‐containing cells, and suggest that they may include both axosomatic and axoaxonic cells. © 1993 Wiley‐Liss, Inc.
Immunocytochemical localization of neuropeptide FF (FMRF amide‐like peptide) in the hypothalamo‐neurohypophyseal system of Wistar and Brattleboro rats by light and electron microscopy
Authors: Boersma C. J. C. , Sonnemans M. A. F. , van Leeuwen F. W.
Published: January 2005

Neuropeptide FF (F8Famide, FMRFamide‐like, or morphine modulating peptide) immunoreactivity was localized by light and electron microscopy in the hypothalamo‐neurohypophyseal system of Wistar and Brattleboro rats. In Wistar rats neuropeptide FF was present in part of the magnocellular neurones of the paraventricular and supraoptic nuclei in which it was coexpressed with vasopressin. Neuropeptide FF containing fibers were present in the paraventricular and the supraoptic nuclei, and in the central part of the neural lobe. At the electron microscopic level, neuropeptide FF containing nerve terminals in the neural lobe formed synaptoid contacts exclusively with pituicytes. No neuropeptide FF containing neurovascular contacts or contacts with other neuronal structures were observed.

In contrast with Wistar rats, neuropeptide FF was almost completely absent in cell bodies of the paraventricular and supraoptic nuclei, and in fibres of the neural lobe in Brattleboro rats. Only a few solitary cells could be observed in these structures. The present results demonstrate that neuropeptide FF coexists with vasopressin within the hypothalamo‐neurohypophyseal system. As we did not observe neuropeptide FF containing neurovascular contacts, neuropeptide FF containing nerve terminals probably have a local function within the neural lobe. Neuropeptide FF may be involved in the modulation ofoxytocin and vasopressin release, with the pituicyte as an intermediate cell. © 1993 Wiley‐Liss, Inc.
Three‐dimensional analysis of the dendritic domains of on‐ and off‐cells in the rostral ventromedial medulla
Authors: Potrebic S. B. , Mason P.
Published: January 2005

The rostral ventromedial medulla contains two classes of physiologically defined neurons, on‐cells and off‐cells, that are implicated in nociceptive modulation. In a continuing effort to detail the neural circuitry that underlies the activity of these two distinct neuronal types, the three‐dimensional somatodendritic morphology of on‐ and off‐cells was studied in the cat and the rat.

Following physiological characterization with intracellular recording, on‐ and off‐cells were injected with horseradish peroxidase and sectioned in the coronal plane. Their somatodendritic arborizations were reconstructed with the aid of a computerized three‐dimensional reconstruction program.

There were no differences between on‐ and off‐cells in any somatodendritic feature analyzed. On‐ and off‐cells possess dendritic arbors that are elongated in the mediolateral axis relative to the dorsoventral and rostrocaudal axes. In the rat, the average dendritic extent was more than 1,400 μm mediolaterally but only about 800 μm in either the dorsoventral or rostrocaudal axis. All somatic and dendritic measures were greater for both cat cells than for any rat neuron. Dendrites and their tips were located predominantly in regions lateral to the soma. The center of total dendritic length was usally located within 150 μm of the soma, most frequently ventral and lateral to the soma.

The present results demonstrate that the dendritic domains of neurons in the nuclei raphe magnus and reticularis paragigantocellularis pars alpha are not contained within cytoarchitechtonic boundaries. On‐ and off‐cell dendrites are interdigitated throughtout the mediolateral extent of the rostral ventromedial medulla. Since on‐ and off‐cell dendritic domains occupy a restricted rostrocaudal plane, afferents to the rostral ventromedial medulla that are confined to a single coronal plane and those that collateralize at several levels are likely to play different roles in the control of on‐and off‐cell activity. © 1993 Wiley‐Liss,Inc.
Prelunate, occipitotemporal, and parahippocampal projections to the basis pontis in rhesus monkey
Authors: Schmahmann Jeremy D. , Pandya Deepak N.
Published: January 2005

We used tritiated amino acids to study projections to the basilar pons from prestriate cortices in 18 rhesus monkeys to determine how connectional and functional heterogeneity of these regions are reflected in corticopontine circuitry. Fibers travelled with those from other parasensory associative cortices before terminating in the pontine nuclei. Prelunate projections were derived from area 19 (OA) at the medial convexity (including areas V3 and PO) and from the lateral convexity dorsal to the caudal tip of the Sylvian fissure (including areas DP and the dorsal part of area V4d). Pontine projections also arose from area 19 (OA), and areas TF, TL, and TH in the posterior aspect of the parahippocampal gyrus. No pontine projections arose from the prelunate convexity ventral to the caudal tip of the Sylvian fissure (ventral part of area V4d and area V4v), area TEO, the inferior temporal gyrus, or the lateral ventral temporal region. Terminations in the pons were distributed in the dorsolateral and lateral nuclei, and the lateral part of the peripeduncular nucleus. Medial convexity injections produced more extensive rostrocaudal pontine labeling, as well as terminations in the extreme dorsolateral nucleus and the nucleus reticularis tegmenti pontis. Dorsal prelunate injections had additional terminations in the ventral pontine nucleus. Posterior parahippocampal gyrus injections resulted in discrete label in the lateral and dorsolateral nuclei.

Corticopontine projections destined for the cerebellum appear to be derived from extrastriate areas concerned mainly with visual spatial parameters, visual motion, and the peripheral field of vision, but not from areas subserving visual object identification and the central field of vision. Pontine afferents from the posterior parahippocampal gyrus may facilitate a cerebellar contribution to visual spatial memory, particularly when invested with motivational valence. © 1993 Wiley‐Liss,Inc.
Choline acetyltransferase‐immunoreactive patches overlap specific efferent cell groups in the cat superior colliculus
Authors: Jeon Chang‐Jin , Mize R. Ranney
Published: January 2005

Fibers containing acetylcholine (ACh) form distinct patches in the dorsal intermediate gray layer (IGL) of the cat superior colliculus (SC). Although these patches are known to overlap several afferent projections to SC, it is not known whether they are associated with specific postsynaptic cell groups. We have examined the relationship of these ACh fiber patches to specific efferent cell groups by combining retrograde transport of horseradish peroxidase (HRP) with choline acetyltransferase (ChAT) immunocytochemistry. Successful HRP injections were made into the predorsal bundle (PB), the tecto‐pontine‐bulbar pathway (TPB) and the cuneiform region (CFR), the inferior olive (IO), the dorsolateral pontine gray nucleus (PGD), and the pedunculopontine tegmental nucleus (PPTN). The distribution of HRP‐labeled neurons which project to these targets was mapped by a computer‐based microscope plotter.

Distinct clusters of HRP‐labeled neurons in the IGL were seen after three injections into the mesencephalic reticular formation that involved the caudal TPB and cuneiform region (CFR), and after one injection into the medial accessory nucleus of IO. As many as seven clusters of labeled neurons were found in some sections through the caudal one‐half of SC after the TPB/CFR injections. Each cluster consisted of 3‐20 cells, all of which were small to medium in size. In sections also tested for ChAT, the cell clusters in the TPB/CFR cases were found to overlap precisely the ACh patches in the IGL. In addition, SC neurons projecting to the IO formed clusters above the ChAT patches and in the intermediate white layer (IWL) of SC. None of the other HRP injections produced any obvious cell clusters in the deep layers of SC. These results are the first to show that specific cell groups, distinguished by size and projection site, form clusters that match the patch‐like innervation of cholinergic afferents to SC. This modular organization may correspond to saccade‐related cells that have also been reported to be organized into clusters in the cat SC. © 1993 Wiley‐Liss,Inc.
Evidence for a multi‐compartmental histochemical organization of the nucleus accumbens in the rat
Authors: Jongen‐Rȩlo Ana L. , Groenewegen Henk J. , Voorn Pieter
Published: January 2005

In the present study, the compartmental organization of the nucleus accumbens was investigated by comparing the pattern of leu‐enkephalin immunoreactivity with that of the opioid receptor ligand, naloxone, an established marker for the compartmental organization of the neostriatum. Both patterns have a nonhomogeneous, patch‐like appearance throughout the rostrocaudal extent of the nucleus and show a good, mutual correspondence. In the core of the nucleus accumbens as well as in the border region between the nucleus accumbens and the caudate‐putamen, leu‐enkephalin‐rich areas are in register with opioid receptor‐dense areas. In the shell region the precise relationship between the enkephalin and the naloxone patterns could not be established. A comparison of the connectivity patterns and neurochemical characteristics of the opioid receptor‐dense compartments in the nucleus accumbens with those in the caudate‐putamen reveals major discrepancies between these two striatal subdivisions. We therefore conclude that, rather than a bicompartmental patch/striosome‐matrix organization, the nucleus accumbens has a multicompartmental organization. © 1993 Wiley‐Liss, Inc.
Age‐related effects of nerve growth factor on the morphology of embryonic sensory neurons in vitro
Authors: Scott Sheryl A. , Davies Alun M.
Published: January 2005

Studies of neonatal and adult mammals have shown that neuronal morphology is regulated in part by the availability of target‐derived neurotrophic factor. To test whether the same is true for embryonic neurons, which are dependet on target‐derived neurotrophic factors for survival, we grew neural crest‐derived sensory neurons from the trigeminal ganglion of avian embryos of different ages in vitro in different concentrations of nerve growth factor (NGF) and measured the number of branch points and total length of the resulting arborizations. Although the size and complexity of arborizations increased with embryonic age up to embryonic day (E)14, neuronal morphology for embryos younger than E14 was unaffected by the concentration of NGF in the culture medium. However, beginning at E14, the stage at which trigeminal neurons start to lose their absolute requirement for NGF for survival, the neurons had significantly more branch points and larger arborizations in higher concentrations of NGF. Thus, it appears that the extent of neurite outgrowth in young embryos is independent of neurotrophic factor concentration; each neuron that receives enough neurotrophic factor to survive elaborates approximately the same size arbor. As trigeminal neurons mature and become less dependent on neurotrophic factor for survival, they acquire the ability to respond to neurotrophic factor with increased neurite growth and branching, as in neonates and adults. © 1993 Wiley‐Liss, Inc.