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PubMed2002

Acupuncture for lateral elbow pain.

BACKGROUND: This review is one in a series of reviews of interventions for lateral elbow pain. Lateral elbow pain, or tennis elbow, is a common condition causing pain in the elbow and forearm and lack of strength and function of the elbow and wrist. Acupuncture has long been used to treat lateral elbow pain in China and in Western countries practitioners and consumers are increasingly exploring acupuncture as a first line treatment for musculoskeletal disorders. No previous systematic review of the available evidence has been conducted to determine whether acupuncture is efficacious in the treatment lateral elbow pain. OBJECTIVES: To determine the effectiveness of acupuncture in the treatment of adults with lateral elbow pain with respect to pain reduction, improvement in function, grip strength and adverse effects. SEARCH STRATEGY: We searched MEDLINE, CINAHL, EMBASE and SCISEARCH and the Cochrane Clinical Trials Register and the Musculoskeletal Review Group's specialist trial database from 1966 to June 2001. Identified keywords and authors were searched in an effort to retrieve as many trials as possible. SELECTION CRITERIA: Two independent reviewers assessed all identified trials against pre-determined inclusion criteria. Randomised and pseudo randomised trials in all languages were included in the review provided they were testing acupuncture compared to placebo or another intervention in adults with lateral elbow pain (tennis elbow). Outcomes of interest were pain, function, disability, quality of life, strength, participant satisfaction with treatment and adverse effect. DATA COLLECTION AND ANALYSIS: For continuous variables means and standard deviations were extracted or imputed to allow the analysis of weighted mean difference, while for binary data numbers of events and total population were analysed and interpreted as relative risks. Trial results were combined only in the absence of clinical and statistical heterogeneity. MAIN RESULTS: Four small randomized controlled trials were included but due to flaws in study designs (particularly small populations, uncertain allocation concealment and substantial loss to follow up) and clinical differences between trials, data from trials could not be combined in a meta-analysis. One randomised controlled trial found that needle acupuncture results in relief of pain for significantly longer than placebo (WMD = 18.8 hours, 95%CI 10.1 to 27.5) and is more likely to result in a 50% or greater reduction in pain after 1 treatment (RR 0.33, 95%CI 0.16 to 0.69) (Molsberger 1994). A second randomized controlled trial demonstrated needle acupuncture to be more likely to result in overall participant reported improvement than placebo in the short term (RR = 0.09 95% CI 0.01 to 0.64) (Haker 1990a). No significant differences were found in the longer term (after 3 or 12 months). A randomized controlled trial of laser acupuncture versus placebo demonstrated no differences between laser acupuncture and placebo with respect to overall benefit (Haker 1990b). A fourth included trial published in Chinese demonstrated no difference between Vitamin B12 injection plus acupuncture, and Vitamin B12 injection alone (Wang 1997). REVIEWER'S CONCLUSIONS: There is insufficient evidence to either support or refute the use of acupuncture (either needle or laser) in the treatment of lateral elbow pain. This review has demonstrated needle acupuncture to be of short term benefit with respect to pain, but this finding is based on the results of 2 small trials, the results of which were not able to be combined in meta-analysis. No benefit lasting more than 24 hours following treatment has been demonstrated. No trial assessed or commented on potential adverse effect. Further trials, utilising appropriate methods and adequate sample sizes, are needed before conclusions can be drawn regarding the effect of acupuncture on tennis elbow.

Acupuncture Therapy↗
PubMed2004

Posterior versus lateral surgical approach for total hip arthroplasty in adults with osteoarthritis.

BACKGROUND: Osteoarthritis (OA) of the hip is a progressive condition that has no cure and often requires a total hip arthroplasty (THA). The principal methods for THA are the posterior and direct lateral approaches. The posterior approach is considered to be easy to perform, however, increased rates of dislocation have been reported. The direct lateral approach facilitates cup positioning which may decrease rates of hip dislocation and diminishes the risk of injury to the sciatic nerve. However, there is an increased risk of limp. Dislocation of a hip prosthesis is a clinically important complication after THA, in terms of morbidity implications and costs. OBJECTIVES: To determine the risks of prosthesis dislocation, postoperative Trendelenburg gait and sciatic nerve palsy after a posterior approach, compared to a direct lateral approach, for adult patients undergoing THA for primary OA. SEARCH STRATEGY: MEDLINE, EMBASE, CINHAL and Cochrane databases were searched until 2002. No language restrictions were applied. SELECTION CRITERIA: Published trials comparing posterior and direct lateral surgical approaches to THA in participants 18 years and older with a diagnosis of primary hip OA. DATA COLLECTION AND ANALYSIS: Retrieved articles were assessed independently by the two reviewers for their methodological quality. MAIN RESULTS: Four prospective cohort studies involving 241 participants met the inclusion criteria. The primary outcome, dislocation, was reported in two studies. No significant difference between posterior and direct lateral surgical approach was found [1/77 (1.3%) versus 3/72 (4.2%); relative risk (RR) 0.35; 95% confidence intervals (CI) 0.04 to 3.22]. The presence of postoperative Trendelenburg gait was not significantly different between these surgical approaches. The risk of nerve palsy or injury was significantly higher among the direct lateral approaches [1/43 (2%) versus 10/49 (20%); RR 0.16, 95% CI 0.03 to 0.83]. However, there were no significant differences when comparing this risk nerve by nerve for both approaches, in particular for the sciatic nerve. Of the other outcomes considered only the average range of internal rotation in extension of the hip was significantly higher (weighted mean difference 16 degrees, 95% CI 8 to 23) in the posterior approach group (mean 35 degrees, standard deviation 13 degrees ) compared to the direct lateral approach (mean 19 degrees, standard deviation 13 degrees ). REVIEWER'S CONCLUSIONS: The quality and quantity of information extracted from the trials performed to date are insufficient to make any firm conclusion on the optimum choice of surgical approach in adult patients undergoing primary THA for OA.

Adult↗
PubMed2006

Posterior versus lateral surgical approach for total hip arthroplasty in adults with osteoarthritis.

BACKGROUND: Osteoarthritis (OA) of the hip is a progressive condition that has no cure and often requires a total hip arthroplasty (THA). The principal methods for THA are the posterior and direct lateral approaches. The posterior approach is considered to be easy to perform, however, increased rates of dislocation have been reported. The direct lateral approach facilitates cup positioning which may decrease rates of hip dislocation and diminishes the risk of injury to the sciatic nerve. However, there is an increased risk of limp. Dislocation of a hip prosthesis is a clinically important complication after THA, in terms of morbidity implications and costs. OBJECTIVES: To determine the risks of prosthesis dislocation, postoperative Trendelenburg gait and sciatic nerve palsy after a posterior approach, compared to a direct lateral approach, for adult patients undergoing THA for primary OA and to update the previous review made in 2003. SEARCH STRATEGY: MEDLINE, EMBASE, CINAHL and Cochrane databases were searched and updated, from the previous search of 2002, to Oct 13, 2005. No language restrictions were applied. SELECTION CRITERIA: Published trials comparing posterior and direct lateral surgical approaches to THA in participants 18 years and older with a diagnosis of primary hip OA. DATA COLLECTION AND ANALYSIS: Retrieved articles were assessed independently by the two reviewers for their methodological quality. MAIN RESULTS: Four prospective cohort studies involving 241 participants met the inclusion criteria. The primary outcome, dislocation, was reported in two studies. No significant difference between posterior and direct lateral surgical approach was found [1/77 (1.3%) versus 3/72 (4.2%); relative risk (RR) 0.35; 95% confidence intervals (CI) 0.04 to 3.22]. The presence of postoperative Trendelenburg gait was not significantly different between these surgical approaches. The risk of nerve palsy or injury (all nerves taken together) was significantly higher among the direct lateral approaches [1/43 (2%) versus 10/49 (20%); RR 0.16, 95% CI 0.03 to 0.83]. However, there were no significant differences when comparing this risk nerve by nerve for both approaches, in particular for the sciatic nerve. Of the other outcomes considered only the average range of internal rotation in extension of the hip was significantly higher (weighted mean difference 16 degrees, 95% CI 8 to 23) in the posterior approach group (mean 35 degrees , standard deviation 13 degrees ) compared to the direct lateral approach (mean 19 degrees , standard deviation 13 degrees ). AUTHORS' CONCLUSIONS: The quality and quantity of information extracted from the trials performed to date are insufficient to make any firm conclusion on the optimum choice of surgical approach in adult patients undergoing primary THA for OA.

Adult↗
PubMed1988

Laterality defects in conjoined twins: implications for normal asymmetry in human embryogenesis.

We evaluated six pairs of conjoined twins: four pairs were dicephalus, and two were of the ischiopagus type. In three of the four dicephalus pairs, the right twin had an abnormality of laterality that included a right aortic arch, reversed great vessel orientation, bilateral right-sided isomerism of the lungs, asplenia, and situs inversus of the viscera. The left twin had normal great vessel orientation and situs solitus in each case. The finding that was unique in these three dicephalus twin pairs was their fused hearts, which were similar in orientation and configuration. The fourth dicephalus twin pair had one normally rotated heart, which was located in the midline and had normally placed chambers and great vessels. Each twin of this pair had normal visceral situs. In the two pairs of ischiopagus twins, each pair had two separate hearts, with normal cardiac structure and great vessel relationships. The viscera expressed normal laterality. Documentation of a defect in laterality in the right twin in three conjoined twin pairs with fusion of the hearts, combined with the presence of normal laterality in three pairs without cardiac fusion, has implications regarding the mechanisms leading to laterality of the human embryo. We suggest that rotation of the heart initiates the embryo's process of lateralization and that the laterality defects of the viscera seen in the right twin are a result of their abnormal cardiac rotation.

Abnormalities, Multiple↗
PubMed2004

Three-dimensional computational reconstruction of lateral skull base with plastinated slices.

The goals of this study were to build the 3D reconstructed model of lateral skull base and to explore the spatial relationships of the important structures for providing the morphological basis for lateral skull base surgery and clinical image diagnosis. Blocks with edges of about 80 mm containing the lateral skull base region and adjacent structures were sawn out from both sides of the heads and sectioned on transverse plane at a thickness of 700 microm using a plastination technique. On an SGI workstation, a Contours-Marching cubes algorithm was selected to reconstruct the 3D model of the lateral skull base. Accurate alignment of the structures in the serial macroscopic sections was obtained by the employment of the plastination technique. The quality of the reconstructed images was distinct and perfect, specifically, the spatial positions and complicated adjacent relationships of various structures of the lateral skull base can be shown in direct viewing when they are displayed in background of the cranial bony substance. The time spent in displaying or rotating one image including 50 sections was 1.5 sec; all reconstructed structures can be represented individually or jointly and rotated in any plane. The plastination technique and computer-aided 3D reconstruction have an obvious advantage in the study of the complex anatomy of the lateral skull base. Plastination technique provides cross-section images of a higher resolution than those obtained from CT scanning. The computerized 3D reconstruction is important in studying the spatial anatomy of the lateral skull base and can serve as a standard for models created with other techniques.

Epoxy Resins↗
PubMed2005

The lateral view radiograph for assessment of the tibiofemoral joint space in knee osteoarthritis: its reliability, sensitivity to change, and longitudinal validity.

OBJECTIVE: To evaluate the reliability, validity, and sensitivity to change of tibiofemoral (TF) narrowing on lateral radiographic views. METHODS: In a natural history study of symptomatic knee osteoarthritis (OA), both lateral view and fluoroscopically positioned posteroanterior (PA) semiflexed view radiographs of the knee in 30 degrees of flexion and with weight bearing were obtained at baseline and at 30 months. Test-retest reliability was evaluated using repeat radiographs, with joint space width measured using electronic calipers. All radiographs were scored on a 0-3 scale, and progression of joint space loss was defined as narrowing of the joint space by 1 grade. We evaluated sensitivity to change compared with the PA view. We evaluated validity by examining whether knees with progression showed expected malalignment on full-limb films. RESULTS: Test-retest reliability of the TF joint space using the lateral view had a root mean square error of 0.303 mm, with 92.5% of repeats within 1 mm. More knees showed progression on the lateral view alone (n = 41) than on the PA view alone (n = 27). Compared with knees without joint space loss, knees with medial compartment loss on the lateral view only were more varus malaligned (P < 0.001), while those with lateral compartment loss were more valgus malaligned (P = 0.008). CONCLUSION: In the assessment of TF joint space loss, lateral view radiographs are reliable, valid, and more sensitive to change than fluoroscopically positioned PA radiographs.

Cartilage, Articular↗
PubMed2003

Lateral femoral cutaneous neuralgia: an anatomical insight.

A detailed anatomic study was carried out on the lateral femoral cutaneous nerve to better understand the etiology and treatment of lateral femoral cutaneous neuralgia. As it passed from the pelvis into the thigh, the lateral femoral cutaneous nerve ran through an "aponeuroticofascial tunnel," beginning at the iliopubic tract and ending at the inguinal ligament; as it passed through the tunnel, an enlargement in its side-to-side diameter was observed, suggesting that the fascial structures proximal to the inguinal ligament may be implicated in the genesis of lateral femoral cutaneous neuralgia. The finding of pseudoneuromas at this location, distant from the inguinal ligament, supports this hypothesis. The anterior superior iliac spine is located approximately 0.7 cm from the lateral femoral cutaneous nerve and serves as the bony landmark for nerve localization. Within the first 3 cm of leaving the pelvis, the lateral femoral cutaneous nerve was observed deep to the fascia lata; therefore, surgical dissection within the subcutaneous fascia may be conducted with relative impunity near the anterior superior iliac spine just inferior to the inguinal ligament. In 36% of cases there was no posterior branch of the nerve, which is correlated to lateral femoral cutaneous neuralgia symptoms often being limited to the anterior branch region. An accessory nerve was found in 30% of cases.

Adult↗
PubMed2003

Lateral arm flap: analysis of its anatomy and modification using a vascularized fragment of the distal humerus.

Soft tissue injuries with associated bone defects are difficult to manage and often require prolonged treatment with repeated interventions. Frequently, a free flap is applied as a first step and bone grafting is carried out in a second procedure. Ideally, these two procedures are combined in one operation, utilizing a soft tissue flap with an attached vascularized bone fragment. The lateral arm flap can provide such an osteoseptocutaneous flap and has been utilized clinically with success; however, the vascular anatomy of the flap, especially the humeral fragment, has not been described in detail previously, and there is broad disagreement concerning its innervation. In this study, the arteries and nerves of 24 fresh cadaver arms were dissected after injection of colored latex. The levels of origin of the periosteal arteries of the humerus were also documented. The lateral arm flap has a consistent arterial supply from three septocutaneous perforating branches that are arranged in a predictable pattern. The lateral supracondylar ridge of the humerus is vascularized by direct branches of the posterior branch of the radial collateral artery and by arteries that arise from muscular branches supplying adjacent muscles. The innervation of the lateral arm flap is by the inferior lateral cutaneous nerve of the arm. Knowledge of the consistent vascular anatomy of the lateral humerus and soft tissue of the donor site allows an osteoseptocutaneous flap to be raised safely with an appropriate technique. We recommend use of the lateral arm flap with a humeral fragment for the treatment of combined soft tissue and bone defects when a single step surgical solution is indicated.

Aged↗
PubMed1976

Afferents to the cerebellar lateral nucleus. Evidence from retrograde transport of horseradish peroxidase after pressure injections through micropipettes.

HRP was injected by pressure from glass capillary micropipettes unilaterally into the lateral nucleus of rat so as to encompass the entire nucleus, but without spread into the interpositus nuclei. The cells of origin of the afferents to the lateral nucleus were studied after retrograde transport of the HRP. The reticulotegmental nucleus of the pons was labelled bilaterally and is the major source of crossed and uncrossed reticular imputs. The pontine nuclei also provide extensive crossed and uncrossed afferents. The inferior olive gives a large crossed olivo-lateral nucleus projection and a minor uncrossed input. The trigeminal nuclear complex--the nucleus of the spinal tract and the mesencephalic, principal sensory, and motor nuclei--all provide uncrossed afferents. The rostral portion of the lateral reticular nucleus gives a small crossed and uncrossed projection while the perihypoglossal nuclei and the dorsal parabrachial body give crossed afferents to the lateral nucleus. The norepinephrine afferent system from the locus coeruleus is represented by one or two heavily labelled cells and the serotonin raphe systems come from at least five raphe subgroups, the dorsal, superior centralis, pontis, obscurus and magnus nuclei. No evidence was found for commissural fibers between ipsilateral or contralateral cerebellar nuclei, or afferent axons from the spinocerebellar nuclei and the paramedian retricular nucleus. The significance of these sources of afferent imputs to the lateral cerebellar nucleus is discussed. The question is raised of the direct relationship between size of terminal axonal arborization and the quantity of HRP granules present in a cell retrograde transport. The limitations of the HRP method for detecting subtle local differences in the distribution of afferents within the heterogeneous groups of neurons in the lateral nucleus are discussed.

Animals↗
PubMed1983

Numbers of axons in lateral and ventral funiculi of rat sacral spinal cord.

The present study determines the numbers of myelinated and unmyelinated axons in the ventral and lateral funiculi of rat sacral spinal cord. On average, there are 55,000 myelinated and 110,000 unmyelinated axons in the lateral funiculus and 26,000 myelinated and 9,000 unmyelinated axons in the ventral funiculus at these levels. These figures combined with data from earlier studies of the posterior funiculus and the tract of Lissauer give approximate figures of 88,500 myelinated and 131,500 unmyelinated axons for the entire white matter of one side of the rat sacral spinal cord. Thus unmyelinated axons predominate in the white matter of the rat sacral spinal cord. The majority of axons, particularly the unmyelinated axons, are located in the lateral funiculus. The axons are concentrated in the dorsolateral part of the lateral funiculus, and so the dorsal part of the lateral funiculus, often referred to as the dorsolateral funiculus, contains more than half the fibers in the white matter of the spinal cord. A small nick in the dorsal and lateral part of the lateral funiculus, which is often done for various experimental reasons, could thus remove 40% of the axons in the white matter of rat sacral spinal cord. The data reported in the present paper will serve as a basis for future studies on the white matter of the isolated spinal cord.

Animals↗
PubMed1984

Collateral innervation of the medial and lateral prefrontal cortex by amygdaloid, thalamic, and brain-stem neurons.

The distribution of the afferents to the rat's prefrontal cortex originating in the thalamic mediodorsal nucleus and the amygdala was investigated with two fluorescent tracers. Special emphasis was laid on detecting the loci of neurons which project via axonal collaterals into both lateral and medial portions of the prefrontal cortex. It was found that a high number of neurons of the anterior portion of the basolateral amygdaloid nucleus terminate via collaterals in both the medial and lateral subfields of the prefrontal cortex. On the other hand, only a small number of mediodorsal thalamic cells were found to project to both sides of the prefrontal hemisphere via bifurcating axonal collaterals. These cells were situated exclusively in the lateral part of the medial segment of the mediodorsal nucleus. The majority of both thalamic and amygdaloid neurons with bifurcating axons originate from subregions whose cells innervate primarily the medial prefrontal cortex. In brain-stem, neurons of the nucleus raphé dorsalis also project via collaterals to the medial and lateral prefrontal regions. Furthermore, neurons of the dorsal and ventral premamillary nuclei, the lateral mamillary nucleus, the ventral tegmental area of Tsai, and the ventral tegmental nucleus of Gudden were found to project to the medial prefrontal cortex. Our results indicate a differential collateral organization of thalamic and amygdaloid afferents to prefrontal cortical fields. The anterior basolateral amygdala (which innervates via collaterals both the medial and lateral prefrontal subfields) may add a common input to either subfield, such as information on the significance of incoming stimuli to the animal's behavior, while the mediodorsal nucleus (whose segments are principally connected to only one prefrontal subfield) may add segment-specific information, for example, of a spatial-cognitive nature for the lateral segment and of an emotional nature for the central and medial segments. The existence of a basolateral limbic circuit, composed of the amygdala, the thalamic mediodorsal nucleus, and the prefrontal cortex, is confirmed and knowledge on its interconnectivity is extended. From an anatomical point of view these data provide arguments for both unitary and diverging functions of the prefrontal cortex.

Amygdala↗
PubMed1984

Peripheral configuration and central projections of the lateral line system in Astronotus ocellatus (Cichlidae): a nonelectroreceptive teleost.

The lateral line system of Astronotus ocellatus comprises one trunk canal, one tail canal, and three head canals. The sensory receptors on the head are innervated by rami of the dorsal anterior, ventral anterior, and posterior lateral line nerves, and those along the trunk and tail by rami of the posterior lateral line nerve. The peripheral configuration of lateral line canals and nerves was examined in whole mount preparations, the central connections of restricted groups of endorgans studied using HRP and degeneration methods, and the neuronal morphology and cytoarchitecture of the lateralis region investigated with Nissl, silver, and Golgi methods. Neurons of the lateralis cell column are diffusely arrayed and of variable morphology. They are oriented primarily in the transverse plane and, with the exception of a dorsal lamina of large multipolar cells, are not organized into zones. Lateralis fibers bifurcate on entering the brainstem, course in lateral tracts, and give off medially directed collaterals to terminate in the ipsilateral nucleus medialis and nucleus caudalis. In addition, fibers terminate in the eminentia granularis of the cerebellum, but only fibers supplying endorgans in the head canals penetrate the granule cell zone of the cerebellar corpus. Fibers supplying sense organs in adjacent canals overlap in their central endings, whereas fibers of distantly separated receptors do not overlap. The rami supplying trunk and tail canal organs do not project as far rostrally in the central neuropil as do the other rami. Endings of posterior lateral line fibers lie dorsal to those of the anterior lateral line nerves, and some lateralis fibers terminate within the confines of the magnocellular, descending, and posterior nuclei of the octavus column. Although there is spatial order to the lateralis projections, there is no clear somatotopic organization in the lateralis region.

Afferent Pathways↗
PubMed1986

Immunoreactivity in Limulus. II. Studies of serotoninlike immunoreactivity, endogenous serotonin, and serotonin synthesis in the brain and lateral eye.

Serotoninlike immunoreactivity was examined by the fluorescein-isothiocyanate-labeled secondary antibody technique in the lateral eye and brain of Limulus. Endogenous serotonin was measured with high-performance liquid chromatography and electrochemical detection. The synthesis of [3H]serotonin from [3H]tryptophan was measured in the presence and absence of reserpine. Fibers with serotoninlike immunoreactivity were found in the proximal stalks of the corpora pedunculata, in the neuropil of the central body, in the neuropils of the visual centers (lamina, medulla, and ocellar ganglion), in the optic tract that connects the ocellar ganglion with the posterior medial medulla, and in the central neuropil of the brain. Immunoreactive somata were found in four groups in the brain. Up to 50 somata were scattered through each side of the dorsal medial group that lies centered on the dorsal surface within the curve of the central body. These neurons innervate the central body neuropil and send processes into the central neuropil. Three or four reactive somata formed the ventral pole of each medullar group. These may provide the innervation of the proximal stalk of the corpora pedunculata. Five to ten reactive neurons were observed anteriorly in the ventral posterior lateral group #2 on each side that send processes into the central neuropil. Ten to 15 reactive somata were found on either side of the midline in the dorsal anterior part of the ventral medial group that contribute processes to the central neuropil. The remainder of the brain was not immunoreactive. No immunoreactive fibers or somata were found in the lateral eye or in the lateral optic nerve. Serotoninlike and substance P-like immunoreactivities were not found to be colocalized anywhere in the brain. Significant amounts of endogenous serotonin were detected in the lamina and medulla whose neuropils are rich in immunoreactive fibers and in the central body and dorsal medial group that are also rich in immunoreactive somata and fibers. No endogenous serotonin was detected in either the lateral eye or the lateral optic nerve. The lamina, medulla, and central body and dorsal medial group also synthesized and stored [3H]serotonin from [3H]tryptophan. It is likely that serotonin is a neurotransmitter in the brain, but not in the lateral eye of the horseshoe crab. In particular, it appears that serotoninergic neurons may play a role in central visual processing.

Animals↗
PubMed1987

Ultrastructural organisation of the projection from the superior colliculus to the ventral lateral geniculate nucleus of the rat.

Retinorecipient regions of the ventral lateral geniculate nucleus of the thalamus and the superior colliculus of the midbrain are linked by reciprocal axonal projections. In this study we have investigated the ultrastructural characteristics, the distribution, and the postsynaptic targets of the terminals of axons projecting to the ventral lateral geniculate nucleus from the superior colliculus. Horseradish peroxidase was injected into the superior colliculi of adult albino rats, and the Hanker-Yates method was used to visualize anterogradely and retrogradely transported peroxidase in the ventral lateral geniculate nuclei 24 hours following the injection. Labelled terminals were found in the lateral and ventrolateral parts of the external division of the ipsilateral ventral lateral geniculate nucleus. The labelled terminals were confined to areas of simple, nonglomerular neuropil. They were 0.45-1.5 micron in diameter; contained small, dark mitochondria and spherical synaptic vesicles; and established Gray type I (asymmetrical) synaptic contacts with the dendritic shafts, dendritic spines, and occasionally cell bodies of cells with the ultrastructural characteristics of projection cells. A few labelled terminals established synaptic contact with retrogradely labelled cells. Thus, in the rat, the projection from the superior colliculus gives rise to a uniform population of axon terminals in the nonglomerular neuropil of the lateral portion of the ventral lateral geniculate nucleus, which synapse with, and are probably excitatory to, geniculocollicular and other projection cells.

Animals↗
PubMed1989

Cells of origin of spinothalamic tract projections to the medial and lateral thalamus in the cat.

The double fluorescent retrograde labeling method was used to examine the distribution of spinothalamic tract (STT) cells that project to the medial and lateral thalamus in the cat. Injections of one fluorescent tracer (Fast Blue or Diamidino Yellow) were made throughout the lateral thalamus and injections of the other tracer were made in the medial thalamus at sites extrapolated from recording track coordinates. Survival times were successively extended (up to 5 weeks) in order to maximize labeling in both the cervical and lumbosacral spinal cord. On average, over 2,000 labeled contralateral STT cells were counted in serial sections from segments C5-7 and L5-S2. Numerical variability of the order of a factor of two was attributable to inherent differences between individual animals. The total number of cells labeled with fluorescent tracers was comparable to the number labeled with horseradish peroxidase in control cases, although there were significant differences between the laminar distributions of labeling produced by the two methods. Injections made anterior to the thalamus to control for labeling due to leakage or passing fibers did not produce substantial spinal labeling. The laminar distribution of fluorescent dye-labeled STT cells was consistent; about half (47%) were located in lamina I, 8% were in lamina V, 5% in lamina VI, 20% in lamina VII, and 20% in lamina VIII. The proportions of STT cells in laminae I and V were higher in cervical segments (57% and 12%, respectively) than in lumbosacral segments (38% and 6%). The dominant contribution of lamina I cells to the STT thus revealed by the fluorescent tracers is striking. The proportions of STT cells labeled from the medial and the lateral thalamus varied with segmental and laminar location and with injection placement. The majority (62%) of STT cells in most cases projected only to the medial thalamus, 25% projected only to the lateral thalamus, and 13% projected to both. The STT cell populations in laminae I, VII, and VIII each displayed this common projection pattern. In contrast, cells in laminae V and VI projected predominantly to the lateral thalamus. Twice as many STT cells in lamina I (19%) projected to both the medial and the lateral thalamus as from other laminae. A greater proportion of laminae V-VIII STT cells in segments L5-6 projected to the lateral thalamus, and in S1-2, more projected to the medial thalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

Amidines↗
PubMed1990

Selective labeling of sensory hair cells and neurons in auditory, vestibular, and lateral line systems by a monoclonal antibody.

This study reports that zn-1, a monoclonal antibody, labels hair cells but not supporting cells in the inner ear and the lateral line of the axolotl salamander, Ambystoma mexicanum. Zn-1 immunocytochemically labels the cytoplasm and stereocilia of mature hair cells in the sacculus, in the utriculus, and in the mechanoreceptive neuromast organs of the lateral line. Lower levels of labeling mark newly formed hair cells in the periphery of the sacculus and in regenerating neuromasts. Zn-1 also selectively labels neuronal processes and perikarya in the lateral line nerves and ganglia and the VIIIth cranial nerve and ganglion. Processes and perikarya are labeled by zn-1 in the dorsolateral medulla oblongata, at sites of termination of the afferent octaval and lateral line neurons. Western blot analysis revealed that zn-1 labels one or more proteins with molecular weights of 80 and 160 kDa. The identity of these protein bands remains to be determined. The presence of a specific epitope expressed in both hair cells and neurons, but not in supporting cells, in the vestibular and auditory epithelia of the ear and in the mechanoreceptive neuromasts of the lateral line suggests shared cytogenetic heritages. These findings are consistent with a close evolutionary relationship between otic and lateral line senses, such as that inherent to the theoretical evolutionary scheme outlined in van Bergeijk's "acousticolateralis hypothesis." The protein recognized by zn-1 is as yet unidentified, but its conservative evolution suggests that it may serve an important function in the statoacoustic and lateral line systems.

Afferent Pathways↗
PubMed1991

Projection of the mammalian superior colliculus upon the dorsal lateral geniculate nucleus: organization of tectogeniculate pathways in nineteen species.

Anterograde and retrograde transport methods have been used to analyze the projection of the superior colliculus upon the dorsal lateral geniculate nucleus in 19 mammalian species. Our retrograde findings reveal that tectogeniculate neurons are relatively small, and lie dorsally within the superficial gray. These small tectogeniculate neurons are spatially related to a dense tier of W-cell retinal input. Our anterograde tracing results show that tectogeniculate axons are visuotopically distributed to small-celled regions of the lateral geniculate in all nineteen species. In the majority of these species, the small-celled, tectally innervated regions of the lateral geniculate lie adjacent to the optic tract and contain W-cell-like neurons. Our findings suggest that neuroanatomical demonstration of the tectogeniculate projection is a relatively simple and straightforward way of revealing regions of the lateral geniculate which contain W-cells. This is true even in species in which the lateral geniculate lacks obvious cellular laminae, and in regions of the lateral geniculate where W-cells are few in number. The present data are especially interesting in light of the cortical projections of tectally innervated, small-celled regions of the lateral geniculate to the patches or puffs within layer III of area 17. Since these regions of small-celled geniculocortical axons are co-extensive with zones ("blobs") rich in cytochrome oxidase, it might be that information carried over the tectogeniculate circuitry plays an important role in the functions of the blob system.

Afferent Pathways↗
PubMed1995

Projection of individual axons from the pretectum to the dorsal lateral geniculate complex in the cat.

The dorsal lateral geniculate nucleus of the thalamus transmits visual signals from the retina to the cortex. Within the lateral geniculate nucleus, the ascending visual signals are modified by the actions of a number of afferent pathways. One such projection originates in the pretectum and appears to be active in association with oculomotor activity. Much remains unknown about the pretectal-geniculate projection. Our purpose was to examine for the first time individual axon arbors from the pretectum that project to the lateral geniculate nucleus, describing their topography and nuclear and laminar targets. We made injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin into the cat pretectum, targeting the nucleus of the optic tract. Serial 40 microns coronal sections were processed by using immunohistochemistry to reveal labeled axons that were then serially reconstructed using light microscopy. Pretectal-geniculate axons appeared morphologically heterogeneous in terms of swelling size, branching patterns, and laminar target. Most axons innervated the geniculate A laminae. A separate, smaller population innervated the C laminae. All axons exhibited substantially greater spread medial-laterally than rostral-caudally in the lateral geniculate nucleus, displaying a topographical organization for visual field elevation, but not azimuth. Many pretectal axons that projected to the LGN also innervated adjacent structures, including the medial interlaminar nucleus, the perigeniculate nucleus, and/or the pulvinar. These results indicate that the projection from the pretectum to the dorsal lateral geniculate nucleus is heterogeneous, is semitopographical, and may coordinate neural activity in the lateral geniculate nucleus and in neighboring visual thalamic structures in association with oculomotor events.

Animals↗