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PubMed1998

Lateralization of human temporal lobe epilepsy by 31P NMR spectroscopic imaging at 4.1 T.

OBJECTIVE: To compare the phosphorous metabolite ratios in the mesial temporal lobe of healthy volunteers (n = 20) with the corresponding ratios in patients with temporal lobe epilepsy (n = 30) using 31P NMR spectroscopic imaging and to lateralize the seizure focus in temporal lobe epilepsy patients using various phosphorous metabolite ratios-phosphocreatine to inorganic phosphate (PCr/Pi), PCr to adenosine triphosphate (PCr/gamma-ATP), and (gamma-ATP/Pi)--and to compare with clinical lateralization results. METHODS: All 31P NMR spectroscopic imaging studies were performed on a high-field, 4.1 T, whole-body NMR spectroscopic imaging system using a 31P/1H double-tuned volume coil. RESULTS: We found an average reduction of 15% in the PCr/Pi and gamma-ATP/Pi ratios compared with the corresponding ratios in healthy volunteers in the entire mesial temporal lobe, and more than a 30% reduction in these two ratios in the anterior region of the epileptogenic mesial temporal lobe. These ratios were also reduced significantly in the ipsilateral lobe when compared with their corresponding values in the contralateral lobe. In patients we lateralized the seizure focus, based on these 31P NMR data, and compared the results with the clinical lateralization. The lateralization based on either the PCr/Pi or the gamma-ATP/Pi ratio yielded a correspondence of 70 to 73% with the final clinical lateralization. In the subgroup of patients (n = 9) that needed intracranial EEG for the presurgical lateralization because of inconclusive results from the noninvasive methods, a 78% correspondence was found with the 31P NMR-based lateralization, whereas MRI provided a correspondence of only 33%, and scalp EEG provided a correspondence of only 56%. CONCLUSIONS: These results suggest the utility of adding the 31P NMR method to the group of noninvasive modalities used for presurgical decision making in temporal lobe epilepsy patients.

Adenosine Triphosphate↗
PubMed1981

Avulsion of the upper lateral cartilage: etiology, diagnosis, surgical anatomy and management.

Relatively little has been published about upper lateral cartilage abnormalities, trauma, and management in rhinoplastic literature. In this paper we would like to present a relatively common problem seen either by trauma or as a result of rhinoplasty. The upper lateral cartilages are a pair of triangular cartilages, one on each side of the dorsum, which comprise the upper cartilaginous vault with the septum and can be avulsed due to direct trauma. This results in loss of their attachments and resultant healing in a new angulated position. The middle third of the nose, being relatively mobile is less susceptible to trauma than the upper third which is rigid and comprised of bone, and that frequently is the reason for less incidence of avulsion of the upper lateral cartilages compared to fractured nasal bones. The surgical treatment of the structures adjacent to the upper lateral cartilage during the process of rhinoplasty severs many attachments of these cartilages and frequently causes them to be free floating. This may not be recognized and not treated. Lack of appropriate realignment in the normal anatomical position may heal the cartilage in a distorted angulated position. Irrespective of etiology, when distortions of the upper lateral cartilage occur, they may cause significant concavity and "hollowed out" appearance on the side of the avulsion which functionally may impede the nasal airway by encroachment and/or "flutter valve" effect. During inspiration this unsupported upper lateral cartilage may interfere with anatomy, physiology and efficiency of the internal nasal valve function. Avulsion of the upper lateral cartilage is a definite entity and should be recognized and treated appropriately to realign the lateral cartilage in its normal anatomical position for a functional as well as a good cosmetic result.

Adult↗
PubMedDate not supplied

[Application of the lateralization sound test in elderly individuals].

BACKGROUND: The ability to determine the direction of a sound source is based on the fact that sounds reach both cars at different times, phase, intensity and/or frequency. The perception of a sound source favors speech intelligibility in noisy environments. AIM: To identify the minimum time of interaural delay--produces lateralization to the car which the stimulus reached first--through ascendant and descendent techniques, using the Sound Lateralization Test in elderly individuals with normal hearing thresholds in the frequencies which are most important for speech comprehension. METHOD: The Lateralization Test was used in 30 individuals with ages above 60 years, who presented hearing thresholds up to 25 dBHL in 500, 1000 and 2000 Hz and with no air-bone gap. RESULTS: Mean times of interaural delay in sound lateralization were: a) ascending technique: 125.56 sec. (female) and 83.61 sec. (male); b) descending technique: 95.06 sec. (female) and 61.68 sec (male). CONCLUSION: There is no difference between the mean time of interaural delay in sound lateralization obtained with the ascending or descending technique regarding the variable initial tested ear (right or left ear); the mean time of interaural delay in sound lateralization is smaller in males, when considering both ascendant and descendent techniques; the mean time of interaural delay in sound lateralization obtained with the descendent technique is smaller than that obtained with the ascendant technique; individuals who present hearing losses beginning at 3000 Hz have smaller mean times of interaural delay in sound lateralization than normal hearing individuals in both techniques.

Aged↗
PubMed1999

Genetic associations between lateral signs.

Only a few authors examined several lateral asymmetries in families simultaneously. Seven lateralities (handedness, footedness, eyedness, earedness, hand clasping, arm folding and leg crossing) were examined in a sample of 292 biologically related parent-offspring triads and 36 sibling pairs. Analysis of the family data showed a significant association between parents and children in most lateralities. The frequency of left-sidedness increased with the number of left-sided parents. Only in the case of footedness and hand clasping there are no significant correlations. Additionally we investigated the inter-relationship between the lateralities in the parental generation. There is a relative strong relation especially among the functional asymmetries. The study analysed also the genetic association (linkage) according to McManus & Mascie-Taylor (1979) between seven different lateralized characteristics. It is shown that the lateral asymmetries correlate genetically relatively imperfectly with each other comparing the inter-relationship between the lateralities in the parental generation. This implicates a multigenetical and also multifactorial determination of laterality in human being.

Adult↗
PubMedDate not supplied

[A reliable symptom in differential diagnosis of cochlear and retrocochlear neurosensory hypoacusis (study of sound lateralization in Weber's test and ultrasound)].

Sound laterality in Weber test occurs mainly in peripheral defects of the acoustic analyzer (lateral conduction or reception acoustic defects of the cochlea). In retrocochlear unilateral hypoacusis or loss of hearing, laterality in this test is absent in 80-90% of the cases (affection of the VIII nerve root, acoustic nuclei, stem and midbrain conductors). This symptom is most reliable in differentiation of cochlear with retrocochlear unilateral hypoacusis and deafness. In combination of retrocochlear hypoacusis of deafness with impaired sound conduction in the same ear, the sound in Weber test can show a paradoxical laterality in an absolutely deaf ear. This indicates that Weber test sound laterality definitely reflects changes in sound conduction. Ultrasound laterality occurs in the better hearing ear in any unilateral cochlear or retrocochlear lesions, thus complicating recognition of cochlear from retrocochlear affections. Laterality of ultrasound is a sensitive indicator of neurosensory abnormalities. Major trepanation bone defects of the parietotemporal skull did not influence sound laterality in Weber test.

Cochlea↗
PubMed1991

Laterality and motor control.

Lateralization in motor control, exemplified by handedness, is a publically observable lateral asymmetry. The understanding of causation of lateral asymmetry in movement is poor for two major reasons. First, structural limitations underlying lateral bias cannot be compelling in the sense that laterality is completely specified. Second, interacting sources of lateral bias are probably represented at several levels of the central nervous system, with some sources being many steps removed from the executing motor structures. Both factors permit flexibility in terms of which side does what. I suggest two approaches to improve understanding of mechanism. First, use of bimanual tasks which reduce flexibility in lateral expression and therefore provide more information than unimanual tasks. Second, analysis of task performances in terms of what levels of lateral specialization are likely to be involved. Such analyses will be especially useful in the understanding of hand use in left-handers who perform different skilled tasks with different hands.

Female↗
PubMedDate not supplied

[Laterality in schizophrenics and their relatives--a trait marker?].

The authors present the results of investigations of a developmental deviation in the functional symmetry of paired motor and sensory organs (laterality) in a group of 160 schizophrenics and 126 healthy relatives of these patients (88 parents, 38 siblings). As a control group served 754 healthy subjects (Prague population). The phenotype of motor laterality (hands and feet) and sensory laterality (eyes and ears) was assessed by diagnostic tests for assessment of laterality. For assessment of the lateral cerebral dominance the torque test was used. For mathematical processing analysis of multidimensional frequency tables by means of Cox'models for binary data was used. The distribution of motor laterality of the upper extremities in schizophrenics is almost reverse, as compared with the distribution in the population. Defined dextrolaterality is lower in patients (P less than 0.0001) and little defined dextrolaterality is, on the other hand, significantly higher (P less than 0.0001). For schizophrenics ambiguousness (ambidextrity) is typical, being twice as frequent as in the healthy population (P less than 0.0001). In parents and siblings similar changes of laterality of the hand were found, in particular as regards defined and little defined dextrolaterality but not as far as ambidexterity is concerned. As regards left-handedness in patients and their relatives no changes were recorded. Incomplete lateralization of functions of the left hemisphere and abnormal cerebral dominance resp. were confirmed by the torque test in a large proportion of schizophrenics and to a smaller extent also in their relatives. Marked preference for the right side (score 0) which was recorded in 47.6% controls was found only in 15.8% schizophrenics, 23.9% parents and 31.4% siblings.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMedDate not supplied

[Distribution of hand laterality in preschool-age children].

Laterality means functional dominance of one in the pair of organs. It represents the external manifestation of integrative activity of cerebral cortex meaning the domination of functionally dominant hand; the usability lateralization depends on the domination of cerebral hemisphere of gestural lateralization and the domination of cerebral hemisphere or gestural lateralization and the influence of the environment. On the basis of laterality population is divided into right-handed and left-handed with a very stressed degree of lateralization and those undecided with a minimal previal of handidness of one hand. In most people the domination of cerebral hemisphere is average or weak and that's the reason why the influence of the environment is of importance when forming the dominant hand. In the clinical practice the hand laterality is used as an index for the type and degree of cerebral hemisphere domination, for condition of gestural laterality with the usability of the dominant hand and form the differentiation of the dominant hand in the case of minimal difference in handidness.

Child↗
PubMedDate not supplied

Lateral crus pull-up: a method for collapse of the external nasal valve.

Collapse of the nasal vestibule during inspiration is a frequently encountered symptom, often caused by weak or medially displaced lateral crura in the lower lateral cartilages. Numerous techniques are available for lateralizing and strengthening the lateral crura using cartilage grafts or suture techniques. In most cases, they involve an external rhinoplasty approach or additional incisions. An elegant endonasal method for widening and strengthening the lateral component of the nasal valve area is described herein. The basis of the procedure is a permanent submucosal spanning suture between the piriform aperture and the distal part of the lower lateral cartilage. The effect of this technique is 2-fold. First, it provides superolateral rotation of the lateral crura, increasing the cross-sectional area, and second, the spanning suture provides additional support for the lateral wall of the nasal vestibule.

Cartilage↗
PubMed1999

Two distinct populations of cholinergic neurons in the septum of raccoon (Procyon lotor): evidence for a separate subset in the lateral septum.

The present study focused on cholinergic neurons in the lateral septal region of the raccoon detected by choline acetyltransferase (ChAT)-immunostaining. For comparison of the cholinergic neurons of the medial and lateral septal nuclei, soma sizes were measured, and several antibodies were applied that differentially characterize these cells in several species: low-affinity neurotrophin receptor p75 (p75(NTR)), calbindin-D(28k) (CALB), and constitutive nitric oxide synthase (cNOS). To compare the basic organization of the raccoon septum with that in other mammals, parvalbumin (PARV) immunocytochemistry and Wisteria floribunda-agglutinin (WFA) lectin histochemistry also were used in double-staining experiments. The ChAT-immunoreactive neurons of the rostral lateral septum are arranged in laminae. Accumulations of cholinergic varicosities, often clearly ensheathing noncholinergic neurons, occupy small territories of the rostral septum. Such regions become larger in the caudal septum. They are assumed to correspond to the septohippocampal and septofimbrial nuclei of the rat. In contrast to the large medial septal cholinergic neurons of the raccoon that contain p75(NTR), CALB, and cNOS, the cholinergic neurons of the lateral septum are smaller and do not express these markers. A further peculiarity is that the region of the lateral septum that contains cholinergic neurons corresponds to WFA-labelled extracellular matrix zones that contain chondroitin sulfate proteoglycans. In addition to clustered thread- or ring-like accumulations of the WFA, sparsely labelled perineuronal nets surround the lateral septal cholinergic neurons. Similar to other species that have been investigated, perineuronal nets are completely absent around cholinergic cells of the medial septum. The PARV-containing neurons of this region, however, are enwrapped by perineuronal nets as they are in the rat. Within the medial septum, the PARV-containing neurons are restricted to ventral bilateral territories that are devoid of cholinergic cells. In this respect, they differ from the more vertically arranged PARV-containing medial septal cells in rodents and primates. Apart from striking differences in numbers and distribution patterns, the raccoon lateral septal cholinergic neurons resemble those detected by Kimura et al. (Brain Res [1990] 533:165-170) in the ventrolateral septal region of rat and monkey. Their participation in the functions of the lateral septum remains to be elucidated.

Animals↗
PubMed2000

Efferent projections of the intergeniculate leaflet and the ventral lateral geniculate nucleus in the rat.

The intergeniculate leaflet (IGL) and the ventral lateral geniculate nucleus (VLG) are ventral thalamic derivatives within the lateral geniculate complex. In this study, IGL and VLG efferent projections were compared by using anterograde transport of Phaseolus vulgaris-leucoagglutinin and retrograde transport of FluoroGold. Projections from the IGL and VLG leave the geniculate in four pathways. A dorsal pathway innervates the thalamic lateral dorsal nucleus (VLG), the reuniens and rhomboid nuclei (VLG and IGL), and the paraventricular nucleus (IGL). A ventral pathway runs through the geniculohypothalamic tract to the suprachiasmatic nucleus and the anterior hypothalamus (IGL). A medial pathway innervates the zona incerta and dorsal hypothalamus (VLG and IGL); the lateral hypothalamus and perifornical area (VLG); and the retrochiasmatic area (RCA), dorsomedial hypothalamic nucleus, and subparaventricular zone (IGL). A caudal pathway projects medially to the posterior hypothalamic area and periaqueductal gray and caudally along the brachium of the superior colliculus to the medial pretectal area and the nucleus of the optic tract (IGL and VLG). Caudal IGL axons also terminate in the olivary pretectal nucleus, the superficial gray of the superior colliculus, and the lateral and dorsal terminal nuclei of the accessory optic system. Caudal VLG projections innervate the lateral posterior nucleus, the anterior pretectal nucleus, the intermediate and deep gray of the superior colliculus, the dorsal terminal nucleus, the midbrain lateral tegmental field, the interpeduncular nucleus, the ventral pontine reticular formation, the medial and lateral pontine gray, the parabrachial region, and the accessory inferior olive. This pattern of IGL and VLG projections is consistent with our understanding of the distinct functions of each of these ventral thalamic derivatives.

Animals↗
PubMed2002

High prevalence of lateral knee osteoarthritis in Beijing Chinese compared with Framingham Caucasian subjects.

OBJECTIVE: We recently reported that, despite their thinness, elderly subjects in Beijing, China had an equal prevalence (in men) or higher prevalence (in women) of both radiographic and symptomatic knee osteoarthritis (OA) compared with that in the Framingham, Massachusetts cohort of elderly subjects. Our objective was to evaluate whether Chinese subjects might have more medial disease than do Caucasians, given a report of varus alignment in the knee joints of Chinese elderly. METHODS: We compared the prevalence of medial and lateral radiographic knee OA and measured anatomic alignment in the knees of elderly subjects from the Beijing and Framingham cohorts. Both studies recruited a random sample of the population. The Beijing OA Study used the Framingham OA Study protocol for radiographs. Anteroposterior weight-bearing films were read for Kellgren and Lawrence (K/L) grade and joint space narrowing (JSN; 0-3 scale) in each compartment. Medial disease was defined when radiographs showed a K/L grade >or=2 and medial JSN >or=1, and lateral disease was assessed in a comparable manner. Using knee-specific analyses, we compared the prevalence of medial and lateral knee OA after adjusting for age, body mass index, and the correlation between the 2 knees. Restricting the analyses to knees with JSN >or=2 and comparing the proportion of OA knees with medial disease and lateral disease yielded similar results. We assessed alignment in knees from 100 persons without OA, measuring the angle subtended by the femoral and tibial anatomic axes. RESULTS: We studied 1,781 Chinese subjects ages 60-88 years, and 1,084 Framingham subjects ages 63-93 years. Whereas medial OA was less prevalent among the Beijing men, lateral OA was more than twice as prevalent among the Beijing men and women, compared with that in the Framingham elderly. For example, of all knees with radiographic OA, 28.5% of Beijing women's knees had lateral OA versus 11% of Framingham women's knees (P < 0.001), and among men, 32.3% of Beijing men's knees versus 8.8% of Framingham men's knees (P < 0.001) had lateral OA. Alignment was more valgus in the Beijing men than in the Framingham men (mean 4.5 degrees versus 2.7 degrees valgus, respectively; P < 0.001), but no differences in alignment were evident in the women. CONCLUSION: In this first attempt to compare the characteristics of OA in different racial groups, we conclude that, opposite to expectations, Chinese subjects have much more lateral OA than do Caucasian subjects in the Framingham cohort, a predilection possibly explained in the men by differences in anatomic alignment.

Aged↗
PubMed2004

Cytoarchitectonic and connectional organization of the ventral lateral geniculate nucleus in the cat.

The ventral lateral geniculate nucleus is a small extrageniculate visual structure that has a complex cytoarchitecture and diverse connections. In addition to small-celled medial and lateral divisions, we cytoarchitectonically defined a small-celled dorsal division. A large-celled intermediate division intercalated between the three small-celled divisions, which we divided into medial and lateral intermediate subdivisions. In WGA-HRP injection experiments, the different cytoarchitectonic divisions were shown to have connections with different nuclei. The medial division was reciprocally connected to the pretectum and projected to the superficial layers of the superior colliculus and the intralaminar nuclei. The medial intermediate division received projections from the intermediate layer of the superior colliculus and the lateral and interpositus posterior cerebellar nuclei, and projected to the intermediate layer of the superior colliculus, the periaqueductal gray of midbrain, and the intralaminar nuclei. The lateral intermediate divisions received projections from the pretectum, the intermediate layer of the superior colliculus, and the lateral and interpositus posterior cerebellar nuclei, and projected to the pretectum, superficial layers of the superior colliculus, and the pulvinar. The lateral division received projections from superficial layers of the superior colliculus and had reciprocal connections with the pretectum. The dorsal division received projections from the pretectum and had reciprocal connections with the periaqueductal gray of midbrain. The different cytoarchitectonic divisions of the ventral lateral geniculate nucleus are thus suggested to play different functional roles related to vision, eye and head movements, attention, and defensive reactions.

Animals↗
PubMed2005

Dendritic morphology, local circuitry, and intrinsic electrophysiology of neurons in the rat medial and lateral habenular nuclei of the epithalamus.

The habenular complex of the epithalamus in the mammalian brain receives input from the limbic forebrain and pallidum and, in turn, projects to numerous midbrain structures. Traditionally, the habenular complex is divided into the medial nucleus and two divisions of the lateral nucleus. Based on their distinct input and output pathways, the habenula is considered to constitute three, partially overlapping channels that regulate information flow from the limbic forebrain and pallidum to the midbrain. As a step to improve our understanding of how information delivered from the limbic forebrain and pallidum is processed in the habenula, we examined the electrical property and morphology of medial and lateral habenular cells. For this study, we generated live brain slices from rat habenula and performed whole cell recording. During recording, we filled habenular cells with biocytin. Medial habenular cells generate tonic trains of action potentials, whereas lateral habenular cells are capable of producing action potentials in burst mode. Lateral habenular cells produce dendrites that are much longer than those of medial habenular cells. Two distinct intrinsic circuits exist in the medial habenular nucleus, whereas in the lateral habenular nucleus, intrinsic axons travel largely from medial to lateral direction. The connection between the two habenular nuclei is asymmetrical in that only the medial habenula sends projection to the lateral habenula. The differences in the electrical and morphological properties of medial and lateral habenular cells indicate that the two nuclei process and integrate information in distinct fashions that is delivered from the limbic forebrain and pallidum.

Action Potentials↗
PubMed1978

Development of the dorsal lateral geniculate nucleus in the cat.

The development of the lateral geniculate nucleus has been studied systematically in Nissl preparations from a series of cats that ranged in age from newborn to adult. In addition, preliminary observations are reported at two stages of fetal development. It was found that laminae develop in the lateral geniculate nucleus near the time of birth and continue to differentiate during the first postnatal week. During development the major axis of the lateral geniculate rotates approximately 180 degrees in the sagittal plane. The rotation begins prenatally and is not completed until after the twentieth postnatal week. The volume of the lateral geniculate was computed at different ages and it was determined that during the first postnatal month the nucleus attains two-thirds of its adult size. However, the rate of growth declines markedly thereafter, and final volume, like final position, is not achieved until late in development. The cross-sectional areas of lateral geniculate neurons were measured at four locations in the nucleus in each animal. The locations represented the following parts of the visual field: the paracentral and inferior peripheral fields in the binocular segment of lamina A; the monocular segment of lamina A; and the paracentral field in lamina A1. Neurons in each of these locations grow at approximately the same rate and are essentially fully grown by 56 days. Cell size histograms show that more large cells are found in lamina A1 and more small cells in the monocular segment than elsewhere in the dorsal laminae. Unlike the retina, there appears not to be a gradient of development in the lateral geniculate nucleus from center to periphery, at least in terms of cell body size at the ages studied. On the contrary, that part of the lateral geniculate nucleus which represents the paracentral visual field is the last segment in the dorsal laminae to achieve a mature cell size distribution. Finally, a discrete class of small spindle-shaped neurons was observed in the lateral geniculate nucleus ventral and caudal to the C laminae during the first two postnatal weeks. These cells possess a leading and trailing cytoplasmic process and are distinctly different from cells in the main laminae. It is suggested that these spindle-shaped cells may be neurons that are still in the process of migration or differentiation in the postnatal animal.

Animals↗
PubMed1981

Ascending auditory afferents to the nuclei of the lateral lemniscus.

Afferents from the hindbrain auditory system to the nuclei of the lateral lemniscus were analyzed by the use of orthograde and retrograde axon-tracing techniques. Three divisions of the nuclei of the lateral lemniscus, a dorsal, an intermediate, and a ventral division are discussed. The dorsal nucleus of the lateral lemniscus is a recipient of afferents from cells located mainly in the superior olivary complex and the contralateral dorsal nucleus of the lateral lemniscus. It receives direct afferents from only a few cells in the cochlear nuclei. In sharp contrast, the ventral nucleus of the lateral lemniscus is the recipient of afferents from many cells in the contralateral ventral cochlear nucleus and from only a few cells in the superior olivary complex. Further, it receives no afferents from cells in the contralateral nuclei of the lateral lemniscus. The intermediate nucleus of the lateral lemniscus receives afferents from some cells in the cochlear nucleus and the superior olivary complex. It is unique among the three nuclei of the lateral lemniscus in that it receives a substantial projection from the medial nucleus of the trapezoid body.

Animals↗
PubMed1987

Development of the precerebellar nuclei in the rat: III. The posterior precerebellar extramural migratory stream and the lateral reticular and external cuneate nuclei.

Sequential thymidine radiograms from rats injected on day E15 and killed thereafter at daily intervals up to day E22 were analyzed to trace the migratory routes and settling patterns of neurons of the lateral reticular nucleus and the external cuneate nucleus. The neurons of the lateral reticular and external cuneate nuclei originate in the primary precerebellar neuroepithelium at the same site as the inferior olivary neurons but follow a different migratory route. The labeled young neurons that are produced on day E15 (the last one-third of the total) join the posterior precerebellar extramural migratory stream. The cells move circumferentially over the wall of the medulla in a ventral direction and by day E17 reach the midline and cross it beneath the inferior olive. The crossing cells apparently continue to migrate circumferentially on the opposite side. One complement of these cells begins to form a ventrolateral extramural condensation on day E19. By day E20 some cells begin to penetrate the parenchyma and settle as neurons of the lateral reticular nucleus. The settling of the lateral reticular neurons continues on the following day, and by day E22 all the cells destined for the lateral reticular nucleus have penetrated the parenchyma. A dorsomedial-to-ventrolateral neurogenetic gradient is indicated for the settling lateral reticular neurons. Another complement of migrating cells continues dorsally and forms a condensation on day E19 that we interpret as the external cuneate component of the crossed stream. These cells begin to penetrate the parenchyma on day E20, and by days E21 and E22 two components of the external cuneate nucleus are identifiable-the dorsal and ventral external cuneate nuclei. The neurons of the lateral reticular and external cuneate nuclei differ from neurons of all the other precerebellar nuclei in that their cerebellar projection is predominantly ipsilateral. We speculate that the axons of all precerebellar neurons are genetically specified to cross the midline ventrally to provide a contralateral efferent projection, but this is modified in the case of the ipsilaterally projecting lateral reticular and external cuneate neurons by the cell bodies following their neurites to the opposite side.

Animals↗
PubMed1992

Lateral dual-energy radiography: artifact error from rib and pelvic bone.

A lateral projection of the lumbar spine with dual-energy radiography (DER) may be a more sensitive tool for the detection of vertebral demineralization than the standard anterior-posterior (AP) DER measurement. The lateral view allows measurement of the vertebral body and selective measurement of the central trabecular compartment, excluding the majority of the cortical envelope and posterior vertebral elements. The lateral DER typically contains L2-4 in the region of interest. The present study was designed to investigate the frequency and bone mineral content (BMC) contribution of rib to the L2 vertebral body BMC measurement in a lateral view DER scan. In addition, the frequency of pelvic overlap of L4 was evaluated. All patients were scanned in the supine position. Abdominal CT images of L2 were examined in 20 women aged 28-82 years to determine the frequency of rib and pelvic interference. QCT images of L2 also were examined in an additional 35 women aged 20-82 years to further investigate the frequency of rib overlap and to calculate the potential contribution of rib superimposition to the L2 BMC in a lateral projection. Pelvic overlap of L4 occurred in 15% of the 20 cases reviewed. Rib overlapped the L2 vertebral body in 100% of the L2 images. The expected contribution of rib BMC to L2 BMC in a lateral DER scan was 10.4% on average. There was no relationship between the percentage of rib BMC contribution and age and relatively poor correlations between rib BMC and that of either the vertebral body or the central trabecular compartment of L2. We conclude that supine positioning allows routine inclusion of L3 and L4 in a lateral lumbar scan. Results also suggest that L2 should be excluded from DER scans on patients scanned in either the lateral decubitus or supine position.

Adult↗