Anatomy Of Central Nervous System Research Articles

Neuro-imaging in children

The development of imaging techniques has occurred at an astounding pace over the last two decades, and neuro-imaging has been at the forefront of those changes. Computed tomography (CT) and, particularly, magnetic resonance imaging (MRI) are now indispensable tools in the management of neurological conditions in patients of all ages and MRI has allowed paediatric neuroradiology to develop as a subspecialty in its own right. MRI techniques not only allow us to obtain high-resolution images of central nervous system anatomy and pathology, but more advanced techniques such as diffusion and perfusion imaging, MRI spectroscopy and functional MRI are now providing insights into brain function as well as structure. Although other modalities such as ultrasound and nuclear medicine are widely used in paediatrics, this article will give a brief introduction to CT and MRI, and concentrate on some selected aspects of their role in clinical paediatric neurosciences.

Evolution of the arthropod neuromuscular system. 1. Arrangement of muscles and innervation in the walking legs of a scorpion: Vaejovis spinigerus (Wood, 1863) Vaejovidae, Scorpiones, Arachnida

(1) The musculature of the walking legs is analysed with regard to both morphology and function in the scorpion, Vaejovis spinigerus (Wood, 1863) (Vaejovidae, Scorpiones, Arachnida), and selected other species. Conspicuous features are multipartite muscles, muscles spanning two joints, and partial lack of antagonistic muscles. The muscle arrangement is compared to that in the walking limbs of other Arthropoda and possible phylogenetic implications are discussed. (2). Histochemical characterisation of selected leg muscles indicates that these are composed of layers of slow, intermediate and fast muscle fibres. Anti-GABA immunohistochemistry shows that mainly the intermediate fibres receive innervation from putative inhibitory motoneurons. (3). Intracellular recording from muscle fibres reveals both excitatory and inhibitory muscle innervation. Individual muscle fibres may receive input from more than one inhibitory motoneuron, as indicated by different IPSP amplitudes. (4). The motoneuron supply of the leg muscles is analysed by retrograde fills of motor nerves. The general arrangement of leg motoneurons in the central nervous system and motoneuron anatomy conforms to the situation in pterygote insects and decapod crustaceans. For example, there are an anterior and a posterior group of leg motoneurons in each hemineuromere, and two contralateral somata near the ganglion midline. Between 12 and 20 motoneurons are found to supply each muscle. Most motoneuron cell bodies supplying a given muscle are arranged in a single cluster with a specific location.

Fiber tracking: principles and strategies - a technical review.

The state of the art of reconstruction of the axonal tracts in the central nervous system (CNS) using diffusion tensor imaging (DTI) is reviewed. This relatively new technique has generated much enthusiasm and high expectations because it presently is the only approach available to non-invasively study the three-dimensional architecture of white matter tracts. While there is no doubt that DTI fiber tracking is providing exciting new opportunities to study CNS anatomy, it is very important to understand its limitations. In this review we therefore assess the basic principles and the assumptions that need to be made for each step of the study, including both data acquisition and the elaborate fiber reconstruction algorithms. Special attention is paid to situations where complications may arise, and possible solutions are reviewed. Validation issues and potential future directions and improvements are also discussed.

Speech Science: An Integrated Approach to Theory and Clinical Practice

Speech Science: An Integrated Approach to Theory and Clinical Practice

Fetal magnetic resonance imaging

Fetal magnetic resonance imaging (MRI) is rapidly establishing a key role in the diagnostic evaluation of fetal central nervous system (CNS) anomalies. We present, a pictorial essay of the effectiveness of fetal MRI in the assessment of cerebral anomalies and ventriculomegaly. High resolution neurosonography remains the cornerstone in antenatal CNS screening. When cerebral anomalies are diagnosed or suspected by ultrasound examination, MRI clearly has a role and often adds useful information or can increase the level of diagnostic confidence and may alter patient counseling and management. MRI examinations also can be used to obtain further opinions from different subspecialists, such as neuroradiologists, neurosurgeons, neurologists and intervention radiologists. Subtleties that may not be distinguishable on ultrasound can be seen on MRI. The MRI should not be seen as a competitor to ultrasound, rather a complementary study from which the imaging specialists can improve their working knowledge in CNS anatomy and pathology.

INJURY-INDUCED CNS PLASTICITY: A SEXUALLY DIMORPHIC RESPONSE IN HIPPOCAMPAL SPROUTING

The following article has been taken from Dr. Morse's dissertation. The combination of the introduction and the experiment of interest is too long for a single article so we have broken it down into two parts. Part I will discuss and define plasticity in general and in the Hippocampus specifically. We will also discuss Hippocampal anatomy during development and in the adult. Finally we will discuss hormones and their role in central nervous system (CNS) anatomy and plasticity. Part II will present the final experiment of this dissertation which directly relates to the background information in part I.

Fetal MRI in the Evaluation of Intrauterine Myelomeningocele

Background: Accurate fetal imaging is essential to the practice of maternal-fetal medicine. While ultrasonography has been the traditional mainstay of fetal imaging, its ability to resolve critical features of central nervous system (CNS) anatomy remains limited. As interest in intrauterine therapy for myelomeningocele has increased, so has the need for more accurate, noninvasive imaging of the CNS. Fetal magnetic resonance imaging (MRI) promises to fill the gap left by ultrasound. Methods: Thirty-seven MRI scans of fetuses previously diagnosed with myelomeningocele were reviewed by 2 neuroradiologists. The ability of fetal MRI to resolve the commonest CNS stigmata of spina bifida, and the incidence and extent of interobserver error, was assessed. In 4 cases, postnatal MRIs were also available. These were compared to the corresponding fetal studies. Results: The imaging quality with the technique used in this study was excellent, even without the use of maternal or fetal sedation. There were no complications, and the imaging times were minimal. Interobserver error was minimal with respect to the evaluation of ventricular dilatation and hindbrain herniation, but moderate in the description and location of the spinal lesion. As had previously been documented with ultrasonography, a reduction was seen in hindbrain herniation when comparing pre- and postnatal MRIs. Conclusion: It is concluded that fetal MRI is an effective, noninvasive means of assessing fetal CNS anatomy. Its ability to resolve posterior fossa anatomy is superior to ultrasonography while, with respect to the evaluation of hydrocephalus and the level and nature of the spinal lesion, it may be equivalent to inferior. Inclusion of the fetal MRI into the standard diagnostic armamentarium will probably await the next major advance in speed and resolution. It is conceivable that, with further advances, MRI might supplant ultrasonography as the diagnostic tool of choice for evaluation of fetal anomalies including myelomeningocele.

Giuseppe Sterzi (1876-1919) of the University of Cagliari: a brilliant neuroanatomist and medical historian.

irst of all, let me explain why weare now writing about Sterzi.Approximately two years ago I(A.R.) received a message from Prof.Colin Wendell Smith, the secretary ofthe FCAT, who happens to live in theantipodal (for me) island of Tasma-nia, asking me if I could find him thearticle on subcutaneous tissue writtenby an Italian professor named Sterzi.This article had been mentioned byProf. DiDio during one FCAT meetingand Prof. Wendell Smith had alreadyunsuccessfully tried to obtain it viathe usual library system. Since I wasaware that Sterzi had been one of mypredecessors in the Anatomy Chair inCagliari, it was easy for me to send acopy of the article to Prof. WendellSmith, who was surprised to hear thatSterzi had been working in the antip-odal (for him) island of Sardinia andso was indirectly associated with me.In order to provide him with an En-glish summary, I had to read the 172-page article myself. I was greatly im-pressed by the rigorous discussion ofprevious reports and by the amount ofnew findings obtained also through acomparative anatomical/embryologi-cal approach. Prompted by this, webecame interested in Sterzi’s life andscientific achievements, being mani-fest that the studies on the subcutane-ous tissue and some others such asthat on the endolymphatic sac,though important and superbly car-ried out, had been just a parenthesisin his production devoted almost ex-clusively to neuroanatomy and thehistory of anatomy. Favaro (1921)maintains, in fact, that Sterzi madethem mainly to show his critics thathis production was not monothe-matic.

Anatomy of the central nervous system

To provide an overview of central nervous system anatomy. Published books and articles. Classification of tumors, location of primary and metastatic tumors, and initial and progressive symptoms are best understood within a solid knowledge base of neuroanatomy. It is essential for nurses caring for neuro-oncology patients to be familiar with normal central nervous system anatomy. This knowledge will enable them to anticipate symptoms, response to treatment, and prognosis for recovery. Understanding of the effects of central nervous system tumors on the function of the central nervous system will help nurses provide holistic care to both patients and significant others.

Principles of avian clinical neuroanatomy

This review of the anatomy of central nervous system will concentrate on clinically important principles. The basic long ascending and descending tracts will be described in relation to the mammalian tracts with which veterinarians are more familiar. By understanding these tracts in relationship to the function and location of cranial nerves and their nuclei in the brain and brain stem, the clinician will be able to understand the neurological examination, better interpret findings, and localize lesions within the central nervous system. These principles will be the focus of this paper.

Cell-type-specific expression and regulation of a c- fos-NGF fusion gene in neurons and astrocytes of transgenic mice

A mouse line transgenic for nerve growth factor (NGF) was developed using the mouse prepro-NGF cDNA inserted within a plasmid containing the proximal region (−10 to −550 bp) of the c- fos promoter and the transcription termination and polyadenylation signals of the rabbit β-globin gene. No significant modification of gross behavior or central nervous system anatomy was detected in adult animals as assessed by immunohistochemistry and in situ hybridization for NGF and choline acetyltransferase. The expression of the transgene and the possible regulation of its expression by agents acting on the promoter were investigated in vitro. Despite the presence of an additional pool of NGF mRNA specific to the transgene, basal levels of NGF in the supernatant of transgenic astrocytes were similar to normal ones. On the other hand, transgenic neurons spontaneously synthesized and released levels of NGF two to three times higher than normal neurons, while mRNA levels were barely detectable by conventional Northern blotting. The tissue-specificity of NGF expression was respected, with higher levels in hippocampal than neocortical neurons. Increases of NGF mRNA by agents acting on the promoter could be observed in normal and transgenic astrocytes only after inhibition of the protein synthesis by cycloheximide, suggesting a similar rapid turnover of normal and transgenic transcripts. Cyclic AMP agonists specifically increased the secretion of NGF protein by transgenic astrocytes and neurons, while activators of the protein kinase C had a similar effect on transgenic and normal cells. Differences between amounts of NGF secreted by neurons and astrocytes with regards to their respective content in mRNA suggest that transgenic transcripts are subject to normal cell- and tissue-specific post-transcriptional regulations. Agents acting on the c- fos promoter through the protein kinase C or cyclic AMP routes differentially increased the secretion of NGF by transgenic astrocytes or neurons, supporting this hypothesis.

Doppler colour flow mapping of fetal intracerebral arteries in the presence of central nervous system anomalies

The adjunctive role of Doppler colour flow mapping in the evaluation of intracerebral morphology and arterial blood flow in the presence of normal and abnormal central nervous system morphology was determined. A total of 59 fetuses with suspected central nervous system pathology between 14 and 37 weeks of gestation was studied (median 31 weeks). One hundred and one fetuses with normal central nervous system anatomy between 14 and 37 weeks (median 19 weeks) served as controls. Visualisation of blood flow in one or more intracerebral arterial vessels was successful in more than 80% of normal fetuses. For the anterior, middle and posterior cerebral artery, the percentages were 63%, 89% and 45%, respectively, at 14–25 weeks and 74%, 100% and 55%, respectively, at 26–37 weeks of gestation. Intracerebral arterial flow identification was attempted in 52/59 (88%) affected fetuses. Identification of blood flow in one or more intracerebral arterial vessels was successful in 40 52 (77%) fetuses. End-diastolic flow velocities were present in at least one of the intracerebral arteries in 39 40 fetuses, absent in one case of hydrocephaly and raised in the presence of an intracerebral vascular tumour. Doppler colour flow mapping seems to provide only limited additional information on intracranial structural pathology.

Transvaginal ultrasonographic definition of the central nervous system in the first and early second trimesters

A 6.5 MHz transvaginal sector scanner was used to describe the fetal central nervous system anatomy from 6 to 14 weeks. One hundred thirty-three pregnant patients were scanned after the crown-rump measurements were found to be within a range of less than or equal to 4 days from menstrual age. The number of possible ultrasonographic sections (slices), as well as the number of successful views in the axial, coronal, and sagittal sections, was tabulated. A detailed list of central nervous system structures that are seen at each gestational age is presented. The results showed that a significant number of brain structures could be imaged. The number and the clarity of the structures and the number of successful views in the three scanning planes increased with gestational age. We concluded that transvaginal scanning for central nervous system maldevelopment can be started in the late first and early second trimesters.

Transvaginal ultrasonographic definition of the central nervous system in the first and early second trimesters

A 6.5 MHz transvaginal sector scanner was used to describe the fetal central nervous system anatomy from 6 to 14 weeks. One hundred thirty-three pregnant patients were scanned after the crown-rump measurements were found to be within a range of less than or equal to 4 days from menstrual age. The number of possible ultrasonographic sections ("slices"), as well as the number of successful views in the axial, coronal, and sagittal sections, was tabulated. A detailed list of central nervous system structures that are seen at each gestational age is presented. The results showed that a significant number of brain structures could be imaged. The number and the clarity of the structures and the number of successful views in the three scanning planes increased with gestational age. We concluded that transvaginal scanning for central nervous system maldevelopment can be started in the late first and early second trimesters.

Vestibular and Other Balance Disorders in Multiple Sclerosis: Differential Diagnosis of Disequilibrium and Topognostic Localization

Disorders of balance and equilibrium are common in multiple sclerosis (MS). This article reviews areas of central nervous system anatomy that may be involved in MS disequilibrium as well as the role of clinical examination, electrophysiologic testing, and magnetic resonance imaging in the diagnosis and assessment of vestibular dysfunction in MS patients. Relevant literature is reviewed and a case history is presented.

Anomalies of Central Nervous System in Infaney; Evaluation by Color Doppler Echoencephalography

We performed 78 color Doppler examinations to demonstrate intracranial vasculature in 61 infants; 30 cases with normal and 19 with abnormal central nervous system anatomy. Developmental abnormalities such as hydrocephalus, hydranencephaly, holoprosencephaly, absent corpus callosum, and Dandy-Walker syndrome were demonstrated. Serial scans were obtained in sagittal, coronal, and axial plains. Most of the major intracranial arteries and veins could be clearly demonstrated in real-time. In patients with hydrocephalus, color Doppler imaging demonstrated a widely streched and elevated sweep of the anterior cerebral arteries, straightening of the middle cerebral arteries by the enlarged ventricles. The internal cerebral veins, great cerebral vein, straight sinus were straighted and displaced posteriorly and inferiorly. In infants with absent corpus callosum, anterior cerebral arteries and their branches appeared to be wavy. However, in patients with developmental abnormalities, visualizations of the vasculature were relatively poor. In conclusion, the color Doppler examination is a useful and practical method of imaging of cerebral vessels in infants, because of its non-invasiveness and portability.

The methylphenidate-induced stereotypy in the awake rat: local cerebral metabolism.

The local cerebral metabolic rate for glucose (1=CMRg) was computed in rats with methylphenidate-induced stereotypy using the quantitative 14C-2-deoxyglucose (2-DG) technique. Four rats received methylphenidate 15 mg per kilogram IP. Compared to five control animals, treated rats showed statistically significant (p less than or equal to 0.05) increases in 1-CMRg in globus pallidus, ventral lateral nucleus of the thalamus, subthalamic nucleus, red nucleus, substantia nigra, entopeduncular nucleus, inferior olivary nucleus, and the lateral cerebellar cortex. Significantly, 1-CMRg decreased in area 4 of the motor cortex. The auditory system showed no change in 1-CMRg, demonstrating the specific action of methylphenidate in the rat brain. This technique allows evaluation of the functional anatomy of the entire central nervous system and may be helpful in understanding the mechanisms of methylphenidate-induced stereotypy.

GROSS ANATOMY OF THE NERVOUS SYSTEM AND RETROCEREBRAL COMPLEX OF ADULT LIOCORIS UNCTUOSUS KELTON (HEMIPTERA:MIRIDAE)

The gross anatomy of the central nervous system and retrocerebral complex of adult Liocoris unctuosus is described and figured. There are three ventral ganglia; the suboesophageal and first thoracic ganglia are separate, while the second and third thoracic are fused with the abdominal ganglia into a common center. Innervation of the reproductive organs in the male is described. The retrocerebral complex consists of the hypocerebral ganglion, paired corpora paracardiaca, and a single corpus allatum, and their associated nerves.

American Retrospect

Epilepsy and other Convulsive Diseases: A Study in Neuro-dynamics and Pathogenesis.—Under this title Dr. Langdon, of Cincinnati, reviews (Journ. Nerv. and Mental Disease, September, 1896) the present state of our knowledge upon certain facts in the anatomy and physiology of the central nervous system; and puts forward some propositions to serve as a working hypothesis to explain epilepsy and other convulsive disorders in the light of modern histological research. He lays particular stress upon Cajal's demonstration of the individuality of the neuron as opposed to the older views. Though anatomically distinct units, neurons are in physiological relation with each other, by means of delicate projections termed gemmules or “contact granules.” The neuron-body (or nerve-cell) is to be considered, in his opinion, as mainly trophic in function; while the nervous activities themselves are to be looked for in the neuron processes, and accounted for upon the theory of inter-molecular and inter-atomic motion—this motion being the result of external stimuli acting upon the peripheral arborisations of neurons. In opposition to the many theories that have been advanced in the explanation and location of the epileptic convulsion, it is now almost universally conceded that: (1) the actual origin of the epileptic convulsion is in the cortex cerebri, and (2) that its nature is an “explosive discharge” in “unstable nerve tissue.” While the nerve-cell was considered the sole seat of all nervous activity, naturally the cause of convulsive phenomena was principally sought for within this nerve-cell. But Langdon quotes researches which show that the ultimate fibrillæ of the axis-cylinder may be traced through the neuron-body to finally ramify in “neuro-plexuses” composed of multitudinous interlacing “end-tufts,” with their contactbuds, and it is in this jungle that, in his opinion, any demonstrable lesions of the various convulsive disorders (including chorea, hysteria, and even uræmia) are to be sought. He is further of opinion that the cerebral cortex, instead of being a “centre of action,” has for its main function that of inhibition, in other words, that it is a centre for preventing, checking, directing and combining various activities which might otherwise occur in different order or intensity. The phenomena observed in the case of Goltz’ dog, which lived for eighteen months after having been deprived of its cerebral hemispheres, are cited in confirmation of this view. His propositions are summarised as follows:—(1) That epilepsy, the choreas, and probably most convulsive disorders, are the dynamical expression of an inhibitory insufficiency; not indications of an over production of nerve-energy, nor “explosions” due to a “molecular instability,” per se. (2) That the cause of this inhibitory insufficiency is to be sought for in the end-brushes of collateral processes of various cortical neurons, the situation varying with the type of the disease, whether sensory, psychic, or motor. (3) That the defect consists most probably in a structural incompleteness (small capacity, defective insulation, imperfect contact) or a numerical deficiency, or both, in the collateral processes of the neurons. (4) Defective collaterals may favour occurrence of convulsions in two ways: (a) by impairing connection with other neurons (inhibitory, storage?); (b) by increased “resistance” to overflow currents, causing temporary over-charging of motor axis-cylinders.