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PubMed1982

An autoradiographic study of the cerebellopontine projections in the rat. I. Projections from the medial cerebellar nucleus.

The medial cerebellar nucleus of the rat is shown by the autoradiographic technique to project to both the contralateral nucleus reticularis tegmenti pontis and the pontine nuclei proper. The former projection is more concentrated in the medial--parvocellular --region. In the pontine gray, the bulk of the projection concerns the dorsal aspect of the medial nucleus. Rostral parts of the medial cerebellar nucleus project to caudal pontine levels whereas caudal parts seem to project throughout the rostrocaudal extent of the basilar pons.

Animals↗
PubMedDate not supplied

Distribution and origins of substance P-immunoreactive projections to the paraventricular and supraoptic nuclei: partial overlap with ascending catecholaminergic projections.

Anatomical and pharmacological evidence suggests a role for substance P (SP) in the control of vasopressin secretion, but the origins of SP-immunoreactive (IR) projections to the paraventricular (PVH) and supraoptic (SO) nuclei of the hypothalamus have not yet been identified. Combined axonal transport, immunohistochemical, and ablation approaches were used to characterize the organization of SP-IR projections to the PVH. The results may be summarized as follows: (1) SP-IR projections are broadly and prominently distributed throughout the SO and both the magnocellular and parvicellular divisions of the PVH. The distribution within the PVH is quite uniform. (2) Combined retrograde transport-immunohistochemical analyses identified multiple potential sources of SP-IR inputs to the PVH. These included a number of hypothalamic cell groups, the laterodorsal and peduculopontine tegmental nuclei, and the rostral and caudal aspects of the ventrolateral medulla. Portions of the tegmental and medullary SP-IR neurons that were retrogradely labelled following tracer deposits in the PVH also stained positively for choline acetyltransferase or tyrosine hydroxylase, respectively. (3) To evaluate the distribution and prominence of medullary SP-IR projections to the PVH and SO, staining for SP and catecholamine-synthesizing enzymes was carried out in animals that had previously received knife cuts at the level of the pontomedullary border. Pronounced, and roughly parallel decrements in staining for peptide and amines were seen in the magnocellular division of the PVH and in the SO; less marked reductions in SP-IR varicosities are in a position to influence multiple visceral regulatory cell types in the PVH and SO. Inputs to the magnocellular neurosecretory system arise in large measure from medullary neurons in which SP coexists with catecholamines. SP-IR projections to the parvicellular division of the PVH appear to originate from a number of sources.

Amino Acid Sequence↗
PubMed1988

Axon extension and retraction by leech neurons: severing early projections to peripheral targets prevents normal retraction of other projections.

During leech embryogenesis, interactions between homologous neurons in neighboring segments lead to the selective retraction of longitudinal axonal projections by midbody AP and AE neurons, which maintain lateral axonal projections to the periphery. Results of experiments reported here show that disconnecting the lateral projections from the periphery rescues the projections normally fated to retract. We propose that these neurons normally progress through two states during early development, one in which they are insensitive to interactions with their homologs (state A) and a second in which they are sensitive (state B). Establishment of lateral connections with their targets triggers the switch from state A to state B; cutting these projections puts neurons back to state A.

Animals↗
PubMed2002

Parabrachio-cortical connections with the lateral hemisphere in the madagascan hedgehog tenrec: prominent projections to layer 1, weak projections from layer 6.

The present study was undertaken to further characterize and subdivide the rhinal cortex (insular and perirhinal areas) in the hedgehog tenrec (Echinops telfairi), a placental mammal with a rather low encephalisation index. Injections of wheat germ agglutinin-horseradish peroxidase into the dorsolateral pontine tegmentum revealed a prominent layer 1 projection to several rhinal target areas, while the rhinal cortex only stained weakly for the calcitonin gene-related peptide. Among the regions retrogradely labeled following tracer injections into the rhinal cortex, the parabrachial nucleus was considered the main origin of the tegmento-cortical projection. This conclusion was based on the circumscribed pattern of termination, as well as the differences noted between the pattern of anterograde labeling and the pattern obtained by thyrosine hydroxylase immunohistochemistry. The tracer injections into the dorsolateral tegmentum also revealed numerous retrogradely labeled cells in the layer 5 of the dorsomedial frontal cortex. In contrast, the rhinal cortex only showed few labeled cells and most of these cells were located in the layer 6/7. A comparison with other species indicates that the tenrec's parabrachial nucleus gives rise to the most extensive cortical projections but receives the least prominent input from the lateral cerebral hemisphere. The layer 6/7 projection may be a common mammalian feature but it is overshadowed by the layer 5 projection in higher mammals.

Animals↗
PubMed1998

Effects of projection geometry and number of projections on accuracy of depth discrimination with tuned-aperture computed tomography in dentistry.

OBJECTIVE: The purpose of this study was to determine the degree to which the number and angular disparity of component projections influence depth discrimination with tuned-aperture computed tomography. STUDY DESIGN: Groups of three tiny steel spheres served as fiducial references on and in four partially edentulous mandibles. Two spheres were attached to the facial and lingual surfaces of each mandible, and the third was fixed in the apical region of an open tooth socket. Errors in estimates of the depth of the apically positioned sphere relative to the other two spheres were determined from three-dimensional tuned-aperture computed tomography reconstructions. These data were compared with actual measurements produced independently with an optical micrometer. Multiple projections required by the tuned-aperture computed tomography reconstruction algorithm were produced from radially symmetric exposures bearing angular disparities of 5, 15, 30, and 45 degrees. The number of symmetrically dispersed projections per tuned-aperture computed tomography reconstruction likewise was varied systematically (2, 4, 8, 12, and 16 projections). These variables were manipulated through the use of a balanced factorial design. Depth estimates were performed by trained observers; the estimates were based on the determination of tuned-aperture computed tomography slices perceived as imaging the respective apical spheres in sharpest focus. Specimen and observer effects were also considered as independent variables. Resulting data were normalized by logarithmic transformation and analyzed statistically by analysis of variance. RESULTS: Significant differences (p < 0.005) were demonstrated for angular disparity and specimen effects, but the number of projections and the effect of the observer were not found to be statistically significant. CONCLUSIONS: In dentistry, angular disparities of 15 degrees or greater should be used when tuned-aperture computed tomography is being applied to diagnostic tasks requiring maximal depth discrimination accuracy.

Algorithms↗
PubMed1999

A comparison of pre-Project 2000 and Project 2000 nurses' perceptions of their research training, research needs and of their use of research in clinical areas.

Most of the literature on the research training and education of nurses has focused on teaching strategies. Only a few authors have assessed systematically the impact of research modules or courses on the knowledge and attitudes of nurses. There is a lack of research on nurses' use of research following their preparation. This paper reports on some of the data from a large-scale survey of the utilization of research among nurses in Northern Ireland. In particular, a comparison is made of the perceptions of pre-Project 2000 and Project 2000 qualified nurses of their research training, research needs, and use of research in clinical areas. A questionnaire was distributed to a convenience sample of 2600 nurses from 23 hospitals in 14 Trusts in Northern Ireland. The response rate was 52.6% (n = 1368). The findings show, among others, a shortfall in research preparation of pre-Project 2000 nurses in important aspects of research. While Project 2000 nurses reported receiving more training, they did not report higher rates of research utilization than pre-Project 2000 nurses. Registered mental nurses (RMNs) and registered nurses mental handicap (RNMHs) also reported lower rates of research utilization than registered general nurses (RGNs), despite reporting the same amount of research preparation as RGNs. The implications of these findings are discussed.

Curriculum↗
PubMed2002

The neglected constituent of the basal forebrain corticopetal projection system: GABAergic projections.

At least half of the basal forebrain neurons which project to the cortex are GABAergic. Whilst hypotheses about the attentional functions mediated by the cholinergic component of this corticopetal projection system have been substantiated in recent years, knowledge about the functional contributions of its GABAergic branch has remained extremely scarce. The possibility that basal forebrain GABAergic neurons that project to the cortex are selectively contacted by corticofugal projections suggests that the functions of the GABAergic branch can be conceptualized in terms of mediating executive aspects of cognitive performance, including the switching between multiple input sources and response rules. Such speculations gain preliminary support from the effects of excitotoxic lesions that preferentially, but not selectively, target the noncholinergic component of the basal forebrain corticopetal system, on performance in tasks involving demands on cognitive flexibility. Progress in understanding the cognitive functions of the basal forebrain system depends on evidence regarding its main noncholinergic components, and the generation of such evidence is contingent on the development of methods to manipulate and monitor selectively the activity of the GABAergic corticopetal projections.

Animals↗
PubMed2000

EPR imaging from projections: errors due to misalignment of projection centres and their rectification by a novel acquisition modality.

Continuous wave and pulsed wave electron paramagnetic resonance imaging (EPRI) makes use of classical methods of acquisition of projections. Acquisition/reconstruction techniques, such as spin-echo, gradient-echo, etc, cannot be applied to EPRI because they would require very short switching times for the gradient coils. Due to the use of the polar acquisition technique, it is necessary to define a centre of rotation about which the measured projections are rotated during the reconstruction process. This centre represents the point at which the field gradient coils must produce zero magnetic field. Due to the presence of a magnetic field control system that serves to compensate for field variations, principally due to heating, some interference can occur in the control system between the main magnetic field and the magnetic field produced by the gradient coils. The effect changes as the orientation changes. This results in a shift of the centres of the projections as a function of the variation of magnetic field produced by the gradient coils on the control Hall probe. If this condition is present, some artefacts can appear on the reconstructed image. This effect is irrelevant when EPR is used for imaging of paramagnetic probes whose linewidths are of the order of 10(-4) T, while it can be significant in the case of linewidths of the order of 10(-5) T or lower or when EPR is used in microimaging applications (i.e. for high values of magnetic field gradient). We describe the effects that misalignments of the projections have on the reconstructed images. We present a useful method for estimating the real position of the centre and correcting the measured projections before the application of the reconstruction algorithm. Moreover, we demonstrate the functioning of our technique by presenting some examples of EPR reconstruction collected by an X-band EPR imaging apparatus.

Algorithms↗
PubMed1978

Two projection computed tomography: the axial and Towne projections.

It is occasionally necessary in evaluating lesions around the third ventricle and posterior fossa to supplement the axial view with another projection. The authors have routinely used the coronal projection as a second projection. However, the Towne view for computed tomography can be used as a second projection instead of the coronal; it is technically easier and faster to perform than the coronal projection, and provided good evaluation of the posterior fossa and para third ventricular areas in children.

Cerebral Ventricle Neoplasms↗
PubMed1981

Organization of projections from the gracile, medial cuneate and lateral nuclei in the North American opossum. Horseradish peroxidase study of the cells projecting to the cerebellum, thalamus and spinal cord.

Using the horseradish peroxidase technique on the North American opossum, we were able to locate the neurons within the dorsal column and lateral cuneate nuclei which innervate the cerebellum and thalamus as well as those within the dorsal column nuclei which project spinalward. The medial and lateral cuneate nuclei supply axons to the anterior lobe, the paramedian lobule and the pyramis of the cerebellum and the lateral nucleus provides an additional projection to the uvula. The cerebellar projections from these nuclei arise from neurons located rostral to the obex. The thalamic projections from the gracile and medial cuneate nuclei originate from neurons throughout their rostral to caudal extent, although most of them are located just rostral to the obex. Neurons within the lateral cuneate nucleus which innervate the thalamus are found at intermediate rostrocaudal levels where most of them approximate the medial cuneate nucleus. The medial cuneate also projects to at least lumbar levels of the spinal cord in the opossum and neurons giving rise to such connections are found at the level of the obex and caudal to it. Neurons within the dorsal part of the dorsal column nuclei were labelled only after thalamic injections. Our results in the opossum are compared with those obtained in several placental mammals.

Animals↗
PubMed1989

[Afferent projections to the uvula in the cat. II. Mossy fiber projections].

The mossy fiber projections to the uvula of the cerebellum were studied by means of retrograde axonal transport of horseradish peroxidase (HRP) in the cat. Following large and small injections into the uvula, distribution of the labeled cells in the brainstem nuclei was investigated. The results showed different afferent projections between the dorsal and ventral uvula. Major sources projecting to the dorsal uvula were the peduncular, paramedian, and lateral nuclei of the pontine nuclei. Labeled cells found in the pontine nuclei amounted to 81.6% of the total number of labeled cells in cat 1. On the other hand, major sources projecting to the ventral uvula were the caudal aspect of the medial and inferior vestibular nuclei, the x- and f-groups of the vestibular nuclei, the dorsal and central aspect of the superior vestibular nucleus, the rostral dorsomedial aspect of the paramedian nucleus of the pontine nuclei, the caudal aspect of the prepositus hypoglossal nucleus, and the infratrigeminal nucleus. Labeled cells in the vestibular nuclei amounted to 72.1% of the total number of the labeled cells in the cat 40. It was revealed that the lateral aspect of the ventral uvula receives inputs from the pontine nuclei, whereas the medial part of the ventral uvula receives inputs from the vestibular nuclei. Mediolateral differences were not found in the dorsal uvula. These mossy fiber zones were mediolaterally wide, and the dorsal uvula was different from the ventral uvula with regard to mossy fiber projection.

Afferent Pathways↗
PubMed1994

[Afferent projections to the nodulus in the cat. II. Mossy fiber projections].

Mossy fiber projections to the nodulus of the cerebellum were studied by retrograde axonal transport of horseradish peroxidase (HRP) in the cat. Following large and small injections into the nodulus, the distribution of labeled cells in the brainstem nuclei was investigated. Our observations provided evidence that the nodular afferents take their major origin from the medial, inferior and superior vestibular nuclei. On the other hand, minor sources projecting to the nodulus were from the x- and z-group. Of the perihypoglossal nuclei, it is only the prepositus hypoglossal nucleus which appears to be interconnected with the nodulus. There were no projections of the pontine nuclei and the nucleus reticularis tegmenti pontis to the nodulus. Injections of the nodular cortex revealed a distinct bilateral projection to this cortical area. The results showed no different projections between the dorsal and ventral nodulus. Mediolateral differences were not found in the nodulus.

Animals↗
PubMed1998

[Cognitive impairment and cardiovascular disease risk factors. Project CASCADE Kraków. I. Project to test exposure to risk factors for cardiovascular disease in the studied sample].

Dementia is found in a small percent of general population but remains a significant problem in the elderly population. Little is known whether prevention of dementia in the elderly is possible. Some evidence exists that both vascular dementia and Alzheimer's type dementia are related to cardiovascular disease risk factors. The main goal of the CASCADE Kraków Project is to study the relation between the exposure to cardiovascular disease risk factors in the middle age and cognitive impairment and cerebral white matter lesions in old age. Project CASCADE Kraków is an independent part of the international project CASCADE, which is carried out in 11 research centres from 9 countries. Polish part of the study includes a longitudinal observation of the sample screened earlier in POL-MONICA Kraków Project, which was selected from population of residents of rural province (Tarnobrzeg Voivodship). Studied sample are 1318 persons, for whom cardiovascular disease risk factors were measured in 1983-84 and who completed at least 64 years in 1997. Two-stage examination was designed. In the first stage collection of the following data was designed: socio-economic factors, history of cardiovascular disease, perceived health, blood pressure and cognitive function assessment using Mini-Mental State Examination (MMSE) procedure. In the second stage (sub-sample of 300 persons included) the following procedures were designed: detailed neuro-psychological testing, neurolo-gical examination, MRI, determination of total- and HDL-cholesterol and determination of apoE isoforms. There were 625 (47%) men and 693 (53%) women selected for the first stage. Out of them 128 (43%) men and 172 (57%) women were selected for the second stage. There were no important differences in age, education, health status and exposure to cardiovascular disease risk factors between the studied groups in the baseline assessment. However, there were important differences between men and women. Compared to men, women had lower education (higher than elementary education in 17% and 9% respectively), more frequent obesity (respectively 12% and 36%), hypertension (respectively 57% and 71%) and hyperlipoproteinemia (respectively 17% and 30%) but lower smoking rate (respectively 53% and 4%). Integration of neuropsychological testing and neuroimaging with the epidemiological approach to risk factors could contribute to better understanding of the mechanisms on which the disease affects the brain morphology and functions. The results of CASCADE and CASCADE Kraków projects will contribute also to the development of the strategies of medical care and management of the cognitive impairment in the elderly.

Aged↗
PubMed1996

Projection on projective techniques = pathology: the problem that is not being addressed.

A replication of the "levels effect" and reported correlation of "projection" and "pathology" was undertaken using a selected set of Thematic Apperception Test (Murray, 1943) cards varied for ambiguity and scored for pathology and projection. The levels effect was not found for pathology in either a normal or psychiatric group, but was found for projection in the normal group. The correlation between projection and pathology was again clearly confirmed. It was concluded that failure to take into consideration the stimulus properties of the cards and the context in which the test was administered may lead to false attribution of pathology to normal test-takers.

Adolescent↗
PubMed2002

[SNP project in the Millennium Genome Project, Japan].

The basic outlines of the Millennium Genome Project were drawn by the Japanese government on December 19, 1999. In the "Disease gene" team, 5 disease have been chosen as the targets of the Project, Alzheimer's disease, cancer, diabetes, hypertension and asthma. Along with the knowledge-based candidate gene approaches, the complementary strategy of the disease gene hunting, the statistics-based approach, is being deployed. The Project decided to go for a genome-wide, gene-based SNP scan through a close collaboration with another team of the Project, "Standard polymorphism" team, which already discovered c. a. 160,000 SNPs in and around the genes of the Japanese people.

Alzheimer Disease↗
PubMed1994

[[The method for projecting households by family type in terms of headship cohort change--Part 2. Projecting marital status and headship rates by family type in household formation stage]].

"This article is Part 2 of the study on the method for projecting households [in Japan] by family type.... Part 1 was on modelling the transition process among different family types of households headed by [persons] over 35 years old, and on the method for projecting households by family type using the transition model.... Part 2 focuses on the method for projecting households in the formation stage headed by [those] under 34 years old.... Among projection outcomes, the proportion never married of males aged 30-34 goes up from 32.8 per cent to 37.3 per cent between 1990 and 2010, and the proportion never married of females aged 25-29 from 40.4 per cent to 47.1 per cent. [The] tendency of late marriage will continue to the beginning of the twenty-first century." (SUMMARY IN ENG)

Asia↗
PubMed1995

Network-based informatics support of research collaborations in the Human Genome Project and the Human Brain Project.

Sophisticated network-based informatics support will increasingly be required for collaborating biomedical laboratories located in different geographic locations, both to accommodate the massive amount of data being generated in certain fields, and to allow different types of data produced at different laboratories to be analyzed in an integrated fashion. The paper describes the experience of the Yale Center for Medical Informatics in providing informatics support for collaborative projects in gene mapping (as part of the national Human Genome Project) and neuroscience (as part of the national Human Brain Project). The paper describes the informatics needs of the two projects and the solutions being developed, describes certain lessons learned, and discusses certain broader issues that arise.

Brain Mapping↗
PubMed1998

Organization of direct hippocampal efferent projections to the cerebral cortex of the rhesus monkey: projections from CA1, prosubiculum, and subiculum to the temporal lobe.

This study investigates direct hippocampal efferent projections to the temporal lobe of the rhesus monkey. Tritiated amino acid injections were placed into the hippocampal formation to identify terminal fields, and complementary fluorescent retrograde tracer injections were placed into the cortex to identify the cells of origin. Tritiated amino acid injections into CA1, prosubicular, or subicular subfields produced anterograde label over parts of the parahippocampal gyrus and temporal pole. Injections of fluorescent retrograde tracers demonstrated that these projections originate from longitudinal strips of neurons that occupy part of the CA1 subfield as well as from strips of neurons in adjacent prosubicular and subicular subfields. Thus, an injection into area TH of the posterior parahippocampal gyrus labeled neurons in a longitudinal strip of proximal CA1 (i.e., near CA2) as well as a strip in the subiculum; injections into areas TF, TL, 35, or Pro labeled neurons in a longitudinal strip of distal CA1 (i.e., near the prosubiculum) as well as one in the prosubiculum; and an injection into area TFO labeled neurons in a longitudinal strip in the middle of CA1. These strips of neurons extended longitudinally throughout the entire rostrocaudal length of the hippocampus. These results demonstrate that, in the monkey, CA1 projections to cortex arise topographically from longitudinally oriented strips of neurons that occupy only a part of the transverse extent of CA1 but that cover most of the anteroposterior extent of the hippocampus. Thus, in the monkey, CA1 is not a single uniform entity and may have a unique role as a source of direct hippocampal projections to the cerebral cortex.

Animals↗