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PubMed2005

The expression of brain sexual dimorphism in artificial selection of rat strains.

Central nervous system sex differences have two morphological patterns. In one pattern, males show larger measurements (volume, number of neurons) than females (male > female; m > f) and, in the other, the opposite is true (female > male; f > m). The bed nucleus of the stria terminalis (BST) is a unique model for the study of sex differences because it has dimorphic and isomorphic subdivisions, with the former showing the two sexually differentiated morphological patterns. Meanwhile, other CNS structures, like the locus coeruleus (LC), present the f > m pattern. The philogenetic maintenance of the two patterns of sexual differentiation can help to disentangle the functional meaning of sex differences. Laboratory rat strains, whether albino or pigmented, descend from the Wistar strain through artificial selection. The present work compares the BST and LC of Wistar and Long-Evans rats. The medial posterior subdivision of the BST (BSTMP) is sexually dimorphic (m > f pattern) in the original (Wistar) and derived (Long-Evans) strains, while the lateral anterior and medial anterior subdivisions of the BST and the LC only present sex differences (f > m pattern) in the ancestor Wistar strain. Isomorphic BST regions are the same in both strains. The fact that the BSTMP, which is implicated in male copulatory behavior, is sexually dimorphic in both strains, as well as in other species, including humans, indicates the relevance of this structure in male sexual behavior in mammals.

Animals↗
PubMed2001

SNRPN methylation patterns in germ cell tumors as a reflection of primordial germ cell development.

Studies examining altered imprinted gene expression in cancer compare the observed expression pattern to the normal expression pattern for a given tissue of origin, usually the somatic expression pattern for the imprinted gene. Germ cell tumors (GCTs), however, require a developmental stage-dependent comparison. To explore using methylation as an indicator of germ cell development, we determined the pattern of methylation at the 5' untranslated region of SNRPN in 89 GCTs from both children and adults. Fifty-one of 84 tumors (60.7%) (12/30 (40%) of cultured pediatric GCTs, 23/36 (63.9%) of frozen adult GCTs, and 16/23 (69.5%) of frozen pediatric GCTs, with five samples having results from both cultured and uncultured material) demonstrated a nonsomatic methylation pattern after dual digestion with XbaI, NotI, and Southern blot analysis. In contrast, only 2 of 18 (11%) control samples (16 non-GCTs and 2 normal ovaries) exhibited a nonsomatic pattern. In both cases, the result was shown to be due to copy number differences between maternal and paternal homologs, unlike the GCTs in which there was no evidence of an uneven homolog number. A comparison of the data for only the gonadal GCTs and the control data showed a highly significant difference in the proportion of tumors with methylation alterations at this locus (P = 0.0000539). Since there is no published evidence of the involvement of SNRPN methylation changes in the development of malignancy, the data suggest that the methylation pattern of SNRPN in GCTs reflects that of the primordial germ cell giving rise to the tumor.

Adolescent↗
PubMed1999

A microcosm of musical expression. III. Contributions of timing and dynamics to the aesthetic impression of pianists' performances of the initial measures of Chopin's Etude in E major.

Four judges repeatedly assessed the overall aesthetic quality of more than 100 recorded performances of the opening of Chopin's Etude in E major on a 10-point scale. The judgments, which exhibited reasonable reliability and modest intercorrelations, were entered into regression analyses with 16 independent variables derived from earlier objective analyses of the expressive timing and dynamics of the performances [Repp, J. Acoust. Soc. Am. 104, 1085-1100 (1998); 105, 1972-1988 (1999)]. Only between 9% and 18% of the variance in the judges' ratings was accounted for. By contrast, timing variables accounted for 53% of the variance in one judge's ratings of synthesized performances that varied in timing only and mimicked the timing patterns of the original performances. These results indicate, first, that the aesthetic impression of the original recordings rested primarily on aspects other than those measured (such as texture, tone, or aspects of timing and dynamics that eluded the earlier analyses) and, second, that very different patterns of timing and dynamics are aesthetically acceptable for the same music, provided that other, aesthetically more crucial performance aspects are present.

Aged↗
PubMedDate not supplied

Neural activity during encoding predicts false memories created by misinformation.

False memories are often demonstrated using the misinformation paradigm, in which a person's recollection of a witnessed event is altered after exposure to misinformation about the event. The neural basis of this phenomenon, however, remains unknown. We used fMRI to investigate encoding processes during the viewing of an event and misinformation to see whether neural activity during either encoding phase could predict what would be remembered. fMRI data were collected as participants studied eight vignettes (Original Event phase). Shortly afterward, participants studied the same vignettes during scanning, but with changes to several details, serving as the misinformation (Misinformation phase). Two days later, their memories for the Original Event were assessed. Activity that subsequently led to true and false memories was examined during both encoding phases. Two interaction patterns between encoding phase (Original Event and Misinformation) and type of memory (true and false) were observed in MTL and PFC regions. In the left hippocampus tail and perirhinal cortex, a predictive item-encoding pattern was observed. During the Original Event phase, activity was greater for true than false memories, whereas during the Misinformation phase, activity was greater for false than true memories. In other regions, a pattern suggestive of source encoding was observed, in which activity for false memories was greater during the Original Event phase than the Misinformation phase. Together, these results suggest that encoding processes play a critical role in determining true and false memory outcome in misinformation paradigms.

Adolescent↗
PubMed2005

Evolutionary innovations in the fossil record: the intersection of ecology, development, and macroevolution.

The origins of evolutionary innovations have been intensively studied, but relatively little is known about their large-scale ecological patterns. For post-Paleozoic benthic marine invertebrates, which have the richest and most densely sampled fossil record, order-level taxa tend to appear first in onshore, disturbed habitats, even in groups that are now exclusively deep-water (so that present-day distributions are not reliable indicators of original environments). New results presented here show that the onshore-origination pattern is robust to shifts in taxonomic methods and to new paleontological discoveries, and the few available studies suggest that this pattern can also be seen in terms of excursions in morphospace or the acquisition of derived character states, without reference to taxonomic categories. The environmental pattern at high levels contrasts significantly with the origin of low-level novelties (such as defined genera and families) in crinoids, echinoids, and bryozoans, where first appearances tend to conform to their clade-specific bathymetric diversity gradients. This discordance seems to eliminate potential driving mechanisms that simply scale up within-population genetic or ecological processes. Little is known about the factors that promote the onshore-offshore expansion of orders across the continental shelf, or that drive some clades to abandon ancestral habitats for an exclusively deep-water distribution. The origin of evolutionary innovation must ultimately reside in developmental changes, but the onshore-origination bias could emerge from two different dynamics: the pattern could be primarily genetic and developmental, i.e., innovations truly arise onshore; or primarily ecological, i.e., innovations arise randomly but preferentially survive onshore. Whatever the ultimate driving mechanisms, these macroevolutionary patterns show that theories of large-scale evolutionary novelty must include an ecological dimension.

Animals↗
PubMed1982

A genetic analysis of the determination of cuticular polarity during development in Drosophila melanogaster.

The polarity mutants pk, sple, mwh, fz and in alter the orientations of cuticular processes in several regions of the body. The mutant polarity patterns are constant and do not result from alterations in cell lineage. Polarity patterns are locus specific rather than allele specific (new alleles express the same polarity patterns as the original alleles). In the wing, polarity formation is largely cell autonomous and is independent of the anteroposterior compartment boundary. By genetic and physiological manipulation it is shown that the mutant polarity patterns are unaffected by the size of the wing blade or the number of cells that form it. Mutants which remove parts of the wing margin or alter the distribution pattern of wing veins do not alter the mutant polarity patterns. Thus, neither the wing margins nor the pattern of vein tissue act as spatial references for polarity formation. The determination of mutant polarity patterns is not dependent on the overall topology of the wing blade but is region-specific. The mutants affect several independent functions. The possible wild-type function of the loci in polarity formation is discussed.

Alleles↗
PubMed1996

Developmental patterns and characteristic symptoms of petroclival meningiomas.

Thirty-six cases of petroclival meningiomas with clearly defined anatomical features were selected to analyze the site of tumor attachment and the displacement of the trigeminal nerve. The tumors were classified into four categories according to the origin and extension of the tumor: clival origin medial to the trigeminal nerve (upper clivus type), clival origin with dumbbell extension to the cavernous sinus (cavernous sinus type), tentorial origin over the trigeminal nerve (tentorium type), and petrous apex origin lateral to the trigeminal nerve (petrous apex type). Patients with tumors in each category had characteristic neurological symptoms. Patients with the upper clivus type had oculomotor nerve paresis as a single symptom, if suprasellar tumor extension was present. Patients with the cavernous sinus type commonly presented with abducens nerve paresis caused by epidural tumor invasion around Dorello's canal. Dumbbell tumor extension along the venous drainage of the cavernous sinus was a significant problem for surgical removal in this type. Half of the patients with the tentorium type had a characteristic symptom of trigeminal neuralgia caused by retrograde tumor invasion into Meckel's cave from its orifice, but the cavernous sinus was not involved. The main complaint of patients with the petrous apex type was hearing disturbance, but no epidural or parasellar extension was present. Clinical symptoms and magnetic resonance imaging provide important information about the origin and extension patterns of these tumors, especially the presence or absence of tumor extension into the cavernous sinus. Abducens nerve paresis or trigeminal neuralgia suggests tumor invasion into the cavernous sinus or Meckel's cave, respectively.

Adult↗
PubMed1975

The fine structure of the centrohelidian heliozoan Heterophrys marina.

The fine structure of Heterophrys marina (Centrohelidia, Heliozoa) is described with special reference to centroplast structure, morphogenesis and "behavior" of kinetocysts (= axopodial granules which perform saltatory movement), and formation of organic spicules in a new type of organelle located in the plasma membrane. A low calcium pretreatment and fixation was used to improve preservation of highly labile axopodia which near their distal end contain a single microtubule (MT) only. Two varieties of H. marina with a respective maximum of 6 and 12 MTs per axopodium, and 2 hitherto undescribed species, H. elati and H. multipoda, were found among 9 stocks collected in Europe and North America. In all species only the central 6 MTs of each axoneme originate from a scaffolding layer of electron dense material which surrounds the central granule. Evidence is presented which indicates that in Heterophrys self-linkage is not the only principle of MT pattern generation but that instead precisely localized MT nucleation and specific linkage of MTs within the cortex of the centroplast lead to the MT patterns observed. Prekinetocysts originate from vesicles found in the neighborhood of the dictyosomes. After maturation the kinetocysts become attached to the plasma membrane which seems to play an important role both in selection of particles transported in the axopodia and particle movement as well.

Animals↗
PubMed2001

Developmental changes within the core of artifact concepts.

Three experiments addressed the relative importance of original function and current function in artifact categorization. Subjects were asked to judge whether an artifact that was made for one purpose (e.g. making tea) and was currently being used for another purpose (e.g. watering flowers) was a teapot or a watering can. Experiment 1 replicated the finding by Hall (1995) (unpublished manuscript) that adults rely on the original function of an artifact over a current function in their kind judgments. Experiments 2 and 3 revealed that whereas the kind judgments of 6-year-olds, like those of adults, patterned with the original function, those of 4-year-olds did not. Four-year-olds were influenced by the order in which the functions were mentioned in the story. Further, in their justifications 6-year-olds and adults referred to the origin of the objects, whereas 4-year-olds virtually never did. We conclude that 6-year-olds have begun to organize their understanding of artifacts around the notion of original function, and that 4-year-olds have not. The data are discussed as they bear on children's understanding of the design stance (Dennett, D. C. (1987).

Adult↗
PubMed1990

Activity of glycolytic enzymes and glucose-6-phosphate dehydrogenase in lipoblastic and neurogenic proliferations.

The alterations in specific activity and/or isozyme pattern of hexokinase, phosphofructokinase, aldolase, enolase, pyruvate kinase and glucose-6-phosphate dehydrogenase were studied in the tissue specimens of 26 patients with lipoblastic tumors and 28 patients with tumors of neurogenic origin. Although the biochemical data demonstrated that the activities of most enzymes studied were elevated in the specimens of the malignant tumors, only the differences in activity of hexokinase, pyruvate kinase and glucose-6-phosphate dehydrogenase measured between benign and malignant neurogenic tumors were significant. In malignant tumors, especially those of neurogenic origin, the isozyme pattern of pyruvate kinase showed a shift towards K-type subunits.

Adolescent↗
PubMed2003

Development of a macromolecular diffusion pathway in the lens.

The mammalian lens consists of an aged core of quiescent cells enveloped by a layer of synthetically active cells. Abundant gap junctions within and between these cell populations ensure that the lens functions as an electrical syncytium and facilitates the exchange of small molecules between surface and core cells. In the present study, we utilized an in vivo mouse model to characterize the properties of an additional pathway, permeable to macromolecules, which co-exists with gap-junction-mediated communication in the lens core. The TgN(GFPU)5Nagy strain of mice carries a green fluorescent protein (GFP) transgene. In the lenses of hemizyous animals, GFP was expressed in a variegated fashion, allowing diffusion of GFP to be visualized directly. Early in development, GFP expression in scattered fiber cells resulted in a checkerboard fluorescence pattern in the lens. However, at E15 and later, the centrally located fiber cells became uniformly fluorescent. In the adult lens, a superficial layer of cells, approximately 100 microm thick, retained the original mosaic fluorescence pattern, but the remainder, and majority, of the tissue was uniformly fluorescent. We reasoned that at the border between the two distinct labeling patterns, a macromolecule-permeable intercellular pathway was established. To test this hypothesis, we microinjected 10 kDa fluorescent dextran into individual fiber cells and followed its diffusion by time-lapse microscopy. Injections at depths of >100 microm resulted in intercellular diffusion of dextran from injected cells. By contrast, when injections were made into superficial fiber cells, the injected cell invariably retained the dextran. Together, these data suggest that, in addition to being coupled by gap junctions, cells in the lens core are interconnected by a macromolecule-permeable pathway. At all ages examined, a significant proportion of the nucleated fiber cell population of the lens was located within this region of the lens.

Animals↗
PubMed1987

[Households and families of migrants of Caribbean origin].

"Households and family patterns of Caribbean migrants in France [are] compared to those of three different populations: first, to the non-migrants living in Guadeloupe, Martinique, Guyane or Reunion; second, to the other migrants in France; third, to the French population of comparable socio-economic status (mainly employees and workers)....Several indicators, mainly drawn from the census of 1982 are used: mean numbers of persons and of children per household, proportions of male-headed households, typology of households and families, [and] relationship of each member of the household to the head." Cultural background and French citizenship are shown to be more closely associated with patterns of family size and characteristics than are socioeconomic factors. (SUMMARY IN ENG)

Americas↗
PubMed1993

Clinical electrophysiology relevant for early glaucoma diagnosis.

This review reports findings of the recent literature about electrophysiologic techniques that are used in glaucoma diagnosis and research. Included in this review are results obtained by recording electrical responses from the eye (electroretinograms) and from the brain (visual evoked potentials). Studies concerned the electroretinogram evoked by patterned stimuli that originates in the proximal retina and with flash-evoked responses that originate from the proximal retina, such as oscillatory potentials and scotopic threshold responses, from middle layers of the retina (B wave), and from the outer retina (A waves and C waves). Regarding the pattern electroretinogram, the authors agree on its usefulness in the diagnosis of glaucoma. However, the optimal stimulus conditions (temporal and spatial frequency, retinal location, contrast, and color), which component of the response to evaluate, and the value of the pattern electroretinogram in follow-up treatment are debatable. Flash-evoked components of the electroretinogram that have been considered in the past to be of low value in diagnosis of glaucoma now seem to be more important. New developments in visual evoked potentials techniques, such as photostress methods, contrast sensitivity measurements, ramp stimulation, and selective adaptation for isolating blue-cone activity seem to be promising in further increasing the diagnostic value of visual evoked potential measurements.

Electrophysiology↗
PubMed1996

Dermatoglyphic variation in Europe.

We describe the geographic variation patterns of 236 dermatoglyphic variables (118 for each sex) for 74 samples in Europe. Using principal components analysis and rotating to simple structure, we simplified these patterns to the first 20 axes, representing 74.2% of covariation. We then used heterogeneity tests, interpolated surfaces, one-dimensional and directional correlograms, and distances between correlograms to analyze the factor scores of these 20 axes. We also ordinated the 74 localities. The data are remarkable for showing little spatial autocorrelation, despite significant heterogeneity among localities. Only three factor axes exhibit consistently significant correlograms, indicating that there are few spatial patterns in the original variables in Europe. Almost all correlations between pairs of variables occur within serially homologous character sets and are thus developmentally determined. There is some support for demic diffusion from the southeast in finger patterns and ridge counts. We compare these results to those of previous studies and note that Lapps and Icelanders are outliers with respect to both genetics and finger tip variables, whereas Tatars are outliers with respect to craniometrics and dermatoglyphics.

Analysis of Variance↗
PubMed2004

Comparative expression analysis of the MAGED genes during embryogenesis and brain development.

The MAGED gene subfamily contains three genes in mouse and four in human. The MAGED1, D2, and D3 proteins are highly conserved between mouse and human, whereas paralogues are less conserved between each other. This finding suggests that each MAGED protein exerts a distinct function. To get a better insight into their physiological roles, we have analyzed their expression patterns during embryogenesis and brain development. In the mouse, Maged3 expression is restricted to the central nervous system where it was mostly detected in postmitotic neurons. Maged2 is mainly expressed in tissues of mesodermal origin. The expression pattern of Maged1 roughly summarizes that of Maged2 and Maged3; however, contrary to that of Maged3, it includes the proliferative zones of the nervous system. We observed a discrepancy between Maged1 expression levels of RNA and protein, suggesting that its expression is regulated at a posttranscriptional level during the mouse development.

Adaptor Proteins, Signal Transducing↗
PubMed1990

The topographic relationship between shifting binocular maps in the developing dorsal lateral geniculate nucleus.

The major mammalian subcortical visual structures receive topographically ordered projections from both eyes. In the adult dorsal lateral geniculate nucleus (dLGN) each projection terminates in separate restricted regions of the nucleus. This pattern is different during development. Initially in ferrets the projections from each eye to the dLGN overlap throughout this structure. Although the projections do not occupy regions that are appropriate given the adult pattern, they are both retinotopically organised. Consequently, the formation of the adult pattern requires that the two retinotopic projections shift in relation to one another. The experiments undertaken here on the newborn ferret demonstrate the relationship between the two unsegregated projections in terms of their retinal origin and relative pattern of projection to the dLGN. By establishing the relationship between the projections at this stage of development it is possible to determine the relative changes that must be made between them in order to bring about the adult pattern of registration. By mapping the two unsegregated projections with a combination of retinal lesions and anterograde tracing methods it is demonstrated that at birth the ipsilateral projection arises from the temporal retina, and the contralateral projection arises from the entire retina. Because of the significant contralateral projection from the temporal retina the relatively sharp nasotemporal division found in the adult is not present at this stage. This element of the contralateral projection maps in continuity with the rest of this projection and terminates at the caudal pole of the nucleus. However, it is probably lost before the adult pattern has clearly started to develop.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Cell proliferation and rearrangement in the development of the malpighian tubules of the hemipteran, Rhodnius prolixus.

The pattern of cell activities resulting in the generation of a simple tubular epithelium, the Malpighian tubules of Rhodnius prolixus, is examined during embryogenesis. The anlage of the tubules is shown to be of ectodermal origin. An evolving pattern of cycling cells in the primordia is revealed using the immunocytochemical localization of a substituted nucleotide, BUdR. A cell unique to each tubule is shown not to enter the cell cycle but to be required for the proliferation of the remaining cells in the tubules. Furthermore, the activity of this cell imposes on each tubule a clear proximo-distal axis.

Animals↗
PubMed1992

Structural changes and enhancements in DNase I footprinting experiments.

In footprinting experiments, an increase in DNA cleavage with addition of ligand to a system may be due to a ligand-induced structural change. Ligand binding also enhances cleavage by displacing the cleavage agent from ligand-binding sites, thus increasing its concentration elsewhere. The theory and characteristics of this mass-action enhancement are given, and it is shown how it may be recognized. Results of DNase I footprinting of small oligomers, with actinomycin D as ligand, are analyzed to reveal which enhancements are due to mass action, and which can reasonably be ascribed to structural changes. Patterns in the footprinting plots from our experiments on actinomycin D binding to a 139-base-pair DNA fragment (with DNase I as a probe) are studied in the same way. The likely origins of these patterns are discussed, as are enhancements occurring with other probes commonly used in footprinting experiments.

Base Sequence↗