Showing papers by "New York University published in 1988"
TL;DR: The revised criteria for the classification of rheumatoid arthritis (RA) were formulated from a computerized analysis of 262 contemporary, consecutively studied patients with RA and 262 control subjects with rheumatic diseases other than RA (non-RA).
Abstract: The revised criteria for the classification of rheumatoid arthritis (RA) were formulated from a computerized analysis of 262 contemporary, consecutively studied patients with RA and 262 control subjects with rheumatic diseases other than RA (non-RA). The new criteria are as follows: 1) morning stiffness in and around joints lasting at least 1 hour before maximal improvement; 2) soft tissue swelling (arthritis) of 3 or more joint areas observed by a physician; 3) swelling (arthritis) of the proximal interphalangeal, metacarpophalangeal, or wrist joints; 4) symmetric swelling (arthritis); 5) rheumatoid nodules; 6) the presence of rheumatoid factor; and 7) radiographic erosions and/or periarticular osteopenia in hand and/or wrist joints. Criteria 1 through 4 must have been present for at least 6 weeks. Rheumatoid arthritis is defined by the presence of 4 or more criteria, and no further qualifications (classic, definite, or probable) or list of exclusions are required. In addition, a "classification tree" schema is presented which performs equally as well as the traditional (4 of 7) format. The new criteria demonstrated 91-94% sensitivity and 89% specificity for RA when compared with non-RA rheumatic disease control subjects.
19,409 citations
TL;DR: Four theoretical models of yes-no recognition memory are described and their associated measures of discrimination and response bias are presented and the indices from the acceptable models are used to characterize recognition memory deficits in dementia and amnesia.
Abstract: SUMMARY This article has two purposes. The first is to describe four theoretical models of yesno recognition memory and present their associated measures of discrimination and response bias. These models are then applied to a set of data from normal subjects to determine which pairs of discrimination and bias indices show independence between discrimination and bias. The following models demonstrated independence: a two-highthreshold model, a signal detection model with normal distributions using d' and C (rather than beta), and a signal detection model with logistic distributions and a bias measure analogous to C. Cis defined as the distance of criterion from the intersection of the two underlying distributions. The second purpose is to use the indices from the acceptable models to characterize recognition memory deficits in dementia and amnesia, \bung normal subjects, Alzheimer's disease patients, and parkinsonian dementia patients were tested with picture recognition tasks with repeated study-test trials. Huntington's disease patients, mixed etiology amnesics, and age-matched normals were tested by Butters, Wolfe, Martone, Granholm, and Cermak (1985) using the same paradigm with word stimuli. Demented and amnesic patients produced distinctly different patterns of abnormal memory performance. Both groups of demented patients showed poor discrimination and abnormally liberal response bias for words (Huntington's disease) and pictures (Alzheimer's disease and parkinsonian dementia), whereas the amnesic patients showed the worst discrimination but normal response bias for words. Although both signal detection theory and twohigh-threshold discrimination parameters showed identical results, the bias measure from the two-high-threshold model was more sensitive to change than the bias measure (C) from signal detection theory. Three major points are emphasized. First, any index of recognition memory performance assumes an underlying model. Second, even acceptable models can lead to different conclusions about patterns of learning and forgetting. Third, efforts to characterize and ameliorate abnormal memory should address both discrimination and bias deficits.
2,898 citations
TL;DR: It is proposed that the autorhythmic electrical properties of central neurons and their connectivity form the basis for an intrinsic functional coordinate system that provides internal context to sensory input.
Abstract: This article reviews the electroresponsive properties of single neurons in the mammalian central nervous system (CNS). In some of these cells the ionic conductances responsible for their excitability also endow them with autorhythmic electrical oscillatory properties. Chemical or electrical synaptic contacts between these neurons often result in network oscillations. In such networks, autorhythmic neurons may act as true oscillators (as pacemakers) or as resonators (responding preferentially to certain firing frequencies). Oscillations and resonance in the CNS are proposed to have diverse functional roles, such as (i) determining global functional states (for example, sleep-wakefulness or attention), (ii) timing in motor coordination, and (iii) specifying connectivity during development. Also, oscillation, especially in the thalamo-cortical circuits, may be related to certain neurological and psychiatric disorders. This review proposes that the autorhythmic electrical properties of central neurons and their connectivity form the basis for an intrinsic functional coordinate system that provides internal context to sensory input.
2,073 citations
TL;DR: In hippocampal neurons, a Ca-activated K channel which may be responsible for the slow AHP has been identified in single channel recordings, however, this channel has unique properties and it is not blocked by Apamin, suggesting that more than one subclass of Ca- activated K channel may mediate slow AHPs.
1,311 citations
TL;DR: Research on reputation-building has formalized the concept and some of the strategic behavioral implications of these formal models are illustrated.
Abstract: A corporate reputation is a set of attributes ascribed to a firm, inferred from the firm's past
actions. While the intuition behind reputation-building is hardly new, recent research has
formalized the concept. We review this research and then, using examples, illustrate some of the strategic behavioral implications of these formal models.
1,258 citations
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TL;DR: This article found that when borrowers have private information about risk, the lowest-risk borrowers tend to pledge collateral, whereas when risk is observable, the highest risk borrowers tend not to pledge.
Abstract: Most commercial loans are made on a secured basis, yet little is known about the relationship between collateral and credit risk. Several theoretical studies find that when borrowers have private information about risk, the lowest-risk borrowers tend to pledge collateral. In contrast, conventional wisdom holds that when risk is observable, the highest-risk borrowers tend to pledge collateral. An additional issue is whether secured loans (as opposed to secured borrowers) tend to be safer or riskier than unsecured loans. Empirical evidence presented here strongly suggests that collateral is most often associated with riskier borrowers, riskier loans and riskier banks.
962 citations
TL;DR: This work has shown that the protease Nexin I antagonist acts as a “spatially aggregating force” to drive down the activity of the plasminogen during the courtship process.
Abstract: PLASMINOGEN ACTIVATOR INHIBITORS 104 Plasminogen Activator Inhibitor 1 104 Plasminogen Activator Inhibitor 2 106 Protease Nexin I .... .... 108 PHYSIOLOGICAL FUNCTIONS OF PLASMINOGEN ACTIVATION ........ 109 Matrix Breakdown 109 Cell Migration 111 Ovulation 113 CONCLUDING REMARKS 115
877 citations
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TL;DR: A parallel implementation of merge sort on a CREW PRAM that uses n processors and O(logn) time; the constant in the running time is small.
Abstract: We give a parallel implementation of merge sort on a CREW PRAM that uses n processors and $O(\log n)$ time; the constant in the running time is small. We also give a more complex version of the algorithm for the EREW PRAM; it also uses n processors and $O(\log n)$ time. The constant in the running time is still moderate, though not as small.
847 citations
TL;DR: It is suggested that heparan sulfate released either directly by cells or through proteolytic degradation of their extracellular milieu may act as carrier for bFGF and facilitate the diffusion of locally produced growth factor by competing with its binding to surrounding matrix structures.
Abstract: Cultured bovine capillary endothelial (BCE) cells were found to synthesize and secrete high molecular mass heparan sulfate proteoglycans and glycosaminoglycans, which bound basic fibroblast growth factor (bFGF). The secreted heparan sulfate molecules were purified by DEAE cellulose chromatography, followed by Sepharose 4B chromatography and affinity chromatography on immobilized bFGF. Most of the heparinase-sensitive sulfated molecules secreted into the medium by BCE cells bound to immobilized bFGF at low salt concentrations. However, elution from bFGF with increasing salt concentrations demonstrated varying affinities for bFGF among the secreted heparan sulfate molecules, with part of the heparan sulfate requiring NaCl concentrations between 1.0 and 1.5 M for elution. Cell extracts prepared from BCE cells also contained a bFGF-binding heparan sulfate proteoglycan, which could be released from the intact cells by a short proteinase treatment. The purified bFGF-binding heparan sulfate competed with 125I-bFGF for binding to low-affinity binding sites but not to high-affinity sites on the cells. Heparan sulfate did not interfere with bFGF stimulation of plasminogen activator activity in BCE cells in agreement with its lack of effect on binding of 125I-bFGF to high-affinity sites. Soluble bFGF was readily degraded by plasmin, whereas bFGF bound to heparan sulfate was protected from proteolytic degradation. Treatment of the heparan sulfate with heparinase before addition of plasmin abolished the protection and resulted in degradation of bFGF by the added proteinase. The results suggest that heparan sulfate released either directly by cells or through proteolytic degradation of their extracellular milieu may act as carrier for bFGF and facilitate the diffusion of locally produced growth factor by competing with its binding to surrounding matrix structures. Simultaneously, the secreted heparan sulfate glycosaminoglycans protect the growth factor from proteolytic degradation by extracellular proteinases, which are abundant at sites of neovascularization or cell invasion.
821 citations
TL;DR: This paper finds that the pivot algorithm is extraordinarily efficient: one “effectively independent” sample can be produced in a computer time of orderN, and presents a rigorous proof of ergodicity and numerical results on self-avoiding walks in two and three dimensions.
Abstract: The pivot algorithm is a dynamic Monte Carlo algorithm, first invented by Lal, which generates self-avoiding walks (SAWs) in a canonical (fixed-N) ensemble with free endpoints (hereN is the number of steps in the walk). We find that the pivot algorithm is extraordinarily efficient: one “effectively independent” sample can be produced in a computer time of orderN. This paper is a comprehensive study of the pivot algorithm, including: a heuristic and numerical analysis of the acceptance fraction and autocorrelation time; an exact analysis of the pivot algorithm for ordinary random walk; a discussion of data structures and computational complexity; a rigorous proof of ergodicity; and numerical results on self-avoiding walks in two and three dimensions. Our estimates for critical exponents areυ=0.7496±0.0007 ind=2 andυ= 0.592±0.003 ind=3 (95% confidence limits), based on SAWs of lengths 200⩽N⩽10000 and 200⩽N⩽ 3000, respectively.
793 citations
TL;DR: In this paper, a review of empirical studies demonstrates that effects of participation on satisfaction and performance vary according to form, and cast doubt on the conclusions of earlier reviews based on a unidimensional view of PDM.
Abstract: Participation in decision making (PDM) takes several distinct forms. A review of empirical studies demonstrates that effects of participation on satisfaction and performance vary according to form. The findings cast doubt on the conclusions of earlier reviews based on a unidimensional view of PDM and raise several issues for the study and practice of PDM.
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TL;DR: In this article, the authors describe some influences on the perceptual filtering processes that executives use as they observe and try to understand their environments, which may not help executives who are living amid current events.
Abstract: Retrospective explanations of past events encourage academics to overstate the contributions of executives and the benefits of accurate perceptions or careful analyses. Because retrospective analyses oversimplify the connections between behaviors and outcomes, prescriptions derived from retrospective understanding may not help executives who are living amid current events. The paper describes some influences on the perceptual filtering processes that executives use as they observe and try to understand their environments.
TL;DR: It is shown that the complex between fos and jun can bind to DNA more tightly than either protein alone and that basic residues adjacent to the leucine repeat offos contribute to the DNA-binding potential of the complex.
Abstract: Mutagenesis of the fos protein supports the hypothesis that a heptad repeat of leucine residues stabilizes the interaction between the fos and jun proteins. We show that the complex between fos and jun can bind to DNA more tightly than either protein alone and that basic residues adjacent to the leucine repeat offos contribute to the DNA-binding potential of the complex.
TL;DR: Set correlation is a realization of the general multi variate linear model, can be viewed as a multivariate generalization of multiple correlation analysis, and may be employed in the analysis of m... as mentioned in this paper.
Abstract: Set correlation is a realization of the general multi variate linear model, can be viewed as a multivariate generalization of multiple correlation analysis, and may be employed in the analysis of m...
TL;DR: This work shows how to construct counterexamples: visual stimuli that are consistently perceived as obviously moving in a fixed direction yet for which Fourier-domain power analysis yields no systematic motion components in any given direction.
Abstract: To some degree, all current models of visual motion-perception mechanisms depend on the power of the visual signal in various spatiotemporal-frequency bands. Here we show how to construct counterexamples: visual stimuli that are consistently perceived as obviously moving in a fixed direction yet for which Fourier-domain power analysis yields no systematic motion components in any given direction. We provide a general theoretical framework for investigating non-Fourier motion-perception mechanisms; central are the concepts of drift-balanced and microbalanced random stimuli. A random stimulus S is drift balanced if its expected power in the frequency domain is symmetric with respect to temporal frequency, that is, if the expected power in S of every drifting sinusoidal component is equal to the expected power of the sinusoid of the same spatial frequency, drifting at the same rate in the opposite direction. Additionally, S is microbalanced if the result WS of windowing S by any space-time-separable function W is drift balanced. We prove that (i) any space-time-separable random (or nonrandom) stimulus is microbalanced; (ii) any linear combination of pairwise independent microbalanced (respectively, drift-balanced) random stimuli is microbalanced and drift balanced if the expectation of each component is uniformly zero; (iii) the convolution of independent microbalanced and drift-balanced random stimuli is microbalanced and drift balanced; (iv) the product of independent microbalanced random stimuli is microbalanced; and (v) the expected response of any Reichardt detector to any microbalanced random stimulus is zero at every instant in time. Examples are provided of classes of microbalanced random stimuli that display consistent and compelling motion in one direction. All the results and examples from the domain of motion perception are transposable to the space-domain problem of detecting orientation in a texture pattern.
TL;DR: The author defines a set of operators which localize in both time and frequency, similar to but different from the low-pass time-limiting operator, the singular functions of which are the prolate spheroidal wave functions.
Abstract: The author defines a set of operators which localize in both time and frequency. These operators are similar to but different from the low-pass time-limiting operator, the singular functions of which are the prolate spheroidal wave functions. The author's construction differs from the usual approach in that she treats the time-frequency plane as one geometric whole (phase space) rather than as two separate spaces. For disk-shaped or ellipse-shaped domains in time-frequency plane, the associated localization operators are remarkably simple. Their eigenfunctions are Hermite functions, and the corresponding eigenvalues are given by simple explicit formulas involving the incomplete gamma functions. >
TL;DR: The predicted amino acid sequences of two forms of tau protein from mouse brain were determined from complementary DNA clones and suggest that tau is an elongated molecule with no extensive alpha-helical or beta-sheet domains.
Abstract: Tau protein is a family of microtubule binding proteins, heterogeneous in molecular weight, that are induced during neurite outgrowth and are found prominently in neurofibrillary tangles in Alzheimer's disease. The predicted amino acid sequences of two forms of tau protein from mouse brain were determined from complementary DNA clones. These forms are identical in their amino-terminal sequences but differ in their carboxyl-terminal domains. Both proteins contain repeated sequences that may be tubulin binding sites. The sequence suggests that tau is an elongated molecule with no extensive alpha-helical or beta-sheet domains. These complementary DNAs should enable the study of various functional domains of tau and the study of tau expression in normal and pathological states.
TL;DR: It is found that the spontaneous migration of bovine aortic endothelial cells from the edge of a denuded area in a confluent monolayer is dependent upon the release of endogenous basic fibroblast growth factor (bFGF).
Abstract: We have found that the spontaneous migration of bovine aortic endothelial cells from the edge of a denuded area in a confluent monolayer is dependent upon the release of endogenous basic fibroblast growth factor (bFGF). Cell movement is blocked by purified polyclonal rabbit IgG to bFGF as well as affinity purified anti-bFGF IgG and anti-bFGF F(ab')2 fragments. The inhibitory effect of the immunoglobulins is dependent upon antibody concentration, is reversible, is overcome by the addition of recombinant bFGF, and is removed by affinity chromatography of the antiserum through a column of bFGF-Sepharose. Cell movement is also reversibly inhibited by the addition of protamine sulfate and suramin; two agents reported to block bFGF binding to its receptor. The addition of recombinant bFGF to wounded monolayers accelerates the movement of cells into the denuded area. Transforming growth factor beta which has been shown to antagonize several other effects of bFGF also inhibits cell movement. The anti-bFGF IgG prevents the movement of bovine capillary endothelial cells, BHK-21, NIH 3T3, and human skin fibroblasts into a denuded area. Antibodies to bFGF, as well as suramin and protamine sulfate also suppress the basal levels of plasminogen activator and DNA synthesis in bovine aortic endothelial cells.
TL;DR: It is suggested that as many as one in five women with breast cancer may carry the AT gene and that the increased radiation sensitivity of AT heterozygotes may be causing radiation therapists to reduce the doses of radiation used for treating cancer in all patients.
Abstract: Ataxia-telangiectasia (AT) is a human autosomal recessive disorder of childhood1,2 characterized by: (1) progressive cerebellar ataxia with degeneration of Purkinje cells; (2) hypersensitivity of fibroblasts and lymphocytes to ionizing radiation3; (3) a 61-fold and 184-fold increased cancer incidence in white and black patients, respectively4; (4) non-random chromosomal rearrangements in lymphocytes; (5) thymic hypoplasia with cellular and humoral (IgA and IgG2) immunodeficiencies; (6) elevated serum level of alphafetoprotein; (7) premature ageing; and (8) endocrine disorders, such as insulin-resistant diabetes mellitus. A DNA processing or repair protein is the suspected common denominator in this pathology5. Heterozygotes are generally healthy; however, the sensitivity of their cultured cells to ionizing radiation is intermediate between normal individuals and that of affected homozygotes6. Furthermore, heterozygous females are at an increased risk of breast cancer7,8. These findings, when coupled with an estimated carrier frequency of 0.5–5.0%, suggest that (1) as many as one in five women with breast cancer may carry the AT gene7 and that (2) the increased radiation sensitivity of AT heterozygotes may be causing radiation therapists to reduce the doses of radiation used for treating cancer in all patients10. To identify the genetic defect responsible for this multifaceted disorder, and to provide effective carrier detection, we performed a genetic linkage analysis of 31 families with AT-affected members. This has allowed us to localize a gene for AT to chromosomal region 11q22-23.
TL;DR: A simple explanation of the Swendsen-Wang algorithm for Potts models in terms of a joint model of Potts spin variables interacting with bond occupation variables is given and how to generalize this representation to arbitrary models is shown.
Abstract: We give a simple explanation of the Swendsen-Wang algorithm for Potts models in terms of a joint model of Potts spin variables interacting with bond occupation variables. We then show how to generalize this representation, as well as the corresponding Monte Carlo algorithm, to arbitrary models. We give initial results of tests of the new algorithm on the two-dimensional XY model.
TL;DR: The authors extend the definitions of the previously introduced family of data flow testing criteria to apply to programs written in a large subset of Pascal and define a family of adequacy criteria called feasible data flowTesting criteria, which are derived from the data-flow testing criteria.
Abstract: The authors extend the definitions of the previously introduced family of data flow testing criteria to apply to programs written in a large subset of Pascal. They then define a family of adequacy criteria called feasible data flow testing criteria, which are derived from the data-flow testing criteria. The feasible data flow testing criteria circumvent the problem of nonapplicability of the data flow testing criteria by requiring the test data to exercise only those definition-use associations which are executable. It is shown that there are significant differences between the relationships among the data flow testing criteria and the relationships among the feasible data flow testing criteria. The authors discuss a generalized notion of the executability of a path through a program unit. A script of a testing session using their data flow testing tool, ASSET, is included. >
TL;DR: In this paper, an empirical examination of the relation between trades and quote revisions for New York Stock Exchange-listed stocks is designed to ascertain asymmetric-information and inventory-control effects.
TL;DR: Normative developmental equations provide reliable descriptors of brain electrical activity in people 6 to 90 years old that may provide independent criteria for diagnostic validity, evaluations of treatment efficacy, and more individualized therapy.
Abstract: Normative developmental equations provide reliable descriptors of brain electrical activity in people 6 to 90 years old. Healthy persons display only chance deviations beyond predicted ranges. Patients with neurological impairment, subtle cognitive dysfunctions, or psychiatric disorders (including dementia and primary depression) show a high incidence of abnormal values. The magnitude of the deviations increases with clinical severity. Different disorders are characterized by distinctive profiles of abnormal values of brain electrical features. Computerized differential classification of some of these disorders can be achieved with high accuracy. Such classification, providing objective corroboration of brain dysfunctions, may be a useful adjunct to psychiatric diagnosis, which relies primarily on subjective clinical impressions. These methods may provide independent criteria for diagnostic validity, evaluations of treatment efficacy, and more individualized therapy.
TL;DR: This article identified 105 patients with lymphoid neoplasia associated with the acquired immunodeficiency syndrome (AIDS) at the New York University Medical Center from 1981 through 1986: 89 had non-Hodgkin lymphoma; 13, Hodgkin disease; and 3, chronic lymphocytic leukemia.
Abstract: We identified 105 patients with lymphoid neoplasia associated with the acquired immunodeficiency syndrome (AIDS) at the New York University Medical Center from 1981 through 1986: 89 had non-Hodgkin lymphoma; 13, Hodgkin disease; and 3, chronic lymphocytic leukemia. Immunophenotypic and antigen receptor gene rearrangement analysis showed the B-cell origin of all non-Hodgkin lymphomas studied and the clonal suppressor-cytotoxic T-cell subset origin of the chronic lymphocytic leukemias. We classified 69% of the non-Hodgkin lymphomas as high grade (small, noncleaved and large cell, immunoblastic-plasmacytoid) and 31% as intermediate grade (diffuse large cell). Each histopathologic category was correlated with distinct clinical features, including a statistically significant difference in median survival. Patients with Hodgkin disease had an atypical, aggressive clinical course, whereas patients with T-cell chronic lymphocytic leukemia had an indolent clinical course. These studies show the clinical, morphologic, and immunophenotypic spectrum of AIDS-associated lymphoid neoplasia, that the natural history of Hodgkin disease is altered in patients with AIDS, and support the Centers For Disease Control's recent revision in diagnostic criteria for AIDS to include intermediate-grade diffuse, aggressive non-Hodgkin lymphomas occurring in patients seropositive for human immunodeficiency virus.
TL;DR: In this article, the authors considered the problem of convex bodies in Euclidean n-space, where the hyperplane through the origin of the body is orthogonal to the origin.
TL;DR: The data imply that the carboxyl-terminal domain containing the 18-amino acid repeats constitutes the microtubule binding site in MAP2, a prominent large-sized component of purified brain microtubules that bears antigenic determinants found in association with the neurofibrillary tangles of Alzheimer's disease.
Abstract: The microtubule-associated protein MAP2 is a prominent large-sized component of purified brain microtubules that, like the 36- to 38-kilodalton tau proteins, bears antigenic determinants found in association with the neurofibrillary tangles of Alzheimer9s disease. The complete sequence of mouse brain MAP2 was determined from a series of overlapping cloned complementary DNAs. The sequence of the carboxyl-terminal 185 amino acids is very similar (67 percent) to a corresponding region of tau protein, and includes a series of three imperfect repeats, each 18 amino acids long and separated by 13 or 14 amino acids. A subcloned fragment spanning the first two of the 18-amino acid repeats was expressed as a polypeptide by translation in vitro. This polypeptide copurified with microtubules through two successive cycles of polymerization and depolymerization, whereas a control polypeptide derived from the amino-terminal region of MAP2 completely failed to copurify. These data imply that the carboxyl-terminal domain containing the 18-amino acid repeats constitutes the microtubule binding site in MAP2. The occurrence of these repeats in tau protein suggests that these may be a general feature of microtubule binding proteins.
TL;DR: Observations to date suggest that pseudohypericin and hypericin could become therapeutic tools against retroviral-induced diseases such as acquired immunodeficiency syndrome (AIDS) and lack of toxicity at therapeutic doses extends to humans.
Abstract: Two aromatic polycyclic diones hypericin and pseudohypericin have potent antiretroviral activity; these substances occur in plants of the Hypericum family. Both compounds are highly effective in preventing viral-induced manifestations that follow infections with a variety of retroviruses in vivo and in vitro. Pseudohypericin and hypericin probably interfere with viral infection and/or spread by direct inactivation of the virus or by preventing virus shedding, budding, or assembly at the cell membrane. These compounds have no apparent activity against the transcription, translation, or transport of viral proteins to the cell membrane and also no direct effect on the polymerase. This property distinguishes their mode of action from that of the major antiretro-virus group of nucleoside analogues. Hypericin and pseudohypericin have low in vitro cytotoxic activity at concentrations sufficient to produce dramatic antiviral effects in murine tissue culture model systems that use radiation leukemia and Friend viruses. Administration of these compounds to mice at the low doses sufficient to prevent retroviral-induced disease appears devoid of undesirable side effects. This lack of toxicity at therapeutic doses extends to humans, as these compounds have been tested in patients as antidepressants with apparent salutary effects. Our observations to date suggest that pseudohypericin and hypericin could become therapeutic tools against retroviral-induced diseases such as acquired immunodeficiency syndrome (AIDS).
TL;DR: It is reported that low concentrations of basic fibroblast growth factor (bFGF, 1-25 ng/ml) maintained the viability and promoted the differentiation of purified granule neurons and indicates that glial cells synthesize bFGF and are possibly an endogenous source of bF GF in cerebellar cultures.
TL;DR: The results indicate that the olivo‐cerebellar pathway, in addition to its activation of the cerebellar cortex, exerts a powerful and complex set of synaptic events on Cerebellar nuclear cells.
Abstract: 1. Intracellular recordings were obtained from cerebellar nuclear neurones in the isolated brain stem-cerebellar preparation of guinea-pigs in vitro. The electrical properties of the cells were quite similar to those reported in in vitro slice studies. They had an average resting potential of -56.7 +/- 1.8 mV, an input resistance of 23.8 +/- 4.9 M omega, and a time constant of 12.5 +/- 2.7 ms. The action potentials had an average amplitude of 57.3 +/- 5.28 mV (n = 20). 2. In addition to the ionic mechanisms required for the generation of the fast action potential, cerebellar nuclear neurones displayed a low-threshold Ca2+-dependent spike which produced a powerful rebound excitation following anodal break. This type of electroresponsiveness was absent in the slice preparation. 3. The anodal break response was further enhanced by the presence of a non-inactivating Na+ conductance similar to that described in Purkinje cells. 4. Following electrical stimulation of the cerebellar cortex or the underlying white matter, excitatory and inhibitory synaptic potentials (EPSP-IPSP sequences) could be recorded in cerebellar nuclear neurones. The EPSPs were elicited by direct activation of collaterals of mossy or climbing fibre afferents. The IPSPs followed direct or orthodromic Purkinje cell activation. 5. The integrity of the olivo-cerebellar system was tested by the administration of harmaline which produced powerful EPSP-IPSP sequences or pure IPSPs in cerebellar nuclear neurones. These IPSPs were often followed by a rebound firing of the cells. 6. These results indicate that the olivo-cerebellar pathway, in addition to its activation of the cerebellar cortex, exerts a powerful and complex set of synaptic events on cerebellar nuclear cells. As such it is a true afferent system, having a distinct role in cerebellar physiology.
TL;DR: In this paper, the authors considered a system of interacting diffusions and derived a nonlinear diffusion equation for the time evolution of the macroscopic charge density at sites indexed by a periodic one-dimensional lattice.
Abstract: We consider a system of interacting diffusions. The variables are to be thought of as charges at sites indexed by a periodic one-dimensional lattice. The diffusion preserves the total charge and the interaction is of nearest neighbor type. With the appropriate scaling of lattice spacing and time, a nonlinear diffusion equation is derived for the time evolution of the macroscopic charge density.