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Sample records for integrating electrophysiology contraction

  1. Electrophysiological analysis of a sensorimotor integration task.

    PubMed

    Velasques, Bruna; Machado, Sergio; Portella, Cláudio Elidio; Silva, Julio Guilherme; Basile, Luis F H; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro

    2007-10-22

    The present experiment aimed at investigating electrophysiologic changes observed as beta band asymmetry, by Quantitative Electroencephalography (qEEG), when individuals performed a reaching motor task (catching a ball in free fall). The sample was composed of 23 healthy individuals, of both sexes, with ages varying between 25 and 40 years old. All the subjects were right handed. A two-way ANOVA was applied for the statistical analysis, to verify the interaction between task moment (i.e., 2s before and 2s after ball's fall) and electrode (i.e., frontal, central and temporal regions). The first analysis compared electrodes placed over the somatosensory cortex. Central sites (C3-C4) were compared with temporal regions (T3-T4). The results showed a main effect for moment and position. The second analysis was focused over the premotor cortex, which was represented by the electrodes placed on the frontal sites (F3-F4 versus F7-F8), and a main effect was observed for position. Taken together, these results show a pattern of asymmetry in the somatosensory cortex, associated with a preparatory mechanism when individuals have to catch an object during free fall. With respect to task moment, after the ball's fall, the asymmetry was reduced. Moreover, the difference in asymmetry between the observed regions were related to a supposed specialization of areas (i.e., temporal and central). The temporal region was associated with cognitive processes involved in the motor action (i.e., explicit knowledge). On the other hand, the central sites were related to the motor control mechanisms per se (i.e., implicit knowledge). The premotor cortex, represented by two frontal regions (i.e., F3-F4 versus F7-F8), showed a decrease on neural activity in the contralateral hemisphere (i.e., to the right hand). This result is in agreement with other experiments suggesting a participation of the frontal cortex in the planning of the apprehension task. This sensorimotor paradigm may contribute to

  2. Implementation of Contraction to Electrophysiological Ventricular Myocyte Models, and Their Quantitative Characterization via Post-Extrasystolic Potentiation.

    PubMed

    Ji, Yanyan Claire; Gray, Richard A; Fenton, Flavio H

    2015-01-01

    Heart failure (HF) affects over 5 million Americans and is characterized by impairment of cellular cardiac contractile function resulting in reduced ejection fraction in patients. Electrical stimulation such as cardiac resynchronization therapy (CRT) and cardiac contractility modulation (CCM) have shown some success in treating patients with HF. Computer simulations have the potential to help improve such therapy (e.g. suggest optimal lead placement) as well as provide insight into the underlying mechanisms which could be beneficial. However, these myocyte models require a quantitatively accurate excitation-contraction coupling such that the electrical and contraction predictions are correct. While currently there are close to a hundred models describing the detailed electrophysiology of cardiac cells, the majority of cell models do not include the equations to reproduce contractile force or they have been added ad hoc. Here we present a systematic methodology to couple first generation contraction models into electrophysiological models via intracellular calcium and then compare the resulting model predictions to experimental data. This is done by using a post-extrasystolic pacing protocol, which captures essential dynamics of contractile forces. We found that modeling the dynamic intracellular calcium buffers is necessary in order to reproduce the experimental data. Furthermore, we demonstrate that in models the mechanism of the post-extrasystolic potentiation is highly dependent on the calcium released from the Sarcoplasmic Reticulum. Overall this study provides new insights into both specific and general determinants of cellular contractile force and provides a framework for incorporating contraction into electrophysiological models, both of which will be necessary to develop reliable simulations to optimize electrical therapies for HF. PMID:26317204

  3. Capitated contracting of integrated health provider organizations.

    PubMed

    Bazzoli, G J; Dynan, L; Burns, L R

    This paper examines global capitation of integrated health provider organizations that link physicians and hospitals, such as physician-hospital organizations and management service organizations. These organizations have proliferated in recent years, but their contracting activity has not been studied. We develop a conceptual model to understand the capitated contracting bargaining process. Exploratory multivariate analysis suggests that global capitation of these organizations is more common in markets with high health maintenance organization (HMO) market share, greater numbers of HMOs, and fewer physician group practices. Additionally, health provider organizations with more complex case mix, nonprofit status, more affiliated physicians, health system affiliations, and diversity in physician organizational arrangements are more likely to have global capitation. Finally, state regulation of provider contracting with self-insured employers appears to have spillover effects on health plan risk contracting with health providers. PMID:10711318

  4. Capitated contracting of integrated health provider organizations.

    PubMed

    Bazzoli, G J; Dynan, L; Burns, L R

    This paper examines global capitation of integrated health provider organizations that link physicians and hospitals, such as physician-hospital organizations and management service organizations. These organizations have proliferated in recent years, but their contracting activity has not been studied. We develop a conceptual model to understand the capitated contracting bargaining process. Exploratory multivariate analysis suggests that global capitation of these organizations is more common in markets with high health maintenance organization (HMO) market share, greater numbers of HMOs, and fewer physician group practices. Additionally, health provider organizations with more complex case mix, nonprofit status, more affiliated physicians, health system affiliations, and diversity in physician organizational arrangements are more likely to have global capitation. Finally, state regulation of provider contracting with self-insured employers appears to have spillover effects on health plan risk contracting with health providers.

  5. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  6. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  7. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  8. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  9. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Contracts with Lead System Integrators. 3016.170 Section 3016.170 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  10. Electrophysiological evidence for speech-specific audiovisual integration.

    PubMed

    Baart, Martijn; Stekelenburg, Jeroen J; Vroomen, Jean

    2014-01-01

    Lip-read speech is integrated with heard speech at various neural levels. Here, we investigated the extent to which lip-read induced modulations of the auditory N1 and P2 (measured with EEG) are indicative of speech-specific audiovisual integration, and we explored to what extent the ERPs were modulated by phonetic audiovisual congruency. In order to disentangle speech-specific (phonetic) integration from non-speech integration, we used Sine-Wave Speech (SWS) that was perceived as speech by half of the participants (they were in speech-mode), while the other half was in non-speech mode. Results showed that the N1 obtained with audiovisual stimuli peaked earlier than the N1 evoked by auditory-only stimuli. This lip-read induced speeding up of the N1 occurred for listeners in speech and non-speech mode. In contrast, if listeners were in speech-mode, lip-read speech also modulated the auditory P2, but not if listeners were in non-speech mode, thus revealing speech-specific audiovisual binding. Comparing ERPs for phonetically congruent audiovisual stimuli with ERPs for incongruent stimuli revealed an effect of phonetic stimulus congruency that started at ~200 ms after (in)congruence became apparent. Critically, akin to the P2 suppression, congruency effects were only observed if listeners were in speech mode, and not if they were in non-speech mode. Using identical stimuli, we thus confirm that audiovisual binding involves (partially) different neural mechanisms for sound processing in speech and non-speech mode.

  11. Integrated microsystem for non-invasive electrophysiological measurements on Xenopus oocytes.

    PubMed

    Dahan, E; Bize, V; Lehnert, T; Horisberger, J-D; Gijs, M A M

    2007-06-15

    We propose a new non-invasive integrated microsystem for electrophysiological measurements on Xenopus laevis oocytes. Xenopus oocyte is a well-known expression system for various kinds of ion channels, that are potential tools in drug screening. In the traditional "Two Electrode Voltage Clamp" (TEVC) method, delicate micromanipulation is required to impale an oocyte with two microelectrodes. In our system, a non-invasive electrical access to the cytoplasm is provided by permeabilizing the cell membrane with an ionophore (e.g. nystatin). Unlike the classical patch-clamp or "macropatch" techniques, this method does not require removal of the vitelline membrane. Cell handling is significantly simplified, resulting in more robust recordings with increased throughput. Moreover, because only part of the oocyte surface is exposed to reagents, the required volume of reagent solutions could be reduced by an order of magnitude compared to the TEVC method. The fabrication process for this disposable microchip, based on poly-dimethylsiloxane (PDMS) molding and glass/PDMS bonding, is cost-efficient and simple. We tested this new microdevice by recording currents in oocytes expressing the human Epithelial Sodium Channel (hENaC) for membrane potentials between -100 and +50 mV. We recorded benzamil-sensitive currents with a large signal-to-noise ratio and we also obtained a benzamil concentration-inhibition curve displaying an inhibition constant IC(50) of about 50 nM, comparable to previously published values obtained with the TEVC technique.

  12. Integration of Optical Manipulation and Electrophysiological Tools to Modulate and Record Activity in Neural Networks

    NASA Astrophysics Data System (ADS)

    Difato, F.; Schibalsky, L.; Benfenati, F.; Blau, A.

    2011-07-01

    We present an optical system that combines IR (1064 nm) holographic optical tweezers with a sub-nanosecond-pulsed UV (355 nm) laser microdissector for the optical manipulation of single neurons and entire networks both on transparent and non-transparent substrates in vitro. The phase-modulated laser beam can illuminate the sample concurrently or independently from above or below assuring compatibility with different types of microelectrode array and patch-clamp electrophysiology. By combining electrophysiological and optical tools, neural activity in response to localized stimuli or injury can be studied and quantified at sub-cellular, cellular, and network level.

  13. Social contract and social integration in adolescent development.

    PubMed

    Hilles, W S; Kahle, L R

    1985-10-01

    Eighty-nine subjects from two high schools were tested during the spring of their sophomore and senior years, when their mean ages were 16 years, 1 month, and 18 years, 1 month, respectively. Composites measured social contract with: (a) independence, (b) implicit social contract, societal norms and expectations, and (c) explicit social contracts, rules. Composites and single items measured social integration with: (d) role commitment, (e) social-American Dream, accepting the belief in the American Dream that hard work would lead to social success, (f) self-American Dream, belief that hard work will produce personal satisfaction and success, (g) raw deal, perceptions of being treated unfairly, (h) self-blame, and (i) feelings of hopelessness. The results of the cross-lagged panel correlations generally support the hypothesis that students respond to implicit social contracts through role commitment, which is further expressed by a belief in the American Dream for social fulfillment, while responding to the perception of explicit social contracts by not believing in the benefits of the American Dream for personal fulfillment. These results were interpreted as supporting Dienstbier's theory of moral development.

  14. Affective processing of loved familiar faces: integrating central and peripheral electrophysiological measures.

    PubMed

    Guerra, Pedro; Vico, Cynthia; Campagnoli, Rafaela; Sánchez, Alicia; Anllo-Vento, Lourdes; Vila, Jaime

    2012-07-01

    A major problem in the electrophysiological studies of emotional processing linked to recognition of familiar faces is the unambiguous differentiation of effects due to emotional valence, arousal, and familiarity. The present paper summarizes a set of three studies aimed at investigating the affective processing of loved familiar faces using Lang's picture-viewing paradigm, with a special emphasis on teasing apart the individual contributions of affective valence, undifferentiated emotional arousal, and familiarity The results of the three studies support the conclusion that viewing the faces of familiar loved ones elicits an intense positive emotional reaction that cannot be explained either by familiarity or arousal alone. PMID:21689694

  15. Integration of electrophysiological recordings with single-cell RNA-seq data identifies neuronal subtypes.

    PubMed

    Fuzik, János; Zeisel, Amit; Máté, Zoltán; Calvigioni, Daniela; Yanagawa, Yuchio; Szabó, Gábor; Linnarsson, Sten; Harkany, Tibor

    2016-02-01

    Traditionally, neuroscientists have defined the identity of neurons by the cells' location, morphology, connectivity and excitability. However, the direct relationship between these parameters and the molecular phenotypes has remained largely unexplored. Here, we present a method for obtaining full transcriptome data from single neocortical pyramidal cells and interneurons after whole-cell patch-clamp recordings in mouse brain slices. In our approach, termed Patch-seq, a patch-clamp stimulus protocol is followed by the aspiration of the entire somatic compartment into the recording pipette, reverse transcription of RNA including addition of unique molecular identifiers, cDNA amplification, Illumina library preparation and sequencing. We show that Patch-seq reveals a close link between electrophysiological characteristics, responses to acute chemical challenges and RNA expression of neurotransmitter receptors and channels. Moreover, it distinguishes neuronal subpopulations that correspond to both well-established and, to our knowledge, hitherto undescribed neuronal subtypes. Our findings demonstrate the ability of Patch-seq to precisely map neuronal subtypes and predict their network contributions in the brain. PMID:26689544

  16. Medicaid Integrity Program; eligible entity and contracting requirements for the Medicaid Integrity audit program. Final rule.

    PubMed

    2008-09-26

    Section 1936 of the Social Security Act (the Act) (as added by section 6034 of the Deficit Reduction Act of 2005 (DRA) established the Medicaid Integrity Program to promote the integrity of the Medicaid program by requiring CMS to enter into contracts with eligible entities to: (1) Review the actions of individuals or entities furnishing items or services (whether on a fee-for-service, risk, or other basis) for which payment may be made under an approved State plan and/or any waiver of such plan approved under section 1115 of the Act; (2) audit claims for payment of items or services furnished, or administrative services rendered, under a State plan; (3) identify overpayments to individuals or entities receiving Federal funds; and (4) educate providers of services, managed care entities, beneficiaries, and other individuals with respect to payment integrity and quality of care. This final rule will provide requirements for an eligible entity to enter into a contract under the Medicaid integrity audit program. The final rule will also establish the contracting requirements for eligible entities. The requirements will include procedures for identifying, evaluating, and resolving organizational conflicts of interest that are generally applicable to Federal acquisition and procurement; competitive procedures to be used; and procedures under which a contract may be renewed.

  17. Mechanisms of Percept-Percept and Image-Percept Integration in Vision: Behavioral and Electrophysiological Evidence

    ERIC Educational Resources Information Center

    Dalvit, Silvia; Eimer, Martin

    2011-01-01

    Previous research has shown that the detection of a visual target can be guided not only by the temporal integration of two percepts, but also by integrating a percept and an image held in working memory. Behavioral and event-related brain potential (ERP) measures were obtained in a target detection task that required temporal integration of 2…

  18. Electrophysiological Evidence for Incremental Lexical-Semantic Integration in Auditory Compound Comprehension

    ERIC Educational Resources Information Center

    Koester, Dirk; Holle, Henning; Gunter, Thomas C.

    2009-01-01

    The present study investigated the time-course of semantic integration in auditory compound word processing. Compounding is a productive mechanism of word formation that is used frequently in many languages. Specifically, we examined whether semantic integration is incremental or is delayed until the head, the last constituent in German, is…

  19. Electrophysiological evidence for incremental lexical-semantic integration in auditory compound comprehension.

    PubMed

    Koester, Dirk; Holle, Henning; Gunter, Thomas C

    2009-07-01

    The present study investigated the time-course of semantic integration in auditory compound word processing. Compounding is a productive mechanism of word formation that is used frequently in many languages. Specifically, we examined whether semantic integration is incremental or is delayed until the head, the last constituent in German, is available. Stimuli were compounds consisting of three nouns, and the semantic plausibility of the second and the third constituent was manipulated independently (high vs. low). Participants' task was to listen to the compounds and evaluate them semantically. Event-related brain potentials in response to the head constituents showed an increased N400 for less plausible head constituents, reflecting the lexical-semantic integration of all three compound constituents. In response to the second (less plausible) constituents, an increased N400 with a central-left scalp distribution was observed followed by a parietal positivity. The occurrence of this N400 effect during the presentation of the second constituents suggests that the initial two non-head constituents are immediately integrated. The subsequent positivity might be an instance of a P600 and is suggested to reflect the structural change of the initially constructed compound structure. The results suggest that lexical-semantic integration of compound constituents is an incremental process and, thus, challenge a recent proposal on the time-course of semantic processing in auditory compound comprehension. PMID:19428417

  20. Electrophysiological correlates of cross-linguistic semantic integration in hearing signers: N400 and LPC.

    PubMed

    Zachau, Swantje; Korpilahti, Pirjo; Hämäläinen, Jarmo A; Ervast, Leena; Heinänen, Kaisu; Suominen, Kalervo; Lehtihalmes, Matti; Leppänen, Paavo H T

    2014-07-01

    We explored semantic integration mechanisms in native and non-native hearing users of sign language and non-signing controls. Event-related brain potentials (ERPs) were recorded while participants performed a semantic decision task for priming lexeme pairs. Pairs were presented either within speech or across speech and sign language. Target-related ERP responses were subjected to principal component analyses (PCA), and neurocognitive basis of semantic integration processes were assessed by analyzing the N400 and the late positive complex (LPC) components in response to spoken (auditory) and signed (visual) antonymic and unrelated targets. Semantically-related effects triggered across modalities would indicate a similar tight interconnection between the signers׳ two languages like that described for spoken language bilinguals. Remarkable structural similarity of the N400 and LPC components with varying group differences between the spoken and signed targets were found. The LPC was the dominant response. The controls׳ LPC differed from the LPC of the two signing groups. It was reduced to the auditory unrelated targets and was less frontal for all the visual targets. The visual LPC was more broadly distributed in native than non-native signers and was left-lateralized for the unrelated targets in the native hearing signers only. Semantic priming effects were found for the auditory N400 in all groups, but only native hearing signers revealed a clear N400 effect to the visual targets. Surprisingly, the non-native signers revealed no semantically-related processing effect to the visual targets reflected in the N400 or the LPC; instead they appeared to rely more on visual post-lexical analyzing stages than native signers. We conclude that native and non-native signers employed different processing strategies to integrate signed and spoken semantic content. It appeared that the signers׳ semantic processing system was affected by group-specific factors like language

  1. An efficient algorithm for electron repulsion integrals over contracted Gaussian-type functions

    NASA Astrophysics Data System (ADS)

    Ten-no, Seiichiro

    1993-08-01

    An efficient new algorithm for two-electron repulsion integrals (ERIs) over contracted Cartesian Gaussian-type functions has been proposed, making use of the contracted recurrence relation (CRR) derived here. The CRR, which is obtained by extending the auxiliary function-based methodologies, enables us to remove all the transformations to increment angular momentum of ERIs from the contraction loops. The new scheme turns out to be very suitable for contracted ERIs. Explicit flop (floating point operation) counts indicate about 60% reduction of computational work in the innermost contraction loop for (pp|pp) and (sp) 4 ERI classes, compared to the recent scheme of Gill, Head-Gordon and Pople.

  2. Contractions

    MedlinePlus

    ... feel tightening of your uterus muscles at irregular intervals or a squeezing sensation in your lower abdomen ... beginning of childbirth. These contractions come at regular intervals, usually move from the back to the lower ...

  3. "Reality" of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study.

    PubMed

    Palmieri, Arianna; Calvo, Vincenzo; Kleinbub, Johann R; Meconi, Federica; Marangoni, Matteo; Barilaro, Paolo; Broggio, Alice; Sambin, Marco; Sessa, Paola

    2014-01-01

    The nature of near-death-experiences (NDEs) is largely unknown but recent evidence suggests the intriguing possibility that NDEs may refer to actually "perceived," and stored, experiences (although not necessarily in relation to the external physical world). We adopted an integrated approach involving a hypnosis-based clinical protocol to improve recall and decrease memory inaccuracy together with electroencephalography (EEG) recording in order to investigate the characteristics of NDE memories and their neural markers compared to memories of both real and imagined events. We included 10 participants with NDEs, defined by the Greyson NDE scale, and 10 control subjects without NDE. Memories were assessed using the Memory Characteristics Questionnaire. Our hypnosis-based protocol increased the amount of details in the recall of all kind of memories considered (NDE, real, and imagined events). Findings showed that NDE memories were similar to real memories in terms of detail richness, self-referential, and emotional information. Moreover, NDE memories were significantly different from memories of imagined events. The pattern of EEG results indicated that real memory recall was positively associated with two memory-related frequency bands, i.e., high alpha and gamma. NDE memories were linked with theta band, a well-known marker of episodic memory. The recall of NDE memories was also related to delta band, which indexes processes such as the recollection of the past, as well as trance states, hallucinations, and other related portals to transpersonal experience. It is notable that the EEG pattern of correlations for NDE memory recall differed from the pattern for memories of imagined events. In conclusion, our findings suggest that, at a phenomenological level, NDE memories cannot be considered equivalent to imagined memories, and at a neural level, NDE memories are stored as episodic memories of events experienced in a peculiar state of consciousness.

  4. Managed care contracting issues in integrated delivery systems.

    PubMed

    Stewart, E E

    1996-01-01

    This article is a checklist for use by health care providers in reviewing proposed managed care contracting agreements. This checklist is not an exhaustive list, but is intended to be used as a framework for review.

  5. Promised and Delivered Inducements and Contributions: An Integrated View of Psychological Contract Appraisal

    ERIC Educational Resources Information Center

    Lambert, Lisa Schurer

    2011-01-01

    The reciprocal exchange of employees' work for pay that is central to employment relationships is viewed here through the lens of the psychological contract. A psychological contract involves promised inducements, promised contributions, delivered inducements, and delivered contributions: How an employee cognitively integrates these 4 elements is…

  6. 77 FR 42339 - Improving Contracting Officers' Access to Relevant Integrity Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-18

    ... information about contractor business ethics in the Federal Awardee Performance and Integrity Information System (FAPIIS). FAPIIS is designed to facilitate the Government's ability to evaluate the business ethics of prospective contractors and protect the Government from awarding contracts to contractors...

  7. [Boundaries and integrity in the "Social Contract for Spanish Science", 1907-1939].

    PubMed

    Gómez, Amparo

    2014-01-01

    This article analyzes the relationship between science and politics in Spain in the early 20th century from the perspective of the Social Contract for Science. The article shows that a genuine social contract for science was instituted in Spain during this period, although some boundary and integrity problems emerged. These problems are analyzed, showing that the boundary problems were a product of the conservative viewpoint on the relationship between science and politics, while the integrity problems involved the activation of networks of influence in the awarding of scholarships to study abroad. Finally, the analysis reveals that these problems did not invalidate the Spanish social contract for science.

  8. A case of premature ventricular contractions, ventricular tachycardia, and arrhythmic storm induced by right ventricular pacing during cardiac resynchronization therapy: Electrophysiological mechanism and catheter ablation

    PubMed Central

    Pedretti, Stefano; Vargiu, Sara; Paolucci, Marco; Lunati, Maurizio

    2015-01-01

    A 77-year-old man with ischemic cardiomyopathy and a cardiac resynchronization therapy-defibrillator (CRT-D) device came to our attention due to incessant ventricular tachycardia and multiple implantable cardioverter defibrillator (ICD) shocks. An electrocardiogram showed non-sustained monomorphic ventricular tachycardias (NSVTs) constantly occurring after each biventricular stimulation. During an electrophysiological study, NSVTs reproducibly recurred only after right ventricular (RV) pacing; LV pacing did not induce any NSVTs. The activation map was consistent with a localized reentry at the interventricular septum, and a double exit; at the LV exit site, a single radiofrequency energy application immediately interrupted the occurrence of the NSVTs. Current evidence supports LV pacing to be pro-arrhythmogenic in few CRT patients. This unusual case shows that RV pacing during CRT could produce frequent ventricular arrhythmias and arrhythmic storm. Catheter ablation can be considered an effective therapeutic option, especially when CRT maintenance is highly advisable. PMID:26702324

  9. The neurobiology of self-generated thought from cells to systems: Integrating evidence from lesion studies, human intracranial electrophysiology, neurochemistry, and neuroendocrinology.

    PubMed

    Fox, Kieran C R; Andrews-Hanna, Jessica R; Christoff, Kalina

    2016-10-29

    Investigation of the neural basis of self-generated thought is moving beyond a simple identification with default network activation toward a more comprehensive view recognizing the role of the frontoparietal control network and other areas. A major task ahead is to unravel the functional roles and temporal dynamics of the widely distributed brain regions recruited during self-generated thought. We argue that various other neuroscientific methods - including lesion studies, human intracranial electrophysiology, and manipulation of neurochemistry - have much to contribute to this project. These diverse data have yet to be synthesized with the growing understanding of self-generated thought gained from neuroimaging, however. Here, we highlight several areas of ongoing inquiry and illustrate how evidence from other methodologies corroborates, complements, and clarifies findings from functional neuroimaging. Each methodology has particular strengths: functional neuroimaging reveals much about the variety of brain areas and networks reliably recruited. Lesion studies point to regions critical to generating and consciously experiencing self-generated thought. Human intracranial electrophysiology illuminates how and where in the brain thought is generated and where this activity subsequently spreads. Finally, measurement and manipulation of neurotransmitter and hormone levels can clarify what kind of neurochemical milieu drives or facilitates self-generated cognition. Integrating evidence from multiple complementary modalities will be a critical step on the way to improving our understanding of the neurobiology of functional and dysfunctional forms of self-generated thought.

  10. The neurobiology of self-generated thought from cells to systems: Integrating evidence from lesion studies, human intracranial electrophysiology, neurochemistry, and neuroendocrinology.

    PubMed

    Fox, Kieran C R; Andrews-Hanna, Jessica R; Christoff, Kalina

    2016-10-29

    Investigation of the neural basis of self-generated thought is moving beyond a simple identification with default network activation toward a more comprehensive view recognizing the role of the frontoparietal control network and other areas. A major task ahead is to unravel the functional roles and temporal dynamics of the widely distributed brain regions recruited during self-generated thought. We argue that various other neuroscientific methods - including lesion studies, human intracranial electrophysiology, and manipulation of neurochemistry - have much to contribute to this project. These diverse data have yet to be synthesized with the growing understanding of self-generated thought gained from neuroimaging, however. Here, we highlight several areas of ongoing inquiry and illustrate how evidence from other methodologies corroborates, complements, and clarifies findings from functional neuroimaging. Each methodology has particular strengths: functional neuroimaging reveals much about the variety of brain areas and networks reliably recruited. Lesion studies point to regions critical to generating and consciously experiencing self-generated thought. Human intracranial electrophysiology illuminates how and where in the brain thought is generated and where this activity subsequently spreads. Finally, measurement and manipulation of neurotransmitter and hormone levels can clarify what kind of neurochemical milieu drives or facilitates self-generated cognition. Integrating evidence from multiple complementary modalities will be a critical step on the way to improving our understanding of the neurobiology of functional and dysfunctional forms of self-generated thought. PMID:27544408

  11. XMR guided cardiac electrophysiology study and radio frequency ablation

    NASA Astrophysics Data System (ADS)

    Rhode, Kawal S.; Sermesant, Maxime; Hegde, Sanjeet; Sanchez-Ortiz, Gerardo I.; Rueckert, Daniel; Razavi, Reza; Hill, Derek L. G.

    2004-04-01

    XMR systems are a new type of interventional facility in which patients can be rapidly transferred between x-ray and MR systems on a floating table. We have previously developed a technique to register MR and x-ray images obtained from such systems. We are carrying out a program of XMR guided cardiac electrophysiology study (EPS) and radio frequency ablation (RFA). The aim of our work was to apply our registration technology to XMR guided EPS/RFA in order to integrate anatomical, electrophysiological and motion information. This would assist in guidance and allow us to validate and refine electromechanical models. Registration of the imaging modalities was achieved by a combination of system calibration and real-time optical tracking. Patients were initially imaged using MR imaging. An SSFP volume scan of the heart was acquired for anatomical information, followed by tagged scans for motion information. The patients were then transferred to the x-ray system. Tracked biplane x-ray images were acquired while electrical measurements were made from catheters placed in the heart. The relationship between the MR and x-ray images was determined. The MR volume scan of the heart was segmented and the tagged scans were analysed using a non-rigid registration algorithm to compute motion. The position of catheters was reconstructed within the MR cardiac anatomy. The anatomical, electrophysiological, and motion information were displayed in the same coordinate system. Simulations of electrical depolarisation and contraction were performed using electromechanical models of the myocardium. We present results for 2 initial cases. For patient 1, a contact mapping system was used for the EPS and for patient 2, a non-contact mapping system was used. Our XMR registration technique allows the integration of anatomical, electrophysiological, and motion information for patients undergoing EPS/RFA. This integrated approach has assisted in interventional guidance and has been used to

  12. Novel accurate and scalable 3-D MT forward solver based on a contracting integral equation method

    NASA Astrophysics Data System (ADS)

    Kruglyakov, M.; Geraskin, A.; Kuvshinov, A.

    2016-11-01

    We present a novel, open source 3-D MT forward solver based on a method of integral equations (IE) with contracting kernel. Special attention in the solver is paid to accurate calculations of Green's functions and their integrals which are cornerstones of any IE solution. The solver supports massive parallelization and is able to deal with highly detailed and contrasting models. We report results of a 3-D numerical experiment aimed at analyzing the accuracy and scalability of the code.

  13. Challenges of commissioning and contracting for integrated care in the National Health Service (NHS) in England.

    PubMed

    Addicott, Rachael

    2016-01-01

    For many years there has been a separation between purchasing and provision of services in the English National Health Service (NHS). Many studies report that this commissioning function has been weak: purchasers have had little impact or power in negotiations with large acute providers, and have had limited strategic control over the delivery of care. Nevertheless, commissioning has become increasingly embedded in the NHS structure since the arrival of Clinical Commissioning Groups (CCGs) in 2012. Recently, some of these CCGs have focused on how they can contract and commission in different ways to stimulate greater collaboration across providers. This paper examines experiences of commissioning and contracting for integrated care in the English NHS, based on a series of national-level interviews and case studies of five health economies that are implementing novel contracting models. The cases illustrated here demonstrate early experiments to drive innovation through contracting in the NHS that have largely relied on the vision of individual teams or leaders, in combination with external legal, procurement and actuarial support. It is unlikely that this approach will be sustainable or replicable across the country or internationally, despite the best intentions of commissioners. Designing and operating novel contractual approaches will require considerable determination, alongside advanced skills in procurement, contract management and commissioning. The cost of developing new contractual approaches is high, and as the process is difficult and resource-intensive, it is likely that dedicated teams or programs will be required to drive significant improvement. PMID:26328512

  14. Challenges of commissioning and contracting for integrated care in the National Health Service (NHS) in England.

    PubMed

    Addicott, Rachael

    2016-01-01

    For many years there has been a separation between purchasing and provision of services in the English National Health Service (NHS). Many studies report that this commissioning function has been weak: purchasers have had little impact or power in negotiations with large acute providers, and have had limited strategic control over the delivery of care. Nevertheless, commissioning has become increasingly embedded in the NHS structure since the arrival of Clinical Commissioning Groups (CCGs) in 2012. Recently, some of these CCGs have focused on how they can contract and commission in different ways to stimulate greater collaboration across providers. This paper examines experiences of commissioning and contracting for integrated care in the English NHS, based on a series of national-level interviews and case studies of five health economies that are implementing novel contracting models. The cases illustrated here demonstrate early experiments to drive innovation through contracting in the NHS that have largely relied on the vision of individual teams or leaders, in combination with external legal, procurement and actuarial support. It is unlikely that this approach will be sustainable or replicable across the country or internationally, despite the best intentions of commissioners. Designing and operating novel contractual approaches will require considerable determination, alongside advanced skills in procurement, contract management and commissioning. The cost of developing new contractual approaches is high, and as the process is difficult and resource-intensive, it is likely that dedicated teams or programs will be required to drive significant improvement.

  15. Promised and delivered inducements and contributions: an integrated view of psychological contract appraisal.

    PubMed

    Lambert, Lisa Schurer

    2011-07-01

    The reciprocal exchange of employees' work for pay that is central to employment relationships is viewed here through the lens of the psychological contract. A psychological contract involves promised inducements, promised contributions, delivered inducements, and delivered contributions: How an employee cognitively integrates these 4 elements is a central question in psychological contract theory. Three alternative approaches for integrating the 4 elements were drawn from discrepancy theory, from equity theory, and from need theories of satisfaction, respectively. Experimental findings disconfirmed the discrepancy and equity approaches. Findings were consistent with the premise of the needs model, which is that appraisal is driven by how psychological contract elements facilitate or hinder an employee's effort to fulfill personal needs. Results showed that promised and delivered pay and work contribute uniquely to appraisal but that they vary in their influence on appraisal. These findings were consistent with the needs model principle that elements proximal to need satisfaction matter more than distal elements. That is, what is delivered (for pay and for work) matters more than what is promised, and pay matters more than work. PMID:21142346

  16. Auditory Integration Training: A Double-Blind Study of Behavioral and Electrophysiological Effects in People with Autism.

    ERIC Educational Resources Information Center

    Edelson, Stephen M.; Arin, Deborah; Bauman, Margaret; Lukas, Scott E.; Rudy, Jane H.; Sholar, Michelle; Rimland, Bernard

    1999-01-01

    Nineteen individuals with autism either listened to auditory integration training processed music or unprocessed music for 20 half-hour sessions. A significant decrease in Aberrant Behavior Checklist Scores was observed in the experimental group at the 30-month follow-up assessment. In addition, three experimental subjects but no controls showed a…

  17. Development of an Electrophysiology (EP)-Enabled Intracardiac Ultrasound Catheter Integrated With NavX 3-Dimensional Electrofield Mapping for Guiding Cardiac EP Interventions

    PubMed Central

    Li, Xiao Kui; Pemberton, James; Thomenius, Kai; Dentinger, Aaron; Lowe, Robert I.; Ashraf, Muhammad; Shung, K. Kirk; Chia, Raymond; Stephens, Douglas N.; O'Donnell, Matthew; Mahajan, Aman; Balaji, Seshadri; Shivkumar, Kalyanam; Sahn, David J.

    2015-01-01

    Objective We have developed an integrated high-resolution intracardiac echocardiography (ICE) catheter for electrophysiology (EP) testing, which can be coregistered in 3-dimensional space with EP testing and ablation catheters using electrofield sensing. Methods Twelve open-chest pigs (34–55 kg) and 3 closed-chest pigs were studied. After introduction from the jugular or femoral venous locations, the 9F side-looking, highly steerable (0°–180°), 64-element array catheters could be manipulated easily throughout the right side of the heart. Multisite cardiac pacing was performed for assessing left ventricular (LV) synchrony using tissue Doppler methods. Also, in the open-chest pigs, right atrial (RA) and right ventricular (RV) ablations were performed with a separate radio frequency catheter under fluoroscopic guidance and visualized with ICE to characterize the changes. In the 3 closed-chest pigs, electrofield NavX 3-dimensional coregistration (St Jude Medical Corp, Minneapolis, MN) allowed us to test whether this additional feature could shorten the time necessary to perform 4 targeted ablations in each animal while imaging the ablation catheter and the adjacent region by ICE. Results Intracardiac anatomy, tricuspid, aortic, pulmonary, and mitral valve function, and pulmonary vein flow were all imaged reproducibly from scanning locations in the RA or RV in all animals, along with assessment of cardiac motion and the effects of multisite pacing. Three-dimensional electrofield displays detailed the spatial relationship between the ICE catheter and ablation catheters such that the time to visualize and ablate 4 sites in each of the 3 closed-chest animals was reduced. Conclusions This new technology is a first step in the integration of ICE with EP procedures. PMID:17957051

  18. “Reality” of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study

    PubMed Central

    Palmieri, Arianna; Calvo, Vincenzo; Kleinbub, Johann R.; Meconi, Federica; Marangoni, Matteo; Barilaro, Paolo; Broggio, Alice; Sambin, Marco; Sessa, Paola

    2014-01-01

    The nature of near-death-experiences (NDEs) is largely unknown but recent evidence suggests the intriguing possibility that NDEs may refer to actually “perceived,” and stored, experiences (although not necessarily in relation to the external physical world). We adopted an integrated approach involving a hypnosis-based clinical protocol to improve recall and decrease memory inaccuracy together with electroencephalography (EEG) recording in order to investigate the characteristics of NDE memories and their neural markers compared to memories of both real and imagined events. We included 10 participants with NDEs, defined by the Greyson NDE scale, and 10 control subjects without NDE. Memories were assessed using the Memory Characteristics Questionnaire. Our hypnosis-based protocol increased the amount of details in the recall of all kind of memories considered (NDE, real, and imagined events). Findings showed that NDE memories were similar to real memories in terms of detail richness, self-referential, and emotional information. Moreover, NDE memories were significantly different from memories of imagined events. The pattern of EEG results indicated that real memory recall was positively associated with two memory-related frequency bands, i.e., high alpha and gamma. NDE memories were linked with theta band, a well-known marker of episodic memory. The recall of NDE memories was also related to delta band, which indexes processes such as the recollection of the past, as well as trance states, hallucinations, and other related portals to transpersonal experience. It is notable that the EEG pattern of correlations for NDE memory recall differed from the pattern for memories of imagined events. In conclusion, our findings suggest that, at a phenomenological level, NDE memories cannot be considered equivalent to imagined memories, and at a neural level, NDE memories are stored as episodic memories of events experienced in a peculiar state of consciousness. PMID:24994974

  19. Electrophysiological evaluation of psychogenic movement disorders.

    PubMed

    Kamble, Nitish L; Pal, Pramod Kumar

    2016-01-01

    Psychogenic movement disorders (PMD) include a group of neurological symptoms which cannot be explained by any organic syndrome. The diagnosis of PMD is challenging for both neurologist and psychiatrist. Electrophysiological examination is a useful tool to evaluate and support a diagnosis PMD. It includes a set of tests which are chosen appropriate to the clinical setting that provides objective criteria for the diagnosis of PMD. The various tests available include accelerometry, surface electromyography, electroencephalography, jerk locked back averaging and pre-movement potentials, somatosensory evoked potentials, transcranial magnetic stimulation (TMS) etc. Electrophysiologically psychogenic tremors display features of variability, entrainability, coactivation, distractibility and increase in the amplitude and frequency on mass loading. Movement related cortical potentials such as Bereitschaftspotential is seen in psychogenic myoclonus. Presence of triphasic contraction of muscles and absence of co-contraction suggests psychogenic myoclonus. Latency of C-reflex is longer in psychogenic myoclonus as compared to organic myoclonus. The role of TMS to differentiate psychogenic from organic dystonia is still not clear. In conclusion, electrophysiological tests are most useful for tremor, followed by jerks and least for dystonia. In patients with long-standing PMD or those with mixed pathology, electrophysiological tests may not be very useful. PMID:26403429

  20. Macroscopic contraction of a gel induced by the integrated motion of light-driven molecular motors

    NASA Astrophysics Data System (ADS)

    Li, Quan; Fuks, Gad; Moulin, Emilie; Maaloum, Mounir; Rawiso, Michel; Kulic, Igor; Foy, Justin T.; Giuseppone, Nicolas

    2015-02-01

    Making molecular machines that can be useful in the macroscopic world is a challenging long-term goal of nanoscience. Inspired by the protein machinery found in biological systems, and based on the theoretical understanding of the physics of motion at the nanoscale, organic chemists have developed a number of molecules that can produce work by contraction or rotation when triggered by various external chemical or physical stimuli. In particular, basic molecular switches that commute between at least two thermodynamic minima and more advanced molecular motors that behave as dissipative units working far from equilibrium when fuelled with external energy have been reported. However, despite recent progress, the ultimate challenge of coordinating individual molecular motors in a continuous mechanical process that can have a measurable effect at the macroscale has remained elusive. Here, we show that by integrating light-driven unidirectional molecular rotors as reticulating units in a polymer gel, it is possible to amplify their individual motions to achieve macroscopic contraction of the material. Our system uses the incoming light to operate under far-from-equilibrium conditions, and the work produced by the motor in the photostationary state is used to twist the entangled polymer chains up to the collapse of the gel. Our design could be a starting point to integrate nanomotors in metastable materials to store energy and eventually to convert it.

  1. Contract Research Organizations (CROs) in China: integrating Chinese research and development capabilities for global drug innovation.

    PubMed

    Shi, Yun-Zhen; Hu, Hao; Wang, Chunming

    2014-01-01

    The significance of R&D capabilities of China has become increasingly important as an emerging force in the context of globalization of pharmaceutical research and development (R&D). While China has prospered in its R&D capability in the past decade, how to integrate the rising pharmaceutical R&D capability of China into the global development chain for innovative drugs remains challenging. For many multinational corporations and research organizations overseas, their attempt to integrate China's pharmaceutical R&D capabilities into their own is always hindered by policy constraints and reluctance of local universities and pharmaceutical firms. In light of the situation, contract research organizations (CROs) in China have made great innovation in value proposition, value chain and value networking to be at a unique position to facilitate global and local R&D integration. Chinese CROs are now being considered as the essentially important and highly versatile integrator of local R&D capability for global drug discovery and innovation. PMID:25406839

  2. Contract Research Organizations (CROs) in China: integrating Chinese research and development capabilities for global drug innovation.

    PubMed

    Shi, Yun-Zhen; Hu, Hao; Wang, Chunming

    2014-11-19

    The significance of R&D capabilities of China has become increasingly important as an emerging force in the context of globalization of pharmaceutical research and development (R&D). While China has prospered in its R&D capability in the past decade, how to integrate the rising pharmaceutical R&D capability of China into the global development chain for innovative drugs remains challenging. For many multinational corporations and research organizations overseas, their attempt to integrate China's pharmaceutical R&D capabilities into their own is always hindered by policy constraints and reluctance of local universities and pharmaceutical firms. In light of the situation, contract research organizations (CROs) in China have made great innovation in value proposition, value chain and value networking to be at a unique position to facilitate global and local R&D integration. Chinese CROs are now being considered as the essentially important and highly versatile integrator of local R&D capability for global drug discovery and innovation.

  3. Advances in Electrophysiological Research

    PubMed Central

    Kamarajan, Chella; Porjesz, Bernice

    2015-01-01

    Electrophysiological measures of brain function are effective tools to understand neurocognitive phenomena and sensitive indicators of pathophysiological processes associated with various clinical conditions, including alcoholism. Individuals with alcohol use disorder (AUD) and their high-risk offspring have consistently shown dysfunction in several electrophysiological measures in resting state (i.e., electroencephalogram) and during cognitive tasks (i.e., event-related potentials and event-related oscillations). Researchers have recently developed sophisticated signal-processing techniques to characterize different aspects of brain dynamics, which can aid in identifying the neural mechanisms underlying alcoholism and other related complex disorders. These quantitative measures of brain function also have been successfully used as endophenotypes to identify and help understand genes associated with AUD and related disorders. Translational research also is examining how brain electrophysiological measures potentially can be applied to diagnosis, prevention, and treatment. PMID:26259089

  4. Tools for Closure Project and Contract Management: Development of the Rocky Flats Integrated Closure Project Baseline

    SciTech Connect

    Gelles, C. M.; Sheppard, F. R.

    2002-02-26

    This paper details the development of the Rocky Flats Integrated Closure Project Baseline - an innovative project management effort undertaken to ensure proactive management of the Rocky Flats Closure Contract in support of the Department's goal for achieving the safe closure of the Rocky Flats Environmental Technology Site (RFETS) in December 2006. The accelerated closure of RFETS is one of the most prominent projects within the Department of Energy (DOE) Environmental Management program. As the first major former weapons plant to be remediated and closed, it is a first-of-kind effort requiring the resolution of multiple complex technical and institutional challenges. Most significantly, the closure of RFETS is dependent upon the shipment of all special nuclear material and wastes to other DOE sites. The Department is actively working to strengthen project management across programs, and there is increasing external interest in this progress. The development of the Rocky Flats Integrated Closure Project Baseline represents a groundbreaking and cooperative effort to formalize the management of such a complex project across multiple sites and organizations. It is original in both scope and process, however it provides a useful precedent for the other ongoing project management efforts within the Environmental Management program.

  5. Objective electrophysiological measures from cochlear implant patients.

    PubMed

    Shallop, J K

    1993-02-01

    Various objective electrophysiological techniques have been used to supplement the behavioral measurements for cochlear implant patients. This report summarizes various studies of these measurements, including stimulus artifact, averaged electrode voltages, electrical stapedius reflexes, electrical auditory brain stem responses, electrical middle latency responses, and cortical auditory responses. These techniques have been shown to provide valuable information in the evaluation of device and electrode integrity in addition to correlated values to behavioral thresholds and comfort levels.

  6. Electrophysiology of Axonal Constrictions

    NASA Astrophysics Data System (ADS)

    Johnson, Christopher; Jung, Peter; Brown, Anthony

    2013-03-01

    Axons of myelinated neurons are constricted at the nodes of Ranvier, where they are directly exposed to the extracellular space and where the vast majority of the ion channels are located. These constrictions are generated by local regulation of the kinetics of neurofilaments the most important cytoskeletal elements of the axon. In this paper we discuss how this shape affects the electrophysiological function of the neuron. Specifically, although the nodes are short (about 1 μm) in comparison to the distance between nodes (hundreds of μm) they have a substantial influence on the conduction velocity of neurons. We show through computational modeling that nodal constrictions (all other features such as numbers of ion channels left constant) reduce the required fiber diameter for a given target conduction velocity by up to 50% in comparison to an unconstricted axon. We further show that the predicted optimal fiber morphologies closely match reported fiber morphologies. Supported by The National Science Foundation (IOS 1146789)

  7. The integrated supplier: key to cost management and multi-franchise capitation contracting.

    PubMed

    Schuweiler, R C

    1996-05-01

    Capitation...most healthcare providers do not work under it, comprehend it, or even want it, yet supply capitation contracting seminars are popping up everywhere creating the feeling that the bandwagon is leaving, and it might be time to get on board. Not true. Supply capitation is not for all organizations. Capitation contracting is not easy and there are not many successful models to help the uninitiated. If a panacea is sought for reducing supply costs, capitation is only one component of a systematic strategy to reduce materiel costs. This article suggests a direction using the Group Health Materiel Management (Group Health Cooperative of Puget Sound, WA) experience as a point of reference. It advocates a systematic approach that focuses on expense reduction in: cost of goods, holding cost of inventory, labor cost associated with all materiel processes, distribution cost (transportation and par stock pick, pack, and replenishment), product utilization, variation in product standards, and waste stream byproducts. At Group Health (GH) these issues are primarily addressed through the use of: information systems, supplier certification/selection processes, group purchasing compliance, supply channel management, supply capitation contracting programs, standardization, and utilization management. Because of managed care organizational structure, Group Health Cooperative supply capitation contracting, as performed at GH, is discussed not as a quick fix solution but in the spirit of sharing our experience with others who may be considering it as a cost savings tactic in the context of a broad-based materiel management strategy. This article highlights the experiences of GH beginning with materiel management's business process assumptions toward multiple-franchise supply capitation. PMID:10158185

  8. Rigorous algorithm for the electron repulsion integral over the generally contracted solid harmonic Gaussian-type orbitals

    NASA Astrophysics Data System (ADS)

    Ishida, Kazuhiro

    2000-11-01

    A rigorous general formula can be derived for the electron repulsion integral (ERI) over the generally contracted (GC) solid harmonic (SH) Gaussian-type orbitals by the use of the "reducing triply mixed solid harmonics" defined in this article. A general algorithm is obtained inductively from the general formula by the use of the "triply mixed solid harmonics" defined in this article. This algorithm is named as ACEb3k3-SH-GC. This ACEb3k3-SH-GC is rigorous and capable of computing the above SH-ERI very fast. Numerical assessment can be performed for (LL|LL) class of SH-ERIs (L=2-5). It is found that the present ACEb3k3-SH-GC is severalfold to a thousandfold faster than the ACEb3k3 algorithm for the usual segment contraction (which is named as ACEb3k3-SH-SC and is the fastest algorithm of all methods in the literature) for the generally contracted (LL|LL) class of SH-ERIs.

  9. ICEPO: the ion channel electrophysiology ontology

    PubMed Central

    Hinard, V.; Britan, A.; Rougier, J.S.; Bairoch, A.; Abriel, H.; Gaudet, P.

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site: ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  10. ICEPO: the ion channel electrophysiology ontology.

    PubMed

    Hinard, V; Britan, A; Rougier, J S; Bairoch, A; Abriel, H; Gaudet, P

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site:ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use.

  11. Advanced Electrophysiologic Mapping Systems

    PubMed Central

    2006-01-01

    integration of anatomic and electrical potential information that enable better visualization of areas of interest for ablation Advanced nonfluoroscopy mapping/navigation systems appear to be safe; they consistently shortened the fluoroscopy duration and radiation exposure. Evidence suggests that nonfluoroscopy mapping and navigation systems may be used as adjuncts to rather than replacements for fluoroscopy in guiding the ablation of complex arrhythmias. Most studies showed a nonsignificant trend toward lower overall failure rate for advanced mapping-guided ablation compared with fluoroscopy-guided mapping. Pooled analyses of small RCTs and non-RCTs that compared fluoroscopy- with nonfluoroscopy-guided ablation of atrial fibrillation and atrial flutter showed that advanced nonfluoroscopy mapping and navigational systems: Yielded acute success rates of 69% to 100%, not significantly different from fluoroscopy ablation. Had overall failure rates at 3 months to 19 months of 1% to 40% (median 25%). Resulted in a 10% relative reduction in overall failure rate for advanced mapping guided-ablation compared to fluoroscopy guided ablation for the treatment of atrial fibrillation. Yielded added benefit over fluoroscopy in guiding the ablation of complex arrhythmia. The advanced systems were shown to reduce the arrhythmia burden and the need for antiarrhythmic drugs in patients with complex arrhythmia who had failed fluoroscopy-guided ablation Based on predominantly observational studies, circumferential PV ablation guided by a nonfluoroscopy system was shown to do the following: Result in freedom from atrial fibrillation (with or without antiarrhythmic drug) in 75% to 95% of patients (median 79%). This effect was maintained up to 28 months. Result in freedom from atrial fibrillation without antiarrhythmic drugs in 47% to 95% of patients (median 63%). Improve patient survival at 28 months after the procedure as compared with drug therapy. Require special skills; patient outcomes are

  12. Electrophysiological Cardiac Modeling: A Review.

    PubMed

    Beheshti, Mohammadali; Umapathy, Karthikeyan; Krishnan, Sridhar

    2016-01-01

    Cardiac electrophysiological modeling in conjunction with experimental and clinical findings has contributed to better understanding of electrophysiological phenomena in various species. As our knowledge on underlying electrical, mechanical, and chemical processes has improved over time, mathematical models of the cardiac electrophysiology have become more realistic and detailed. These models have provided a testbed for various hypotheses and conditions that may not be easy to implement experimentally. In addition to the limitations in experimentally validating various scenarios implemented by the models, one of the major obstacles for these models is computational complexity. However, the ever-increasing computational power of supercomputers facilitates the clinical application of cardiac electrophysiological models. The potential clinical applications include testing and predicting effects of pharmaceutical agents and performing patient-specific ablation and defibrillation. A review of studies involving these models and their major findings are provided.

  13. Electrophysiological Cardiac Modeling: A Review.

    PubMed

    Beheshti, Mohammadali; Umapathy, Karthikeyan; Krishnan, Sridhar

    2016-01-01

    Cardiac electrophysiological modeling in conjunction with experimental and clinical findings has contributed to better understanding of electrophysiological phenomena in various species. As our knowledge on underlying electrical, mechanical, and chemical processes has improved over time, mathematical models of the cardiac electrophysiology have become more realistic and detailed. These models have provided a testbed for various hypotheses and conditions that may not be easy to implement experimentally. In addition to the limitations in experimentally validating various scenarios implemented by the models, one of the major obstacles for these models is computational complexity. However, the ever-increasing computational power of supercomputers facilitates the clinical application of cardiac electrophysiological models. The potential clinical applications include testing and predicting effects of pharmaceutical agents and performing patient-specific ablation and defibrillation. A review of studies involving these models and their major findings are provided. PMID:27652454

  14. Electrophysiological studies with prenalterol.

    PubMed

    Weisswange, A; Csapo, G; Kalusche, D; Keck, M

    1982-01-01

    Electrophysiological studies with prenalterol in 19 patients (6 women, 13 men, 5 with sinus node disease, 4 with AV node disease, 7 with double node disease, 2 with conduction disturbance below His bundle, 1 normal) showed that sinus node function (heart rate, sinus node recovery time) is uniformly improved by this beta-stimulator. Also AV conduction is significantly and uniformly improved (shortening of AH interval and of the functional refractory period of AV conduction). There is no or little influence on intra-atrial conduction and on conduction below the His bundle. However, spontaneous depolarisation in His-Purkinje fibers--as tested in patients with complete AV block and ventricular demand pacemaker--is increased through beta-stimulation with prenalterol as reflected by shorter escape intervals and higher frequency escape rhythm. Prenalterol may be of clinical use in patients with cardiomyopathies who developed bradycardia under digitalisation or patients with severe bradyarrhythmia either with or without digitalis. It might also be useful in rare emergency situations, when complete pacemaker failure develops. PMID:6127883

  15. Electrophysiological responses of osteoclasts to hormones.

    PubMed

    Ferrier, J; Ward, A; Kanehisa, J; Heersche, J N

    1986-07-01

    Electrophysiological measurements were carried out on osteoclasts in vitro. Such isolated osteoclasts are able to resorb bone in vitro and contract in response to calcitonin (CT). Our measurements show that individual osteoclasts respond to CT with a significant transient hyperpolarization of membrane potential. Application of parathyroid hormone (PTH) and dibutyryl cAMP produced a transient hyperpolarization in some osteoclasts. Measurements on an osteoblastlike line (ROS 17/2.8) showed a sustained hyperpolarizing response to CT, which is similar to but smaller than the hyperpolarizing response to PTH and dibutyryl cAMP in this and some other osteoblastlike lines. In contrast to osteoblastlike cells, the osteoclasts have no long term membrane potential response to CT, to PTH, or to dibutyryl cAMP. These results show that there are distinct differences between osteoclasts and osteoblasts in their ion transport responses to hormones.

  16. Gesundes Kinzigtal Integrated Care: improving population health by a shared health gain approach and a shared savings contract

    PubMed Central

    H., Hildebrandt; C., Hermann; R., Knittel; M., Richter-Reichhelm; A., Siegel; W., Witzenrath

    2010-01-01

    Introduction Integrated care solutions need supportive financial incentives. In this paper, we describe the financial architecture and operative details of the integrated pilot Gesundes Kinzigtal. Description of integrated care case Located in Southwest Germany, Gesundes Kinzigtal is one of the few population-based integrated care approaches in Germany, organising care across all health service sectors and indications. The system serving around half of the population of the region is run by a regional health management company (Gesundes Kinzigtal GmbH) in cooperation with the physicians' network in the region (MQNK), a German health care management company with a background in medical sociology and health economics (OptiMedis AG) and with two statutory health insurers (among them is the biggest health insurer in Southwest Germany: AOK Baden-Württemberg). Discussion and (preliminary) conclusion The shared savings contract between Gesundes Kinzigtal GmbH and the two health insurers, providing financial incentives for managers and health care providers to realize a substantial efficiency gain, could be an appropriate contractual base of Gesundes Kinzigtal's population health gain approach. This approach is based on the assumption that a more effective trans-sector organization of Germany's health care system and increased investments in well-designed preventive programmes will lead to a reduction in morbidity, and in particular to a reduced incidence and prevalence of chronic diseases. This, in turn, is to lead to a comparative reduction in health care cost. Although the comparative cost in the Kinzigtal region has been reduced from the onset of Gesundes Kinzigtal Integrated Care, only future research will have to demonstrate whether—and to what extent—cost reduction may be attributed to a real population health gain. PMID:20689772

  17. Biofeedback in psychomotor training. Electrophysiological basis.

    PubMed

    Bazanova, O M; Mernaya, E M; Shtark, M B

    2009-06-01

    The influences of individual musical practice and the same practice supplemented with biofeedback using electrophysiological markers for optimum music-performing activity were studied in 39 music students. Traditional technical practice produced increases in integral EMG power and decreases in alpha activity in most of the students with initially low maximum alpha activity peak frequencies. Similar practice but combined with individual sessions of alpha-EEG/EMG biofeedback were accompanied by increases in the frequency, bandwidth, and activation responses of EEG alpha rhythms in all subjects, along with decreases in EEG integral power. The efficacy of training with biofeedback and the ability to experience psychomotor learning depended on the initial individual characteristics of EEG alpha activity.

  18. Electrophysiological profile in arsenic neuropathy.

    PubMed

    Oh, S J

    1991-12-01

    Comprehensive electrophysiological studies were performed on 13 patients with arsenic neuropathy. The most prominent finding was a marked abnormality in sensory nerve conduction in the presence of moderate abnormalities in motor nerve conduction. The motor nerve conduction studies and needle EMG were typical of those seen in axonal degeneration which was confirmed by sural nerve biopsy.

  19. Children's Electrophysiological Responses to Music.

    ERIC Educational Resources Information Center

    Flohr, John W.; And Others

    This study examined the electrophysiological differences between baseline EEG frequencies and EEG frequencies obtained while listening to music stimuli. The experimental group comprised 22 children, ages 4 to 6 years old, who received special music instruction twice a week for 25 minutes for 7 weeks. The control group received no music…

  20. Resuscitation great. Luigi Galvani and the foundations of electrophysiology.

    PubMed

    Cajavilca, Christian; Varon, Joseph; Sternbach, George L

    2009-02-01

    Luigi Galvani became one of the greatest scientists of the 18th century with his research and the development of his theory on animal electricity. His work was appreciated by many scientists. Nevertheless, it gave rise to one of the most passionate scientific debates in history when Alessandro Volta postulated that Galvani had confused intrinsic animal electricity with small currents produced by metals. This debate would result in the creation of electrophysiology, electromagnetism, electrochemistry and the electrical battery. Galvani responded to each of the postulated theories of Volta giving irrefutable proof of the involvement of electricity in the contraction of muscles. However, his work was subsequently abandoned and silenced for many years but his ideas and theories were finally confirmed by the creation of new instruments and the interest of new scientists who helped position Galvani as the father of electrophysiology.

  1. Resuscitation great. Luigi Galvani and the foundations of electrophysiology.

    PubMed

    Cajavilca, Christian; Varon, Joseph; Sternbach, George L

    2009-02-01

    Luigi Galvani became one of the greatest scientists of the 18th century with his research and the development of his theory on animal electricity. His work was appreciated by many scientists. Nevertheless, it gave rise to one of the most passionate scientific debates in history when Alessandro Volta postulated that Galvani had confused intrinsic animal electricity with small currents produced by metals. This debate would result in the creation of electrophysiology, electromagnetism, electrochemistry and the electrical battery. Galvani responded to each of the postulated theories of Volta giving irrefutable proof of the involvement of electricity in the contraction of muscles. However, his work was subsequently abandoned and silenced for many years but his ideas and theories were finally confirmed by the creation of new instruments and the interest of new scientists who helped position Galvani as the father of electrophysiology. PMID:19059693

  2. Accompanying coordinate expansion and recurrence relation method using a transfer relation scheme for electron repulsion integrals with high angular momenta and long contractions

    SciTech Connect

    Hayami, Masao; Seino, Junji; Nakai, Hiromi

    2015-05-28

    An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals.

  3. Redox artifacts in electrophysiological recordings

    PubMed Central

    Berman, Jonathan M.

    2013-01-01

    Electrophysiological techniques make use of Ag/AgCl electrodes that are in direct contact with cells or bath. In the bath, electrodes are exposed to numerous experimental conditions and chemical reagents that can modify electrode voltage. We examined voltage offsets created in Ag/AgCl electrodes by exposure to redox reagents used in electrophysiological studies. Voltage offsets were measured in reference to an electrode separated from the solution by an agar bridge. The reducing reagents Tris-2-carboxyethly-phosphine, dithiothreitol (DTT), and glutathione, as well as the oxidizing agent H2O2 used at experimentally relevant concentrations reacted with Ag in the electrodes to produce voltage offsets. Chloride ions and strong acids and bases produced offsets at millimolar concentrations. Electrolytic depletion of the AgCl layer, to replicate voltage clamp and sustained use, resulted in increased sensitivity to flow and DTT. Offsets were sensitive to electrode silver purity and to the amount and method of chloride deposition. For example, exposure to 10 μM DTT produced a voltage offset between 10 and 284 mV depending on the chloride deposition method. Currents generated by these offsets are significant and dependent on membrane conductance and by extension the expression of ion channels and may therefore appear to be biological in origin. These data demonstrate a new source of artifacts in electrophysiological recordings that can affect measurements obtained from a variety of experimental techniques from patch clamp to two-electrode voltage clamp. PMID:23344161

  4. Pediatric & Congenital Electrophysiology Society: building an international paediatric electrophysiology organisation.

    PubMed

    Cohen, Mitchell; Sanatani, Shubhayan; Stephenson, Elizabeth; Skinner, Jon; Drago, Fabrizio; Davis, Andrew; Janousek, Jan; Rosenthal, Eric; Collins, Kathryn K; Triedman, John

    2016-08-01

    The Pediatric and Congenital Electrophysiology Society (PACES) is a non-profit organisation comprised of individuals dedicated to improving the care of children and young adults with cardiac rhythm disturbances. Although PACES is a predominantly North American-centric organisation, international members have been a part of PACES for the last two decades. This year, PACES expanded its North American framework into a broadly expansive international role. On 12 May, 2015, paediatric electrophysiology leaders from within the United States of America and Canada met with over 30 international paediatric electrophysiologists from 17 countries and five continents discussing measures to (1) expand PACES' global vision, (2) address ongoing challenges such as limited resource allocation that may be present in developing countries, (3) expand PACES' governance to include international representation, (4) promote joint international sessions at future paediatric EP meetings, and (5) facilitate a global multi-centre research consortium. This meeting marked the inception of a formal international collaborative spirit in PACES. This editorial addresses some solutions to breakdown the continental silos paediatric electrophysiologists have practiced within; however, there remain ongoing limitations, and future discussions will be needed to continue to move the PACES global international vision forward.

  5. Pediatric & Congenital Electrophysiology Society: building an international paediatric electrophysiology organisation.

    PubMed

    Cohen, Mitchell; Sanatani, Shubhayan; Stephenson, Elizabeth; Skinner, Jon; Drago, Fabrizio; Davis, Andrew; Janousek, Jan; Rosenthal, Eric; Collins, Kathryn K; Triedman, John

    2016-05-01

    The Pediatric and Congenital Electrophysiology Society (PACES) is a non-profit organisation comprised of individuals dedicated to improving the care of children and young adults with cardiac rhythm disturbances. Although PACES is a predominantly North American-centric organisation, international members have been a part of PACES for the last two decades. This year, PACES expanded its North American framework into a broadly expansive international role. On May 12, 2015, paediatric electrophysiology leaders from within the United States of America and Canada met with over 30 international paediatric electrophysiologists from 17 countries and five continents discussing measures to (1) expand PACES' global vision, (2) address ongoing challenges such as limited resource allocation that may be present in developing countries, (3) expand PACES' governance to include international representation, (4) promote joint international sessions at future paediatric EP meetings, and (5) facilitate a global multi-centre research consortium. This meeting marked the inception of a formal international collaborative spirit in PACES. This editorial addresses some solutions to breakdown the continental silos paediatric electrophysiologists have practiced within; however, there remain ongoing limitations, and future discussions will be needed to continue to move the PACES global international vision forward.

  6. Personal miniature electrophysiological tape recorder

    NASA Astrophysics Data System (ADS)

    Green, H.

    1981-11-01

    The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.

  7. Personal miniature electrophysiological tape recorder

    NASA Technical Reports Server (NTRS)

    Green, H.

    1981-01-01

    The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.

  8. Electrophysiological correlates of observational learning in children.

    PubMed

    Rodriguez Buritica, Julia M; Eppinger, Ben; Schuck, Nicolas W; Heekeren, Hauke R; Li, Shu-Chen

    2016-09-01

    Observational learning is an important mechanism for cognitive and social development. However, the neurophysiological mechanisms underlying observational learning in children are not well understood. In this study, we used a probabilistic reward-based observational learning paradigm to compare behavioral and electrophysiological markers of individual and observational reinforcement learning in 8- to 10-year-old children. Specifically, we manipulated the amount of observable information as well as children's similarity in age to the observed person (same-aged child vs. adult) to examine the effects of similarity in age on the integration of observed information in children. We show that the feedback-related negativity (FRN) during individual reinforcement learning reflects the valence of outcomes of own actions. Furthermore, we found that the feedback-related negativity during observational reinforcement learning (oFRN) showed a similar distinction between outcome valences of observed actions. This suggests that the oFRN can serve as a measure of observational learning in middle childhood. Moreover, during observational learning children profited from the additional social information and imitated the choices of their own peers more than those of adults, indicating that children have a tendency to conform more with similar others (e.g. their own peers) compared to dissimilar others (adults). Taken together, our results show that children can benefit from integrating observable information and that oFRN may serve as a measure of observational learning in children.

  9. Electrophysiological and contractile function of cardiomyocytes derived from human embryonic stem cells

    PubMed Central

    Blazeski, Adriana; Zhu, Renjun; Hunter, David W.; Weinberg, Seth H.; Boheler, Kenneth R.; Zambidis, Elias T.; Tung, Leslie

    2013-01-01

    Human embryonic stem cells have emerged as the prototypical source from which cardiomyocytes can be derived for use in drug discovery and cell therapy. However, such applications require that these cardiomyocytes (hESC-CMs) faithfully recapitulate the physiology of adult cells, especially in relation to their electrophysiological and contractile function. We review what is known about the electrophysiology of hESC-CMs in terms of beating rate, action potential characteristics, ionic currents, and cellular coupling as well as their contractility in terms of calcium cycling and contraction. We also discuss the heterogeneity in cellular phenotypes that arises from variability in cardiac differentiation, maturation, and culture conditions, and summarize present strategies that have been implemented to reduce this heterogeneity. Finally, we present original electrophysiological data from optical maps of hESC-CM clusters. PMID:22958937

  10. Cryoanalgesia: electrophysiology at different temperatures.

    PubMed

    Zhou, Linqiu; Shao, Zhenhai; Ou, Shihuan

    2003-02-01

    Somatosensory evoked potentials (SEP) and sensory conduction velocity (SCV) were measured in rabbit sciatic nerves following graded cold lesioning. The SEP disappeared when injury was induced at temperatures below -60 degrees C, but returned on day 41+/-4 (mean+/-SD). SEP returned on day 56+/-11 days when the lesion was induced at 100 to -180 degrees C. The SEP latency was prolonged after creating lesions at -100 to -180 degrees C, compared with both the sham operated and the -20 degrees C groups. These experiments suggest the cryolesions produced at temperatures between -60 and -100 degrees C are most suitable for altering the electrophysiological conduction of the nerve, and may result in suitable post-operative analgesia. PMID:12623025

  11. [Towards optical in vivo electrophysiology].

    PubMed

    Lambot, Laurie; Gall, David

    Optical imaging of voltage indicators is a promising approach for detecting the activity of neuronal circuits with high spatial and temporal resolution. In this context, genetically encoded voltage indicators, combining genetic targeting and optical readout of transmembrane voltage, represent a technological breaktrough that will without doubt have a major impact in neuroscience. However, so far the existing genetically encoded voltage indicators lacked the capabilities to detect individual action potentials and fast spike trains in live animals. Here, we present a novel indicator allowing high-fidelity imaging of individual spikes and dentritic voltage dynamics in vivo. Used in combination with optogenetics, which allows to manipulate neuronal activity, this opens the possibility of an all-optical electrophysiology. PMID:27615186

  12. The Cardiac Electrophysiology Web Lab.

    PubMed

    Cooper, Jonathan; Scharm, Martin; Mirams, Gary R

    2016-01-19

    Computational modeling of cardiac cellular electrophysiology has a long history, and many models are now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviors so that we can choose a model as a suitable basis for a new study or to characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models in a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models encoded in CellML, and a website (https://chaste.cs.ox.ac.uk/WebLab) provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyperkalemia. This resource is publicly available, open source, and free, and we invite the community to use it and become involved in future developments. Investigators interested in comparing competing hypotheses using models can make a more informed decision, and those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols.

  13. The Cardiac Electrophysiology Web Lab.

    PubMed

    Cooper, Jonathan; Scharm, Martin; Mirams, Gary R

    2016-01-19

    Computational modeling of cardiac cellular electrophysiology has a long history, and many models are now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviors so that we can choose a model as a suitable basis for a new study or to characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models in a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models encoded in CellML, and a website (https://chaste.cs.ox.ac.uk/WebLab) provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyperkalemia. This resource is publicly available, open source, and free, and we invite the community to use it and become involved in future developments. Investigators interested in comparing competing hypotheses using models can make a more informed decision, and those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols. PMID:26789753

  14. The digital hearing aid, wearable computing, and electrophysiological response.

    PubMed

    Doyle, T E; Kucerovsky, Z; Greason, W D

    2002-01-01

    Presbycusis is the most common form of hearing loss caused by aging and long-term exposure to sound energy. This type of ailment decreases the ear's ability to perceive high frequencies and localize sound, thus making comprehension more difficult. To compensate for this loss, the choice of a digital hearing aid has become more common. However, most digital hearing aids do little more that their analogue predecessor's by providing a single, fixed hearing response. Such a fixed response is not suitable for all of a user's auditory environments and typically causes a more rapid loss of hearing. Significant advancement in processing power and reduction in size of computing hardware has produced increasingly more powerful, more portable, and more personal computing devices. These advances have spurred research and development of wearable computing devices towards integrating both man and machine. By definition, the digital hearing aid is a wearable computing device. The development of a digital hearing aid with increased onboard processing that is aware of its owner's electrophysiological and auditory environments is an obvious progression. This awareness will give the hearing aid the ability to autonomously modify its own parameters to improve audibility and comprehension. Electrophysiological signals can be classified as naturally occurring or voluntarily controlled. Employing these signals will allow the hearing aid to adapt to its owner's external and internal stimuli. Research and initial experiments into the monitoring and use of electrophysiological response for the control of the digital hearing aid shall be presented.

  15. Closed-Loop, Open-Source Electrophysiology

    PubMed Central

    Rolston, John D.; Gross, Robert E.; Potter, Steve M.

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  16. Closed-loop, open-source electrophysiology.

    PubMed

    Rolston, John D; Gross, Robert E; Potter, Steve M

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  17. Microsystems for cell-based electrophysiology

    NASA Astrophysics Data System (ADS)

    Yobas, Levent

    2013-08-01

    Among the electrophysiology techniques, the voltage clamp and its subsequent scaling to smaller mammalian cells, the so-called patch clamp, led to fundamental discoveries in the last century, revealing the ionic mechanisms and the role of single-ion channels in the generation and propagation of action potentials through excitable membranes (e.g. nerves and muscles). Since then, these techniques have gained a reputation as the gold standard of studying cellular ion channels owing to their high accuracy and rich information content via direct measurements under a controlled membrane potential. However, their delicate and skill-laden procedure has put a serious constrain on the throughput and their immediate utilization in the discovery of new cures targeting ion channels until researchers discovered ‘lab-on-a-chip’ as a viable platform for the automation of these techniques into a reliable high-throughput screening functional assay on ion channels. This review examines the innovative ‘lab-on-a-chip’ microtechnologies demonstrated towards this target over a period of slightly more than a decade. The technologies are categorically reviewed according to their considerations for design, fabrication, as well as microfluidic integration from a performance perspective with reference to their ability to secure G Ω seals (gigaseals) on cells, the norm broadly accepted among electrophysiologists for quality recordings that reflect ion-channel activity with high fidelity.

  18. Working memory of emotional stimuli: Electrophysiological characterization.

    PubMed

    Kessel, Dominique; García-Rubio, María J; González, E Kirstin; Tapia, Manuel; López-Martín, Sara; Román, Francisco J; Capilla, Almudena; Martínez, Kenia; Colom, Roberto; Carretié, Luis

    2016-09-01

    Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory.

  19. The electrophysiological development of cardiomyocytes.

    PubMed

    Liu, Jie; Laksman, Zachary; Backx, Peter H

    2016-01-15

    The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered. PMID:26788696

  20. The electrophysiological development of cardiomyocytes.

    PubMed

    Liu, Jie; Laksman, Zachary; Backx, Peter H

    2016-01-15

    The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered.

  1. Behavioral and electrophysiological recovery following cryogenic nerve injury.

    PubMed

    Kalichman, M W; Myers, R R

    1987-06-01

    Postthoracotomy pain can be reduced by cryoanalgesia of intercostal nerves. The technique involves focal freezing of peripheral nerves to interrupt pain pathways, producing immediate functional changes that recover as the nerves regenerate. To assess the time-course of functional changes that follow nerve injury, unilateral freeze lesions of sciatic nerve were induced in rats with a cryosurgical unit. The contralateral nerves were used as sham-operated controls. Following nerve injury, behavioral and electrophysiologic tests were repeated to 90 days. The acute effect of nerve injury was a decrease in behavioral measures of hind limb function (P less than 0.05), an increase in electrical threshold to elicit hind limb contraction (P less than 0.005), and an absence of stimulus-evoked compound action potential (P less than 0.005). Morphologic changes included substantial endoneurial edema associated with Wallerian degeneration. Remyelination occurred subsequently during the following 35 days. Although all physiologic measures returned toward normal, nerve conduction velocities were still much slower in the experimental group. In a second study, the long-term effects of cryogenic injury were compared with neurolytic injury with 10% procaine HCl, both of which produced a conduction velocity deficit that persisted at least 90 days after the initial injury. These behavioral and electrophysiologic results complement previous reports of morphologic deficits in the nerves including incomplete recovery of nerve fiber diameter and increased thickness of the perineurial sheath. PMID:3582553

  2. Electrophysiological characteristics according to activity level of myofascial trigger points.

    PubMed

    Yu, Seong Hun; Kim, Hyun Jin

    2015-09-01

    [Purpose] This study compared the differences in electrophysiological characteristics of normal muscles versus muscles with latent or active myofascial trigger points, and identified the neuromuscular physiological characteristics of muscles with active myofascial trigger points, thereby providing a quantitative evaluation of myofascial pain syndrome and clinical foundational data for its diagnosis. [Subjects] Ninety adults in their 20s participated in this study. Subjects were equally divided into three groups: the active myofascial trigger point group, the latent myofascial trigger point group, and the control group. [Methods] Maximum voluntary isometric contraction (MVIC), endurance, median frequency (MDF), and muscle fatigue index were measured in all subjects. [Results] No significant differences in MVIC or endurance were revealed among the three groups. However, the active trigger point group had significantly different MDF and muscle fatigue index compared with the control group. [Conclusion] Given that muscles with active myofascial trigger points had an increased MDF and suffered muscle fatigue more easily, increased recruitment of motor unit action potential of type II fibers was evident. Therefore, electrophysiological analysis of these myofascial trigger points can be applied to evaluate the effect of physical therapy and provide a quantitative diagnosis of myofascial pain syndrome.

  3. Historical perspectives on interventional electrophysiology.

    PubMed

    Lüderitz, Berndt

    2003-10-01

    The history of interventional electrophysiology is long and fascinating. In the beginning, there is not simply the anatomy and physiology of the heart, but also analysis of the pulse, which indicates the activity of the heart. The analysis of the (peripheral) pulse as a mechanical expression of heart activity goes back several millennia. In China, in 280 B.C., Wang Chu Ho wrote ten books about the pulse. The Greeks called the pulse "sphygmos", and the sphygmology thus deals with a theory of this natural occurrence. In Roman times, Galen interpreted the various types of pulse according to the widespread presumption of the time, that each organ in every disease has its own form of pulse. The basic tool for arrhythmia diagnosis became the electrocardiography introduced by Willem Einthoven who obtained the first human electrogram 1902 in Leiden, The Netherlands. The growing clinical importance of electrical cardiac stimulation has been recognized and renewed as Zoll (1911-1999) in 1952 reported a successful resuscitation in cardiac standstill by external stimulation. Meanwhile all over the world, millions of patients with cardiac arrhythmias have been treated with pacemakers in the last 45 years. The concept of a fully automatic implantable cardioverter-defibrillator system (ICD) for recognition and treatment of ventricular tachyarrhythmias was first suggested in 1970. The first implantation of the device in a human being was performed in February 1980. Further developments concern atrial and atrioventricular defibrillators, radiofrequency ablation, laser therapy and advanced antiarrhythmic surgery, new antiarrhythmic drugs and sophisticated devices for preventive pacing. The advances in the field of diagnostic and therapeutic application of pharmacologic and electrical tools as well as alternative methods will continue as rapidly as before in order to give us further significant aid in taking care of the patient.

  4. Clinical electrophysiology in myasthenia gravis.

    PubMed Central

    Stalberg, E

    1980-01-01

    Effective diagnostic methods are of great importance in order to recognise myasthenic patients among those with muscle fatigability. Intracellular recordings are useful for research work within the field and for detailed description of the motor end-plate's physiology in the individual case. The method is not used for the routine diagnosis of myasthenia gravis. The decrement of the electrical muscle response with nerve stimulation is the most commonly used method. The diagnostic yield is higher in proximal muscles, in warmed muscles, after exercise, and after ischaemia. A significant number of patients may be undiagnosed with this technique. The mechanical response with nerve stimulation shows the same type of decrement but also an abnormal response to long stimulation. The diagnostic value of this is under dispute. Single fibre ENG needs more patient cooperation than do these tests. The diagnostic yield is significantly higher. Some patients considered to have myasthenia gravis do not show any abnormalities with this technique, particularly those with the pure ocular form. Conventional EMG is not useful for the diagnosis of myasthenia, but may be indicated in these patients when concurrent nerve or muscle disease is in question. Tests for eye movement fatique have not proved useful. Stapedius reflex fatigability is demonstrated in about the same proportion of patients as have positive SFEMG findings. The technique is not uncomfortable for the patient and requires minimal cooperation. The general usefulness must be assessed by further routine use. Even with the advent of immunological tests, neurophysiological investigations are indispensable in helping establish the diagnosis of myasthenia gravis. Discrepancies between the results comparing electrophysiological and immunological tests may indicate that myasthenia gravis is a heterogenous entity within which subgroups may be identified. PMID:6249895

  5. Architect's Contract.

    ERIC Educational Resources Information Center

    Ohio State Board of Education, Columbus.

    An actual contract form used for architectural services is presented. Fees, duties, and services are included. Services are listed in the following phases--(1) schematic design, (2) design development, (3) contract document, and (4) construction. Extra services are listed, and owner's responsibility with regard to cost estimates is given.…

  6. Performance Contracting.

    ERIC Educational Resources Information Center

    Allen, Tom

    The management team at Minooka (Illinois) School District 201 is actively pursuing school improvement measures by establishing Performance Contracts to increase productivity. The format of the Performance Contract highlights yearly short-term and long-term goals, which are presented in the form of Job Improvement Targets stating the goal itself, a…

  7. Student Contracts.

    ERIC Educational Resources Information Center

    Aldridge, Hal

    1971-01-01

    Discussion of the nature of student-teacher contracts pertaining to academic work to be performed by the student and evaluated by the teacher covers a wide range of related issues in this article. The nature of contracts, evaluation procedures, instructional materials, community attitudes, and the individualization of instruction are commented on…

  8. Integrative modeling of the cardiac ventricular myocyte

    PubMed Central

    Winslow, Raimond L.; Cortassa, Sonia; O'Rourke, Brian; Hashambhoy, Yasmin L.; Rice, John Jeremy; Greenstein, Joseph L.

    2011-01-01

    Cardiac electrophysiology is a discipline with a rich 50-year history of experimental research coupled with integrative modeling which has enabled us to achieve a quantitative understanding of the relationships between molecular function and the integrated behavior of the cardiac myocyte in health and disease. In this paper, we review the development of integrative computational models of the cardiac myocyte. We begin with a historical overview of key cardiac cell models that helped shape the field. We then narrow our focus to models of the cardiac ventricular myocyte and describe these models in the context of their subcellular functional systems including dynamic models of voltage-gated ion channels, mitochondrial energy production, ATP-dependent and electrogenic membrane transporters, intracellular Ca dynamics, mechanical contraction, and regulatory signal transduction pathways. We describe key advances and limitations of the models as well as point to new directions for future modeling research. PMID:20865780

  9. Electrophysiologic follow-up in Whipple's disease.

    PubMed

    Cruz Martínez, A; González, P; Garza, E; Bescansa, E; Anciones, B

    1987-09-01

    Neurologic and electrophysiologic findings in a 57-year-old man with Whipple's disease are reported. The patient had severe proximal weakness and weight loss of more than 20 kg. Conventional electromyography and nerve conduction studies suggested mild neuropathy in distal segments of lower limbs and myopathy in proximal muscles. Automatic analysis of the electromyogram in proximal muscles was consistent with myopathy. Conduction velocity of muscle fibers in situ showed low propagation velocity of the impulse. Weakness, weight loss, and all the electrophysiologic parameters improved after treatment, including a compression of the peroneal nerve at the knee, perhaps related to weight loss (slimmer's paralysis).

  10. The emerging role of in vitro electrophysiological methods in CNS safety pharmacology.

    PubMed

    Accardi, Michael V; Pugsley, Michael K; Forster, Roy; Troncy, Eric; Huang, Hai; Authier, Simon

    2016-01-01

    Adverse CNS effects account for a sizeable proportion of all drug attrition cases. These adverse CNS effects are mediated predominately by off-target drug activity on neuronal ion-channels, receptors, transporters and enzymes - altering neuronal function and network communication. In response to these concerns, there is growing support within the pharmaceutical industry for the requirement to perform more comprehensive CNS safety testing prior to first-in-human trials. Accordingly, CNS safety pharmacology commonly integrates several in vitro assay methods for screening neuronal targets in order to properly assess therapeutic safety. One essential assay method is the in vitro electrophysiological technique - the 'gold standard' ion channel assay. The in vitro electrophysiological method is a useful technique, amenable to a variety of different tissues and cell configurations, capable of assessing minute changes in ion channel activity from the level of a single receptor to a complex neuronal network. Recent advances in automated technology have further expanded the usefulness of in vitro electrophysiological methods into the realm of high-throughput, addressing the bottleneck imposed by the manual conduct of the technique. However, despite a large range of applications, manual and automated in vitro electrophysiological techniques have had a slow penetrance into the field of safety pharmacology. Nevertheless, developments in throughput capabilities and in vivo applicability have led to a renewed interest in in vitro electrophysiological techniques that, when complimented by more traditional safety pharmacology methods, often increase the preclinical predictability of potential CNS liabilities.

  11. The Electrophysiological MEMS Device with Micro Channel Array for Cellular Network Analysis

    NASA Astrophysics Data System (ADS)

    Tonomura, Wataru; Kurashima, Toshiaki; Takayama, Yuzo; Moriguchi, Hiroyuki; Jimbo, Yasuhiko; Konishi, Satoshi

    This paper describes a new type of MCA (Micro Channel Array) for simultaneous multipoint measurement of cellular network. Presented MCA employing the measurement principles of the patch-clamp technique is designed for advanced neural network analysis which has been studied by co-authors using 64ch MEA (Micro Electrode Arrays) system. First of all, sucking and clamping of cells through channels of developed MCA is expected to improve electrophysiological signal detections. Electrophysiological sensing electrodes integrated around individual channels of MCA by using MEMS (Micro Electro Mechanical System) technologies are electrically isolated for simultaneous multipoint measurement. In this study, we tested the developed MCA using the non-cultured rat's cerebral cortical slice and the hippocampal neurons. We could measure the spontaneous action potential of the slice simultaneously at multiple points and culture the neurons on developed MCA. Herein, we describe the experimental results together with the design and fabrication of the electrophysiological MEMS device with MCA for cellular network analysis.

  12. Optic Nerve Dysfunction in Obstructive Sleep Apnea: An Electrophysiological Study

    PubMed Central

    Liguori, Claudio; Palmieri, Maria Giuseppina; Pierantozzi, Mariangela; Cesareo, Massimo; Romigi, Andrea; Izzi, Francesca; Marciani, Maria Grazia; Oliva, Corrado; Mercuri, Nicola Biagio; Placidi, Fabio

    2016-01-01

    Study Objectives: The aim of this study was to evaluate the integrity of the visual system in patients affected by obstructive sleep apnea (OSA) by means of electroretinogram (ERG) and visual evoked potential (VEP). Methods: We performed electrophysiological study of the visual system in a population of severe OSA (apnea-hypopnea events/time in bed ≥ 30/h) patients without medical comorbidities compared to a group of healthy controls similar for age, sex, and body mass index. Patients and controls did not have visual impairment or systemic disorders with known influence on the visual system. ERG and VEP were elicited by a reversal pattern generated on a television monitor at low (55') and high (15') spatial frequencies stimulation. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS) in both patients and controls. Results: In comparison with healthy controls (n = 27), patients with OSA (n = 27) showed a significant latency delay coupled with a significant amplitude reduction of P100 wave of VEP at all spatial frequencies in both eyes. No significant differences between groups were detected as concerning ERG components. No correlations were found between polygraphic parameters, ESS scores, or VEP and ERG components in OSA patients. Conclusions: This study documented that patients with OSA, without medical comorbidities, present VEP alteration as documented by lower amplitude and longer latency of the P100 component than healthy controls. These altered electrophysiological findings may be the expression of optic nerve dysfunction provoked by hypoxia, acidosis, hypercarbia and airway obstruction, frequently observed in patients with OSA. Hence, we hypothesize that OSA per se may impair optic nerve function. Citation: Liguori C, Palmieri MG, Pierantozzi M, Cesareo M, Romigi A, Izzi F, Marciani MG, Oliva C, Mercuri NB, Placidi F. Optic nerve dysfunction in obstructive sleep apnea: an electrophysiological study. SLEEP 2016;39(1):19–23. PMID

  13. Minimum Information about a Cardiac Electrophysiology Experiment (MICEE): standardised reporting for model reproducibility, interoperability, and data sharing.

    PubMed

    Quinn, T A; Granite, S; Allessie, M A; Antzelevitch, C; Bollensdorff, C; Bub, G; Burton, R A B; Cerbai, E; Chen, P S; Delmar, M; Difrancesco, D; Earm, Y E; Efimov, I R; Egger, M; Entcheva, E; Fink, M; Fischmeister, R; Franz, M R; Garny, A; Giles, W R; Hannes, T; Harding, S E; Hunter, P J; Iribe, G; Jalife, J; Johnson, C R; Kass, R S; Kodama, I; Koren, G; Lord, P; Markhasin, V S; Matsuoka, S; McCulloch, A D; Mirams, G R; Morley, G E; Nattel, S; Noble, D; Olesen, S P; Panfilov, A V; Trayanova, N A; Ravens, U; Richard, S; Rosenbaum, D S; Rudy, Y; Sachs, F; Sachse, F B; Saint, D A; Schotten, U; Solovyova, O; Taggart, P; Tung, L; Varró, A; Volders, P G; Wang, K; Weiss, J N; Wettwer, E; White, E; Wilders, R; Winslow, R L; Kohl, P

    2011-10-01

    Cardiac experimental electrophysiology is in need of a well-defined Minimum Information Standard for recording, annotating, and reporting experimental data. As a step towards establishing this, we present a draft standard, called Minimum Information about a Cardiac Electrophysiology Experiment (MICEE). The ultimate goal is to develop a useful tool for cardiac electrophysiologists which facilitates and improves dissemination of the minimum information necessary for reproduction of cardiac electrophysiology research, allowing for easier comparison and utilisation of findings by others. It is hoped that this will enhance the integration of individual results into experimental, computational, and conceptual models. In its present form, this draft is intended for assessment and development by the research community. We invite the reader to join this effort, and, if deemed productive, implement the Minimum Information about a Cardiac Electrophysiology Experiment standard in their own work.

  14. Extensional vs contractional Cenozoic deformation in Ibiza (Balearic Promontory, Spain): Integration in the West Mediterranean back-arc setting

    NASA Astrophysics Data System (ADS)

    Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Martos, Raquel; Roca, Eduard; Blanpied, Christian

    2016-07-01

    Based on field work and seismic reflection data, we investigate the Cenozoic tectono-sedimentary evolution offshore and onshore Ibiza allowing the proposal of a new tectonic agenda for the region and its integration in the geodynamic history of the West Mediterranean. The late Oligocene-early Miocene rifting event, which characterizes the Valencia Trough and the Algerian Basin, located north and south of the study area respectively, is also present in Ibiza and particularly well-expressed in the northern part of the island. Among these two rifted basins initiated in the frame of the European Cenozoic Rift System, the Valencia Trough failed rapidly while the Algerian Basin evolved after as a back-arc basin related to the subduction of the Alpine-Maghrebian Tethys. The subsequent middle Miocene compressional deformation was localized by the previous extensional faults, which were either inverted or passively translated depending on their initial orientation. Despite the lateral continuity between the External Betics and the Balearic Promontory, it appears from restored maps that this tectonic event cannot be directly related to the Betic orogen, but results from compressive stresses transmitted through the Algerian Basin. A still active back-arc asthenospheric rise likely explains the stiff behavior of this basin, which has remained poorly deformed up to recent time. During the late Miocene a new extensional episode reworked the southern part of the Balearic Promontory. It is suggested that this extensional deformation developed in a trans-tensional context related to the westward translation of the Alboran Domain and the coeval right-lateral strike-slip movement along the Emile Baudot Escarpment bounding the Algerian Basin to the north.

  15. [Fundamental ophthalmology: the role of electrophysiological studies].

    PubMed

    Zueva, M V

    2014-01-01

    Studying of functional aspects of eye disease pathogenesis by electrophysiological methods is widely demanded in fundamental ophthalmology. Introduction of modern methods of functional assessment into experimental and clinical projects significantly broadens knowledge of normal and pathological functioning of the visual system and is the basis for further development of new strategies of pathogenetic treatment, diagnostics and expert evaluation. Some problems of ophthalmology, including those that concern age-related macular degeneration, glaucoma, diabetic retinopathy, and other diseases, are considered in the context of how much electrophysiology contributes to their solution. The role of functional examinations of the retina in studying pathophysiology of neurodegenerative brain diseases, such as Alzheimer's and Parkinson's, is also discussed. PMID:25715550

  16. On the electrophysiology of aesthetic processing.

    PubMed

    Jacobsen, Thomas

    2013-01-01

    One important method that can be applied for gaining an understanding of the underpinning of aesthetics in the brain is that of electrophysiology. Cognitive electrophysiology, in particular, allows the identification of components in a mental processing architecture. The present chapter reviews findings in the neurocognitive psychology of aesthetics, or neuroaesthetics, that have been obtained with the method of event-related brain potentials, as derived from the human electroencephalogram. The cognitive-perceptual bases as well as affective substages of aesthetic processing have been investigated and those are described here. The event-related potential method allows for the identification of mental processing modes in cognitive and aesthetic processing. It also provides an assessment of the mental chronometry of cognitive and affective stages in aesthetic appreciation. As the work described here shows, distinct processes in the brain are engaged in aesthetic judgments. PMID:24041323

  17. Python for large-scale electrophysiology.

    PubMed

    Spacek, Martin; Blanche, Tim; Swindale, Nicholas

    2008-01-01

    Electrophysiology is increasingly moving towards highly parallel recording techniques which generate large data sets. We record extracellularly in vivo in cat and rat visual cortex with 54-channel silicon polytrodes, under time-locked visual stimulation, from localized neuronal populations within a cortical column. To help deal with the complexity of generating and analysing these data, we used the Python programming language to develop three software projects: one for temporally precise visual stimulus generation ("dimstim"); one for electrophysiological waveform visualization and spike sorting ("spyke"); and one for spike train and stimulus analysis ("neuropy"). All three are open source and available for download (http://swindale.ecc.ubc.ca/code). The requirements and solutions for these projects differed greatly, yet we found Python to be well suited for all three. Here we present our software as a showcase of the extensive capabilities of Python in neuroscience.

  18. Re-visiting the electrophysiology of language.

    PubMed

    Obleser, Jonas

    2015-09-01

    This editorial accompanies a special issue of Brain and Language re-visiting old themes and new leads in the electrophysiology of language. The event-related potential (ERP) as a series of characteristic deflections ("components") over time and their distribution on the scalp has been exploited by speech and language researchers over decades to find support for diverse psycholinguistic models. Fortunately, methodological and statistical advances have allowed human neuroscience to move beyond some of the limitations imposed when looking at the ERP only. Most importantly, we currently witness a refined and refreshed look at "event-related" (in the literal sense) brain activity that relates itself more closely to the actual neurobiology of speech and language processes. It is this imminent change in handling and interpreting electrophysiological data of speech and language experiments that this special issue intends to capture.

  19. The P300 as an Electrophysiological Probe of Alcohol Expectancy

    PubMed Central

    Fishman, Inna; Goldman, Mark S.; Donchin, Emanuel

    2008-01-01

    Language-based measures indicate that alcohol expectancies influence alcohol consumption. To relate these measures to brain actions that precede verbal output, the P300 component of the Event-related potentials (ERPs) was used to detect violations of individually held alcohol expectancies. As predicted, P300 amplitude elicited by negative alcohol expectancy stimuli was positively correlated with endorsement of positive/arousing alcohol expectancies on the language-based measure, such that the higher an individual's positive/arousing expectancies, the larger was the P300 elicited by negative alcohol expectancy stimuli. These results demonstrated concordance between language-based measures of alcohol expectancies and electrophysiological probes of expectancy. Although whether these expectancy processes are integral to decision pathways that influence consumption is unknown, these findings suggest that such processing can occur very quickly outside of conscious deliberation. PMID:18729689

  20. [New systems of mapping and navigation in electrophysiology].

    PubMed

    de Chillou, C; Magnin-Poull, I; Andronache, M; Abdelaal, A; Dotto, P; Beurrier, D; State, S; Massing, J L; Bineau-Jorisse, A; Thiel, B; Houriez, P; Blangy, H; Sadoul, N; Aliot, E

    2004-11-01

    The indications of radiofrequency ablation of arrhythmias have considerably increased since the introduction of the technique in the early 1990s. Interventional rhythmologists now treat arrhythmias which are more and more complex by their mechanism. This requires accurate representation of the ablation catheter position and the integration of spatial and temporal data to identify the arrhythmogenic substrate. The systems of mapping and navigation developed over the last ten years are important tools for interventional rhythmologists. They are very useful for the identification of complex arrhythmogenic substrates which require "individualised" ablations in specific cases. The aim of this article is to review different systems of mapping, and/or navigation currently on the market and their principal characteristics without entering into the details of their use in interventional electrophysiology.

  1. Electrophysiological methods for hearing assessment in pinnipeds

    NASA Astrophysics Data System (ADS)

    Reichmuth Kastak, Colleen; Kastak, David; Finneran, James J.; Houser, Dorian S.; Supin, Alexander

    2005-04-01

    Studies of auditory sensitivity in marine mammals generally rely on behavioral psychophysical methodologies. While these studies are the standard for hearing assessment in marine mammals, data are limited to only a few individuals representing a small proportion of species. Accumulating research on dolphin auditory physiology has resulted in the refinement of electrophysiological methods appropriate for odontocete cetaceans and an increase in available audiometric information. Electrophysiological methods have also been used with pinnipeds, but there are significant gaps in our understanding of pinniped auditory physiology that must be addressed before such appoaches can be broadly applied to investigations of pinniped hearing. We are taking a bottom-up approach to developing suitable methods for evoked potential audiometry in pinnipeds, including technology transfer from studies of cetaceans and other mammals, mapping of response amplitude with respect to recording positions on the skull, characterization of responses in relationship to various stimulus types and presentation parameters, and determination of whether useful frequency-specific data can be reliably obtained using electrophysiological methods. This approach is being taken with representative pinniped species including California sea lions (Zalophus californianus), harbor seals (Phoca vitulina), and northern elephant seals (Mirounga angustirostris) using both training and chemical immobilization techniques. [Work supported by NOPP.

  2. Cellular cardiac electrophysiology modeling with Chaste and CellML

    PubMed Central

    Cooper, Jonathan; Spiteri, Raymond J.; Mirams, Gary R.

    2014-01-01

    Chaste is an open-source C++ library for computational biology that has well-developed cardiac electrophysiology tissue simulation support. In this paper, we introduce the features available for performing cardiac electrophysiology action potential simulations using a wide range of models from the Physiome repository. The mathematics of the models are described in CellML, with units for all quantities. The primary idea is that the model is defined in one place (the CellML file), and all model code is auto-generated at compile or run time; it never has to be manually edited. We use ontological annotation to identify model variables describing certain biological quantities (membrane voltage, capacitance, etc.) to allow us to import any relevant CellML models into the Chaste framework in consistent units and to interact with them via consistent interfaces. This approach provides a great deal of flexibility for analysing different models of the same system. Chaste provides a wide choice of numerical methods for solving the ordinary differential equations that describe the models. Fixed-timestep explicit and implicit solvers are provided, as discussed in previous work. Here we introduce the Rush–Larsen and Generalized Rush–Larsen integration techniques, made available via symbolic manipulation of the model equations, which are automatically rearranged into the forms required by these approaches. We have also integrated the CVODE solvers, a ‘gold standard’ for stiff systems, and we have developed support for symbolic computation of the Jacobian matrix, yielding further increases in the performance and accuracy of CVODE. We discuss some of the technical details of this work and compare the performance of the available numerical methods. Finally, we discuss how this is generalized in our functional curation framework, which uses a domain-specific language for defining complex experiments as a basis for comparison of model behavior. PMID:25610400

  3. Individual Differences in Reinforcement Learning: Behavioral, Electrophysiological, and Neuroimaging Correlates

    PubMed Central

    Santesso, Diane L.; Dillon, Daniel G.; Birk, Jeffrey L.; Holmes, Avram J.; Goetz, Elena; Bogdan, Ryan; Pizzagalli, Diego A.

    2008-01-01

    During reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate cortex (dACC) and basal ganglia and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded (“rich”) stimulus (“learners”) versus subjects who did not (“non-learners”). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger basal ganglia responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and basal ganglia responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans. PMID:18595740

  4. Cellular cardiac electrophysiology modeling with Chaste and CellML.

    PubMed

    Cooper, Jonathan; Spiteri, Raymond J; Mirams, Gary R

    2014-01-01

    Chaste is an open-source C++ library for computational biology that has well-developed cardiac electrophysiology tissue simulation support. In this paper, we introduce the features available for performing cardiac electrophysiology action potential simulations using a wide range of models from the Physiome repository. The mathematics of the models are described in CellML, with units for all quantities. The primary idea is that the model is defined in one place (the CellML file), and all model code is auto-generated at compile or run time; it never has to be manually edited. We use ontological annotation to identify model variables describing certain biological quantities (membrane voltage, capacitance, etc.) to allow us to import any relevant CellML models into the Chaste framework in consistent units and to interact with them via consistent interfaces. This approach provides a great deal of flexibility for analysing different models of the same system. Chaste provides a wide choice of numerical methods for solving the ordinary differential equations that describe the models. Fixed-timestep explicit and implicit solvers are provided, as discussed in previous work. Here we introduce the Rush-Larsen and Generalized Rush-Larsen integration techniques, made available via symbolic manipulation of the model equations, which are automatically rearranged into the forms required by these approaches. We have also integrated the CVODE solvers, a 'gold standard' for stiff systems, and we have developed support for symbolic computation of the Jacobian matrix, yielding further increases in the performance and accuracy of CVODE. We discuss some of the technical details of this work and compare the performance of the available numerical methods. Finally, we discuss how this is generalized in our functional curation framework, which uses a domain-specific language for defining complex experiments as a basis for comparison of model behavior.

  5. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation.

    PubMed

    Heijman, Jordi; Erfanian Abdoust, Pegah; Voigt, Niels; Nattel, Stanley; Dobrev, Dobromir

    2016-02-01

    The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and

  6. Electrophysiologic features of fetal ventricular aneurysms and diverticula

    PubMed Central

    PETERS, CARLI; WACKER-GUSSMANN, ANNETTE; STRASBURGER, JANETTE F; CUNEO, BETTINA F; GOTTEINER, NINA; GULECYUZ, MEHEMET; WAKAI, RONALD T

    2014-01-01

    Objective Congenital ventricular wall defects are very rare and include congenital ventricular aneurysms (CVAs) and diverticula (CVDs). Method We report a series of five fetuses: three with CVAs and two with CVDs referred due to fetal arrhythmia. In addition to routine fetal echocardiography, fetal magnetocardiography (fMCG) was used. The literature in CVA and CVD is reviewed. Results Incessant premature ventricular contractions (PVC), mainly bigeminy and trigeminy were found in three fetuses with CVAs and in one with CVD, who also had ventricular couplets. The other fetus with CVD, referred because of PVCs, had only sinus tachycardia. ST elevation was noted in two. Fetal movement had a variable impact on PVC’s. Postnatal evaluation demonstrated two persistent left ventricular aneurysms and one persistent right CVD; one CVD resolved at 35 weeks gestation. Two neonates had incessant PVCs. Both arrhythmias resolved spontaneously while being treated with propranolol. Conclusion FMCG is complementary to echocardiographic imaging. In fetuses with left ventricular wall defects, additional electrophysiological diagnosis can be made by fMCG, including the complexity of ventricular ectopy, arrhythmic response to fetal movement, presence of ST-T wave abnormalities, and atrial amplitude increases. Prenatal risk factor assessment using fMCG can additionally support post-natal treatment and follow-up. PMID:25284224

  7. Contract sanctity

    SciTech Connect

    Seeley, R.S.

    1995-10-01

    Increased competition and the pressure to keep rates low is driving utilities and independent power producers alike to consider more options to keep costs down. While an important strategy for them, the results are creating some conflicts. The April 12, 1995 Federal Energy Regulatory Commission (FERC) decision against New York State Electric & Gas (NYSEG) attempt to breach contracts with two independent power producers, observers say, is one of the most important decisions on contract disputes between independents and utilities. It reveals the complex issues and compelling arguments on both sides. It opens the question of utilities` ability to pay, and the future direction of independent power. The conflicts create a problem for utilities and independents alike.

  8. Electrophysiological endophenotypes in rodent models of schizophrenia and psychosis

    PubMed Central

    Rosen, Andrew M.; Spellman, Timothy; Gordon, Joshua A.

    2015-01-01

    Schizophrenia is caused by a diverse array of risk factors, and results in a similarly diverse set of symptoms. Electrophysiological endophenotypes lie between risks and symptoms, and have the potential to link the two. Electrophysiological studies in rodent models, described here, demonstrate that widely differing risk factors result in a similar set of core electrophysiological endophenotypes, suggesting the possibility of a shared neurobiological substrate. PMID:25910423

  9. Portuguese National Registry on Cardiac Electrophysiology, 2013 and 2014.

    PubMed

    Cavaco, Diogo; Morgado, Francisco; Bonhorst, Daniel

    2016-01-01

    The authors present the results of the national registry of electrophysiology of the Portuguese Association for Arrhythmology, Pacing and Electrophysiology (APAPE) for 2013 and 2014. The registry is annual and voluntary, and data are collected retrospectively. Data for electrophysiological studies, ablations and cardioverter-defibrillator implantations for 2013 and 2014 are presented. Developments over the years and their implications are analyzed and discussed. PMID:27396627

  10. 76 FR 81807 - Operational Contract Support

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ...This part establishes policy, assigns responsibilities, and provides procedures for operational contract support (OCS), including OCS program management, contract support integration, and integration of defense contractor personnel into contingency operations outside the United States. An interim final rule is required to procedurally close gaps and ensure the correct planning, oversight and......

  11. Cell-Specific Cardiac Electrophysiology Models

    PubMed Central

    Groenendaal, Willemijn; Ortega, Francis A.; Kherlopian, Armen R.; Zygmunt, Andrew C.; Krogh-Madsen, Trine; Christini, David J.

    2015-01-01

    The traditional cardiac model-building paradigm involves constructing a composite model using data collected from many cells. Equations are derived for each relevant cellular component (e.g., ion channel, exchanger) independently. After the equations for all components are combined to form the composite model, a subset of parameters is tuned, often arbitrarily and by hand, until the model output matches a target objective, such as an action potential. Unfortunately, such models often fail to accurately simulate behavior that is dynamically dissimilar (e.g., arrhythmia) to the simple target objective to which the model was fit. In this study, we develop a new approach in which data are collected via a series of complex electrophysiology protocols from single cardiac myocytes and then used to tune model parameters via a parallel fitting method known as a genetic algorithm (GA). The dynamical complexity of the electrophysiological data, which can only be fit by an automated method such as a GA, leads to more accurately parameterized models that can simulate rich cardiac dynamics. The feasibility of the method is first validated computationally, after which it is used to develop models of isolated guinea pig ventricular myocytes that simulate the electrophysiological dynamics significantly better than does a standard guinea pig model. In addition to improving model fidelity generally, this approach can be used to generate a cell-specific model. By so doing, the approach may be useful in applications ranging from studying the implications of cell-to-cell variability to the prediction of intersubject differences in response to pharmacological treatment. PMID:25928268

  12. Multifunctional Catheters Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    PubMed Central

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Nikoozadeh, Amin; Oralkan, Omer; Khuri-Yakub, Pierre T.; Sahn, David J.

    2015-01-01

    A family of 3 multifunctional intracardiac imaging and electrophysiology (EP) mapping catheters has been in development to help guide diagnostic and therapeutic intracardiac EP procedures. The catheter tip on the first device includes a 7.5 MHz, 64-element, side-looking phased array for high resolution sector scanning. The second device is a forward-looking catheter with a 24-element 14 MHz phased array. Both of these catheters operate on a commercial imaging system with standard software. Multiple EP mapping sensors were mounted as ring electrodes near the arrays for electrocardiographic synchronization of ultrasound images and used for unique integration with EP mapping technologies. To help establish the catheters’ ability for integration with EP interventional procedures, tests were performed in vivo in a porcine animal model to demonstrate both useful intracardiac echocardiographic (ICE) visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheters also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. The companion paper of this work discusses the catheter design of the side-looking catheter with special attention to acoustic lens design. The third device in development is a 10 MHz forward-looking ring array that is to be mounted at the distal tip of a 9F catheter to permit use of the available catheter lumen for adjunctive therapy tools. PMID:18986948

  13. Electrophysiology and metabolism of caveolin-3-overexpressing mice.

    PubMed

    Schilling, Jan M; Horikawa, Yousuke T; Zemljic-Harpf, Alice E; Vincent, Kevin P; Tyan, Leonid; Yu, Judith K; McCulloch, Andrew D; Balijepalli, Ravi C; Patel, Hemal H; Roth, David M

    2016-05-01

    Caveolin-3 (Cav-3) plays a critical role in organizing signaling molecules and ion channels involved in cardiac conduction and metabolism. Mutations in Cav-3 are implicated in cardiac conduction abnormalities and myopathies. Additionally, cardiac-specific overexpression of Cav-3 (Cav-3 OE) is protective against ischemic and hypertensive injury, suggesting a potential role for Cav-3 in basal cardiac electrophysiology and metabolism involved in stress adaptation. We hypothesized that overexpression of Cav-3 may alter baseline cardiac conduction and metabolism. We examined: (1) ECG telemetry recordings at baseline and during pharmacological interventions, (2) ion channels involved in cardiac conduction with immunoblotting and computational modeling, and (3) baseline metabolism in Cav-3 OE and transgene-negative littermate control mice. Cav-3 OE mice had decreased heart rates, prolonged PR intervals, and shortened QTc intervals with no difference in activity compared to control mice. Dobutamine or propranolol did not cause significant changes between experimental groups in maximal (dobutamine) or minimal (propranolol) heart rate. Cav-3 OE mice had an overall lower chronotropic response to atropine. The expression of Kv1.4 and Kv4.3 channels, Nav1.5 channels, and connexin 43 were increased in Cav-3 OE mice. A computational model integrating the immunoblotting results indicated shortened action potential duration in Cav-3 OE mice linking the change in channel expression to the observed electrophysiology phenotype. Metabolic profiling showed no gross differences in VO2, VCO2, respiratory exchange ratio, heat generation, and feeding or drinking. In conclusion, Cav-3 OE mice have changes in ECG intervals, heart rates, and cardiac ion channel expression. These findings give novel mechanistic insights into previously reported Cav-3 dependent cardioprotection. PMID:27023865

  14. Subacute arsenic neuropathy: clinical and electrophysiological observations.

    PubMed

    Murphy, M J; Lyon, L W; Taylor, J W

    1981-10-01

    Two patients with subacute arsenic neuropathy are described and the results of serial conduction velocity determinations from the very early stages of the illness to partial recovery are reported. Sensory and motor deficits were maximal within four weeks of the estimated time of exposure. Recovery was slow, with only partial improvement of the neurological deficits two years after onset of the illness. Progressive slowing of motor conduction velocity was observed in the first three months followed by a gradual increase in velocity thereafter. The possible mechanisms underlying the temporal profile of the electrophysiological changes are considered. The need for initiating chelation therapy before the development of the neuropathy is emphasised.

  15. Electrophysiological Recording From Drosophila Labellar Taste Sensilla

    PubMed Central

    Delventhal, Rebecca; Kiely, Aidan; Carlson, John R.

    2014-01-01

    The peripheral taste response of insects can be powerfully investigated with electrophysiological techniques. The method described here allows the researcher to measure gustatory responses directly and quantitatively, reflecting the sensory input that the insect nervous system receives from taste stimuli in its environment. This protocol outlines all key steps in performing this technique. The critical steps in assembling an electrophysiology rig, such as selection of necessary equipment and a suitable environment for recording, are delineated. We also describe how to prepare for recording by making appropriate reference and recording electrodes, and tastant solutions. We describe in detail the method used for preparing the insect by insertion of a glass reference electrode into the fly in order to immobilize the proboscis. We show traces of the electrical impulses fired by taste neurons in response to a sugar and a bitter compound. Aspects of the protocol are technically challenging and we include an extensive description of some common technical challenges that may be encountered, such as lack of signal or excessive noise in the system, and potential solutions. The technique has limitations, such as the inability to deliver temporally complex stimuli, observe background firing immediately prior to stimulus delivery, or use water-insoluble taste compounds conveniently. Despite these limitations, this technique (including minor variations referenced in the protocol) is a standard, broadly accepted procedure for recording Drosophila neuronal responses to taste compounds. PMID:24638081

  16. [The electrophysiologic diagnosis for muscle ion channelopathies].

    PubMed

    Arimura, Yumiko; Nakamura, Tomonori; Yoshimura, Michiyoshi; Uehara, Akiko; Arimura, Kimiyoshi; Sakoda, Shin-Ichi; Takashima, Hiroshi

    2012-01-01

    The periodic paralysis (PP) and myotonic syndromes have been recognized as muscle ion channelopathies (MIC) consequent to the discovery of genetic abnormalities of muscle ion channels. Genetic studies are therefore indispensable in the diagnosis of MIC. However, it is not practical to examine all muscle ion channels immediately upon identification of clinical symptoms. Clinical symptoms of MIC occur due to the abnormal excitability of the muscle membrane which is in turn related to abnormal ion channel genes. Therefore, a series of electrophysiologic tests is useful in examining the characteristics of abnormal excitability and predicting the abnormal ion channel Needle EMG studies can detect myotonic discharges while the prolonged exercise test can distinguish between primary and secondary PP. For myotonia, pattern I which includes the repeated short exercise test at room temperature or at cold skin temperature is specific for paramyotonia congenita, pattern II is characteristic for myotonia congenita, and pattern III is useful for Na channel myotonia. The decrement of CMAP with 10 Hz repetitive stimulation is related to mutation type in myotonia congenita. Thus, these electrophysiological tests may be of use in screening for MIC to narrow down the diagnosis and the selection of candidates for gene analysis. PMID:23196580

  17. A Novel Long-term, Multi-Channel and Non-invasive Electrophysiology Platform for Zebrafish

    PubMed Central

    Hong, SoonGweon; Lee, Philip; Baraban, Scott C.; Lee, Luke P.

    2016-01-01

    Zebrafish are a popular vertebrate model for human neurological disorders and drug discovery. Although fecundity, breeding convenience, genetic homology and optical transparency have been key advantages, laborious and invasive procedures are required for electrophysiological studies. Using an electrode-integrated microfluidic system, here we demonstrate a novel multichannel electrophysiology unit to record multiple zebrafish. This platform allows spontaneous alignment of zebrafish and maintains, over days, close contact between head and multiple surface electrodes, enabling non-invasive long-term electroencephalographic recording. First, we demonstrate that electrographic seizure events, induced by pentylenetetrazole, can be reliably distinguished from eye or tail movement artifacts, and quantifiably identified with our unique algorithm. Second, we show long-term monitoring during epileptogenic progression in a scn1lab mutant recapitulating human Dravet syndrome. Third, we provide an example of cross-over pharmacology antiepileptic drug testing. Such promising features of this integrated microfluidic platform will greatly facilitate high-throughput drug screening and electrophysiological characterization of epileptic zebrafish. PMID:27305978

  18. Whole Heart Modeling: Applications to Cardiac Electrophysiology and Electromechanics

    PubMed Central

    Trayanova, Natalia A

    2010-01-01

    Rationale Recent developments in cardiac simulation have rendered the heart the most highly integrated example of a virtual organ. We are on the brink of a revolution in cardiac research–one in which computational modeling of proteins, cells, tissues and the organ allow to link genomic and proteomic information to the integrated organ behavior, in the quest to provide quantitative understanding of the functioning of the heart in health and disease. Objective The goal of this article is to assess the current state-of-the-art in whole-heart modeling and the plethora of its applications in cardiac research. Methods and Results General whole-heart modeling approaches are presented, and the applications of whole-heart models in cardiac electrophysiology and electromechanics research are reviewed. The article showcases the contributions that whole-heart modeling and simulation have made to our understanding of the functioning of the heart. A summary of the future developments envisioned for the field of cardiac simulation and modeling is also presented. Conclusions Biophysically-based computational modeling of the heart, applied to human heart physiology and the diagnosis and treatment of cardiac disease, has the potential to dramatically change twenty-first century cardiac research and the field of cardiology. PMID:21212393

  19. Transparent, Flexible, Low Noise Graphene Electrodes for Simultaneous Electrophysiology and Neuroimaging

    PubMed Central

    Kuzum, Duygu; Takano, Hajime; Shim, Euijae; Reed, Jason C; Juul, Halvor; Richardson, Andrew G.; de Vries, Julius; Bink, Hank; Dichter, Marc A.; Lucas, Timothy H.; Coulter, Douglas A.; Cubukcu, Ertugrul; Litt, Brian

    2014-01-01

    Calcium imaging is a versatile experimental approach capable of resolving single neurons with single-cell spatial resolution in the brain. Electrophysiological recordings provide high temporal, but limited spatial resolution, due to the geometrical inaccessibility of the brain. An approach that integrates the advantages of both techniques could provide new insights into functions of neural circuits. Here, we report a transparent, flexible neural electrode technology based on graphene, which enables simultaneous optical imaging and electrophysiological recording. We demonstrate that hippocampal slices can be imaged through transparent graphene electrodes by both confocal and two-photon microscopy without causing any light-induced artifacts in the electrical recordings. Graphene electrodes record high frequency bursting activity and slow synaptic potentials that are hard to resolve by multi-cellular calcium imaging. This transparent electrode technology may pave the way for high spatio-temporal resolution electrooptic mapping of the dynamic neuronal activity. PMID:25327632

  20. Integrating electrophysiological data into an image-guided surgery system

    NASA Astrophysics Data System (ADS)

    Davey, Bruce L. K.; MacDonald, David; Gotman, J.; Peters, Terence M.

    1996-04-01

    Image-guided neurosurgery (IGNS), in which anatomical images generated from patient MRI or CT scans provide surgical guidance, is now routinely employed in numerous institutions. However, IGNS systems generally lack the ability to display functional data, a significant shortcoming for many types of procedures. We have enhanced the IGNS system used at our institution (the ISG viewing wand) allowing the surgeon to display and interact with patient electroencephalography (EEG) data in the operating room. The surgeon can: determine 3D electrode locations; display electrode locations with respect to the underlying 3D patient anatomy obtained from MRI; visualize the EEG potential field map interpolated onto the scalp; graphically analyze the time evolution of these maps; and view the location of equivalent sources within the patient cerebral structures. Display of EEG information is clinically significant in cases involving the surgical treatment of epilepsy, where EEG data plays an important role in characterizing and localizing epileptic foci, both preoperatively and during the operation.

  1. Audiovisual integration for speech during mid-childhood: Electrophysiological evidence

    PubMed Central

    Kaganovich, Natalya; Schumaker, Jennifer

    2014-01-01

    Previous studies have demonstrated that the presence of visual speech cues reduces the amplitude and latency of the N1 and P2 event-related potential (ERP) components elicited by speech stimuli. However, the developmental trajectory of this effect is not yet fully mapped. We examined ERP responses to auditory, visual, and audiovisual speech in two groups of school-age children (7–8-year-olds and 10–11-year-olds) and in adults. Audiovisual speech led to the attenuation of the N1 and P2 components in all groups of participants, suggesting that the neural mechanisms underlying these effects are functional by early school years. Additionally, while the reduction in N1 was largest over the right scalp, the P2 attenuation was largest over the left and midline scalp. The difference in the hemispheric distribution of the N1 and P2 attenuation supports the idea that these components index at least somewhat disparate neural processes within the context of audiovisual speech perception. PMID:25463815

  2. Audiovisual integration for speech during mid-childhood: electrophysiological evidence.

    PubMed

    Kaganovich, Natalya; Schumaker, Jennifer

    2014-12-01

    Previous studies have demonstrated that the presence of visual speech cues reduces the amplitude and latency of the N1 and P2 event-related potential (ERP) components elicited by speech stimuli. However, the developmental trajectory of this effect is not yet fully mapped. We examined ERP responses to auditory, visual, and audiovisual speech in two groups of school-age children (7-8-year-olds and 10-11-year-olds) and in adults. Audiovisual speech led to the attenuation of the N1 and P2 components in all groups of participants, suggesting that the neural mechanisms underlying these effects are functional by early school years. Additionally, while the reduction in N1 was largest over the right scalp, the P2 attenuation was largest over the left and midline scalp. The difference in the hemispheric distribution of the N1 and P2 attenuation supports the idea that these components index at least somewhat disparate neural processes within the context of audiovisual speech perception.

  3. Clinically and electrophysiologically diagnosed botulinum intoxication.

    PubMed

    Kotan, Dilcan; Aygul, Recep; Ceylan, Mustafa; Yilikoglu, Yalcin

    2013-01-03

    In this case report, clinical and electrophysiological findings of 43-year-old female patient who developed Clostridium botulinum intoxication after consumption of home-made canned food are presented. Following the sudden onset of severe nausea and vomiting, diplopia, blurred vision, bilateral ptosis, weakness, speech and swallowing difficulties have developed and the patient declared that she has just tasted the canned beans after she had rinsed them several times. The case, where serological tests cannot be performed, was diagnosed clinically and treated with antitoxin immediately. During follow-up, consecutive nerve stimulation was performed and significant incremental response was observed. There was an improvement in symptoms within 2 weeks, and in 5 or 6 weeks the symptoms had disappeared completely. Electrodiagnostic studies revealed that the findings turned to normal. The case showed that immediate antitoxin treatment is life-saving even the diagnosis of botulinum intoxication is based on clinical findings.

  4. Rheumatoid neuropathy: a histological and electrophysiological study

    PubMed Central

    Weller, R. O.; Bruckner, F. E.; Chamberlain, M. Anne

    1970-01-01

    Peripheral nerves in five patients with rheumatoid neuropathy were examined electrophysiologically and by sural nerve biopsy. There was close correlation between the clinical severity of the disease and the degree of nerve damage found histologically and by EMG. Group 1 patients with a mild distal sensory neuropathy showed varying degrees of axonal degeneration in the large myelinated fibres and some segmental demyelination. Group 2 patients with a severe, rapidly progressive sensori-motor neuropathy had extensive loss of myelinated fibres. In one case all the large fibres had degenerated. The second case had lost both large and small myelinated fibres together with many of the non-myelinated axons. The major nerve damage in both groups appeared to be axonal degeneration but some segmental demyelination was detected. Occlusive vascular disease in the vasa nervorum was considered to be the major cause of the nerve damage. Images PMID:4320255

  5. Lyme carditis. Electrophysiologic and histopathologic study

    SciTech Connect

    Reznick, J.W.; Braunstein, D.B.; Walsh, R.L.; Smith, C.R.; Wolfson, P.M.; Gierke, L.W.; Gorelkin, L.; Chandler, F.W.

    1986-11-01

    To further define the nature of Lyme carditis, electrophysiologic study and endomyocardial biopsy were performed in a patient with Lyme disease, whose principal cardiac manifestation was high-degree atrioventricular block. Intracardiac recording demonstrated supra-Hisian block and complete absence of an escape mechanism. Gallium 67 scanning demonstrated myocardial uptake, and right ventricular endomyocardial biopsy revealed active lymphocytic myocarditis. A structure compatible with a spirochetal organism was demonstrated in one biopsy specimen. It is concluded that Lyme disease can produce active myocarditis, as suggested by gallium 67 imaging and confirmed by endomyocardial biopsy. Furthermore, the presence of high-grade atrioventricular block in this disease requires aggressive management with temporary pacemaker and corticosteroid therapy.

  6. Contracting and Higher Education.

    ERIC Educational Resources Information Center

    Ferris, James M.

    1991-01-01

    The potential gains in efficiency of three types of contracts in college administration are contrasted. Contract types include explicit contracts in the budgeting process between the state and higher education institutions; institutional contracting for inputs; and interinstitutional contracting. The tradeoff between production cost savings and…

  7. The Acoustic Lens Design and in Vivo Use of a Multifunctional Catheter Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    PubMed Central

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Sahn, David

    2009-01-01

    A multifunctional 9F intracardiac imaging and electrophysiology mapping catheter was developed and tested to help guide diagnostic and therapeutic intracardiac electrophysiology (EP) procedures. The catheter tip includes a 7.25-MHz, 64-element, side-looking phased array for high resolution sector scanning. Multiple electrophysiology mapping sensors were mounted as ring electrodes near the array for electrocardiographic synchronization of ultrasound images. The catheter array elevation beam performance in particular was investigated. An acoustic lens for the distal tip array designed with a round cross section can produce an acceptable elevation beam shape; however, the velocity of sound in the lens material should be approximately 155 m/s slower than in tissue for the best beam shape and wide bandwidth performance. To help establish the catheter’s unique ability for integration with electrophysiology interventional procedures, it was used in vivo in a porcine animal model, and demonstrated both useful intracardiac echocardiographic visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheter also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. PMID:18407850

  8. A low-cost, multiplexed electrophysiology system for chronic μECoG recordings in rodents.

    PubMed

    Wang, JuiChih; Trumpis, Michael; Insanally, Michele; Froemke, Robert; Viventi, Jonathan

    2014-01-01

    Micro-Electrocorticography (μECoG) offers a minimally invasive, high resolution interface with large areas of cortex. However, large arrays of electrodes with many contacts that are individually wired to external recording systems are cumbersome and make chronic recording in freely behaving small animals challenging. Multiplexed headstages overcome this limitation by combining the signals from many electrodes to a smaller number of connections directly on the animal's head. Commercially available multiplexed headstages provide high performance integrated amplification, multiplexing and analog to digital conversion. However, the cost of these systems can be prohibitive for small labs or for experiments that require a large number of animals to be continuously recorded at the same time. Here we have developed a multiplexed 60-channel headstage amplifier optimized to chronically record electrophysiological signals from high-density μECoG electrode arrays. A single, ultraflexible (2 mm thickness) microHDMI cable provided the data interface. Using low cost components, we have reduced the cost of the multiplexed headstage to ~$125. Paired with a custom interface printed circuit board (PCB) and a general purpose data acquisition system (M-series DAQ, National Instruments), an inexpensive and customizable electrophysiology system is assembled. Open source LabVIEW software that we have previously released controlled the system. It can also be used with other open source neural data acquisition packages. Combined, we have presented a scalable, low-cost platform for high-channel count electrophysiology.

  9. Rabbit-Specific Ventricular Model of Cardiac Electrophysiological Function including Specialized Conduction System

    PubMed Central

    Bordas, R.; Gillow, K.; Lou, Q.; Efimov, I. R.; Gavaghan, D.; Kohl, P.; Grau, V.; Rodriguez, B.

    2011-01-01

    The function of the ventricular specialized conduction system in the heart is to ensure the coordinated electrical activation of the ventricles. It is therefore critical to the overall function of the heart, and has also been implicated as an important player in various diseases, including lethal ventricular arrhythmias such as ventricular fibrillation and drug-induced torsades de pointes. However, current ventricular models of electrophysiology usually ignore, or include highly simplified representations of the specialized conduction system. Here, we describe the development of a image-based, species-consistent, anatomically-detailed model of rabbit ventricular electrophysiology that incorporates a detailed description of the free-running part of the specialized conduction system. Techniques used for the construction of the geometrical model of the specialized conduction system from a magnetic resonance dataset and integration of the system model into a ventricular anatomical model, developed from the same dataset, are described. Computer simulations of rabbit ventricular electrophysiology are conducted using the novel anatomical model and rabbit-specific membrane kinetics to investigate the importance of the components and properties of the conduction system in determining ventricular function under physiological conditions. Simulation results are compared to panoramic optical mapping experiments for model validation and results interpretation. Full access is provided to the anatomical models developed in this study. PMID:21672547

  10. Direct-growth carbon nanotubes on 3D structural microelectrodes for electrophysiological recording.

    PubMed

    Pan, Alice Ian; Lin, Min-Hsuan; Chung, Hui-Wen; Chen, Hsin; Yeh, Shih-Rung; Chuang, Yung-Jen; Chang, Yen-Chung; Yew, Tri-Rung

    2016-01-01

    A novel 3D carbon nanotube (CNT) microelectrode was developed through direct growth of CNTs on a gold pin-shaped 3D microelectrode at a low temperature (400 °C) for applications in neural and cardiac recording. With an electroplated Ni catalyst layer covering the entire surface of the pin-shaped structure, CNTs were synthesized on a 3D microelectrode by catalytic thermal chemical vapor deposition (CVD). According to the analyses by electrochemical impedance spectroscopy, the impedance of 3D microelectrodes after CNT growth and UV/O3 treatment decreased from 9.3 Ω mm(-2) to 1.2 Ω mm(-2) and the capacitance increased largely from 2.2 mF cm(-2) to 73.3 mF cm(-2). The existence of UVO3-treated CNT led to a large improvement of interfacial capacitance, contributing to the decrease of impedance. The electrophysiological detection capability of this 3D CNT microelectrode was demonstrated by the distinguished P waves, QRS complex and T waves in the electrocardiogram of the zebrafish heart and the action potential recorded from individual rat hippocampal neurons. The compatibility of integration with ICs, high resolution in space, electrophysiological signals, and non-invasive long-term recording suggest that the 3D CNT microelectrode exhibits promising potential for applications in electrophysiological research and clinical trials.

  11. Effects of transcranial direct current stimulation (tDCS) on behaviour and electrophysiology of language production.

    PubMed

    Wirth, Miranka; Rahman, Rasha Abdel; Kuenecke, Janina; Koenig, Thomas; Horn, Helge; Sommer, Werner; Dierks, Thomas

    2011-12-01

    Excitatory anodal transcranial direct current stimulation (A-tDCS) over the left dorsal prefrontal cortex (DPFC) has been shown to improve language production. The present study examined neurophysiological underpinnings of this effect. In a single-blinded within-subject design, we traced effects of A-tDCS compared to sham stimulation over the left DPFC using electrophysiological and behavioural correlates during overt picture naming. Online effects were examined during A-tDCS by employing the semantic interference (SI-)Effect - a marker that denotes the functional integrity of the language system. The behavioural SI-Effect was found to be reduced, whereas the electrophysiological SI-Effect was enhanced over left compared to right temporal scalp-electrode sites. This modulation is suggested to reflect a superior tuning of neural responses within language-related generators. After -(offline) effects of A-tDCS were detected in the delta frequency band, a marker of neural inhibition. After A-tDCS there was a reduction in delta activity during picture naming and the resting state, interpreted to indicate neural disinhibition. Together, these findings demonstrate electrophysiological modulations induced by A-tDCS of the left DPFC. They suggest that A-tDCS is capable of enhancing neural processes during and after application. The present functional and oscillatory neural markers could detect positive effects of prefrontal A-tDCS, which could be of use in the neuro-rehabilitation of frontal language functions.

  12. The virtual intestine: in silico modeling of small intestinal electrophysiology and motility and the applications.

    PubMed

    Du, Peng; Paskaranandavadivel, Niranchan; Angeli, Timothy R; Cheng, Leo K; O'Grady, Gregory

    2016-01-01

    The intestine comprises a long hollow muscular tube organized in anatomically and functionally discrete compartments, which digest and absorb nutrients and water from ingested food. The intestine also plays key roles in the elimination of waste and protection from infection. Critical to all of these functions is the intricate, highly coordinated motion of the intestinal tract, known as motility, which is coregulated by hormonal, neural, electrophysiological and other factors. The Virtual Intestine encapsulates a series of mathematical models of intestinal function in health and disease, with a current focus on motility, and particularly electrophysiology. The Virtual Intestine is being cohesively established across multiple physiological scales, from sub/cellular functions to whole organ levels, facilitating quantitative evaluations that present an integrative in silico framework. The models are also now finding broad physiological applications, including in evaluating hypotheses of slow wave pacemaker mechanisms, smooth muscle electrophysiology, structure-function relationships, and electromechanical coupling. Clinical applications are also beginning to follow, including in the pathophysiology of motility disorders, diagnosing intestinal ischemia, and visualizing colonic dysfunction. These advances illustrate the emerging potential of the Virtual Intestine to effectively address multiscale research challenges in interdisciplinary gastrointestinal sciences.

  13. Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data.

    PubMed

    Brinkmann, Benjamin H; Bower, Mark R; Stengel, Keith A; Worrell, Gregory A; Stead, Matt

    2009-05-30

    The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single-neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single-neuron action potentials, high frequency oscillations, and high amplitude ultra-slow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range-encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information.

  14. Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data.

    PubMed

    Brinkmann, Benjamin H; Bower, Mark R; Stengel, Keith A; Worrell, Gregory A; Stead, Matt

    2009-05-30

    The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single-neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single-neuron action potentials, high frequency oscillations, and high amplitude ultra-slow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range-encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information. PMID:19427545

  15. Large-scale Electrophysiology: Acquisition, Compression, Encryption, and Storage of Big Data

    PubMed Central

    Brinkmann, Benjamin H.; Bower, Mark R.; Stengel, Keith A.; Worrell, Gregory A.; Stead, Matt

    2009-01-01

    The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32 kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single neuron action potentials, high frequency oscillations, and high amplitude ultraslow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information. PMID:19427545

  16. Direct-growth carbon nanotubes on 3D structural microelectrodes for electrophysiological recording.

    PubMed

    Pan, Alice Ian; Lin, Min-Hsuan; Chung, Hui-Wen; Chen, Hsin; Yeh, Shih-Rung; Chuang, Yung-Jen; Chang, Yen-Chung; Yew, Tri-Rung

    2016-01-01

    A novel 3D carbon nanotube (CNT) microelectrode was developed through direct growth of CNTs on a gold pin-shaped 3D microelectrode at a low temperature (400 °C) for applications in neural and cardiac recording. With an electroplated Ni catalyst layer covering the entire surface of the pin-shaped structure, CNTs were synthesized on a 3D microelectrode by catalytic thermal chemical vapor deposition (CVD). According to the analyses by electrochemical impedance spectroscopy, the impedance of 3D microelectrodes after CNT growth and UV/O3 treatment decreased from 9.3 Ω mm(-2) to 1.2 Ω mm(-2) and the capacitance increased largely from 2.2 mF cm(-2) to 73.3 mF cm(-2). The existence of UVO3-treated CNT led to a large improvement of interfacial capacitance, contributing to the decrease of impedance. The electrophysiological detection capability of this 3D CNT microelectrode was demonstrated by the distinguished P waves, QRS complex and T waves in the electrocardiogram of the zebrafish heart and the action potential recorded from individual rat hippocampal neurons. The compatibility of integration with ICs, high resolution in space, electrophysiological signals, and non-invasive long-term recording suggest that the 3D CNT microelectrode exhibits promising potential for applications in electrophysiological research and clinical trials. PMID:26588673

  17. Contracts in radiology practices: contract types and key provisions.

    PubMed

    Muroff, Julie A; Muroff, Lawrence R

    2004-07-01

    A contract between a radiology group and its physician member(s) provides the foundation for the professional relationships in a group practice. The parties are not in positions of parity; contract provisions are structured to maintain the primacy of the group over the individual members. An integration clause should be included to preclude reliance on communications that are not memorialized by the language of the contract. Precise, unambiguous terms must be used to convey the intentions of the parties. The contract should have a clear date of initiation and, if applicable, an effective date of termination. Mechanisms for termination and modification should be expressed clearly to minimize the risk of judicial interference. The method of determining and adjusting the salary and other benefits of the radiologist should be stated, as consideration is necessary to support the existence of a legal contract. The obligations of the radiologist to the practice are often stated in general terms to maximize the group's flexibility. Finally, other key clauses that are discussed in the paper should be incorporated into the contract.

  18. Steady State Responses: Electrophysiological Assessment of Sensory Function in Schizophrenia

    PubMed Central

    Brenner, Colleen A.; Krishnan, Giri P.; Vohs, Jenifer L.; Ahn, Woo-Young; Hetrick, William P.; Morzorati, Sandra L.; O'Donnell, Brian F.

    2009-01-01

    Persons with schizophrenia experience subjective sensory anomalies and objective deficits on assessment of sensory function. Such deficits could be produced by abnormal signaling in the sensory pathways and sensory cortex or later stage disturbances in cognitive processing of such inputs. Steady state responses (SSRs) provide a noninvasive method to test the integrity of sensory pathways and oscillatory responses in schizophrenia with minimal task demands. SSRs are electrophysiological responses entrained to the frequency and phase of a periodic stimulus. Patients with schizophrenia exhibit pronounced auditory SSR deficits within the gamma frequency range (35–50 Hz) in response to click trains and amplitude-modulated tones. Visual SSR deficits are also observed, most prominently in the alpha and beta frequency ranges (7–30 Hz) in response to high-contrast, high-luminance stimuli. Visual SSR studies that have used the psychophysical properties of a stimulus to target specific visual pathways predominantly report magnocellular-based deficits in those with schizophrenia. Disruption of both auditory and visual SSRs in schizophrenia are consistent with neuropathological and magnetic resonance imaging evidence of anatomic abnormalities affecting the auditory and visual cortices. Computational models suggest that auditory SSR abnormalities at gamma frequencies could be secondary to γ-aminobutyric acid–mediated or N-methyl-D-aspartic acid dysregulation. The pathophysiological process in schizophrenia encompasses sensory processing that probably contributes to alterations in subsequent encoding and cognitive processing. The developmental evolution of these abnormalities remains to be characterized. PMID:19726534

  19. Electrophysiological differentiation of new neurons in the olfactory bulb.

    PubMed

    Belluzzi, Ottorino; Benedusi, Mascia; Ackman, James; LoTurco, Joseph J

    2003-11-12

    The subventricular zone produces neuroblasts that migrate to the olfactory bulb (OB) and differentiate into interneurons throughout postnatal life (Altman and Das, 1966; Hinds, 1968; Altman, 1969; Kishi et al., 1990; Luskin, 1993; Lois and Alvarez-Buylla, 1994). Although such postnatally generated interneurons have been characterized morphologically, their physiological differentiation has not been thoroughly described. Combining retroviral-mediated labeling of newly generated neurons with patch-clamp electrophysiology, we demonstrated that soon after new cells enter the layers of the olfactory bulb, they display voltage-dependent currents typical of more mature neurons. We also show that these "newcomers" express functional GABA and glutamate receptor channels, respond synaptically to stimulation of the olfactory nerve, and may establish both axodendritic and dendrodendritic synaptic contacts within the olfactory bulb. These data provide a basic description of the physiology of newly generated cells in the OB and show that such new cells are functional neurons that synaptically integrate into olfactory bulb circuitry soon after their arrival.

  20. A Motivation Contract Model of Employee Appraisal.

    ERIC Educational Resources Information Center

    Glenn, Robert B.

    The purpose of this paper is to develop a process model for identification and assessment of employee job performance, through motivation contracting. The model integrated various components of expectancy theories of motivation and performance contracting and is based on humanistic assumptions about the nature of people. More specifically, the…

  1. Electrophysiological effects of semantic context in picture and word naming.

    PubMed

    Janssen, Niels; Carreiras, Manuel; Barber, Horacio A

    2011-08-01

    Recent language production studies have started to use electrophysiological measures to investigate the time course of word selection processes. An important contribution with respect to this issue comes from studies that have relied on an effect of semantic context in the semantic blocking task. Here we used this task to further establish the empirical pattern associated with the effect of semantic context, and whether the effect arises during output processing. Electrophysiological and reaction time measures were co-registered while participants overtly named picture and word stimuli in the semantic blocking task. The results revealed inhibitory reaction time effects of semantic context for both words and pictures, and a corresponding electrophysiological effect that could not be interpreted in terms of output processes. These data suggest that the electrophysiological effect of semantic context in the semantic blocking task does not reflect output processes, and therefore undermine an interpretation of this effect in terms of word selection.

  2. Multiscale Electrophysiology Format: An Open Open-source Electrophysiology Format Using Data Compression, Encryption, and Cyclic Redundancy Check

    PubMed Central

    Brinkmann, Benjamin H.; Bower, Mark R.; Stengel, Keith A.; Worrell, Gregory A.; Stead, Matt

    2010-01-01

    Continuous, long-term (up to 10 days) electrophysiological monitoring using hybrid intracranial electrodes is an emerging tool for presurgical epilepsy evaluation and fundamental investigations of seizure generation. Detection of high-frequency oscillations and microseizures could provide valuable insights into causes and therapies for the treatment of epilepsy, but requires high spatial and temporal resolution. Our group is currently using hybrid arrays composed of up to 320 micro- and clinical macroelectrode arrays sampled at 32 kHz per channel with 18-bits of A/D resolution. Such recordings produce approximately 3 terabytes of data per day. Existing file formats have limited data compression capabilities, and do not offer mechanisms for protecting patient identifying information or detecting data corruption during transmission or storage. We present a novel file format that employs range encoding to provide a high degree of data compression, a three-tiered 128-bit encryption system for patient information and data security, and a 32-bit cyclic redundancy check to verify the integrity of compressed data blocks. Open-source software to read, write, and process these files are provided. PMID:19963940

  3. Multiscale electrophysiology format: an open-source electrophysiology format using data compression, encryption, and cyclic redundancy check.

    PubMed

    Brinkmann, Benjamin H; Bower, Mark R; Stengel, Keith A; Worrell, Gregory A; Stead, Matt

    2009-01-01

    Continuous, long-term (up to 10 days) electrophysiological monitoring using hybrid intracranial electrodes is an emerging tool for presurgical epilepsy evaluation and fundamental investigations of seizure generation. Detection of high-frequency oscillations and microseizures could provide valuable insights into causes and therapies for the treatment of epilepsy, but requires high spatial and temporal resolution. Our group is currently using hybrid arrays composed of up to 320 micro- and clinical macroelectrode arrays sampled at 32 kHz per channel with 18-bits of A/D resolution. Such recordings produce approximately 3 terabytes of data per day. Existing file formats have limited data compression capabilities, and do not offer mechanisms for protecting patient identifying information or detecting data corruption during transmission or storage. We present a novel file format that employs range encoding to provide a high degree of data compression, a three-tiered 128-bit encryption system for patient information and data security, and a 32-bit cyclic redundancy check to verify the integrity of compressed data blocks. Open-source software to read, write, and process these files are provided.

  4. Essentials of photometry for clinical electrophysiology of vision.

    PubMed

    McCulloch, Daphne L; Hamilton, Ruth

    2010-08-01

    Electrophysiological testing of the visual system requires familiarity with photometry. This technical note outlines the concepts of photometry with a focus on information relevant to clinical ERG and VEP testing. Topics include photometric quantities, consideration of pupil size, specification of brief extended flash stimuli, and the influence of the spectral composition of visual stimuli. Standard units and terms are explained in the context of the ISCEV standards and guidelines for clinical electrophysiology of vision.

  5. [On the first studies of electrophysiology].

    PubMed

    de Micheli, Alfredo

    2011-01-01

    A historical outline of the evolution of electrophysiology from the eighteenth century is shortly presented. Topics concerning the so called animal electricity starting from the observations on descharges of Torpedo fish until Bolognese Galvani's researches on the frogs are exposed. The points of view of their oppositionists also are examined. These ones, leaded by the physicist Alessandro Volta, professor in the University of Pavia, believed that electricity detected by galvanists was not inherent to animal but was due to the action of the metallic conductors present in the circuit: contact electricity. Only towards the middle of the nineteenth century the physicist Carlo Matteucci attained to demonstrate the existente of the real animal electricity in form of injury current. It was possible to determine that quantitatively thanks to the capillary electrometer built in 1872 by the French physicist Gabriel Lippmann. This instrument was used by the English physiologist Waller in order to obtain the primitive electrocardiographic tracings in humans (1887). At beginnings of the twentieth century, the Dutch professor Willem Einthoven, of the University of Leiden, introduced his string galvanometer which permitted to allow the modern electrocardiography. So it was possible to record the electrical potentials of myocardial cells, first in vitro, later in isolated and perfused heart, son after in dog's heart in situ and finally in human heart. Therefore now it is possible to effectuate endocardial and epicardial mappings, indispensable in order to diagnose and treat the cardiac arrhythmias.

  6. Electrophysiology of pumpkin seeds: Memristors in vivo.

    PubMed

    Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Greeman, Esther A; Markin, Vladislav S

    2016-01-01

    Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds.

  7. [Electrophysiological bases of semantic processing of objects].

    PubMed

    Kahlaoui, Karima; Baccino, Thierry; Joanette, Yves; Magnié, Marie-Noële

    2007-02-01

    How pictures and words are stored and processed in the human brain constitute a long-standing question in cognitive psychology. Behavioral studies have yielded a large amount of data addressing this issue. Generally speaking, these data show that there are some interactions between the semantic processing of pictures and words. However, behavioral methods can provide only limited insight into certain findings. Fortunately, Event-Related Potential (ERP) provides on-line cues about the temporal nature of cognitive processes and contributes to the exploration of their neural substrates. ERPs have been used in order to better understand semantic processing of words and pictures. The main objective of this article is to offer an overview of the electrophysiologic bases of semantic processing of words and pictures. Studies presented in this article showed that the processing of words is associated with an N 400 component, whereas pictures elicited both N 300 and N 400 components. Topographical analysis of the N 400 distribution over the scalp is compatible with the idea that both image-mediated concrete words and pictures access an amodal semantic system. However, given the distinctive N 300 patterns, observed only during picture processing, it appears that picture and word processing rely upon distinct neuronal networks, even if they end up activating more or less similar semantic representations. PMID:17291430

  8. The Electrophysiology of Basic Phrase Building

    PubMed Central

    Lapinskaya, Natalia; Heffner, Christopher C.; Malko, Anton; Lau, Ellen F.

    2016-01-01

    A defining trait of linguistic competence is the ability to combine elements into increasingly complex structures to denote, and to comprehend, a potentially infinite number of meanings. Recent magnetoencephalography (MEG) work has investigated these processes by comparing the response to nouns in combinatorial (blue car) and non-combinatorial (rnsh car) contexts. In the current study we extended this paradigm using electroencephalography (EEG) to dissociate the role of semantic content from phonological well-formedness (yerl car). We used event-related potential (ERP) recordings in order to better relate the observed neurophysiological correlates of basic combinatorial operations to prior ERP work on comprehension. We found that nouns in combinatorial contexts (blue car) elicited a greater centro-parietal negativity between 180-400ms, independent of the phonological well-formedness of the context word. We discuss the potential relationship between this ‘combinatorial’ effect and classic N400 effects. We also report preliminary evidence for an early anterior negative deflection immediately preceding the critical noun in combinatorial contexts, which we tentatively interpret as an electrophysiological reflex of syntactic structure initialization. PMID:27711111

  9. Electrophysiology of pumpkin seeds: Memristors in vivo

    PubMed Central

    Volkov, Alexander G.; Nyasani, Eunice K.; Tuckett, Clayton; Greeman, Esther A.; Markin, Vladislav S.

    2016-01-01

    ABSTRACT Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K+ channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds. PMID:26926652

  10. Electrophysiology of pumpkin seeds: Memristors in vivo.

    PubMed

    Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Greeman, Esther A; Markin, Vladislav S

    2016-01-01

    Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds. PMID:26926652

  11. [On the first studies of electrophysiology].

    PubMed

    de Micheli, Alfredo

    2011-01-01

    A historical outline of the evolution of electrophysiology from the eighteenth century is shortly presented. Topics concerning the so called animal electricity starting from the observations on descharges of Torpedo fish until Bolognese Galvani's researches on the frogs are exposed. The points of view of their oppositionists also are examined. These ones, leaded by the physicist Alessandro Volta, professor in the University of Pavia, believed that electricity detected by galvanists was not inherent to animal but was due to the action of the metallic conductors present in the circuit: contact electricity. Only towards the middle of the nineteenth century the physicist Carlo Matteucci attained to demonstrate the existente of the real animal electricity in form of injury current. It was possible to determine that quantitatively thanks to the capillary electrometer built in 1872 by the French physicist Gabriel Lippmann. This instrument was used by the English physiologist Waller in order to obtain the primitive electrocardiographic tracings in humans (1887). At beginnings of the twentieth century, the Dutch professor Willem Einthoven, of the University of Leiden, introduced his string galvanometer which permitted to allow the modern electrocardiography. So it was possible to record the electrical potentials of myocardial cells, first in vitro, later in isolated and perfused heart, son after in dog's heart in situ and finally in human heart. Therefore now it is possible to effectuate endocardial and epicardial mappings, indispensable in order to diagnose and treat the cardiac arrhythmias. PMID:22188891

  12. Organic transistors for electrophysiology (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Rivnay, Jonathan

    2015-10-01

    Efficient local transduction of biological signals is of critical importance for mapping brain activity and diagnosing pathological conditions. Traditional devices used to record electrophysiological signals are passive electrodes that require (pre)amplification with downstream electronics. Organic electrochemical transistors (OECTs) that utilize conducting polymer films as the channel have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance (>3 mS). The materials properties and physics of such transistors, however, remains largely unexplored thus limiting their potential. Here we show that the uptake of ionic charge from an electrolyte into a poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) OECT channel leads to a dependence of the effective capacitance on the entire volume of the film. Subsequently, device transconductance and time response vary with channel thickness, a defining characteristic that differentiates OECTs from field effect transistors, and provides a new degree of freedom for device engineering. Using this understanding we tailor OECTs for a variety of low (1-100 Hz) and high (1-10 kHz) frequency applications, including human electroencephalography, where high transconductance devices impart richer signal content without the need for additional amplification circuitry. We also show that the materials figure of merit OECTs is the product of hole mobility and volumetric capacitance of the channel, leading to design rules for novel high performance materials.

  13. Autism--genetics, electrophysiology and clinical syndromes.

    PubMed

    Pop-Jordanova, Nada; Plasevska-Karanfilska, Dijana

    2014-01-01

    Autism is a severe and the most heritable developmental disorder, whose pathogenesis is still largely unknown. The rising incidence of autism in the last decade has increased the scientific interest and research. More than a thousand papers concerned with information about the etiology of this "static disorder of the immature brain" can be found on Pub Med. The aim of this paper is to give a review of published genetic chromosomal anomalies associated with autistic spectrum disorders, as well as to discuss common syndromes associated with autistic traits. In addition, some of our own findings in genetics, as well as in quantitative electroencephalography and neurofeedback training in autistic children, will be presented and discussed. Generally, the subsequent analyses indicate that the causes of autism include fewer common single-gene mutations and chromosomal abnormalities, as well as multiple interacting genes of weak effect. Genome-wide linkage analysis has identified several susceptibility loci and positional and functional candidate genes which appear to represent possible risks of the autistic spectrum. Electrophysiological findings showed high delta/theta activity in frontal-central regions, while in 25% high beta activity was detected as a result of anxiety. Neurofeedback is a promising therapy for symptom mitigation.

  14. Bayesian Quantitative Electrophysiology and Its Multiple Applications in Bioengineering

    PubMed Central

    Barr, Roger C.; Nolte, Loren W.; Pollard, Andrew E.

    2014-01-01

    Bayesian interpretation of observations began in the early 1700s, and scientific electrophysiology began in the late 1700s. For two centuries these two fields developed mostly separately. In part that was because quantitative Bayesian interpretation, in principle a powerful method of relating measurements to their underlying sources, often required too many steps to be feasible with hand calculation in real applications. As computer power became widespread in the later 1900s, Bayesian models and interpretation moved rapidly but unevenly from the domain of mathematical statistics into applications. Use of Bayesian models now is growing rapidly in electrophysiology. Bayesian models are well suited to the electrophysiological environment, allowing a direct and natural way to express what is known (and unknown) and to evaluate which one of many alternatives is most likely the source of the observations, and the closely related receiver operating characteristic (ROC) curve is a powerful tool in making decisions. Yet, in general, many people would ask what such models are for, in electrophysiology, and what particular advantages such models provide. So to examine this question in particular, this review identifies a number of electrophysiological papers in bio-engineering arising from questions in several organ systems to see where Bayesian electrophysiological models or ROC curves were important to the results that were achieved. PMID:22275206

  15. Comparison of the electrophysiological pattern of fatigue between athletes required to perform explosive and endurance sports.

    PubMed

    Vatine, J J; Blank, A; Shochina, M; Swissa, A; Mahler, Y; Gonen, B; Magora, A

    1990-01-01

    The electrophysiological behavior of an isometric contraction sustained to fatigue, was examined in 6 long distance runners and 9 athletes involved in explosive (burst) sports, by on line computer analysis of the electrical activity of vastus medialis, rectus femoris and vastus lateralis. The experiments were carried out with a counterload of 50% of the maximal strength of the muscle. The duration of spike increased and the frequency decreased in the 3 examined muscles, in both types of sport. In the burst sports the changes of value of both parameters were statistically significant in the 3 muscles. In endurance sports the variations of duration were not significant and the changes of frequency were statistically significant only in the vastus lateralis. These results could be explained by the gradual activation of motor units of more strikingly different sizes in burst sports. Thus it may be speculated that prolonged training in burst sports may result in the automatic mobilization of higher number of small motor units, for the initiation of contraction while in endurance sports the onset of contraction is more gradual and carried out by large motor units.

  16. Traumatic Brain Injury Detection Using Electrophysiological Methods

    PubMed Central

    Rapp, Paul E.; Keyser, David O.; Albano, Alfonso; Hernandez, Rene; Gibson, Douglas B.; Zambon, Robert A.; Hairston, W. David; Hughes, John D.; Krystal, Andrew; Nichols, Andrew S.

    2015-01-01

    Measuring neuronal activity with electrophysiological methods may be useful in detecting neurological dysfunctions, such as mild traumatic brain injury (mTBI). This approach may be particularly valuable for rapid detection in at-risk populations including military service members and athletes. Electrophysiological methods, such as quantitative electroencephalography (qEEG) and recording event-related potentials (ERPs) may be promising; however, the field is nascent and significant controversy exists on the efficacy and accuracy of the approaches as diagnostic tools. For example, the specific measures derived from an electroencephalogram (EEG) that are most suitable as markers of dysfunction have not been clearly established. A study was conducted to summarize and evaluate the statistical rigor of evidence on the overall utility of qEEG as an mTBI detection tool. The analysis evaluated qEEG measures/parameters that may be most suitable as fieldable diagnostic tools, identified other types of EEG measures and analysis methods of promise, recommended specific measures and analysis methods for further development as mTBI detection tools, identified research gaps in the field, and recommended future research and development thrust areas. The qEEG study group formed the following conclusions: (1) Individual qEEG measures provide limited diagnostic utility for mTBI. However, many measures can be important features of qEEG discriminant functions, which do show significant promise as mTBI detection tools. (2) ERPs offer utility in mTBI detection. In fact, evidence indicates that ERPs can identify abnormalities in cases where EEGs alone are non-disclosing. (3) The standard mathematical procedures used in the characterization of mTBI EEGs should be expanded to incorporate newer methods of analysis including non-linear dynamical analysis, complexity measures, analysis of causal interactions, graph theory, and information dynamics. (4) Reports of high specificity in q

  17. Electrophysiological methods in early glaucoma detection.

    PubMed

    Fernández-Tirado, F J; Uclés, P; Pablo, L; Honrubia, F M

    1994-04-01

    Electrophysiological methods like pattern electroretinogram and pattern visual evoked potentials may be the best approach for early glaucoma detection, as they have demonstrated to be sensitive to the ganglion cells functional changes. Reported values of both P50 and N95 pattern electroretinogram components differ widely, a fact perhaps related to a heterogeneous grouping of patients suffering from ocular hypertension and glaucoma, rather than to the type of technique utilized. This study is based on a total of 42 subjects: 14 normals, 16 subjects suffering from ocular hypertension, and 12 patients with glaucoma, with 79 eyes examined. Pattern electroretinogram and pattern visual evoked potentials were used as successive techniques. Setting condition for pattern electroretinogram, such as low temporal frequency (2 Hz), 30 min check size, high contrast (99%) and luminance (93 cd/m2), identified the N95 component as the best index for early glaucoma detection. In the control group N95 mean amplitude was 1.62 muV +/- 0.59 SD and showed almost significant difference with ocular hypertension (p = 0.07) and highly significant difference with the glaucoma group (p < 0.01), with decrement of 58.6% in the glaucoma group. P50 mean amplitude, on the contrary, did not show significant differences among the groups (Newman-Keul test), its reduction in glaucoma being 28%. The mean pattern visual evoked potentials latency was alos highly significant between glaucoma and control groups, but not between ocular hypertension and control groups; the mean amplitude did not show significant differences. A proportion of 26.6% abnormal pattern electroretinogram was found in the group suspected of having glaucoma where conventional methods had proved normal.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8079620

  18. Comparison of Electrophysiological Auditory Measures in Fishes.

    PubMed

    Maruska, Karen P; Sisneros, Joseph A

    2016-01-01

    Sounds provide fishes with important information used to mediate behaviors such as predator avoidance, prey detection, and social communication. How we measure auditory capabilities in fishes, therefore, has crucial implications for interpreting how individual species use acoustic information in their natural habitat. Recent analyses have highlighted differences between behavioral and electrophysiologically determined hearing thresholds, but less is known about how physiological measures at different auditory processing levels compare within a single species. Here we provide one of the first comparisons of auditory threshold curves determined by different recording methods in a single fish species, the soniferous Hawaiian sergeant fish Abudefduf abdominalis, and review past studies on representative fish species with tuning curves determined by different methods. The Hawaiian sergeant is a colonial benthic-spawning damselfish (Pomacentridae) that produces low-frequency, low-intensity sounds associated with reproductive and agonistic behaviors. We compared saccular potentials, auditory evoked potentials (AEP), and single neuron recordings from acoustic nuclei of the hindbrain and midbrain torus semicircularis. We found that hearing thresholds were lowest at low frequencies (~75-300 Hz) for all methods, which matches the spectral components of sounds produced by this species. However, thresholds at best frequency determined via single cell recordings were ~15-25 dB lower than those measured by AEP and saccular potential techniques. While none of these physiological techniques gives us a true measure of the auditory "perceptual" abilities of a naturally behaving fish, this study highlights that different methodologies can reveal similar detectable range of frequencies for a given species, but absolute hearing sensitivity may vary considerably.

  19. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    NASA Astrophysics Data System (ADS)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, <30% of drugs withdrawals from the market were due to cardiac toxicity, where unintended interactions with ion channels disrupt the heart's normal electrical function. Consequently, all new drugs must undergo preclinical testing for cardiac liability, adding to an already expensive and lengthy process. Recognition that proarrhythmic effects often result from drug action on multiple ion channels demonstrates a need for integrative and comprehensive measurements. Additionally, patient-specific therapies relying on emerging technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  20. Dynamic BOLD functional connectivity in humans and its electrophysiological correlates.

    PubMed

    Tagliazucchi, Enzo; von Wegner, Frederic; Morzelewski, Astrid; Brodbeck, Verena; Laufs, Helmut

    2012-01-01

    Neural oscillations subserve many human perceptual and cognitive operations. Accordingly, brain functional connectivity is not static in time, but fluctuates dynamically following the synchronization and desynchronization of neural populations. This dynamic functional connectivity has recently been demonstrated in spontaneous fluctuations of the Blood Oxygen Level-Dependent (BOLD) signal, measured with functional Magnetic Resonance Imaging (fMRI). We analyzed temporal fluctuations in BOLD connectivity and their electrophysiological correlates, by means of long (≈50 min) joint electroencephalographic (EEG) and fMRI recordings obtained from two populations: 15 awake subjects and 13 subjects undergoing vigilance transitions. We identified positive and negative correlations between EEG spectral power (extracted from electrodes covering different scalp regions) and fMRI BOLD connectivity in a network of 90 cortical and subcortical regions (with millimeter spatial resolution). In particular, increased alpha (8-12 Hz) and beta (15-30 Hz) power were related to decreased functional connectivity, whereas gamma (30-60 Hz) power correlated positively with BOLD connectivity between specific brain regions. These patterns were altered for subjects undergoing vigilance changes, with slower oscillations being correlated with functional connectivity increases. Dynamic BOLD functional connectivity was reflected in the fluctuations of graph theoretical indices of network structure, with changes in frontal and central alpha power correlating with average path length. Our results strongly suggest that fluctuations of BOLD functional connectivity have a neurophysiological origin. Positive correlations with gamma can be interpreted as facilitating increased BOLD connectivity needed to integrate brain regions for cognitive performance. Negative correlations with alpha suggest a temporary functional weakening of local and long-range connectivity, associated with an idling state. PMID

  1. Reviving Ulysses contracts.

    PubMed

    Spellecy, Ryan

    2003-12-01

    Ulysses contracts have faced paternalism objections since they first were proposed. Since the contracts are designed to override a present request from a legally competent patient in favor of a past request made by that patient, enforcement of these contracts was argued to be unjustifiable strong paternalism. Recent legal developments and new theories of practical reasoning suggest that the discussion of Ulysses contracts should be revived. This paper argues that with a proper understanding of the future-directed planning embodied in Ulysses contracts, the charge of strong paternalism can be answered, and the enforcement of some Ulysses contracts may be justified under the rubric of weak paternalism.

  2. Natural stimuli from three coherent modalities enhance behavioral responses and electrophysiological cortical activity in humans.

    PubMed

    Sella, Irit; Reiner, Miriam; Pratt, Hillel

    2014-07-01

    Cues that involve a number of sensory modalities are processed in the brain in an interactive multimodal manner rather than independently for each modality. We studied multimodal integration in a natural, yet fully controlled scene, implemented as an interactive game in an auditory-haptic-visual virtual environment. In this imitation of a natural scene, the targets of perception were ecologically valid uni-, bi- and tri-modal manifestations of a simple event-a ball hitting a wall. Subjects were engaged in the game while their behavioral and early cortical electrophysiological responses were measured. Behavioral results confirmed that tri-modal cues were detected faster and more accurately than bi-modal cues, which, likewise, showed advantages over unimodal responses. Event-Related Potentials (ERPs) were recorded, and the first 200 ms following stimulus onset was analyzed to reveal the latencies of cortical multimodal interactions as estimated by sLORETA. These electrophysiological findings indicated bi-modal as well as tri-modal interactions beginning very early (~30 ms), uniquely for each multimodal combination. The results suggest that early cortical multimodal integration accelerates cortical activity and, in turn, enhances performance measures. This acceleration registers on the scalp as sub-additive cortical activation.

  3. Optrodes for combined optogenetics and electrophysiology in live animals

    PubMed Central

    Dufour, Suzie; De Koninck, Yves

    2015-01-01

    Abstract. Optical tissue properties limit visible light depth penetration in tissue. Because of this, the recent development of optogenetic tools was quickly followed by the development of light delivery devices for in vivo optogenetics applications. We summarize the efforts made in the last decade to design neural probes that combine conventional electrophysiological recordings and optical channel(s) for optogenetic activation, often referred to as optodes or optrodes. Several aspects including challenges for light delivery in living brain tissue, the combination of light delivery with electrophysiological recordings, probe designs, multimodality, wireless implantable system, and practical considerations guiding the choice of configuration depending on the questions one seeks to address are presented. PMID:26158014

  4. The roboocyte: automated electrophysiology based on Xenopus oocytes.

    PubMed

    Leisgen, Christine; Kuester, Mike; Methfessel, Christoph

    2007-01-01

    Automated electrophysiological assays are of great importance for modern drug discovery, and various approaches have been developed into practical devices. Here, we describe the automation of two-electrode voltage-clamp (TEVC) recording from Xenopus oocytes using the Roboocyte automated workstation, jointly developed by Multi Channel Systems and Bayer Technology Services. We briefly discuss the technology, including its advantages and limitations relative to patch clamp and other TEVC systems. We provide a step-by-step description of typical operating procedures and show that the Roboocyte represents a practical and highly effective way to perform automated electrophysiology in an industrial setting.

  5. An electrophysiological study of the intermediate syndrome of organophosphate poisoning.

    PubMed

    Lorenzoni, Paulo José; Gasparetto, Juliano; Kay, Cláudia Suemi Kamoi; Scola, Rosana Herminia; Werneck, Lineu César

    2010-09-01

    Acute organophosphate (OP) poisoning is commonly seen in emergency medicine. Neurologists must be alert to detect neuromuscular transmission failure and other neurological complications that follow OP poisoning. We report a 37-year-old male with acute OP poisoning to emphasize the electrophysiological abnormalities during the intermediate syndrome (IMS). Motor nerve conduction studies revealed that a single nerve stimulation evoked a repetitive compound muscle action potential, whereas repetitive nerve stimulation resulted in a combination of a decrement-increment pattern and a repetitive fade response. Thus, electrophysiological studies can be used to monitor patients with IMS, and these test results correlate well with clinical findings in acute OP poisoning. PMID:20483619

  6. Teaching about Contracts.

    ERIC Educational Resources Information Center

    Froman, Michael; Kosnoff, Kathy

    1978-01-01

    Presents teaching strategies for introducing high school students to contract law. Offers as a case study a contract agreement between pro football players and team owners. Stresses basic elements of contracts (offer, acceptance, consideration, and understanding the bargaining process). Journal available from the American Bar Association, 1155…

  7. The Joy of Contracts.

    ERIC Educational Resources Information Center

    Hegarty, Kevin

    This paper is a practical guide that explains and illustrates contracts between libraries and vendors for computerized circulation systems. It describes the elements of a typical contract to include the equipment and services that should be specified in the contract and establishes scheduling and acceptance testing needs. Included in a contract…

  8. Contracting for Services.

    ERIC Educational Resources Information Center

    Jenkins, Robin E.; Nord, Roy

    1982-01-01

    The major steps a college should undertake in contracting for services, including the initial determination as to whether or not contracting is the best way to provide a particular service, are described. Three general activities that apply to decisions about contracting in most circumstances are: investigating service characteristics; identifying…

  9. Russian Teaching Contracts.

    ERIC Educational Resources Information Center

    Stevens, Betsy

    2000-01-01

    Analyzes two Russian teaching contracts, rhetorically comparing purpose and audience, culture, gender, and the role of the individual versus the state. Uses anecdotal episodes as a framework for examining Russian culture and analyzing university teaching contracts, concluding that the contracts are not only brief and factual but also reflect a…

  10. Clinical and electrophysiological assessment of inferior alveolar nerve function after lateral nerve transposition.

    PubMed

    Nocini, P F; De Santis, D; Fracasso, E; Zanette, G

    1999-04-01

    Inferior alveolar nerve (IAN) transposition surgery may cause some degree of sensory impairment. Accurate and reproducible tests are mandatory to assess IAN conduction capacity following nerve transposition. In this study subjective (heat, pain and tactile-discriminative tests) and objective (electrophysiological) assessments were performed in 10 patients receiving IAN transposition (bilaterally in 8 cases) in order to evaluate any impairment of the involved nerves one year post-operatively. All patients reported a tingling, well-tolerated sensation in the areas supplied by the mental nerve with no anaesthesia or burning paresthesia. Tactile discrimination was affected the most (all but 1 patient). No action potential was recorded in 4 patients' sides (23.5%); 12 sides showed a decreased nerve conduction velocity (NCV) (70.5%) and 1 side normal NCV values (6%). There was no significant difference in NCV decrease between partial and total transposition sides, if examined separately. Nerve conduction findings were related 2-point discrimination scores, but not to changes in pain and heat sensitivity. These findings show that lateral nerve transposition, though resulting in a high percentage of minor IAN injuries, as determined by electrophysiological testing, provides a viable surgical procedure to allow implant placement in the posterior mandible without causing severe sensory complaints. Considering ethical and forensic implications, patients should be fully informed that a certain degree of nerve injury might be expected to occur from the procedure. Electrophysiological evaluation is a reliable way to assess the degree of IAN dysfunction, especially if combined with a clinical examination. Intraoperative monitoring of IAN conduction might help identify the pathogenetic mechanisms of nerve injury and the surgical steps that are most likely to harm nerve integrity. PMID:10219131

  11. Electrophysiological correlates of the BOLD signal for EEG-informed fMRI

    PubMed Central

    Murta, Teresa; Leite, Marco; Carmichael, David W; Figueiredo, Patrícia; Lemieux, Louis

    2015-01-01

    Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are important tools in cognitive and clinical neuroscience. Combined EEG–fMRI has been shown to help to characterise brain networks involved in epileptic activity, as well as in different sensory, motor and cognitive functions. A good understanding of the electrophysiological correlates of the blood oxygen level-dependent (BOLD) signal is necessary to interpret fMRI maps, particularly when obtained in combination with EEG. We review the current understanding of electrophysiological–haemodynamic correlates, during different types of brain activity. We start by describing the basic mechanisms underlying EEG and BOLD signals and proceed by reviewing EEG-informed fMRI studies using fMRI to map specific EEG phenomena over the entire brain (EEG–fMRI mapping), or exploring a range of EEG-derived quantities to determine which best explain colocalised BOLD fluctuations (local EEG–fMRI coupling). While reviewing studies of different forms of brain activity (epileptic and nonepileptic spontaneous activity; cognitive, sensory and motor functions), a significant attention is given to epilepsy because the investigation of its haemodynamic correlates is the most common application of EEG-informed fMRI. Our review is focused on EEG-informed fMRI, an asymmetric approach of data integration. We give special attention to the invasiveness of electrophysiological measurements and the simultaneity of multimodal acquisitions because these methodological aspects determine the nature of the conclusions that can be drawn from EEG-informed fMRI studies. We emphasise the advantages of, and need for, simultaneous intracranial EEG–fMRI studies in humans, which recently became available and hold great potential to improve our understanding of the electrophysiological correlates of BOLD fluctuations. PMID:25277370

  12. Electrophysiological Modeling of Cardiac Ventricular Function: From Cell to Organ

    PubMed Central

    Winslow, R. L.; Scollan, D. F.; Holmes, A.; Yung, C. K.; Zhang, J.; Jafri, M. S.

    2005-01-01

    Three topics of importance to modeling the integrative function of the heart are reviewed. The first is modeling of the ventricular myocyte. Emphasis is placed on excitation-contraction coupling and intracellular Ca2+ handling, and the interpretation of experimental data regarding interval-force relationships. Second, data on use of diffusion tensor magnetic resonance (DTMR) imaging for measuring the anatomical structure of the cardiac ventricles are presented. A method for the semi-automated reconstruction of the ventricles using a combination of gradient recalled acquisition in the steady state (GRASS) and DTMR images is described. Third, we describe how these anatomically and biophysically based models of the cardiac ventricles can be implemented on parallel computers. PMID:11701509

  13. Integrating sodium reduction strategies in the procurement process and contracting of food venues in the County of Los Angeles government, 2010-2012.

    PubMed

    Cummings, Patricia L; Kuo, Tony; Gase, Lauren N; Mugavero, Kristy

    2014-01-01

    Since sodium is ubiquitous in the food supply, recent approaches to sodium reduction have focused on increasing the availability of lower-sodium products through system-level and environmental changes. This article reviews integrated efforts by the Los Angeles County Sodium Reduction Initiative to implement these strategies at food venues in the County of Los Angeles government. The review used mixed methods, including a scan of the literature, key informant interviews, and lessons learned during 2010-2012 to assess program progress. Leveraging technical expertise and shared resources, the initiative strategically incorporated sodium reduction strategies into the overall work plan of a multipartnership food procurement program in Los Angeles County. To date, 3 County departments have incorporated new or updated nutrition requirements that included sodium limits and other strategies. The strategic coupling of sodium reduction to food procurement and general health promotion allowed for simultaneous advancement and acceleration of the County's sodium reduction agenda.

  14. A highly versatile and easily configurable system for plant electrophysiology.

    PubMed

    Gunsé, Benet; Poschenrieder, Charlotte; Rankl, Simone; Schröeder, Peter; Rodrigo-Moreno, Ana; Barceló, Juan

    2016-01-01

    In this study we present a highly versatile and easily configurable system for measuring plant electrophysiological parameters and ionic flow rates, connected to a computer-controlled highly accurate positioning device. The modular software used allows easy customizable configurations for the measurement of electrophysiological parameters. Both the operational tests and the experiments already performed have been fully successful and rendered a low noise and highly stable signal. Assembly, programming and configuration examples are discussed. The system is a powerful technique that not only gives precise measuring of plant electrophysiological status, but also allows easy development of ad hoc configurations that are not constrained to plant studies. •We developed a highly modular system for electrophysiology measurements that can be used either in organs or cells and performs either steady or dynamic intra- and extracellular measurements that takes advantage of the easiness of visual object-oriented programming.•High precision accuracy in data acquisition under electrical noisy environments that allows it to run even in a laboratory close to electrical equipment that produce electrical noise.•The system makes an improvement of the currently used systems for monitoring and controlling high precision measurements and micromanipulation systems providing an open and customizable environment for multiple experimental needs.

  15. [Transesophageal electrophysiologic study: utility in the diagnosis of syncope].

    PubMed

    Hidalgo Ottolenghi, F

    2001-01-01

    Neurocardiogenic and arrhythmic syncope are very common and may be found in many patients in Emergency Departments or admitted to hospitals. Technologic advances now allow etiologic diagnosis to be determined but the importance of a detailed clinical history and physical examination can not be overemphasized in the evaluation of syncope, thereby to avoid some costly or invasive procedures. The recent introduction of the head-up tilt test alone or in combination with electrophysiologic studies, has significantly improved our ability to diagnose the etiology of syncope in many cases. Suspicion of an arrhythmic cause of syncope does not always require an invasive electrophysiologic study since the transesophageal electrophysiologic study is useful and provides a high diagnostic yield in the evaluation of non ventricular arrhythmic syncope, such as in the sick sinus syndrome, atrio-ventricular block or in supraventricular tachycardia and for the study of atrial stability. The transesophageal electrophysiologic study is an inexpensive non invasive procedure which does not require complex hospitalary installations. PMID:11535186

  16. Arrhythmogenesis Research: A Perspective from Computational Electrophysiology Viewpoint

    PubMed Central

    Trayanova, Natalia; Plank, Gernot

    2012-01-01

    The mechanisms by which arrhythmias are generated in the heart remains a field of intensive research. Recent advances in computational biology and electrophysiology have enabled researchers to use an alternative tool in the study of arrhythmia mechanisms, the multi-scale modeling and simulation of cardiac arrhythmogenesis at the organ level. This article reviews the recent advances and achievements using this approach. PMID:18001976

  17. Electrophysiological studies in patients with pulmonary hypertension: a retrospective investigation.

    PubMed

    Bandorski, Dirk; Schmitt, Jörn; Kurzlechner, Claudia; Erkapic, Damir; Hamm, Christian W; Seeger, Werner; Ghofrani, Ardeschir; Höltgen, Reinhard; Gall, Henning

    2014-01-01

    Few studies have investigated patients with pulmonary hypertension and arrhythmias. Data on electrophysiological studies in these patients are rare. In a retrospective dual-centre design, we analysed data from patients with indications for electrophysiological study. Fifty-five patients with pulmonary hypertension were included (Dana Point Classification: group 1: 14, group 2: 23, group 3: 4, group 4: 8, group 5: 2, and 4 patients with exercised-induced pulmonary hypertension). Clinical data, 6-minute walk distance, laboratory values, and echocardiography were collected/performed. Nonsustained ventricular tachycardia was the most frequent indication (n = 15) for an electrophysiological study, followed by atrial flutter (n = 14). In summary 36 ablations were performed and 25 of them were successful (atrial flutter 12 of 14 and atrioventricular nodal reentrant tachycardia 4 of 4). Fluoroscopy time was 16 ± 14.4 minutes. Electrophysiological studies in patients with pulmonary hypertension are feasible and safe. Ablation procedures are as effective in these patients as in non-PAH patients with atrial flutter and atrioventricular nodal reentrant tachycardia and should be performed likewise. The prognostic relevance of ventricular stimulations and inducible ventricular tachycardias in these patients is still unclear and requires further investigation.

  18. Electrophysiological Studies in Patients with Pulmonary Hypertension: A Retrospective Investigation

    PubMed Central

    Bandorski, Dirk; Schmitt, Jörn; Kurzlechner, Claudia; Erkapic, Damir; Hamm, Christian W.; Seeger, Werner; Ghofrani, Ardeschir; Höltgen, Reinhard; Gall, Henning

    2014-01-01

    Few studies have investigated patients with pulmonary hypertension and arrhythmias. Data on electrophysiological studies in these patients are rare. In a retrospective dual-centre design, we analysed data from patients with indications for electrophysiological study. Fifty-five patients with pulmonary hypertension were included (Dana Point Classification: group 1: 14, group 2: 23, group 3: 4, group 4: 8, group 5: 2, and 4 patients with exercised-induced pulmonary hypertension). Clinical data, 6-minute walk distance, laboratory values, and echocardiography were collected/performed. Nonsustained ventricular tachycardia was the most frequent indication (n = 15) for an electrophysiological study, followed by atrial flutter (n = 14). In summary 36 ablations were performed and 25 of them were successful (atrial flutter 12 of 14 and atrioventricular nodal reentrant tachycardia 4 of 4). Fluoroscopy time was 16 ± 14.4 minutes. Electrophysiological studies in patients with pulmonary hypertension are feasible and safe. Ablation procedures are as effective in these patients as in non-PAH patients with atrial flutter and atrioventricular nodal reentrant tachycardia and should be performed likewise. The prognostic relevance of ventricular stimulations and inducible ventricular tachycardias in these patients is still unclear and requires further investigation. PMID:24977152

  19. The Electrophysiological Correlates of Scientific Innovation Induced by Heuristic Information

    ERIC Educational Resources Information Center

    Luo, Junlong; Du, Xiumin; Tang, Xiaochen; Zhang, Entao; Li, Haijiang; Zhang, Qinglin

    2013-01-01

    In this study, novel and old scientific innovations (NSI and OSI) were selected as materials to explore the electrophysiological correlates of scientific innovation induced by heuristic information. Using event-related brain potentials (ERPs) to do so, college students solved NSI problems (for which they did not know the answers) and OSI problems…

  20. Changes in electrophysiological parameters after open carpal tunnel release

    PubMed Central

    Tahririan, Mohammad A.; Moghtaderi, Alireza; Aran, Farzaneh

    2012-01-01

    Background: Carpal tunnel syndrome (CTS) is the most frequent compressive mononeuropathy, affecting mostly females. Few studies have been performed to assess the electrophysiological parameters before and after carpal tunnel release. The purpose of our study was to evaluate these changes postoperatively and in the course of a 9-month period after operation in comparison with the preoperative values. Materials and Methods: A case-series study was carried out and included 17 cases of moderate or severe electrophysiologically confirmed CTS, who underwent open carpal tunnel release (CTR) from December 2010 to May 2011. Severity grade was assigned following American Association of the Electrodiagnostic Medicine criteria of CTS. Distal motor and sensory latencies and sensory nerve conduction velocity of the median nerve across the carpal tunnel were evaluated and compared before, at 6, and 9 months after surgery. Results: From the 17 evaluated hand with moderate, moderate to severe and severe CTS, severity improvement was reported in 82.3% 6 months and in 88.2% 9 months after surgery, but only 47% had satisfied or completely satisfied opinion about the results. Others, though still complaining of serious symptoms, had improved or normal NCS. Discussion: Electrophysiological investigations outlined severity improvement after CTR. In the current study, the electrophysiological studies were not meaningful in determining outcome. PMID:23326777

  1. Electrophysiological Monitoring of Brain Injury and Recovery after Cardiac Arrest.

    PubMed

    Deng, Ruoxian; Xiong, Wei; Jia, Xiaofeng

    2015-01-01

    Reliable prognostic methods for cerebral functional outcome of post cardiac-arrest (CA) patients are necessary, especially since therapeutic hypothermia (TH) as a standard treatment. Traditional neurophysiological prognostic indicators, such as clinical examination and chemical biomarkers, may result in indecisive outcome predictions and do not directly reflect neuronal activity, though they have remained the mainstay of clinical prognosis. The most recent advances in electrophysiological methods--electroencephalography (EEG) pattern, evoked potential (EP) and cellular electrophysiological measurement--were developed to complement these deficiencies, and will be examined in this review article. EEG pattern (reactivity and continuity) provides real-time and accurate information for early-stage (particularly in the first 24 h) hypoxic-ischemic (HI) brain injury patients with high sensitivity. However, the signal is easily affected by external stimuli, thus the measurements of EP should be combined with EEG background to validate the predicted neurologic functional result. Cellular electrophysiology, such as multi-unit activity (MUA) and local field potentials (LFP), has strong potential for improving prognostication and therapy by offering additional neurophysiologic information to understand the underlying mechanisms of therapeutic methods. Electrophysiology provides reliable and precise prognostication on both global and cellular levels secondary to cerebral injury in cardiac arrest patients treated with TH. PMID:26528970

  2. Spatiotemporal electrophysiological changes in a murine ablation model

    PubMed Central

    Bernstein, Scott A.; Duggirala, Srikant; Floberg, Michael; Elfvendal, Pehr; Kuznekoff, Laura M.; Lader, Joshua M.; Vasquez, Carolina; Morley, Gregory E.

    2011-01-01

    Aims High recurrence rates after complex radiofrequency ablation procedures, such as for atrial fibrillation, remain a major clinical problem. Local electrophysiological changes that occur following cardiac ablation therapy are incompletely described in the literature. The purpose of this study was to determine whether alterations in conduction velocity, action potential duration (APD), and effective refractory period resolve dynamically following cardiac ablation. Methods and results  Lesions were delivered to the right ventricle of mice using a subxiphoid approach. The sham-operated control group (SHAM) received the same procedure without energy delivery. Hearts were isolated at 0, 1, 7, 30, and 60 days following the procedure and electrophysiological parameters were obtained using high-resolution optical mapping with a voltage-sensitive dye. Conduction velocity was significantly decreased at the lesion border in the 0, 7, and 30 day groups compared to SHAM. APD70 at the lesion border was significantly increased at all time points compared to SHAM. Effective refractory period was significantly increased at the lesion border at 0, 1, 7, and 30 days but not at 60 days post-ablation. This study demonstrated that post-ablation electrophysiological changes take place immediately following energy delivery and resolve within 60 days. Conclusions Cardiac ablation causes significant electrophysiological changes both within the lesion and beyond the border zone. Late recovery of electrical conduction in individual lesions is consistent with clinical data demonstrating that arrhythmia recurrence is associated with failure to maintain bi-directional conduction block. PMID:21712278

  3. A highly versatile and easily configurable system for plant electrophysiology.

    PubMed

    Gunsé, Benet; Poschenrieder, Charlotte; Rankl, Simone; Schröeder, Peter; Rodrigo-Moreno, Ana; Barceló, Juan

    2016-01-01

    In this study we present a highly versatile and easily configurable system for measuring plant electrophysiological parameters and ionic flow rates, connected to a computer-controlled highly accurate positioning device. The modular software used allows easy customizable configurations for the measurement of electrophysiological parameters. Both the operational tests and the experiments already performed have been fully successful and rendered a low noise and highly stable signal. Assembly, programming and configuration examples are discussed. The system is a powerful technique that not only gives precise measuring of plant electrophysiological status, but also allows easy development of ad hoc configurations that are not constrained to plant studies. •We developed a highly modular system for electrophysiology measurements that can be used either in organs or cells and performs either steady or dynamic intra- and extracellular measurements that takes advantage of the easiness of visual object-oriented programming.•High precision accuracy in data acquisition under electrical noisy environments that allows it to run even in a laboratory close to electrical equipment that produce electrical noise.•The system makes an improvement of the currently used systems for monitoring and controlling high precision measurements and micromanipulation systems providing an open and customizable environment for multiple experimental needs. PMID:27298766

  4. Electrophysiological Signals of Familiarity and Recency in the Infant Brain

    ERIC Educational Resources Information Center

    Snyder, Kelly A.; Garza, John; Zolot, Liza; Kresse, Anna

    2010-01-01

    Electrophysiological work in nonhuman primates has established the existence of multiple types of signals in the temporal lobe that contribute to recognition memory, including information regarding a stimulus's relative novelty, familiarity, and recency of occurrence. We used high-density event-related potentials (ERPs) to examine whether young…

  5. Animal electricity and the birth of electrophysiology: the legacy of Luigi Galvani.

    PubMed

    Piccolino, M

    1998-07-15

    Preceded by a companion paper on Galvani's life, this article is written on the occasion of the bicentenary of the death of Luigi Galvani. From his studies on the effects of electricity on frogs, the scientist of Bologna derived the hypothesis that animal tissues are endowed with an intrinsic electricity that is involved in fundamental physiological processes such as nerve conduction and muscle contraction. Galvani's work swept away from life sciences mysterious fluids and elusive entities like "animal spirits" and led to the foundation of a new science, electrophysiology. Two centuries of research work have demonstrated how insightful was Galvani's conception of animal electricity. Nevertheless, the scholar of Bologna is still largely misrepresented in the history of science, because the importance of his researches seems to be limited to the fact that they opened the paths to the studies of the physicist Alessandro Volta, which culminated in 1800 with the invention of the electric battery. Volta strongly opposed Galvani's theories on animal electricity. The matter of the scientific controversy between Galvani and Volta is examined here in the light of two centuries of electrophysiological studies leading to the modern understanding of electrical excitability in nerve and muscle. By surveying the work of scientists such as Nobili, Matteucci, du Bois-Reymond, von Helmholtz, Bernstein, Hermann, Lucas, Adrian, Hodgkin, Huxley, and Katz, the real matter of the debate raised by Galvani's discoveries is here reconsidered. In addition, a revolutionary phase of the 18th century science that opened the way for the development of modern neurosciences is reevaluated.

  6. Animal electricity and the birth of electrophysiology: the legacy of Luigi Galvani.

    PubMed

    Piccolino, M

    1998-07-15

    Preceded by a companion paper on Galvani's life, this article is written on the occasion of the bicentenary of the death of Luigi Galvani. From his studies on the effects of electricity on frogs, the scientist of Bologna derived the hypothesis that animal tissues are endowed with an intrinsic electricity that is involved in fundamental physiological processes such as nerve conduction and muscle contraction. Galvani's work swept away from life sciences mysterious fluids and elusive entities like "animal spirits" and led to the foundation of a new science, electrophysiology. Two centuries of research work have demonstrated how insightful was Galvani's conception of animal electricity. Nevertheless, the scholar of Bologna is still largely misrepresented in the history of science, because the importance of his researches seems to be limited to the fact that they opened the paths to the studies of the physicist Alessandro Volta, which culminated in 1800 with the invention of the electric battery. Volta strongly opposed Galvani's theories on animal electricity. The matter of the scientific controversy between Galvani and Volta is examined here in the light of two centuries of electrophysiological studies leading to the modern understanding of electrical excitability in nerve and muscle. By surveying the work of scientists such as Nobili, Matteucci, du Bois-Reymond, von Helmholtz, Bernstein, Hermann, Lucas, Adrian, Hodgkin, Huxley, and Katz, the real matter of the debate raised by Galvani's discoveries is here reconsidered. In addition, a revolutionary phase of the 18th century science that opened the way for the development of modern neurosciences is reevaluated. PMID:9739001

  7. Software and hardware infrastructure for research in electrophysiology.

    PubMed

    Mouček, Roman; Ježek, Petr; Vařeka, Lukáš; Rondík, Tomáš; Brůha, Petr; Papež, Václav; Mautner, Pavel; Novotný, Jiří; Prokop, Tomáš; Stěbeták, Jan

    2014-01-01

    As in other areas of experimental science, operation of electrophysiological laboratory, design and performance of electrophysiological experiments, collection, storage and sharing of experimental data and metadata, analysis and interpretation of these data, and publication of results are time consuming activities. If these activities are well organized and supported by a suitable infrastructure, work efficiency of researchers increases significantly. This article deals with the main concepts, design, and development of software and hardware infrastructure for research in electrophysiology. The described infrastructure has been primarily developed for the needs of neuroinformatics laboratory at the University of West Bohemia, the Czech Republic. However, from the beginning it has been also designed and developed to be open and applicable in laboratories that do similar research. After introducing the laboratory and the whole architectural concept the individual parts of the infrastructure are described. The central element of the software infrastructure is a web-based portal that enables community researchers to store, share, download and search data and metadata from electrophysiological experiments. The data model, domain ontology and usage of semantic web languages and technologies are described. Current data publication policy used in the portal is briefly introduced. The registration of the portal within Neuroscience Information Framework is described. Then the methods used for processing of electrophysiological signals are presented. The specific modifications of these methods introduced by laboratory researches are summarized; the methods are organized into a laboratory workflow. Other parts of the software infrastructure include mobile and offline solutions for data/metadata storing and a hardware stimulator communicating with an EEG amplifier and recording software.

  8. Age-Related Changes in 1/f Neural Electrophysiological Noise

    PubMed Central

    Kramer, Mark A.; Case, John; Lepage, Kyle Q.; Tempesta, Zechari R.; Knight, Robert T.; Gazzaley, Adam

    2015-01-01

    Aging is associated with performance decrements across multiple cognitive domains. The neural noise hypothesis, a dominant view of the basis of this decline, posits that aging is accompanied by an increase in spontaneous, noisy baseline neural activity. Here we analyze data from two different groups of human subjects: intracranial electrocorticography from 15 participants over a 38 year age range (15–53 years) and scalp EEG data from healthy younger (20–30 years) and older (60–70 years) adults to test the neural noise hypothesis from a 1/f noise perspective. Many natural phenomena, including electrophysiology, are characterized by 1/f noise. The defining characteristic of 1/f is that the power of the signal frequency content decreases rapidly as a function of the frequency (f) itself. The slope of this decay, the noise exponent (χ), is often <−1 for electrophysiological data and has been shown to approach white noise (defined as χ = 0) with increasing task difficulty. We observed, in both electrophysiological datasets, that aging is associated with a flatter (more noisy) 1/f power spectral density, even at rest, and that visual cortical 1/f noise statistically mediates age-related impairments in visual working memory. These results provide electrophysiological support for the neural noise hypothesis of aging. SIGNIFICANCE STATEMENT Understanding the neurobiological origins of age-related cognitive decline is of critical scientific, medical, and public health importance, especially considering the rapid aging of the world's population. We find, in two separate human studies, that 1/f electrophysiological noise increases with aging. In addition, we observe that this age-related 1/f noise statistically mediates age-related working memory decline. These results significantly add to this understanding and contextualize a long-standing problem in cognition by encapsulating age-related cognitive decline within a neurocomputational model of 1/f noise

  9. Software and hardware infrastructure for research in electrophysiology

    PubMed Central

    Mouček, Roman; Ježek, Petr; Vařeka, Lukáš; Řondík, Tomáš; Brůha, Petr; Papež, Václav; Mautner, Pavel; Novotný, Jiří; Prokop, Tomáš; Štěbeták, Jan

    2014-01-01

    As in other areas of experimental science, operation of electrophysiological laboratory, design and performance of electrophysiological experiments, collection, storage and sharing of experimental data and metadata, analysis and interpretation of these data, and publication of results are time consuming activities. If these activities are well organized and supported by a suitable infrastructure, work efficiency of researchers increases significantly. This article deals with the main concepts, design, and development of software and hardware infrastructure for research in electrophysiology. The described infrastructure has been primarily developed for the needs of neuroinformatics laboratory at the University of West Bohemia, the Czech Republic. However, from the beginning it has been also designed and developed to be open and applicable in laboratories that do similar research. After introducing the laboratory and the whole architectural concept the individual parts of the infrastructure are described. The central element of the software infrastructure is a web-based portal that enables community researchers to store, share, download and search data and metadata from electrophysiological experiments. The data model, domain ontology and usage of semantic web languages and technologies are described. Current data publication policy used in the portal is briefly introduced. The registration of the portal within Neuroscience Information Framework is described. Then the methods used for processing of electrophysiological signals are presented. The specific modifications of these methods introduced by laboratory researches are summarized; the methods are organized into a laboratory workflow. Other parts of the software infrastructure include mobile and offline solutions for data/metadata storing and a hardware stimulator communicating with an EEG amplifier and recording software. PMID:24639646

  10. Age-Related Changes in 1/f Neural Electrophysiological Noise.

    PubMed

    Voytek, Bradley; Kramer, Mark A; Case, John; Lepage, Kyle Q; Tempesta, Zechari R; Knight, Robert T; Gazzaley, Adam

    2015-09-23

    Aging is associated with performance decrements across multiple cognitive domains. The neural noise hypothesis, a dominant view of the basis of this decline, posits that aging is accompanied by an increase in spontaneous, noisy baseline neural activity. Here we analyze data from two different groups of human subjects: intracranial electrocorticography from 15 participants over a 38 year age range (15-53 years) and scalp EEG data from healthy younger (20-30 years) and older (60-70 years) adults to test the neural noise hypothesis from a 1/f noise perspective. Many natural phenomena, including electrophysiology, are characterized by 1/f noise. The defining characteristic of 1/f is that the power of the signal frequency content decreases rapidly as a function of the frequency (f) itself. The slope of this decay, the noise exponent (χ), is often <-1 for electrophysiological data and has been shown to approach white noise (defined as χ = 0) with increasing task difficulty. We observed, in both electrophysiological datasets, that aging is associated with a flatter (more noisy) 1/f power spectral density, even at rest, and that visual cortical 1/f noise statistically mediates age-related impairments in visual working memory. These results provide electrophysiological support for the neural noise hypothesis of aging. Significance statement: Understanding the neurobiological origins of age-related cognitive decline is of critical scientific, medical, and public health importance, especially considering the rapid aging of the world's population. We find, in two separate human studies, that 1/f electrophysiological noise increases with aging. In addition, we observe that this age-related 1/f noise statistically mediates age-related working memory decline. These results significantly add to this understanding and contextualize a long-standing problem in cognition by encapsulating age-related cognitive decline within a neurocomputational model of 1/f noise-induced deficits in

  11. The contribution of electrophysiology to knowledge of the acute and chronic effects of ethanol.

    PubMed

    Little, H J

    1999-12-01

    This review describes the effects of ethanol on the components of neuronal transmission and the relationship of such effects to the behavioural actions of ethanol. The concentrations of ethanol with acute actions on voltage-sensitive ion channels are first described, then the actions of ethanol on ligand-gated ion channels, including those controlled by cholinergic receptors, 5-hydroxytryptamine receptors, the various excitatory amino acid receptors, and gamma-aminobutyric acid receptors. Acute effects of ethanol are then described on brain areas thought to be involved in arousal and attention, the reinforcing effects of ethanol, the production of euphoria, the actions of ethanol on motor control, and the amnesic effects of ethanol; the acute effects of ethanol demonstrated by EEG studies are also discussed. Chronic effects of alcohol on neuronal transmission are described in the context of the various components of the ethanol withdrawal syndrome, withdrawal hyperexcitability, dysphoria and anhedonia, withdrawal anxiety, craving, and relapse drinking. Electrophysiological studies on the genetic influences on the effects of ethanol are discussed, particularly the acute actions of ethanol and electrophysiological differences reported in individuals predisposed to alcoholism. The conclusion notes the concentration of studies on the classical transmitters, with relative neglect of the effects of ethanol on peptides and on neuronal interactions between brain areas and integrated patterns of neuronal activity. PMID:10665833

  12. Cloudwave: distributed processing of "big data" from electrophysiological recordings for epilepsy clinical research using Hadoop.

    PubMed

    Jayapandian, Catherine P; Chen, Chien-Hung; Bozorgi, Alireza; Lhatoo, Samden D; Zhang, Guo-Qiang; Sahoo, Satya S

    2013-01-01

    Epilepsy is the most common serious neurological disorder affecting 50-60 million persons worldwide. Multi-modal electrophysiological data, such as electroencephalography (EEG) and electrocardiography (EKG), are central to effective patient care and clinical research in epilepsy. Electrophysiological data is an example of clinical "big data" consisting of more than 100 multi-channel signals with recordings from each patient generating 5-10GB of data. Current approaches to store and analyze signal data using standalone tools, such as Nihon Kohden neurology software, are inadequate to meet the growing volume of data and the need for supporting multi-center collaborative studies with real time and interactive access. We introduce the Cloudwave platform in this paper that features a Web-based intuitive signal analysis interface integrated with a Hadoop-based data processing module implemented on clinical data stored in a "private cloud". Cloudwave has been developed as part of the National Institute of Neurological Disorders and Strokes (NINDS) funded multi-center Prevention and Risk Identification of SUDEP Mortality (PRISM) project. The Cloudwave visualization interface provides real-time rendering of multi-modal signals with "montages" for EEG feature characterization over 2TB of patient data generated at the Case University Hospital Epilepsy Monitoring Unit. Results from performance evaluation of the Cloudwave Hadoop data processing module demonstrate one order of magnitude improvement in performance over 77GB of patient data. (Cloudwave project: http://prism.case.edu/prism/index.php/Cloudwave). PMID:24551370

  13. Neural ensemble communities: open-source approaches to hardware for large-scale electrophysiology.

    PubMed

    Siegle, Joshua H; Hale, Gregory J; Newman, Jonathan P; Voigts, Jakob

    2015-06-01

    One often-overlooked factor when selecting a platform for large-scale electrophysiology is whether or not a particular data acquisition system is 'open' or 'closed': that is, whether or not the system's schematics and source code are available to end users. Open systems have a reputation for being difficult to acquire, poorly documented, and hard to maintain. With the arrival of more powerful and compact integrated circuits, rapid prototyping services, and web-based tools for collaborative development, these stereotypes must be reconsidered. We discuss some of the reasons why multichannel extracellular electrophysiology could benefit from open-source approaches and describe examples of successful community-driven tool development within this field. In order to promote the adoption of open-source hardware and to reduce the need for redundant development efforts, we advocate a move toward standardized interfaces that connect each element of the data processing pipeline. This will give researchers the flexibility to modify their tools when necessary, while allowing them to continue to benefit from the high-quality products and expertise provided by commercial vendors. PMID:25528614

  14. Cloudwave: distributed processing of "big data" from electrophysiological recordings for epilepsy clinical research using Hadoop.

    PubMed

    Jayapandian, Catherine P; Chen, Chien-Hung; Bozorgi, Alireza; Lhatoo, Samden D; Zhang, Guo-Qiang; Sahoo, Satya S

    2013-01-01

    Epilepsy is the most common serious neurological disorder affecting 50-60 million persons worldwide. Multi-modal electrophysiological data, such as electroencephalography (EEG) and electrocardiography (EKG), are central to effective patient care and clinical research in epilepsy. Electrophysiological data is an example of clinical "big data" consisting of more than 100 multi-channel signals with recordings from each patient generating 5-10GB of data. Current approaches to store and analyze signal data using standalone tools, such as Nihon Kohden neurology software, are inadequate to meet the growing volume of data and the need for supporting multi-center collaborative studies with real time and interactive access. We introduce the Cloudwave platform in this paper that features a Web-based intuitive signal analysis interface integrated with a Hadoop-based data processing module implemented on clinical data stored in a "private cloud". Cloudwave has been developed as part of the National Institute of Neurological Disorders and Strokes (NINDS) funded multi-center Prevention and Risk Identification of SUDEP Mortality (PRISM) project. The Cloudwave visualization interface provides real-time rendering of multi-modal signals with "montages" for EEG feature characterization over 2TB of patient data generated at the Case University Hospital Epilepsy Monitoring Unit. Results from performance evaluation of the Cloudwave Hadoop data processing module demonstrate one order of magnitude improvement in performance over 77GB of patient data. (Cloudwave project: http://prism.case.edu/prism/index.php/Cloudwave).

  15. Morphological and electrophysiological properties of atypically oriented layer 2 pyramidal cells of the juvenile rat neocortex.

    PubMed

    van Brederode, J F; Foehring, R C; Spain, W J

    2000-01-01

    We used whole-cell patch clamp recordings combined with intracellular dye-filling to examine the morphological and electrophysiological properties of atypically oriented pyramidal cells located at the layer 1/2 border of the juvenile rat neocortex. Orientation of the apical dendrite varied from oblique (>20 degrees from vertical) to truly horizontal (90 degrees from vertical). The length of the apical dendrite ranged from 150 to 400 microm. The total horizontal domain of the dendritic tree (including basal dendrites) of the longest horizontal pyramids exceeded 500 microm, but we also found short horizontal cells with horizontal dendritic domains of less than 300 microm. In addition, atypically oriented pyramids had long horizontal axon collaterals in layer 1/2. Electrophysiologically, atypically oriented pyramidal cells had intrinsic membrane properties similar to regularly oriented pyramids that have been described in the superficial layers at this age in the rat. Cells that fired repetitively were all regular spiking. In addition, we identified a subgroup of neurons (20%) in this sample, which were unable to fire more than a few spikes at the beginning of the current pulse. We suggest that the unique orientation and size of their dendritic trees and the length and arrangement of their local axons collaterals make atypically oriented pyramids in layer 2 ideally suited to perform horizontal integration of synaptic inputs in the neocortex.

  16. Electrophysiological Correlates of Rapid Auditory and Linguistic Processing in Adolescents with Specific Language Impairment

    PubMed Central

    Weber-Fox, Christine; Leonard, Laurence B.; Wray, Amanda Hampton; Tomblin, J. Bruce

    2010-01-01

    Brief tonal stimuli and spoken sentences were utilized to examine whether adolescents (aged 14;3-18;1) with specific language impairments (SLI) exhibit atypical neural activity for rapid auditory processing of non-linguistic stimuli and linguistic processing of verb-agreement and semantic constraints. Further, we examined whether the behavioral and electrophysiological indices for rapid auditory processing were correlated with those for linguistic processing. Fifteen adolescents with SLI and 15 adolescents with normal language met strict criteria for displaying consistent diagnoses from kindergarten through the eighth grade. The findings provide evidence that auditory processing for non-linguistic stimuli is atypical in a significant number of adolescents with SLI compared to peers with normal language and indicate that reduced efficiency in auditory processing in SLI is more vulnerable to rapid rates (200 ms ISI) of stimuli presentation (indexed by reduced accuracy, a tendency for longer RTs, reduced N100 over right anterior sites, and reduced amplitude P300). Many adolescents with SLI displayed reduced behavioral accuracy for detecting verb-agreement violations and semantic anomalies, along with less robust P600s elicited by verb-agreement violations. The results indicate that ERPs elicited by morphosyntactic aspects of language processing are atypical in many adolescents with SLI. Additionally, correlational analyses between behavioral and electrophysiological indices of processing non-linguistic stimuli and verb-agreement violations suggest that the integrity of neural functions for auditory processing may only account for a small proportion of the variance in morphosyntactic processing in some adolescents. PMID:20889197

  17. Neural ensemble communities: Open-source approaches to hardware for large-scale electrophysiology

    PubMed Central

    Siegle, Joshua H.; Hale, Gregory J.; Newman, Jonathan P.; Voigts, Jakob

    2014-01-01

    One often-overlooked factor when selecting a platform for large-scale electrophysiology is whether or not a particular data acquisition system is “open” or “closed”: that is, whether or not the system’s schematics and source code are available to end users. Open systems have a reputation for being difficult to acquire, poorly documented, and hard to maintain. With the arrival of more powerful and compact integrated circuits, rapid prototyping services, and web-based tools for collaborative development, these stereotypes must be reconsidered. We discuss some of the reasons why multichannel extracellular electrophysiology could benefit from open-source approaches and describe examples of successful community-driven tool development within this field. In order to promote the adoption of open-source hardware and to reduce the need for redundant development efforts, we advocate a move toward standardized interfaces that connect each element of the data processing pipeline. This will give researchers the flexibility to modify their tools when necessary, while allowing them to continue to benefit from the high-quality products and expertise provided by commercial vendors. PMID:25528614

  18. Mechanobiology of lymphatic contractions.

    PubMed

    Munn, Lance L

    2015-02-01

    The lymphatic system is responsible for controlling tissue fluid pressure by facilitating flow of lymph (i.e. the plasma and cells that enter the lymphatic system). Because lymph contains cells of the immune system, its transport is not only important for fluid homeostasis, but also immune function. Lymph drainage can occur via passive flow or active pumping, and much research has identified the key biochemical and mechanical factors that affect output. Although many studies and reviews have addressed how tissue properties and fluid mechanics (i.e. pressure gradients) affect lymph transport [1-3] there is less known about lymphatic mechanobiology. As opposed to passive mechanical properties, mechanobiology describes the active coupling of mechanical signals and biochemical pathways. Lymphatic vasomotion is the result of a fascinating system affected by mechanical forces exerted by the flowing lymph, including pressure-induced vessel stretch and flow-induced shear stresses. These forces can trigger or modulate biochemical pathways important for controlling the lymphatic contractions. Here, I review the current understanding of lymphatic vessel function, focusing on vessel mechanobiology, and summarize the prospects for a comprehensive understanding that integrates the mechanical and biomechanical control mechanisms in the lymphatic system.

  19. Simultaneous wireless electrophysiological and neurochemical monitoring

    NASA Astrophysics Data System (ADS)

    Murari, Kartikeya; Mollazadeh, Mohsen; Thakor, Nitish; Cauwenberghs, Gert

    2008-08-01

    Information processing and propagation in the central nervous system is mostly electrical in nature. At synapses, electrical signals cause the release of neurotransmitters like dopamine, glutamate etc., that are sensed by post-synaptic neurons resulting in signal propagation or inhibition. It can be very informative to monitor electrical and neurochemical signals simultaneously to understand the mechanisms underlying normal or abnormal brain function. We present an integrated system for the simultaneous wireless acquisition of neurophysiological and neurochemical activity. Applications of the system to neuroscience include monitoring EEG and glutamate in rat somatosensory cortex following global ischemia.

  20. Issues in physician contracting.

    PubMed

    Fanburg, John D; Leone, Alyson M

    2005-09-01

    Dermatologists will enter into a number of different contracts during their professional careers. It is important that in each agreement they enter, dermatologists reap the benefits that they aspire for and understand the consequences of each provision. This article addresses just a few of the different issues that arise in physician contracting, such as choosing the appropriate form of business entity; the importance of a writing; term and termination of the contract; compensation models; benefits, vacation and other time off included in the contract; malpractice insurance; and restrictive covenants. Each provision should be carefully analyzed to ensure that it will protect the best interests of the dermatologist in that situation. PMID:16202950

  1. Comparison of electrophysiological data from human-induced pluripotent stem cell-derived cardiomyocytes to functional preclinical safety assays.

    PubMed

    Harris, Kate; Aylott, Mike; Cui, Yi; Louttit, James B; McMahon, Nicholas C; Sridhar, Arun

    2013-08-01

    Human-induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) are a potential source to develop assays for predictive electrophysiological safety screening. Published studies show that the relevant physiology and pharmacology exist but does not show the translation between stem cell cardiomyocyte assays and other preclinical safety screening assays, which is crucial for drug discovery and safety scientists and the regulators. Our studies are the first to show the pharmacology of ion channel blockade and compare them with existing functional cardiac electrophysiology studies. Ten compounds (a mixture of pure hERG [E-4031 and Cisapride], hERG and sodium [Flecainide, Mexiletine, Quinidine, and Terfenadine], calcium channel blockers [Nifedipine and Verapamil], and two proprietary compounds [GSK A and B]) were tested, and results from hiPSC-CMs studied on multielectrode arrays (MEA) were compared with other preclincial models and clinical drug concentrations and effects using integrated risk assessment plots. All ion channel blockers produced (1) functional effects on repolarization and depolarization around the IC25 and IC50 values and (2) excessive blockade of hERG and/or blockade of sodium current precipitated arrhythmias. Our MEA data show that hiPSC-CMs demonstrate relevant pharmacology and show excellent correlations to current functional cardiac electrophysiological studies. Based on these results, MEA assays using iPSC-CMs offer a reliable, cost effective, and surrogate to preclinical in vitro testing, in addition to the 3Rs (refine, reduce, and replace animals in research) benefit. PMID:23690542

  2. Stac3 is a component of the excitation-contraction coupling machinery and mutated in Native American myopathy

    PubMed Central

    Horstick, Eric J.; Linsley, Jeremy W.; Dowling, James J.; Hauser, Michael A.; McDonald, Kristin K.; Ashley-Koch, Allison; Saint-Amant, Louis; Satish, Akhila; Cui, Wilson W.; Zhou, Weibin; Sprague, Shawn M.; Stamm, Demetra S.; Powell, Cynthia M.; Speer, Marcy C.; Franzini-Armstrong, Clara; Hirata, Hiromi; Kuwada, John Y.

    2013-01-01

    Excitation-contraction coupling, the process that regulates contractions by skeletal muscles, transduces changes in membrane voltage by activating release of Ca2+ from internal stores to initiate muscle contraction. Defects in EC coupling are associated with muscle diseases. Here we identify Stac3 as a novel component of the EC coupling machinery. Using a zebrafish genetic screen, we generate a locomotor mutation that is mapped to stac3. We provide electrophysiological, Ca2+ imaging, immunocytochemical and biochemical evidence that Stac3 participates in excitation-contraction coupling in muscles. Furthermore, we reveal that a mutation in human STAC3 as the genetic basis of the debilitating Native American myopathy (NAM). Analysis of NAM stac3 in zebrafish shows that the NAM mutation decreases excitation-contraction coupling. These findings enhance our understanding of both excitation-contraction coupling and the pathology of myopathies. PMID:23736855

  3. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... contract type. 235.006 Section 235.006 Federal Acquisition Regulations System DEFENSE ACQUISITION... CONTRACTING 235.006 Contracting methods and contract type. (b)(i) For major defense acquisition programs as... award a fixed-price type contract for a development program effort unless— (1) The level of program...

  4. Electrogenesis in the lower Metazoa and implications for neuronal integration.

    PubMed

    Meech, Robert W

    2015-02-15

    Electrogenic communication appears to have evolved independently in a variety of animal and plant lineages. Considered here are metazoan cells as disparate as the loose three-dimensional parenchyma of glass sponges, the two-dimensional epithelial sheets of hydrozoan jellyfish and the egg cell membranes of the ctenophore Beroe ovata, all of which are capable of generating electrical impulses. Neuronal electrogenesis may have evolved independently in ctenophores and cnidarians but the dearth of electrophysiological data relating to ctenophore nerves means that our attention is focused on the Cnidaria, whose nervous systems have been the subject of extensive study. The aim here is to show how their active and passive neuronal properties interact to give integrated behaviour. Neuronal electrogenesis, goes beyond simply relaying 'states of excitement' and utilizes the equivalent of a set of basic electrical 'apps' to integrate incoming sensory information with internally generated pacemaker activity. A small number of membrane-based processes make up these analogue applications. Passive components include the decremental spread of current determined by cellular anatomy; active components include ion channels specified by their selectivity and voltage dependence. A recurring theme is the role of inactivating potassium channels in regulating performance. Although different aspects of cnidarian behaviour are controlled by separate neuronal systems, integrated responses and coordinated movements depend on interactions between them. Integrative interactions discussed here include those between feeding and swimming, between tentacle contraction and swimming and between slow and fast swimming in the hydrozoan jellyfish Aglantha digitale. PMID:25696817

  5. Electrogenesis in the lower Metazoa and implications for neuronal integration

    PubMed Central

    Meech, Robert W.

    2015-01-01

    Electrogenic communication appears to have evolved independently in a variety of animal and plant lineages. Considered here are metazoan cells as disparate as the loose three-dimensional parenchyma of glass sponges, the two-dimensional epithelial sheets of hydrozoan jellyfish and the egg cell membranes of the ctenophore Beroe ovata, all of which are capable of generating electrical impulses. Neuronal electrogenesis may have evolved independently in ctenophores and cnidarians but the dearth of electrophysiological data relating to ctenophore nerves means that our attention is focused on the Cnidaria, whose nervous systems have been the subject of extensive study. The aim here is to show how their active and passive neuronal properties interact to give integrated behaviour. Neuronal electrogenesis, goes beyond simply relaying ‘states of excitement’ and utilizes the equivalent of a set of basic electrical ‘apps’ to integrate incoming sensory information with internally generated pacemaker activity. A small number of membrane-based processes make up these analogue applications. Passive components include the decremental spread of current determined by cellular anatomy; active components include ion channels specified by their selectivity and voltage dependence. A recurring theme is the role of inactivating potassium channels in regulating performance. Although different aspects of cnidarian behaviour are controlled by separate neuronal systems, integrated responses and coordinated movements depend on interactions between them. Integrative interactions discussed here include those between feeding and swimming, between tentacle contraction and swimming and between slow and fast swimming in the hydrozoan jellyfish Aglantha digitale. PMID:25696817

  6. Nanomaterial-Enabled Dry Electrodes for Electrophysiological Sensing: A Review

    NASA Astrophysics Data System (ADS)

    Yao, Shanshan; Zhu, Yong

    2016-04-01

    Long-term, continuous, and unsupervised tracking of physiological data is becoming increasingly attractive for health/wellness monitoring and ailment treatment. Nanomaterials have recently attracted extensive attention as building blocks for flexible/stretchable conductors and are thus promising candidates for electrophysiological electrodes. Here we provide a review on nanomaterial-enabled dry electrodes for electrophysiological sensing, focusing on electrocardiography (ECG). The dry electrodes can be classified into contact surface electrodes, contact-penetrating electrodes, and noncontact capacitive electrodes. Different types of electrodes including their corresponding equivalent electrode-skin interface models and the sources of the noise are first introduced, followed by a review on recent developments of dry ECG electrodes based on various nanomaterials, including metallic nanowires, metallic nanoparticles, carbon nanotubes, and graphene. Their fabrication processes and performances in terms of electrode-skin impedance, signal-to-noise ratio, resistance to motion artifacts, skin compatibility, and long-term stability are discussed.

  7. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment

    PubMed Central

    Crisp, Kevin M.; Lin, Hunter; Prosper, Issa

    2016-01-01

    Electrophysiology is a valuable skill for the neuroscientist, but the learning curve for students can be steep. Here we describe a very simple electromyography (EMG) amplifier that can be built from scratch by students with no electronics experience in about 30 minutes, making it ideal for incorporating into a laboratory activity. With few parts and no adjustments except the gain, students can begin physiology experiments quickly while having the satisfaction of having built the equipment themselves. Because the output of the circuit goes to a computer sound card, students can listen to electrophysiological activity as they see it on the computer screen, a feature many of our students greatly appreciated. Various applications are discussed, including dual channel recording, using streaming media platforms with remote lab partners and acquiring data in the field on a smart phone. Our students reported that they enjoyed being able to build a working device and using it to record from their own muscles. PMID:27385921

  8. [Value of functional and electrophysiological studies in amblyopia].

    PubMed

    Korol, S; Fiore, C

    1976-04-01

    In a group of patients suffering from amblyopia, the authors confront the results after orthoptic treatment with data provided by functional and electrophysiological examination. In 37 patients the clinical diagnosis of functional amblyopia had been made, but in 8 of these cases complimentary functional and electrophysiological examinations showed organic perturbations. This explains the failure, in these cases, of the orthoptic treatment. In the remaining 29 patients, clinical forms of functional amblyopia were found. In this group, the authors studied 20 cases showing no improvement with treatment: in 15 out of the 20 the VERs were pathological. In the 9 remaining cases which have showed improvement the VER'S were never abnormal. VER study can be undertaken, without general anaesthesia, as from 3 to 4 years of age. The authors conclude that all clinical forms of amblyopia should undergo VER investigation: patients showing pathological changes should be excluded from orthoptic treatment, from which they have no possibility of deriving benefit. PMID:135545

  9. Pants on fire: the electrophysiological signature of telling a lie.

    PubMed

    Pfister, Roland; Foerster, Anna; Kunde, Wilfried

    2014-01-01

    Even though electroencephalography has played a prominent role for lie detection via personally relevant information, the electrophysiological signature of active lying is still elusive. We addressed this signature with two experiments in which participants helped a virtual police officer to locate a knife. Crucially, before this response, they announced whether they would lie or tell the truth about the knife's location. This design allowed us to study the signature of lie-telling in the absence of rare and personally significant oddball stimuli that are typically used for lie detection via electrophysiological markers, especially the P300 component. Our results indicate that active lying attenuated P300 amplitudes as well as N200 amplitudes for such non-oddball stimuli. These results support accounts that stress the high cognitive demand of lie-telling, including the need to suppress the truthful response and to generate a lie.

  10. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment.

    PubMed

    Crisp, Kevin M; Lin, Hunter; Prosper, Issa

    2016-01-01

    Electrophysiology is a valuable skill for the neuroscientist, but the learning curve for students can be steep. Here we describe a very simple electromyography (EMG) amplifier that can be built from scratch by students with no electronics experience in about 30 minutes, making it ideal for incorporating into a laboratory activity. With few parts and no adjustments except the gain, students can begin physiology experiments quickly while having the satisfaction of having built the equipment themselves. Because the output of the circuit goes to a computer sound card, students can listen to electrophysiological activity as they see it on the computer screen, a feature many of our students greatly appreciated. Various applications are discussed, including dual channel recording, using streaming media platforms with remote lab partners and acquiring data in the field on a smart phone. Our students reported that they enjoyed being able to build a working device and using it to record from their own muscles. PMID:27385921

  11. Pants on fire: the electrophysiological signature of telling a lie.

    PubMed

    Pfister, Roland; Foerster, Anna; Kunde, Wilfried

    2014-01-01

    Even though electroencephalography has played a prominent role for lie detection via personally relevant information, the electrophysiological signature of active lying is still elusive. We addressed this signature with two experiments in which participants helped a virtual police officer to locate a knife. Crucially, before this response, they announced whether they would lie or tell the truth about the knife's location. This design allowed us to study the signature of lie-telling in the absence of rare and personally significant oddball stimuli that are typically used for lie detection via electrophysiological markers, especially the P300 component. Our results indicate that active lying attenuated P300 amplitudes as well as N200 amplitudes for such non-oddball stimuli. These results support accounts that stress the high cognitive demand of lie-telling, including the need to suppress the truthful response and to generate a lie. PMID:24972014

  12. Performance Contracting Overview.

    ERIC Educational Resources Information Center

    Wohlferd, Gerald H.

    Conclusions reached after three years of performance contracting experience and materials with which to judge the validity of the conclusions are presented in this overview of performance contracting. The conclusions are: (1) commercial firms are no better at teaching children than are public schools; (2) commercial firms expend as much or more…

  13. The New Employment Contract?

    ERIC Educational Resources Information Center

    Levine, David I.

    2002-01-01

    In the classic employment contract, especially at large companies, wages were not strongly responsive to the labor market. Instead, individual companies had distinctive company wage levels and patterns. An exhaustive study of employers and employees in the United States and Japan examined whether the "old employment contract" has been replaced.…

  14. Contracting for Telecommunications Systems.

    ERIC Educational Resources Information Center

    Brautigam, Arthur W.

    1984-01-01

    Reasons for changing telephone systems at colleges and universities and the preparation and evaluation of requests for proposals (RFP) are discussed. The negotiation and monitoring of the contract are also addressed. It is noted that contracting for a new telecommunications system is extremely complex. Reasons for changing systems include cost…

  15. Whither Performance Contracting?

    ERIC Educational Resources Information Center

    Green, Norman S.

    This report describes briefly performance contracts; discusses their shortcomings, pitfalls, and advantages; and gives some insight into the future development of this new concept. Two shortcomings of performance contracting include (1) teaching to the test and (2) board abdication of its responsibility for making final decisions about educational…

  16. From Galvani to patch clamp: the development of electrophysiology.

    PubMed

    Verkhratsky, Alexei; Krishtal, O A; Petersen, Ole H

    2006-12-01

    The development of electrophysiology is traced from the early beginnings represented by the work of the Dutch microscopist, Jan Swammerdam, in the 17th century through the first notion of an aqueous transmembrane pore as a substrate of excitability made by Luigi Galvani in late 18th century to the invention late in the 20th century of the patch-clamp technique by Erwin Neher and Bert Sakmann.

  17. Space Motion Sickness and Stress Training Simulator using Electrophysiological Biofeedback

    NASA Astrophysics Data System (ADS)

    Gaudeau, C.; Golding, J. F.; Thevot, F.; Lucas, Y.; Bobola, P.; Thouvenot, J.

    2005-06-01

    An important problem in manned spaceflight is the nausea that typically appears during the first 3 days and then disappears after 5 days. Methods of detecting changes in electrophysiological signals are being studied in order to reduce susceptibility to space motion sickness through biofeedback training, and for the early detection of nausea during EVA. A simulator would allow subjects to control their body functions and to use biofeedback to control space motion sickness and stress.

  18. From Galvani to patch clamp: the development of electrophysiology.

    PubMed

    Verkhratsky, Alexei; Krishtal, O A; Petersen, Ole H

    2006-12-01

    The development of electrophysiology is traced from the early beginnings represented by the work of the Dutch microscopist, Jan Swammerdam, in the 17th century through the first notion of an aqueous transmembrane pore as a substrate of excitability made by Luigi Galvani in late 18th century to the invention late in the 20th century of the patch-clamp technique by Erwin Neher and Bert Sakmann. PMID:17072639

  19. Signaling in muscle contraction.

    PubMed

    Kuo, Ivana Y; Ehrlich, Barbara E

    2015-02-02

    Signaling pathways regulate contraction of striated (skeletal and cardiac) and smooth muscle. Although these are similar, there are striking differences in the pathways that can be attributed to the distinct functional roles of the different muscle types. Muscles contract in response to depolarization, activation of G-protein-coupled receptors and other stimuli. The actomyosin fibers responsible for contraction require an increase in the cytosolic levels of calcium, which signaling pathways induce by promoting influx from extracellular sources or release from intracellular stores. Rises in cytosolic calcium stimulate numerous downstream calcium-dependent signaling pathways, which can also regulate contraction. Alterations to the signaling pathways that initiate and sustain contraction and relaxation occur as a consequence of exercise and pathophysiological conditions.

  20. Slow cortical rhythms: from single-neuron electrophysiology to whole-brain imaging in vivo.

    PubMed

    Olcese, Umberto; Faraguna, Ugo

    2015-01-01

    The slow cortical oscillation is the major brain rhythm occurring during sleep, and has been the object of thorough investigation for over thirty years. Despite all these efforts, the function and the neuronal mechanisms behind slow cortical rhythms remain only partially understood. In this review we will provide an overview of the techniques available for the in vivo study of slow cortical oscillations in animal models. Our goal is to provide an up to date resource for the selection of the best experimental strategies to study specific aspects of slow oscillations. We will cover both traditional, population-level electrophysiological approaches (electroencephalography - EEG, local field potentials) as well as more recent techniques, such as two photon calcium imaging and optogenetics. Overall, we believe that new breakthroughs in our understanding of slow cortical rhythms will require the integration of different techniques, to bridge the gap between different spatio-temporal scales and go from a correlative to a causal level of analysis. PMID:26742663

  1. Electrophysiological Imaging of Brain Activity and Connectivity – Challenges and Opportunities

    PubMed Central

    He, Bin; Yang, Lin; Wilke, Christopher; Yuan, Han

    2011-01-01

    Unlocking the dynamic inner workings of the brain continues to remain a grand challenge of the 21st century. To this end, functional neuroimaging modalities represent an outstanding approach to better understand the mechanisms of both normal and abnormal brain function. The ability to image brain function with ever increasing spatial and temporal resolution utilizing minimal or non-invasive procedures has made a significant leap over the past several decades. Further delineation of functional networks could lead to improved understanding of brain function in both normal as well as diseased states. This article reviews recent advancements and current challenges in dynamic functional neuroimaging techniques, including electrophysiological source imaging, multimodal neuroimaging integrating fMRI with EEG/MEG, and functional connectivity imaging. PMID:21478071

  2. Electrophysiological evidence of early word learning.

    PubMed

    Junge, Caroline; Cutler, Anne; Hagoort, Peter

    2012-12-01

    Around their first birthday infants begin to talk, yet they comprehend words long before. This study investigated the event-related potentials (ERP) responses of nine-month-olds on basic level picture-word pairings. After a familiarization phase of six picture-word pairings per semantic category, comprehension for novel exemplars was tested in a picture-word matching paradigm. ERPs time-locked to pictures elicited a modulation of the negative central (Nc) component, associated with visual attention and recognition. It was attenuated by category repetition as well as by the type-token ratio of picture context. ERPs time-locked to words in the training phase became more negative with repetition (N300-600), but there was no influence of picture type-token ratio, suggesting that infants have identified the concept of each picture before a word was presented. Results from the test phase provided clear support that infants integrated word meanings with (novel) picture context. Here, infants showed different ERP responses for words that did or did not align with the picture context: a phonological mismatch (N200) and a semantic mismatch (N400). Together, results were informative of visual categorization, word recognition and word-to-world-mappings, all three crucial processes for vocabulary construction. PMID:23108241

  3. A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability

    PubMed Central

    Gagnon-Turcotte, Gabriel; Avakh Kisomi, Alireza; Ameli, Reza; Dufresne Camaro, Charles-Olivier; LeChasseur, Yoan; Néron, Jean-Luc; Brule Bareil, Paul; Fortier, Paul; Bories, Cyril; de Koninck, Yves; Gosselin, Benoit

    2015-01-01

    We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm2 at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals. PMID:26371006

  4. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons.

    PubMed

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-01-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven't been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries. PMID:27052791

  5. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    NASA Astrophysics Data System (ADS)

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-04-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries.

  6. Atrial Electrophysiological Remodeling and Fibrillation in Heart Failure

    PubMed Central

    Pandit, Sandeep V.; Workman, Antony J.

    2016-01-01

    Heart failure (HF) causes complex, chronic changes in atrial structure and function, which can cause substantial electrophysiological remodeling and predispose the individual to atrial fibrillation (AF). Pharmacological treatments for preventing AF in patients with HF are limited. Improved understanding of the atrial electrical and ionic/molecular mechanisms that promote AF in these patients could lead to the identification of novel therapeutic targets. Animal models of HF have identified numerous changes in atrial ion currents, intracellular calcium handling, action potential waveform and conduction, as well as expression and signaling of associated proteins. These studies have shown that the pattern of electrophysiological remodeling likely depends on the duration of HF, the underlying cardiac pathology, and the species studied. In atrial myocytes and tissues obtained from patients with HF or left ventricular systolic dysfunction, the data on changes in ion currents and action potentials are largely equivocal, probably owing mainly to difficulties in controlling for the confounding influences of multiple variables, such as patient’s age, sex, disease history, and drug treatments, as well as the technical challenges in obtaining such data. In this review, we provide a summary and comparison of the main animal and human electrophysiological studies to date, with the aim of highlighting the consistencies in some of the remodeling patterns, as well as identifying areas of contention and gaps in the knowledge, which warrant further investigation. PMID:27812293

  7. [Electrophysiological evaluation of pathophysiological and pharmacological characteristics of chronic pain].

    PubMed

    Tanabe, Mitsuo

    2014-01-01

    Recent studies have revealed considerable evidence for our understanding of the mechanisms underlying the development and maintenance of chronic pain including neuropathic and inflammatory pain. It is considered that plastic changes in the spinal dorsal horn contribute to the amplification of pain signaling. Moreover, persistent pain affects brain function and also the endogenous descending pain regulatory system. To characterize these pathophysiological changes and pharmacological properties in chronic pain conditions at the synaptic level, we have employed in vitro electrophysiology in slices of the spinal cord and supraspinal regions such as brainstem and hippocampus of adult mice and in vivo electrophysiology in anesthetized rats. In particular, we have successfully prepared spinal slices with an attached dorsal root, where A-fiber- or C-fiber-evoked monosynaptic excitatory postsynaptic currents or miniature excitatory postsynaptic currents were recorded from voltage-clamped dorsal horn neurons. In anesthetized rats, C-fiber-evoked field potentials were recorded from the spinal dorsal horn in response to electrical stimulation of the sciatic nerve fibers, and their long-term potentiation was elicited to mimic increased synaptic efficacy after peripheral nerve injury. Of interest is the finding that some drugs exerted the injury-specific effects on synaptic transmission, thus strongly suggesting the importance of pharmacological analysis at the synaptic level combined with electrophysiological techniques to obtain pathophysiological information and new insights into drug research in this field. PMID:24584022

  8. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    PubMed Central

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-01-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries. PMID:27052791

  9. In silico cell electrophysiology for measuring transcellular calcium currents

    NASA Astrophysics Data System (ADS)

    ul Haque, A.; Rokkam, M.; De Carlo, A. R.; Wereley, S. T.; Wells, H. W.; McLamb, W. T.; Roux, S. J.; Irazoqui, P. P.; Porterfield, D. M.

    2006-10-01

    Trans-cellular calcium currents play a central role in the establishment of polarity in differentiating cells. Typically these currents are measured and studied experimentally using ion selective glass microelectrodes. We have recently developed an in silico cell electrophysiology lab-on-a-chip device with the specific science objectives of measuring these transcellular calcium currents in an advanced throughput format. The device consists of 16 pyramidal pores on a silicon substrate with four Ag/AgCl electrodes leading into each pore on the four poles. An SU-8 layer is used as the structural and insulating layer and a calcium ion selective membrane is used to impart ion selectivity to the Ag/AgCl electrodes. In this paper we demonstrate the utility of the cell electrophysiology biochip in measuring these transcellular calcium currents from single cells using the model biological system Ceratopteris richardii. We monitored these fern spores during germination and pharmacologically inhibited biophysical calcium transport. These results demonstrate the utility and versatility of the in silico cell electrophysiology biochip. While this version of the biochip was engineered to fulfill the specific science objectives of measuring trans-cellular calcium currents from Ceratopteris fern spores, the chip can easily be modified for a variety of biomedical and pharmacological applications. Future

  10. Electrophysiological evidence for an early processing of human voices

    PubMed Central

    Charest, Ian; Pernet, Cyril R; Rousselet, Guillaume A; Quiñones, Ileana; Latinus, Marianne; Fillion-Bilodeau, Sarah; Chartrand, Jean-Pierre; Belin, Pascal

    2009-01-01

    Background Previous electrophysiological studies have identified a "voice specific response" (VSR) peaking around 320 ms after stimulus onset, a latency markedly longer than the 70 ms needed to discriminate living from non-living sound sources and the 150 ms to 200 ms needed for the processing of voice paralinguistic qualities. In the present study, we investigated whether an early electrophysiological difference between voice and non-voice stimuli could be observed. Results ERPs were recorded from 32 healthy volunteers who listened to 200 ms long stimuli from three sound categories - voices, bird songs and environmental sounds - whilst performing a pure-tone detection task. ERP analyses revealed voice/non-voice amplitude differences emerging as early as 164 ms post stimulus onset and peaking around 200 ms on fronto-temporal (positivity) and occipital (negativity) electrodes. Conclusion Our electrophysiological results suggest a rapid brain discrimination of sounds of voice, termed the "fronto-temporal positivity to voices" (FTPV), at latencies comparable to the well-known face-preferential N170. PMID:19843323

  11. Application of electrophysiological methods and magnetic resonance tomographic angiography in the differentiation between hemifacial spasm and Meige syndrome.

    PubMed

    Huang, Chuyi; Miao, Suhua; Chu, Heling; Muheremu, Aikeremujiang; Wu, Jinting; Zhou, Rongsong; Zuo, Huancong; Ma, Yu

    2016-05-01

    Bilateral hemifacial spasm and Meige syndrome can be easily confused due to their similar clinical manifestation. Here, we aimed to investigate the application of electrophysiological methods and magnetic resonance tomographic angiography (MRTA) in the differentiation between hemifacial spasm and Meige syndrome. 10 patients with bilateral hemifacial spasm and 9 patients with Meige syndrome received electrophysiological monitoring of nerves. There were two males and eight females with bilateral hemifacial spasm, aged 16-58 years with a course of 5-54 months. For the patients with Meige syndrome, there were three males and six females, aged 51-68 years with a course of 12-36 months. All patients received conventional MRTA of the brain blood vessels before decompression. We found that all patients with Meige syndrome showed synchronous contraction of bilateral orbicularis oculi muscles and (or) burst discharge from orbicularis oris muscles in surface electromyography (sEMG). However, those with hemifacial spasm presented with bilaterally asynchronous burst discharge. Electromyography for patients with Meige syndrome did not record abnormal muscle response (AMR), but recorded AMR for those with bilateral hemifacial spasm. The offending vessels were compressed in patients with hemifacial spasm in MRTA, while MRTA results were generally negative for those with Meige syndrome. Combining sEMG and AMR detection in EMG and MRTA, bilateral hemifacial spasm can be differentiated from Meige syndrome with a reduction of misdiagnosis rate.

  12. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris).

    PubMed

    Hunt, James; Murrell, Jo; Knazovicky, David; Harris, John; Kelly, Sara; Knowles, Toby G; Lascelles, B Duncan X

    2016-01-01

    Naturally occurring canine osteoarthritis represents a welfare issue for affected dogs (Canis familiaris), but is also considered very similar to human osteoarthritis and has therefore been proposed as a model of disease in humans. Central sensitisation is recognized in human osteoarthritis sufferers but identification in dogs is challenging. Electromyographic measurement of responses to nociceptive stimulation represents a potential means of investigating alterations in central nociceptive processing, and has been evaluated in conscious experimental dogs, but is likely to be aversive. Development of a suitable anaesthetic protocol in experimental dogs, which facilitated electrophysiological nociceptive withdrawal reflex assessment, may increase the acceptability of using the technique in owned dogs with naturally occurring osteoarthritis. Seven purpose bred male hound dogs underwent electromyographic recording sessions in each of three states: acepromazine sedation, alfaxalone sedation, and alfaxalone anaesthesia. Electromyographic responses to escalating mechanical and electrical, and repeated electrical, stimuli were recorded. Subsequently the integral of both early and late rectified responses was calculated. Natural logarithms of the integral values were analysed within and between the three states using multi level modeling. Alfaxalone increased nociceptive thresholds and decreased the magnitude of recorded responses, but characteristics of increasing responses with increasing stimulus magnitude were preserved. Behavioural signs of anxiety were noted in two out of seven dogs during recordings in the acepromazine sedated state. There were few significant differences in response magnitude or nociceptive threshold between the two alfaxalone states. Following acepromazine premedication, induction of anaesthesia with 1-2 mg kg-1 alfaxalone, followed by a continuous rate infusion in the range 0.075-0.1 mg kg-1 min-1 produced suitable conditions to enable assessment

  13. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris)

    PubMed Central

    Hunt, James; Murrell, Jo; Knazovicky, David; Harris, John; Kelly, Sara; Knowles, Toby G.; Lascelles, B. Duncan X.

    2016-01-01

    Naturally occurring canine osteoarthritis represents a welfare issue for affected dogs (Canis familiaris), but is also considered very similar to human osteoarthritis and has therefore been proposed as a model of disease in humans. Central sensitisation is recognized in human osteoarthritis sufferers but identification in dogs is challenging. Electromyographic measurement of responses to nociceptive stimulation represents a potential means of investigating alterations in central nociceptive processing, and has been evaluated in conscious experimental dogs, but is likely to be aversive. Development of a suitable anaesthetic protocol in experimental dogs, which facilitated electrophysiological nociceptive withdrawal reflex assessment, may increase the acceptability of using the technique in owned dogs with naturally occurring osteoarthritis. Seven purpose bred male hound dogs underwent electromyographic recording sessions in each of three states: acepromazine sedation, alfaxalone sedation, and alfaxalone anaesthesia. Electromyographic responses to escalating mechanical and electrical, and repeated electrical, stimuli were recorded. Subsequently the integral of both early and late rectified responses was calculated. Natural logarithms of the integral values were analysed within and between the three states using multi level modeling. Alfaxalone increased nociceptive thresholds and decreased the magnitude of recorded responses, but characteristics of increasing responses with increasing stimulus magnitude were preserved. Behavioural signs of anxiety were noted in two out of seven dogs during recordings in the acepromazine sedated state. There were few significant differences in response magnitude or nociceptive threshold between the two alfaxalone states. Following acepromazine premedication, induction of anaesthesia with 1–2 mg kg-1 alfaxalone, followed by a continuous rate infusion in the range 0.075–0.1 mg kg-1 min-1 produced suitable conditions to enable

  14. Electrophysiology of skilled performances in children.

    PubMed

    Chiarenza, G A

    1986-04-01

    Skilled performance is a result of appropriate integration of sensorimotor, cognitive and motivational functions. When Piaget was asked about the nature of reality and our knowledge of it, he answered: "I know an object only when I can act on it; before this action I cannot say anything about it". It has been proposed that motor actions are the source from which mental operations emerge. The intellectual growth of a child goes through stages during which actions, perceptions and ability for concrete or abstract thought hold in turn a predominant role. On the grounds of this theoretical framework it could be argued that neuropsychophysiological investigations of skilled performance in children which incorporate the study of performance-related brain electrical activity could contribute unique information with theoretical and clinical implications. A pattern of slow and phasic brain electrical activity is consistently associated with the execution of skilled ballistic tasks. The slow potentials of the preparatory period (Bereitschfts Potential-BP) are of low amplitude in low demand tasks and in young children. The potentials closely associated with the execution of the act and reflecting sensory feedback activity (Motor Cortex Potential-MCP) are constantly present in children of all ages. The potential associated with knowledge of results (Skilled Performance Positivity-SPP) is only present if task relevant exteroceptive information is expected and occurs. The SPP is independent of the action itself and of the existence of non-informative exteroceptive stimulation. The SPP is absent in unskilled tasks and in young children. The motor performance related with the execution of the motor act improves with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3759404

  15. [Negative symptoms of schizophrenia: from electrophysiology to electrotherapy].

    PubMed

    Micoulaud Franchi, J-A; Quiles, C; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    The aim of this review of the literature is to summarize the state of the knowledge concerning the relationship between negative symptoms in schizophrenia, electrophysiology and electrotherapy. The scientific literature search of international articles was performed during August and September 2015 using the PubMed electronic database. We used the following MeSH terms: "Negative symptoms", "Schizophrenia", "Electrophysiology", "Neurophysiology", "EEG power", "Alpha rhythm", "Transcranial magnetic stimulation", "Transcranial direct current stimulation", "Electroconvulsive therapy", "Neurofeedback", "Vagus Nerve Stimulation", "Deep Brain Stimulation", and "State dependent". Negative symptoms in schizophrenia are associated with altered activity in prefrontal cortex in functional neuroimaging studies. This is in line with electrophysiological measurements that found a change in EEG spectral power in the alpha frequency band over prefrontal brain regions. The notion of functional hypofrontality has led to hypotheses that electrotherapy applied to the prefrontal cortex may be an effective treatment of negative symptoms in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) were used to increase cortical activity in schizophrenia and achieve a clinical effect on negative symptoms. Three meta-analyses confirmed, with a moderate effect size, that rTMS is an effective treatment option for negative symptoms in schizophrenia. The two subsequently published prospective multicenter studies, however, found opposite results from each other. Two randomized controlled studies suggested that tDCS is an effective treatment option for negative symptoms. There is no study on the efficacy of neurofeedback, vagal nerve stimulation or deep brain stimulation on negative symptoms in schizophrenia. Additional studies are needed to confirm the efficacy of rTMS and tDCS on negative symptoms in schizophrenia. Influencing factors

  16. [Negative symptoms of schizophrenia: from electrophysiology to electrotherapy].

    PubMed

    Micoulaud Franchi, J-A; Quiles, C; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    The aim of this review of the literature is to summarize the state of the knowledge concerning the relationship between negative symptoms in schizophrenia, electrophysiology and electrotherapy. The scientific literature search of international articles was performed during August and September 2015 using the PubMed electronic database. We used the following MeSH terms: "Negative symptoms", "Schizophrenia", "Electrophysiology", "Neurophysiology", "EEG power", "Alpha rhythm", "Transcranial magnetic stimulation", "Transcranial direct current stimulation", "Electroconvulsive therapy", "Neurofeedback", "Vagus Nerve Stimulation", "Deep Brain Stimulation", and "State dependent". Negative symptoms in schizophrenia are associated with altered activity in prefrontal cortex in functional neuroimaging studies. This is in line with electrophysiological measurements that found a change in EEG spectral power in the alpha frequency band over prefrontal brain regions. The notion of functional hypofrontality has led to hypotheses that electrotherapy applied to the prefrontal cortex may be an effective treatment of negative symptoms in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) were used to increase cortical activity in schizophrenia and achieve a clinical effect on negative symptoms. Three meta-analyses confirmed, with a moderate effect size, that rTMS is an effective treatment option for negative symptoms in schizophrenia. The two subsequently published prospective multicenter studies, however, found opposite results from each other. Two randomized controlled studies suggested that tDCS is an effective treatment option for negative symptoms. There is no study on the efficacy of neurofeedback, vagal nerve stimulation or deep brain stimulation on negative symptoms in schizophrenia. Additional studies are needed to confirm the efficacy of rTMS and tDCS on negative symptoms in schizophrenia. Influencing factors

  17. 48 CFR 916.307 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 916.307 Contract clauses. (g) Insert the... solicitations and contracts when a cost-reimbursement research and development contract with a State or...

  18. The Case for Performance Contracting.

    ERIC Educational Resources Information Center

    Miller, Sutherland; Wilson, Nancy

    1981-01-01

    Discussed the State of Colorado's introduction of performance contracting into its relationships with community mental health centers. Describes the nature of the contract and its implementation. Particular emphasis is placed on the implications of the contract for program evaluation. (Author)

  19. Electrophysiological, vasoactive, and gastromodulatory effects of stevia in healthy Wistar rats.

    PubMed

    Yesmine, Saquiba; Connolly, Kylie; Hill, Nicholas; Coulson, Fiona R; Fenning, Andrew S

    2013-07-01

    Antihypertensive and antidiabetic effects of stevia, Stevia rebaudiana (Asteraceae), have been demonstrated in several human and animal models. The current study aims to define stevia's role in modifying the electrophysiological and mechanical properties of cardiomyocytes, blood vessels, and gastrointestinal smooth muscle. Tissues from thoracic aorta, mesenteric arteries, ileum, and left ventricular papillary muscles were excised from 8-week-old healthy Wistar rats. The effects of stevia (1 × 10-9 M to 1 × 10-4 M) were measured on these tissues. Stevia's effects in the presence of verapamil, 4-AP, and L-NAME were also assessed. In cardiomyocytes, stevia attenuated the force of contraction, decreased the average peak amplitude, and shortened the repolarisation phase of action potential - repolarisation phase of action potential20 by 25 %, repolarisation phase of action potential50 by 34 %, and repolarisation phase of action potential90 by 36 %. Stevia caused relaxation of aortic tissues which was significantly potentiated in the presence of verapamil. In mesenteric arteries, incubation with L-NAME failed to block stevia-induced relaxation indicating the mechanism of action may not be fully via nitric oxide-dependent pathways. Stevia concentration-dependently reduced electrical field stimulated and carbachol-induced contractions in the isolated ileum. This study is the first to show the effectiveness of stevia in reducing cardiac action potential duration at 20 %, 50 %, and 90 % of repolarisation. Stevia also showed beneficial modulatory effects on cardiovascular and gastrointestinal tissues via calcium channel antagonism, activation of the M2 muscarinic receptor function, and enhanced nitric oxide release.

  20. 48 CFR 232.617 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF DEFENSE GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Debts 232.617 Contract clause... personnel at civilian schools, colleges, and universities; (B) Basic agreements with telephone companies...

  1. Checking software contracts

    SciTech Connect

    Mitchell, R.; Maung, I.; Howse, J.; Heathcote, T.

    1995-12-31

    In object-oriented software, contracts between classes can be expressed in terms of preconditions, postconditions and invariants. In the programming language Eiffel, contracts can be checked at run-time. Within inheritance hierarchies, contracts can be used to control the redefinition of services. In Eiffel, the rules ensure that redefinition is safe in the presence of polymorphism and dynamic binding. This paper shows that Eiffel`s support for contracts can be extended, both to cover the polymorphic case more fully, and to cover other uses of inheritance, including its use for selectively reusing code from a parent class. The paper proposes that software designers should state what properties they claim for any uses of inheritance, in order that extra checks on consistency can be applied, and shows that some extra debugging power could be obtained easily, by changing only the run-time system for Eiffel, rather than the language itself.

  2. Mechanics of Vorticella Contraction

    PubMed Central

    Misra, Gaurav; Dickinson, Richard B.; Ladd, Anthony J.C.

    2010-01-01

    Abstract Vorticella convallaria is one of a class of fast-moving organisms that can traverse its body size in less than a millisecond by rapidly coiling a slender stalk anchoring it to a nearby surface. The stalk houses a fiber called the spasmoneme, which winds helically within the stalk and rapidly contracts in response to calcium signaling. We have developed a coupled mechanical-chemical model of the coiling process, accounting for the coiling of the elastic stalk and the binding of calcium to the protein spasmin. Simulations of the model describe the contraction and recovery processes quantitatively. The stalk-spasmoneme system is shown to satisfy geometric constraints, which explains why the cell body sometimes rotates during contraction. The shape of the collapsing and recovering stalk bounds its effective bending stiffness. Simulations suggest that recovery from the contracted state is driven by the stalk at a rate controlled by dissociation of calcium from spasmin. PMID:20550905

  3. 3 CFR - Government Contracting

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... contract oversight could reduce such sums significantly. Government outsourcing for services also raises... governmental functions. Agencies and departments must operate under clear rules prescribing when outsourcing is... oversee acquisitions appropriately; and (4) clarify when governmental outsourcing for services is and...

  4. Electrophysiologic Measurement in Neural Processing Disorders: Application of Auditory Brainstem Response Techniques.

    ERIC Educational Resources Information Center

    Talbott, Richard E.

    1979-01-01

    The application of electrophysiologic measurement techniques in the study of mental retardation, autism, and other disorders previously considered "behavioral" or "psychological" is discussed. (Author)

  5. Morphological and electrophysiological properties of cat lumbar paravertebral neurones.

    PubMed

    Percy, W H; Walsh, J; Krier, J

    1988-10-01

    The morphological and electrophysiological properties of neurones in the 3rd, 4th and 5th cat lumbar paravertebral ganglia were studied in vitro utilising intracellular injection of horseradish peroxidase (HRP) and intracellular electrophysiological recording techniques. Projections of neurones (T13-L5) were determined by in vivo HRP techniques. Two distinct soma morphologies were noted in all ganglia. Those whose long and short axes were approximately equal in length were designated as being 'spherical' and had a mean cross sectional area of 730 micron2. The remainder, whose long axis was at least 1.5 times the length of their short axis were called 'fusiform' and had a mean soma area of 540 micron2. The two cell types occurred in an approximate 2:1 ratio, respectively. The mean numbers of primary, secondary and tertiary dendrites for the population studied were 6.5, 6.3 and 3.4, respectively. Spherical cells had significantly more of each than fusiform cells as well as having a greater number of branch points and overall length of dendritic arbor. Neither cell type could be distinguished from the other based on the estimated number of fast excitatory postsynaptic potentials, the duration of the afterspike hyperpolarization or the duration of action potential discharge in response to 8-10-s depolarizing current pulses. The estimated number of synaptic potentials associated with both types of neurones (mean 10.6 +/- 1.6) correlated inversely only with the soma diameters (see Materials and Methods). It is concluded that while cat lumbar paravertebral neuronal soma may be classified into two morphologically distinct types, this is not reflected in their electrophysiological profiles. In addition, these data suggest that cat lumbar paravertebral neurones have a dendritic appearance and a degree of convergence of synaptic input previously shown to occur in this system. PMID:3209804

  6. Morphological Characteristics of Electrophysiologically Characterized Layer Vb Pyramidal Cells in Rat Barrel Cortex

    PubMed Central

    Loucif, Alexandre J. C.; Schubert, Dirk; Möck, Martin

    2016-01-01

    Layer Vb pyramidal cells are the major output neurons of the neocortex and transmit the outcome of cortical columnar signal processing to distant target areas. At the same time they contribute to local tactile information processing by emitting recurrent axonal collaterals into the columnar microcircuitry. It is, however, not known how exactly the two types of pyramidal cells, called slender-tufted and thick-tufted, contribute to the local circuitry. Here, we investigated in the rat barrel cortex the detailed quantitative morphology of biocytin-filled layer Vb pyramidal cells in vitro, which were characterized for their intrinsic electrophysiology with special emphasis on their action potential firing pattern. Since we stained the same slices for cytochrome oxidase, we could also perform layer- and column-related analyses. Our results suggest that in layer Vb the unambiguous action potential firing patterns "regular spiking (RS)" and "repetitive burst spiking (RB)" (previously called intrinsically burst spiking) correlate well with a distinct morphology. RS pyramidal cells are somatodendritically of the slender-tufted type and possess numerous local intralaminar and intracolumnar axonal collaterals, mostly reaching layer I. By contrast, their transcolumnar projections are less well developed. The RB pyramidal cells are somatodendritically of the thick-tufted type and show only relatively sparse local axonal collaterals, which are preferentially emitted as long horizontal or oblique infragranular collaterals. However, contrary to many previous slice studies, a substantial number of these neurons also showed axonal collaterals reaching layer I. Thus, electrophysiologically defined pyramidal cells of layer Vb show an input and output pattern which suggests RS cells to be more "locally segregating" signal processors whereas RB cells seem to act more on a "global integrative" scale. PMID:27706253

  7. Clinical, Electrophysiological Findings in Adult Patients with Non-traumatic Plexopathies

    PubMed Central

    Ko, Kiljun; Kang, Min Jae; Ko, Moon Ju; Do, Jong Gul; Sunwoo, Hyuk; Kwon, Tae Gun; Hwang, Jung Min; Park, Yoonhong

    2011-01-01

    Objective To ascertain the etiology of non-traumatic plexopathy and clarify the clinical, electrophysiological characteristics according to its etiology. Method We performed a retrospective analysis of 63 non-traumatic plexopathy patients that had been diagnosed by nerve conduction studies (NCS) and needle electromyography (EMG). Clinical, electrophysiological, imaging findings were obtained from medical records. Results We identified 36 cases with brachial plexopathy (BP) and 27 cases with lumbosacral plexopathy (LSP). The causes of plexopathy were neoplastic (36.1%), thoracic outlet syndrome (TOS) (25.0%), radiation induced (16.7%), neuralgic amyotrophy (8.3%), perioperative (5.6%), unknown (8.3%) in BP, while neoplastic (59.3%), radiation induced (22.2%), neuralgic amyotrophy (7.4%), psoas muscle abscess (3.7%), and unknown (7.4%) in LSP. In neoplastic plexopathy, pain presented as the first symptom in most patients (82.8%), with the lower trunk of the brachial plexus predominantly involved. In radiation induced plexopathy (RIP), pain was a common initial symptom, but the proportion was smaller (50%), and predominant involvements of bilateral lumbosacral plexus and whole trunk of brachial or lumbosacral plexus were characteristic. Myokymic discharges were noted in 41.7% patients with RIP. Abnormal NCS finding in the medial antebrachial cutaneous nerve was the most sensitive to diagnose TOS. Neuralgic amyotrophy of the brachial plexus showed upper trunk involvement in all cases. Conclusion By integrating anatomic, pathophysiologic knowledge with detailed clinical assessment and the results of ancillary studies, physicians can make an accurate diagnosis and prognosis. PMID:22506209

  8. [Photophobic response in Stentor coeruleus--electrophysiologic investigations].

    PubMed

    Walerczyk, M; Fabczak, H; Fabczak, S

    2000-01-01

    It is widely known that the phototransduction process in vertebrate photoreceptor cells are mediated by cGMP-gated ionic channels. The recent electrophysiological study showed that the cGMP-gated channels are also present in light sensitive protozoan ciliate Stentor coeruleus. These channels might play a key role in phototransduction process which leads to the photophobic behavior in the ciliate. The basic biophysical and pharmaceutical properties of cGMP-gated channels in Stentor indicate high similarity to those in vertebrate photoreceptor cells. PMID:10941267

  9. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus

    PubMed Central

    Tse, Vivian; Yeo, Jie Ming

    2016-01-01

    Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population. PMID:27642609

  10. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus.

    PubMed

    Tse, Gary; Lai, Eric Tsz Him; Tse, Vivian; Yeo, Jie Ming

    2016-01-01

    Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population. PMID:27642609

  11. The Electrophysiological Biosensor for Batch-Measurement of Cell Signals

    NASA Astrophysics Data System (ADS)

    Suzuki, Kengo; Tanabe, Masato; Ezaki, Takahiro; Konishi, Satoshi; Oka, Hiroaki; Ozaki, Nobuhiko

    This paper presents the development of electrophysiological biosensor. The developed sensor allows a batch-measurement by detecting all signals from a large number of cells together. The developed sensor employs the same measurement principle as the patch-clamp technique. A single cell is sucked and clamped in a micro hole with detecting electrode. Detecting electrodes in arrayed micro holes are connected together for the batch-measurement of signals a large number of cell signals. Furthermore, an array of sensors for batch-measurement is designed to improve measurement-throughput to satisfy requirements for the drug screening application.

  12. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus

    PubMed Central

    Tse, Vivian; Yeo, Jie Ming

    2016-01-01

    Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population.

  13. Affine Contractions on the Plane

    ERIC Educational Resources Information Center

    Celik, D.; Ozdemir, Y.; Ureyen, M.

    2007-01-01

    Contractions play a considerable role in the theory of fractals. However, it is not easy to find contractions which are not similitudes. In this study, it is shown by counter examples that an affine transformation of the plane carrying a given triangle onto another triangle may not be a contraction even if it contracts edges, heights or medians.…

  14. Educational Performance Contracting. PREP-28.

    ERIC Educational Resources Information Center

    National Center for Educational Communication (DHEW/OE), Washington, DC. Div. of Practice Improvement.

    This document explicates what is involved in educational performance contracting. Four basic types of contracts can be used to procure goods and services: fixed and performance contracts for resources and fixed and performance contracts for results. The basic considerations in choice of type are risk, relative technologies, management skills…

  15. Service contract management and negotiation.

    PubMed

    Wickesser, T A

    1994-04-01

    Service contract management can have a profound impact on the life cycle cost and general performance of serviced equipment. Negotiating service contracts from the client's perspective can help to ensure that the facility is receiving the best possible service and terms during the contract period. This document shows examples of contract considerations.

  16. Human melanocytes mitigate keratinocyte-dependent contraction in an in vitro collagen contraction assay.

    PubMed

    Rakar, Jonathan; Krammer, Markus P; Kratz, Gunnar

    2015-08-01

    Scarring is an extensive problem in burn care, and treatment can be especially complicated in cases of hypertrophic scarring. Contraction is an important factor in scarring but the contribution of different cell types remains unclear. We have investigated the contractile behavior of keratinocytes, melanocytes and fibroblasts by using an in vitro collagen gel assay aimed at identifying a modulating role of melanocytes in keratinocyte-mediated contraction. Cells were seeded on a collagen type I gel substrate and the change in gel dimensions were measured over time. Hematoxylin & Eosin-staining and immunohistochemistry against pan-cytokeratin and microphthalmia-associated transcription factor showed that melanocytes integrated between keratinocytes and remained there throughout the experiments. Keratinocyte- and fibroblast-seeded gels contracted significantly over time, whereas melanocyte-seeded gels did not. Co-culture assays showed that melanocytes mitigate the keratinocyte-dependent contraction (significantly slower and 18-32% less). Fibroblasts augmented the contraction in most assays (approximately 6% more). Non-contact co-cultures showed some influence on the keratinocyte-dependent contraction. Results show that mechanisms attributable to melanocytes, but not fibroblasts, can mitigate keratinocyte contractile behavior. Contact-dependent mechanisms are stronger modulators than non-contact dependent mechanisms, but both modes carry significance to the contraction modulation of keratinocytes. Further investigations are required to determine the mechanisms involved and to determine the utility of melanocytes beyond hypopigmentation in improved clinical regimes of burn wounds and wound healing.

  17. Nested and Dynamic Contract Boundaries

    NASA Astrophysics Data System (ADS)

    Strickland, T. Stephen; Felleisen, Matthias

    Previous work on software contracts assumes fixed and statically known boundaries between the parties to a contract. Implementations of contract monitoring systems rely on this assumption to explain the nature of contract violations and to assign blame to violators. In this paper, we explain how to implement arbitrary, nested, and dynamic contract boundaries with two examples. First, we add nestable contract regions to a static, first-order module system. Second, we show that even a dynamic, higher-order, and hierarchical module system can be equipped with software contracts that support precise blame assignment.

  18. Electrophysiological study of intravenous pinaverium bromide in cardiology.

    PubMed

    Guerot, C; Khemache, A; Sebbah, J; Noel, B

    1988-01-01

    Pinaverium bromide is a musculotropic spasmolytic agent which acts by inhibiting transmembrane calcium movements, an effect similar to that of verapamil. Because of this, an investigation was carried out to see if it had any electrophysiological effects in patients with various cardiac disorders. In an open study, 10 patients received 2 mg pinaverium bromide intravenously. In a double-blind study, 10 patients received 4 mg pinaverium bromide intravenously and 10 patients placebo. Patients included those with either normal or pathological basal conduction, such as bundle-branch block and 1st degree atrioventricular block. Measurements were made of electrophysiological parameters before and 10 minutes after injection. The results showed that neither of the two doses of pinaverium bromide had any effect on atrial excitability, sino-atrial conduction, node and trunk atrioventricular conduction or on intraventricular conduction. No significant difference was seen in comparison with placebo. Pinaverium bromide had no anti-arrhythmic properties in these studies. Local, cardiac and general clinical tolerability was good in all patients. PMID:3219882

  19. Electrophysiologic abnormalities of children with ostium secundum atrial septal defect.

    PubMed

    Ruschhaupt, D G; Khoury, L; Thilenius, O G; Replogle, R L; Arcilla, R A

    1984-06-01

    Sinus node (SN) and atrioventricular node (AVN) function were evaluated in 49 patients with secundum type atrial septal defect (ASD). Automaticity and conduction system function were assessed by intracardiac recording of the AH and HV intervals at rest, corrected SN recovery time, sinoatrial conduction time, AVN refractory period and the ability of the AVN to conduct rapidly paced atrial beats to the ventricles. Electrophysiologic abnormalities were found in 41% of the 34 patients who were studied before surgery. However, no preoperative abnormalities were present in children younger than 2.5 years. If only children older than 2.5 years were analyzed, the incidence of conduction abnormalities was similar for the patients studied before operation (62%) and those studied after operation (71%). The size and ejection fractions of the right and left ventricles, the magnitude of shunt flow and the size of the ASD did not differ between the patients with and those without electrophysiologic abnormalities. AVN dysfunction was present in 40% of the patients who were studied after surgical repair. While this frequency was more than twice the preoperative incidence of AVN dysfunction, it was not statistically significant. The data suggest that patient age is the major factor that influences the presence of conduction system dysfunction in patients with ASD.

  20. Electrophysiological correlates of mental navigation in blind and sighted people.

    PubMed

    Kober, Silvia Erika; Wood, Guilherme; Kampl, Christiane; Neuper, Christa; Ischebeck, Anja

    2014-10-15

    The aim of the present study was to investigate functional reorganization of the occipital cortex for a mental navigation task in blind people. Eight completely blind adults and eight sighted matched controls performed a mental navigation task, in which they mentally imagined to walk along familiar routes of their hometown during a multi-channel EEG measurement. A motor imagery task was used as control condition. Furthermore, electrophysiological activation patterns during a resting measurement with open and closed eyes were compared between blind and sighted participants. During the resting measurement with open eyes, no differences in EEG power were observed between groups, whereas sighted participants showed higher alpha (8-12Hz) activity at occipital sites compared to blind participants during an eyes-closed resting condition. During the mental navigation task, blind participants showed a stronger event-related desynchronization in the alpha band over the visual cortex compared to sighted controls indicating a stronger activation in this brain region in the blind. Furthermore, groups showed differences in functional brain connectivity between fronto-central and parietal-occipital brain networks during mental navigation indicating stronger visuo-spatial processing in sighted than in blind people during mental navigation. Differences in electrophysiological parameters between groups were specific for mental navigation since no group differences were observed during motor imagery. These results indicate that in the absence of vision the visual cortex takes over other functions such as spatial navigation.

  1. Electrophysiological fingerprints of OFF bipolar cells in rat retina.

    PubMed

    Vielma, Alex H; Schmachtenberg, Oliver

    2016-01-01

    Retinal bipolar cells (BCs) divide photoreceptor output into different channels for the parallel extraction of temporal and chromatic stimulus properties. In rodents, five types of OFF BCs have been differentiated, based on morphological and functional criteria, but their electrophysiological characterization remains incomplete. This study analyzed OFF BCs with the patch clamp technique in acute slices of rat retina. Their specific voltage-dependent currents and glutamate responses are shown to represent individual fingerprints which define the signal processing and filtering properties of each cell type and allow their unequivocal identification. Two additions to the rat BC repertoire are presented: OFF BC-2', a variation of BC-2 with wider axonal arbours and prominent Na(+) currents, is described for the first time in rodents, and OFF BC-3b, previously identified in mouse, is electrophysiologically characterized in rat. Moreover, the glutamate responses of rat OFF BCs are shown to be differentially sensitive to AMPA- and kainate-receptor blockers and to modulation by nitric oxide (NO) through a cGMP-dependent mechanism. These results contribute to our understanding of the diversity and function of bipolar cells in mammals. PMID:27457753

  2. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study

    PubMed Central

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18–25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function. PMID:27512383

  3. Electrophysiological mechanisms of the SI SII SIII electrocardiographic morphology

    SciTech Connect

    Bayes de Luna, A.; Carrio, I.; Subirana, M.T.; Torner, P.; Cosin, J.; Sagues, F.; Guindo, J.

    1987-01-01

    We studied three groups of individuals by means of spatial-velocity electrocardiograms and thallium-201 myocardial imaging to figure out the electrophysiological explanation of the SI SII SIII electrocardiographic morphology. We studied twelve healthy individuals without SI SII SIII, seven healthy individuals with SI SII SIII and fifteen patients with chronic obstructive pulmonary disease with SI SII SIII. The average values of the QRS-E and QRS-F intervals were higher in the second and third groups than in the first. One patient of the second group and thirteen of the third showed right ventricular enlargement. The slowing down of the right ventricular conduction explained the SI SII SIII morphology in normal individuals in more than half the cases. In patients with chronic obstructive pulmonary disease with SI SII SIII the conduction delay plays an important part in the electrogenesis of the right ventricular enlargement electrocardiographic morphology. We think that these observations can give further data about the electrophysiologic mechanism of the SI SII SIII morphology.

  4. COMMUNICATION: Electrophysiological response dynamics during focal cortical infarction

    NASA Astrophysics Data System (ADS)

    Chiganos, Terry C., Jr.; Jensen, Winnie; Rousche, Patrick J.

    2006-12-01

    While the intracellular processes of hypoxia-induced necrosis and the intercellular mechanisms of post-ischemic neurotoxicity associated with stroke are well documented, the dynamic electrophysiological (EP) response of neurons within the core or periinfarct zone remains unclear. The present study validates a method for continuous measurement of the local EP responses during focal cortical infarction induced via photothrombosis. Single microwire electrodes were acutely implanted into the primary auditory cortex of eight rats. Multi-unit neural activity, evoked via a continuous 2 Hz click stimulus, was recorded before, during and after infarction to assess neuronal function in response to local, permanent ischemia. During sham infarction, the average stimulus-evoked peak firing rate over 20 min remained stable at 495.5 ± 14.5 spikes s-1, indicating temporal stability of neural function under normal conditions. Stimulus-evoked peak firing was reliably reduced to background levels (firing frequency in the absence of stimulus) following initiation of photothrombosis over a period of 439 ± 92 s. The post-infarction firing patterns exhibited unique temporal degradation of the peak firing rate, suggesting a variable response to ischemic challenge. Despite the inherent complexity of cerebral ischemia secondary to microvascular occlusion, complete loss of EP function consistently occurred 300-600 s after photothrombosis. The results suggest that microwire recording during photothrombosis provides a simple and highly efficacious strategy for assessing the electrophysiological dynamics of cortical infarction.

  5. How do astrocytes shape synaptic transmission? Insights from electrophysiology

    PubMed Central

    Dallérac, Glenn; Chever, Oana; Rouach, Nathalie

    2013-01-01

    A major breakthrough in neuroscience has been the realization in the last decades that the dogmatic view of astroglial cells as being merely fostering and buffering elements of the nervous system is simplistic. A wealth of investigations now shows that astrocytes actually participate in the control of synaptic transmission in an active manner. This was first hinted by the intimate contacts glial processes make with neurons, particularly at the synaptic level, and evidenced using electrophysiological and calcium imaging techniques. Calcium imaging has provided critical evidence demonstrating that astrocytic regulation of synaptic efficacy is not a passive phenomenon. However, given that cellular activation is not only represented by calcium signaling, it is also crucial to assess concomitant mechanisms. We and others have used electrophysiological techniques to simultaneously record neuronal and astrocytic activity, thus enabling the study of multiple ionic currents and in depth investigation of neuro-glial dialogues. In the current review, we focus on the input such approach has provided in the understanding of astrocyte-neuron interactions underlying control of synaptic efficacy. PMID:24101894

  6. Modern Electrophysiological Methods for Brain-Computer Interfaces

    PubMed Central

    Grave de Peralta Menendez, Rolando; Noirhomme, Quentin; Cincotti, Febo; Mattia, Donatella; Aloise, Fabio; González Andino, Sara

    2007-01-01

    Modern electrophysiological studies in animals show that the spectrum of neural oscillations encoding relevant information is broader than previously thought and that many diverse areas are engaged for very simple tasks. However, EEG-based brain-computer interfaces (BCI) still employ as control modality relatively slow brain rhythms or features derived from preselected frequencies and scalp locations. Here, we describe the strategy and the algorithms we have developed for the analysis of electrophysiological data and demonstrate their capacity to lead to faster accurate decisions based on linear classifiers. To illustrate this strategy, we analyzed two typical BCI tasks. (1) Mu-rhythm control of a cursor movement by a paraplegic patient. For this data, we show that although the patient received extensive training in mu-rhythm control, valuable information about movement imagination is present on the untrained high-frequency rhythms. This is the first demonstration of the importance of high-frequency rhythms in imagined limb movements. (2) Self-paced finger tapping task in three healthy subjects including the data set used in the BCI-2003 competition. We show that by selecting electrodes and frequency ranges based on their discriminative power, the classification rates can be systematically improved with respect to results published thus far. PMID:18288256

  7. Use of electrophysiological monitoring in selective rhizotomy treating glossopharyngeal neuralgia.

    PubMed

    Zhang, Wenhao; Chen, Minjie; Zhang, Weijie; Chai, Ying

    2014-07-01

    The aim of this study was to evaluate the effects of electrophysiological monitoring on selective rhizotomy of the glossopharyngeal nerve (SRGN) in treatment of glossopharyngeal neuralgia (GPN). From December, 2009 to May, 2012, SRGN was carried out on 8 patients with GPN, through a suboccipital sigmoid sinus posterior approach. The electrodes were placed on the cricothyroid muscle (vagus nerve). Two groups of amplitudes (A1 and A2) were recorded. A1 was recorded when the mixed nerve root was stimulated, and A2 when the part of the vagus nerve was stimulated. The glossopharyngeal nerve was sectioned and the vagus nerve was preserved. If A1/A2 < 50%, the mixed nerve root should be sectioned, otherwise the mixed nerve root should be retained. As the representation of vagus nerve, the averages of A1 and A2 were 22 and 36 μV respectively. The 8 patients were followed up for 9-39 months. Seven patients (87.5%) obtained complete pain relief (excellent) without complications such as hoarseness, dysphagia, and cough. One case (12.5%) obtained moderate relief (good), and was under control with carbamazepine at a dosage of 600 mg/d. Cough was occurred in this patient, but relieved in two months. Electrophysiological monitoring in SRGN can improve the efficiency of pain relief and reduce the incidence of complications.

  8. Simulation Methods and Validation Criteria for Modeling Cardiac Ventricular Electrophysiology

    PubMed Central

    Krishnamoorthi, Shankarjee; Perotti, Luigi E.; Borgstrom, Nils P.; Ajijola, Olujimi A.; Frid, Anna; Ponnaluri, Aditya V.; Weiss, James N.; Qu, Zhilin; Klug, William S.; Ennis, Daniel B.; Garfinkel, Alan

    2014-01-01

    We describe a sequence of methods to produce a partial differential equation model of the electrical activation of the ventricles. In our framework, we incorporate the anatomy and cardiac microstructure obtained from magnetic resonance imaging and diffusion tensor imaging of a New Zealand White rabbit, the Purkinje structure and the Purkinje-muscle junctions, and an electrophysiologically accurate model of the ventricular myocytes and tissue, which includes transmural and apex-to-base gradients of action potential characteristics. We solve the electrophysiology governing equations using the finite element method and compute both a 6-lead precordial electrocardiogram (ECG) and the activation wavefronts over time. We are particularly concerned with the validation of the various methods used in our model and, in this regard, propose a series of validation criteria that we consider essential. These include producing a physiologically accurate ECG, a correct ventricular activation sequence, and the inducibility of ventricular fibrillation. Among other components, we conclude that a Purkinje geometry with a high density of Purkinje muscle junctions covering the right and left ventricular endocardial surfaces as well as transmural and apex-to-base gradients in action potential characteristics are necessary to produce ECGs and time activation plots that agree with physiological observations. PMID:25493967

  9. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study.

    PubMed

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18-25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function. PMID:27512383

  10. Stroop interference effect in schizophrenic patients: an electrophysiological approach.

    PubMed

    Markela-Lerenc, Jaana; Schmidt-Kraepelin, Christian; Roesch-Ely, Daniela; Mundt, Christoph; Weisbrod, Matthias; Kaiser, Stefan

    2009-03-01

    Schizophrenic patients present deficits in executive control functions. The Stroop test requires executive control functions, in particular response inhibition. So far only one study has employed the high temporal resolution of electrophysiological methods to investigate the neural correlates of the Stroop effect in schizophrenia. This study investigated medicated patients with schizophrenia or schizoaffective disorder (n=15) and healthy controls (n=15) using event-related potentials. The analyses of the P1 and N1 components revealed no differences between the groups indicating intact sensory processing in schizophrenia during the Stroop test. We found greater negativity in the incongruent as compared to the congruent and neutral conditions between 350 and 450 ms over prefrontal scalp areas in healthy subjects but not in schizophrenic patients. Later on, a sustained positivity was observed over parietal scalp regions in healthy subjects. This later sustained potential was attenuated in patients but only in the first block. This suggests that following practice patients show similar parietal effects as healthy subjects. The total errors in the incongruent condition in patients correlated negatively with the difference in mean activity between incongruent and congruent conditions over the left parietal area (time window 600-1000 ms). In other words the more errors were made by patients, the more attenuated was the Stroop related electrophysiological effect. This suggests that the parietal activity is related to successful resolution of the Stroop conflict in schizophrenic patients. Furthermore, the absence of the frontal deflection in patients reflects dysfunctional neural processes associated with executive control.

  11. Correlations of clinical, neuroimaging, and electrophysiological features in Hirayama disease

    PubMed Central

    Liao, Ming-Feng; Chang, Hong-Shiu; Chang, Kuo-Hsuan; Ro, Long-Sun; Chu, Chun-Che; Kuo, Hung-Chou; Lyu, Rong-Kuo

    2016-01-01

    Abstract Hirayama disease (HD) is characterized by development of asymmetric forearm muscle atrophy during adolescence with or without focal cervical spinal cord atrophy. The purpose of this study is to assess the correlation of clinical symptoms, disease progression, and electrophysiological findings with cervical spine magnetic resonance imaging (MRI) findings. The medical records, cervical spine MRIs, and electrophysiological findings of 44 HD patients were retrospectively reviewed and analyzed. Denervation changes in any single C5 to C7 root-innervated muscle (deltoid, biceps, triceps, or extensor digitorum communis) occurred more frequently in the 25 patients with cord atrophy than the 19 patients without cord atrophy (88% vs 53%, P = 0.02). Onset age, duration of disease progression, neurological examinations, nerve conduction study, and electromyographic findings from individual muscles were similar between patient groups. Compared with HD patients without cord atrophy, HD patients with cord atrophy experience a more severe denervation change in C5 to C7 root-innervated muscles. PMID:27428223

  12. Electrophysiological fingerprints of OFF bipolar cells in rat retina

    PubMed Central

    Vielma, Alex H.; Schmachtenberg, Oliver

    2016-01-01

    Retinal bipolar cells (BCs) divide photoreceptor output into different channels for the parallel extraction of temporal and chromatic stimulus properties. In rodents, five types of OFF BCs have been differentiated, based on morphological and functional criteria, but their electrophysiological characterization remains incomplete. This study analyzed OFF BCs with the patch clamp technique in acute slices of rat retina. Their specific voltage-dependent currents and glutamate responses are shown to represent individual fingerprints which define the signal processing and filtering properties of each cell type and allow their unequivocal identification. Two additions to the rat BC repertoire are presented: OFF BC-2′, a variation of BC-2 with wider axonal arbours and prominent Na+ currents, is described for the first time in rodents, and OFF BC-3b, previously identified in mouse, is electrophysiologically characterized in rat. Moreover, the glutamate responses of rat OFF BCs are shown to be differentially sensitive to AMPA- and kainate-receptor blockers and to modulation by nitric oxide (NO) through a cGMP-dependent mechanism. These results contribute to our understanding of the diversity and function of bipolar cells in mammals. PMID:27457753

  13. Relationship of Vascular Factors on Electrophysiologic Severity of Diabetic Neuropathy

    PubMed Central

    Hwang, Jeong-Won; Kwon, Hee Kyu

    2016-01-01

    Objective To investigate the impact of vascular factors on the electrophysiologic severity of diabetic neuropathy (DPN). Methods Total 530 patients with type 2 diabetes were enrolled retrospectively. We rated severity of DPN from 1 (normal) to 4 (severe) based on electrophysiologic findings. We collected the data concerning vascular factors (including brachial-ankle pulse wave velocity [PWV], ankle brachial index, ultrasound of carotid artery, lipid profile from the blood test, and microalbuminuria [MU] within 24 hours urine), and metabolic factors of diabetes (such as glycated hemoglobin [HbA1c]). We analyzed the differences among the four subgroups using χ2 test and ANOVA, and ordinal logistic regression analysis was performed to investigate the relationship between significant variables and severity of DPN. Results The severity of DPN was significantly associated with duration of diabetes, HbA1c, existence of diabetic retinopathy and nephropathy, PWV, presence of plaque, low density lipoprotein-cholesterol and MU (p<0.05). Among these variables, HbA1c and presence of plaque were more significantly related with severity of DPN in logistic regression analysis (p<0.001), and presence of plaque showed the highest odds ratio (OR=2.52). Conclusion Our results suggest that markers for vascular wall properties, such as PWV and presence of plaque, are significantly associated with the severity of DPN. The presence of plaque was more strongly associated with the severity of DPN than other variables. PMID:26949670

  14. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study.

    PubMed

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18-25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function.

  15. Automatic fitting of spiking neuron models to electrophysiological recordings.

    PubMed

    Rossant, Cyrille; Goodman, Dan F M; Platkiewicz, Jonathan; Brette, Romain

    2010-01-01

    Spiking models can accurately predict the spike trains produced by cortical neurons in response to somatically injected currents. Since the specific characteristics of the model depend on the neuron, a computational method is required to fit models to electrophysiological recordings. The fitting procedure can be very time consuming both in terms of computer simulations and in terms of code writing. We present algorithms to fit spiking models to electrophysiological data (time-varying input and spike trains) that can run in parallel on graphics processing units (GPUs). The model fitting library is interfaced with Brian, a neural network simulator in Python. If a GPU is present it uses just-in-time compilation to translate model equations into optimized code. Arbitrary models can then be defined at script level and run on the graphics card. This tool can be used to obtain empirically validated spiking models of neurons in various systems. We demonstrate its use on public data from the INCF Quantitative Single-Neuron Modeling 2009 competition by comparing the performance of a number of neuron spiking models. PMID:20224819

  16. Consensus, contracts, and committees.

    PubMed

    Moreno, J D

    1991-08-01

    Following a brief account of the puzzle that ethics committees present for the Western Philosophical tradition, I will examine the possibility that social contract theory can contribute to a philosophical account of these committees. Passing through classical as well as contemporary theories, particularly Rawls' recent constructivist approach, I will argue that social contract theory places severe constraints on the authority that may legitimately be granted to ethics committees. This, I conclude, speaks more about the suitability of the theory to this level of analysis than about the ethics committee phenomenon itself.

  17. 48 CFR 417.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 417.204 Contracts. The head of the contracting activity is authorized to approve contracts which exceed the 5 year limitation in FAR 17.204(e)....

  18. Electrophysiological Auditory Responses and Language Development in Infants with Periventricular Leukomalacia

    ERIC Educational Resources Information Center

    Avecilla-Ramirez, G. N.; Ruiz-Correa, S.; Marroquin, J. L.; Harmony, T.; Alba, A.; Mendoza-Montoya, O.

    2011-01-01

    This study presents evidence suggesting that electrophysiological responses to language-related auditory stimuli recorded at 46 weeks postconceptional age (PCA) are associated with language development, particularly in infants with periventricular leukomalacia (PVL). In order to investigate this hypothesis, electrophysiological responses to a set…

  19. Whole-Retina Reduced Electrophysiological Activity in Mice Bearing Retina-Specific Deletion of Vesicular Acetylcholine Transporter

    PubMed Central

    Bedore, Jake; Martyn, Amanda C.; Li, Anson K. C.; Dolinar, Eric A.; McDonald, Ian S.; Coupland, Stuart G.; Prado, Vania F.; Prado, Marco A.; Hill, Kathleen A.

    2015-01-01

    Background Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT) in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina. Methods & Results A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina- targeted (embryonic day 12.5) deletion of VAChT (VAChTSix3-Cre-flox/flox) and littermate controls at 5 and 12 months of age. VAChTSix3-Cre-flox/flox mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChTSix3-Cre-flox/flox mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP) amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses. Significance This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina. PMID:26226617

  20. NeuroChip: A Microfluidic Electrophysiological Device for Genetic and Chemical Biology Screening of Caenorhabditis elegans Adult and Larvae

    PubMed Central

    Hu, Chunxiao; Dillon, James; Kearn, James; Murray, Caitriona; O’Connor, Vincent; Holden-Dye, Lindy; Morgan, Hywel

    2013-01-01

    Genetic and chemical biology screens of C. elegans have been of enormous benefit in providing fundamental insight into neural function and neuroactive drugs. Recently the exploitation of microfluidic devices has added greater power to this experimental approach providing more discrete and higher throughput phenotypic analysis of neural systems. Here we make a significant addition to this repertoire through the design of a semi-automated microfluidic device, NeuroChip, which has been optimised for selecting worms based on the electrophysiological features of the pharyngeal neural network. We demonstrate this device has the capability to sort mutant from wild-type worms based on high definition extracellular electrophysiological recordings. NeuroChip resolves discrete differences in excitatory, inhibitory and neuromodulatory components of the neural network from individual animals. Worms may be fed into the device consecutively from a reservoir and recovered unharmed. It combines microfluidics with integrated electrode recording for sequential trapping, restraining, recording, releasing and recovering of C. elegans. Thus mutant worms may be selected, recovered and propagated enabling mutagenesis screens based on an electrophysiological phenotype. Drugs may be rapidly applied during the recording thus permitting compound screening. For toxicology, this analysis can provide a precise description of sub-lethal effects on neural function. The chamber has been modified to accommodate L2 larval stages showing applicability for small size nematodes including parasitic species which otherwise are not tractable to this experimental approach. We also combine NeuroChip with optogenetics for targeted interrogation of the function of the neural circuit. NeuroChip thus adds a new tool for exploitation of C. elegans and has applications in neurogenetics, drug discovery and neurotoxicology. PMID:23717588

  1. Involuntary painful muscle contractions in Satoyoshi syndrome: a surface electromyographic study.

    PubMed

    Drost, Gea; Verrips, Aad; van Engelen, Baziel G M; Stegeman, Dick F; Zwarts, Machiel J

    2006-11-01

    We report a child with Satoyoshi syndrome manifested by involuntary painful muscle contractions and alopecia. Although an autoimmune origin of Satoyoshi syndrome seems likely, its exact etiology remains as yet unknown, as is the origin of the involuntary contractions. To gain a better understanding of the electrophysiological characteristics of the involuntary contractions, we performed a surface electromyographic (EMG) study. We investigated muscle contractions in the legs using two noninvasive techniques: high-density surface EMG (HD-sEMG) recordings on one muscle, and polymyographic surface EMG (sEMG) recordings on various muscles. During the involuntary contractions, HD-sEMG showed a fourfold increase in amplitude compared to maximal voluntary contractions. These high potentials were widely distributed across the whole muscle and showed a pronounced oscillatory behavior with a frequency around 45 Hz. Polymyographic sEMG revealed that the involuntary contractions often occur simultaneously in various muscles or showed a switch of activity from one muscle to another. These findings point to hyperactivity or a disinhibition at the alpha motor neuron level, originating probably at that level, although a central origin cannot be excluded. (c) 2006 Movement Disorder Society. PMID:16972238

  2. Acting Out Muscle Contraction.

    ERIC Educational Resources Information Center

    Hudson, Margaret

    2003-01-01

    Describes a science activity that can be implemented into anatomy and physiology courses that demonstrates the interactions between action and myosin, the roles of sodium and calcium ions in the regulation of contraction, and the functions of the plasma membrane and the sarcoplasmic reticulum. (YDS)

  3. Contracting for Audit Services.

    ERIC Educational Resources Information Center

    Heifetz, Harry S.

    1987-01-01

    The Single Audit Act of 1984 requires most school districts receiving over $25,000 in federal funds to undergo financial audits. This article highlights requirements for selecting certified public accountants to perform the audit and suggests factors to be considered before drafting a contract or letter of engagement. A sample letter is included.…

  4. Paradental Training Contract.

    ERIC Educational Resources Information Center

    Lane Community Coll., Eugene, OR.

    This report describes institutional, faculty, and student activities and problems resulting from Lane Community College's acceptance of a federal contract to develop a paradental training program designed specifically to provide training/retraining required to quality military-trained dental corpsmen for examination by the Oregon State Board of…

  5. Copyright or Contract?

    ERIC Educational Resources Information Center

    Okerson, Ann

    1997-01-01

    Most authors and publishers of electronic information believe that current copyright law does not address technical capabilities or reader uses and have turned to contracts or licenses to define the rights of owners and users. Discusses copyrights, fair use, and licenses and highlights licensing's unresolved issues: use and users; archiving;…

  6. Contracting for Learning.

    ERIC Educational Resources Information Center

    Donald, Janet G.

    1976-01-01

    A learning contract is a document, drawn up by a student and his instructor or advisor that specifies what the student will learn, how this will be accomplished, within what period of time, and what the criteria of evaluation will be. The student and instructor agree upon specific objectives, resources to be used, and feedback sessions.…

  7. Contracting for Classroom Services.

    ERIC Educational Resources Information Center

    McLaughlin, John; Brown, Senn

    2000-01-01

    Like county governments, hospitals, and municipalities, superintendents must develop policies and protocols for requesting proposals, administering contracts, and ensuring desired results of private-sector services. Administrators should consider performance criteria, legal issues, cost and efficiency analysis, contractor evaluation criteria, and…

  8. Biochemical and electrophysiological characteristics of mammalian GABA receptors.

    PubMed

    Enna, S J; Gallagher, J P

    1983-01-01

    The concept that GABA is a neurotransmitter in the mammalian CNS is supported by both electrophysiological and biochemical data. Whereas the electrophysiological studies are essential for demonstrating a specific functional response to GABA, the biochemical approach is useful for characterizing the molecular properties of this site. As a result of these studies the concept of the GABA receptor has progressed from a simple model of a single recognition site associated with a chloride channel to a more complex structure having a variety of interacting components. Thus, both electrophysiological and biochemical data support the existence of at least two pharmacologically distinct types of GABA receptors, based on the sensitivity to bicuculline. Also, anatomically, there appear to be two different types of receptors, those located postsynaptically on the soma or dendrites of a neighboring cell and those found presynaptically on GABAergic and other neurotransmitter terminals. From biochemical studies it appears that the GABA receptor may be composed of at least three distinct interacting components. One of these, the recognition site, may exist in two conformations, with one preferring agonists and the other having a higher affinity for antagonists. Ion channels may be considered a second component, with some of these regulating the passage of chloride ion, whereas others may be associated with calcium transport. The third major element of GABA receptors appears to be a benzodiazepine recognition site, although only a certain population of GABA receptors may be endowed with this property. In addition to these, the GABA receptor complex appears to contain substances that modulate the recognition site by influencing the availability of higher affinity binding proteins. It would appear therefore that changes affecting any one of these constituents can influence the characteristics of the others. While increasing the complexity of the system, this arrangement makes for a

  9. 3-OST-7 regulates BMP-dependent cardiac contraction.

    PubMed

    Samson, Shiela C; Ferrer, Tania; Jou, Chuanchau J; Sachse, Frank B; Shankaran, Sunita S; Shaw, Robin M; Chi, Neil C; Tristani-Firouzi, Martin; Yost, H Joseph

    2013-12-01

    The 3-O-sulfotransferase (3-OST) family catalyzes rare modifications of glycosaminoglycan chains on heparan sulfate proteoglycans, yet their biological functions are largely unknown. Knockdown of 3-OST-7 in zebrafish uncouples cardiac ventricular contraction from normal calcium cycling and electrophysiology by reducing tropomyosin4 (tpm4) expression. Normal 3-OST-7 activity prevents the expansion of BMP signaling into ventricular myocytes, and ectopic activation of BMP mimics the ventricular noncontraction phenotype seen in 3-OST-7 depleted embryos. In 3-OST-7 morphants, ventricular contraction can be rescued by overexpression of tropomyosin tpm4 but not by troponin tnnt2, indicating that tpm4 serves as a lynchpin for ventricular sarcomere organization downstream of 3-OST-7. Contraction can be rescued by expression of 3-OST-7 in endocardium, or by genetic loss of bmp4. Strikingly, BMP misregulation seen in 3-OST-7 morphants also occurs in multiple cardiac noncontraction models, including potassium voltage-gated channel gene, kcnh2, affected in Romano-Ward syndrome and long-QT syndrome, and cardiac troponin T gene, tnnt2, affected in human cardiomyopathies. Together these results reveal 3-OST-7 as a key component of a novel pathway that constrains BMP signaling from ventricular myocytes, coordinates sarcomere assembly, and promotes cardiac contractile function.

  10. Employee contract issues for dermatologists.

    PubMed

    Brown, Christopher E; Indest, George F

    2013-12-01

    Employees and employers routinely face negotiating and preparing physician employment contracts. It is important for both sides to know and understand the basic information on what a comprehensive employment contract for a dermatologist should contain. There are various employment contract provisions from both the employee's perspective and the employer's perspective that must be considered when preparing physician employment contracts. This article provides basic advice and recommendations on requirements that should be included in such contracts. It suggests legal pitfalls that can be avoided through various contract clauses.

  11. Employee contract issues for dermatologists.

    PubMed

    Brown, Christopher E; Indest, George F

    2013-12-01

    Employees and employers routinely face negotiating and preparing physician employment contracts. It is important for both sides to know and understand the basic information on what a comprehensive employment contract for a dermatologist should contain. There are various employment contract provisions from both the employee's perspective and the employer's perspective that must be considered when preparing physician employment contracts. This article provides basic advice and recommendations on requirements that should be included in such contracts. It suggests legal pitfalls that can be avoided through various contract clauses. PMID:24800433

  12. Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia

    PubMed Central

    Josephson, Mark E

    2016-01-01

    Atrioventricular nodal reentrant tachycardia (AVNRT) should be classified as typical or atypical. The term ‘fast-slow AVNRT’ is rather misleading. Retrograde atrial activation during tachycardia should not be relied upon as a diagnostic criterion. Both typical and atypical atrioventricular nodal reentrant tachycardia are compatible with varying retrograde atrial activation patterns. Attempts at establishing the presence of a ‘lower common pathway’ are probably of no practical significance. When the diagnosis of AVNRT is established, ablation should be only directed towards the anatomic position of the slow pathway. If right septal attempts are unsuccessful, the left septal side should be tried. Ablation targeting earliest atrial activation sites during typical atrioventricular nodal reentrant tachycardia or the fast pathway in general for any kind of typical or atypical atrioventricular nodal reentrant tachycardia, are not justified. In this review we discuss current concepts about the tachycardia circuit, electrophysiologic diagnosis, and ablation of this arrhythmia. PMID:27617092

  13. Photochromic potassium channel blockers: design and electrophysiological characterization.

    PubMed

    Mourot, Alexandre; Fehrentz, Timm; Kramer, Richard H

    2013-01-01

    Voltage-gated potassium (K v) channels are membrane proteins that open a selective pore upon membrane depolarization, allowing K(+) ions to flow down their electrochemical gradient. In neurons, K v channels play a key role in repolarizing the membrane potential during the falling phase of the action potential, often resulting in an after hyperpolarization. Opening of K v channels results in a decrease of cellular excitability, whereas closing (or pharmacological block) has the opposite effect, increased excitability. We have developed a series of photosensitive blockers for K v channels that enable reversible, optical regulation of potassium ion flow. Such molecules can be used for remote control of neuronal excitability using light as an on/off switch. Here we describe the design and electrophysiological characterization of photochromic blockers of ion channels. Our focus is on K v channels but in principle, the techniques described here can be applied to other ion channels and signaling proteins.

  14. Cardiac electrophysiology in mice: a matter of size

    PubMed Central

    Kaese, Sven; Verheule, Sander

    2012-01-01

    Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias. PMID:22973235

  15. [Electrophysiology principles of Na(+)/HCO3(-) cotransporters].

    PubMed

    Chen, Li-Ming; Liu, Mei; Liu, Ying

    2016-06-25

    Ion channels and transporters represent two major types of pathways of transmembrane transport for ions. Distinct from ion channels which conduct passive ionic diffusion, ion transporters mediate active transport of ions. In the perspective of biochemistry, ion transporters are enzymes that catalyze the movement of ions across the plasma membrane. In the present review, we selected the Na(+)/HCO3(-) cotransporter (NBC) as an example to analyze the key biochemical and biophysical properties of ion transporters, including stoichiometry, turnover number and transport capacity. Moreover, we provided an analysis of the electrophysiological principles of NBC based on the laws of thermodynamics. Based on the thermodynamical analysis, we showed how the stoichiometry of an NBC determines the direction of its ion transport. Finally, we reviewed the methodology for experimental determination of the stoichiometry of NBC, as well as the physiological significance of the stoichiometry of NBCs in specific tissues. PMID:27350205

  16. Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia

    PubMed Central

    Josephson, Mark E

    2016-01-01

    Atrioventricular nodal reentrant tachycardia (AVNRT) should be classified as typical or atypical. The term ‘fast-slow AVNRT’ is rather misleading. Retrograde atrial activation during tachycardia should not be relied upon as a diagnostic criterion. Both typical and atypical atrioventricular nodal reentrant tachycardia are compatible with varying retrograde atrial activation patterns. Attempts at establishing the presence of a ‘lower common pathway’ are probably of no practical significance. When the diagnosis of AVNRT is established, ablation should be only directed towards the anatomic position of the slow pathway. If right septal attempts are unsuccessful, the left septal side should be tried. Ablation targeting earliest atrial activation sites during typical atrioventricular nodal reentrant tachycardia or the fast pathway in general for any kind of typical or atypical atrioventricular nodal reentrant tachycardia, are not justified. In this review we discuss current concepts about the tachycardia circuit, electrophysiologic diagnosis, and ablation of this arrhythmia.

  17. Low-energy x-ray irradiation for electrophysiological studies

    SciTech Connect

    Schauer, D.A.; Zeman, G.H.; Pellmar, T.C.

    1989-01-01

    High-dose-rate acute whole-body exposures have been the main focus of radiobiology research conducted at the Armed Forces Radiobiology Research Institute (AFRRI) for many years. Extensive quantitative studies have been conducted analyzing behavioral effects, radiation-induced syndromes, and combined injury phenomena. Tolliver and Pellmar initiated a study to evaluate radiation damage to brain neurophysiology. A 50-kVp molybdenum target/filter x-ray tube was installed inside a lead-shielded Faraday cage. High-dose rates of up to 1.54 Gy/min (17.4-keV weighted average photons) were used to conduct local in vitro irradiations of the hippocampal region of guinea pig brains. Electrophysiological recordings of subtle changes in neuronal activity indicate this system is suitable for this application.

  18. Photochromic Potassium Channel Blockers: Design and Electrophysiological Characterization

    PubMed Central

    Mourot, Alexandre; Fehrentz, Timm; Kramer, Richard H.

    2016-01-01

    Voltage-gated potassium (Kv) channels are membrane proteins that open a selective pore upon membrane depolarization, allowing K+ ions to flow down their electrochemical gradient. In neurons, Kv channels play a key role in repolarizing the membrane potential during the falling phase of the action potential, often resulting in an after hyperpolarization. Opening of Kv channels results in a decrease of cellular excitability, whereas closing (or pharmacological block) has the opposite effect, increased excitability. We have developed a series of photosensitive blockers for Kv channels that enable reversible, optical regulation of potassium ion flow. Such molecules can be used for remote control of neuronal excitability using light as an on/off switch. Here we describe the design and electrophysiological characterization of photochromic blockers of ion channels. Our focus is on Kv channels but in principle, the techniques described here can be applied to other ion channels and signaling proteins. PMID:23494374

  19. Ataxia telangiectasia in Chinese children. A clinical and electrophysiological study.

    PubMed

    Wong, V; Yu, Y L; Chan-Lui, W Y; Woo, E; Yeung, C Y

    1987-01-01

    The clinical manifestations, immunological, chromosomal, and multimodal electrophysiological studies of five Chinese patients with ataxia telangiectasia are described. One died of hepatocellular carcinoma not associated with Hepatitis B-antigenaemia. Another died of respiratory failure. Two siblings are free of sinopulmonary infections although they are wheelchair bound. Computed tomography of the brain showed cerebellar atrophy in four cases. Nerve conduction studies showed evidence of axonal neuropathy in all cases with the earliest detection at six years. Electromyography showed mild denervation changes in two cases. Two patients had abnormal somatosensory evoked potentials and one had abnormal visual and brain stem auditory evoked potentials. The level of alpha foetal protein was elevated whereas the serum carcino-embryonic antigen was normal in all patients. PMID:3665286

  20. Electrophysiologic Assessment of Auditory Training Benefits in Older Adults.

    PubMed

    Anderson, Samira; Jenkins, Kimberly

    2015-11-01

    Older adults often exhibit speech perception deficits in difficult listening environments. At present, hearing aids or cochlear implants are the main options for therapeutic remediation; however, they only address audibility and do not compensate for central processing changes that may accompany aging and hearing loss or declines in cognitive function. It is unknown whether long-term hearing aid or cochlear implant use can restore changes in central encoding of temporal and spectral components of speech or improve cognitive function. Therefore, consideration should be given to auditory/cognitive training that targets auditory processing and cognitive declines, taking advantage of the plastic nature of the central auditory system. The demonstration of treatment efficacy is an important component of any training strategy. Electrophysiologic measures can be used to assess training-related benefits. This article will review the evidence for neuroplasticity in the auditory system and the use of evoked potentials to document treatment efficacy. PMID:27587912

  1. [Electrophysiology principles of Na(+)/HCO3(-) cotransporters].

    PubMed

    Chen, Li-Ming; Liu, Mei; Liu, Ying

    2016-06-25

    Ion channels and transporters represent two major types of pathways of transmembrane transport for ions. Distinct from ion channels which conduct passive ionic diffusion, ion transporters mediate active transport of ions. In the perspective of biochemistry, ion transporters are enzymes that catalyze the movement of ions across the plasma membrane. In the present review, we selected the Na(+)/HCO3(-) cotransporter (NBC) as an example to analyze the key biochemical and biophysical properties of ion transporters, including stoichiometry, turnover number and transport capacity. Moreover, we provided an analysis of the electrophysiological principles of NBC based on the laws of thermodynamics. Based on the thermodynamical analysis, we showed how the stoichiometry of an NBC determines the direction of its ion transport. Finally, we reviewed the methodology for experimental determination of the stoichiometry of NBC, as well as the physiological significance of the stoichiometry of NBCs in specific tissues.

  2. The sense of smell in Odonata: an electrophysiological screening.

    PubMed

    Piersanti, Silvana; Frati, Francesca; Conti, Eric; Rebora, Manuela; Salerno, Gianandrea

    2014-11-01

    Volatile chemicals mediate a great range of intra- and interspecific signalling and information in insects. Olfaction has been widely investigated mostly in Neoptera while the knowledge of this sense in most basal insects such as Paleoptera (Odonata and Ephemeroptera) is still poor. In the present study we show the results of an electrophysiological screening on two model species, Libellula depressa (Libellulidae) and Ischnura elegans (Coenagrionidae), representatives of the two Odonata suborders Anisoptera and Zygoptera, with the aim to deep the knowledge on the sense of smell of this insect order. The antennal olfactory sensory neurons (OSNs) of these two species responded to the same 22 compounds (out of 48 chemicals belonging to different functional groups) encompassing mostly amines, carboxylic acids or aldehydes and belonging to green leaf volatiles, vertebrate related volatiles and volatiles emitted by standing waters bacteria. The properties of Odonata OSNs are very similar to those of ionotropic receptors (IRs) expressing OSNs in other insects.

  3. Electrophysiological correlates of language switching in second language learners.

    PubMed

    Van Der Meij, Maartje; Cuetos, Fernando; Carreiras, Manuel; Barber, Horacio A

    2011-01-01

    This study analyzed the electrophysiological correlates of language switching in second language learners. Participants were native Spanish speakers classified in two groups according to English proficiency (high and low). Event-related potentials (ERPs) were recorded while they read English sentences, half of which contained an adjective in Spanish in the middle of the sentence. The ERP results show the time-course of language switch processing for both groups: an initial detection of the switch driven by language-specific orthography (left-occipital N250) followed by costs at the level of the lexico-semantic system (N400), and finally a late updating or reanalysis process (LPC). In the high proficiency group, effects in the N400 time window extended to left anterior electrodes and were followed by larger LPC amplitudes at posterior sites. These differences suggest that proficiency modulates the different processes triggered by language switches.

  4. Correlation between muscle electrophysiology and strength after fibular nerve injury.

    PubMed

    Won, Yu Hui; Kim, Kang-Won; Choi, Jun Tak; Ko, Myoung-Hwan; Park, Sung-Hee; Seo, Jeong-Hwan

    2016-08-01

    Muscle strength measurement is important when evaluating the degree of impairment in patients with nerve injury. However, accurate and objective evaluation may be difficult in patients with severe pain or those who intentionally try to avoid full exertion. We investigated the usefulness of the affected-to-unaffected side electrophysiological parameter ratios as a measure of objective ankle dorsiflexion (ADF) strength in patients with unilateral fibular nerve injury (FNI). ADF strength was measured in patients with FNI via handheld dynamometer and manual muscle test (MMT). Fibular nerve compound muscle action potential (CMAP) amplitude and latency and ADF strength of the affected side were presented as ratios to the corresponding measurements of the unaffected side. We analysed the correlation of the CMAP ratio with the ADF strength ratio using a dynamometer and compared the CMAP ratios according to MMT grade. Fifty-two patients with FNI were enrolled. The mean CMAP latency ratio did not differ between MMT groups (p = 0.573). The CMAP amplitude ratio proportionally increased with the quantified ADF strength ratio via dynamometer increase (ρ = 0.790; p < 0.001), but the CMAP latency ratio and the quantified ADF strength ratio did not significantly correlate (ρ = 0.052; p = 0.713). The average CMAP amplitude ratio significantly differed between MMT groups (p < 0.001), and post hoc tests showed significant differences in all paired comparisons except of Fair and Good grades (p = 0.064). Electrophysiological parameter ratio, such as the affected-to-unaffected side CMAP amplitude ratio, might be sensitive parameters for ADF power estimation after FNI. PMID:27142447

  5. Ganzfeld-induced hallucinatory experience, its phenomenology and cerebral electrophysiology.

    PubMed

    Wackermann, Jirí; Pütz, Peter; Allefeld, Carsten

    2008-01-01

    Ganzfeld, i.e., exposure to an unstructured, uniform stimulation field, elicits in most observers pseudo-hallucinatory percepts, and may even induce global functional state changes ('altered states of consciousness'). The present paper gives a comprehensive overview of the phenomenology of subjective experience in the ganzfeld and its electrophysiological correlates. Laboratory techniques for visual or multi-modal ganzfeld induction are explained. The spectrum of ganzfeld-induced phenomena, ranging from elementary percepts to complex, vivid, dream-like imagery is described, and the latter illustrated by transcripts of subjects' reports. Similarities and differences to related sensory/perceptual phenomena are also discussed. Earlier findings on electrophysiological correlates of the ganzfeld are reviewed. Our own studies of electroencephalographic (EEG) activity in the ganzfeld are presented in some detail, and a re-analysis of data on EEG correlates of hallucinatory percepts in statu nascendi is reported. The results do not support the hypothesis of the hypnagogic origin of the percepts; the ganzfeld-induced steady-state is an activated state, and the spectral EEG dynamics in the alpha frequency range reveals processes of attention shifts and percept formation. The final section is devoted to the controversial topic of allegedly anomalous communication between human subjects ('ganzfeld telepathy'). It is shown that the use of ganzfeld in this research field relies partly on unsupported hypotheses concerning ganzfeld-induced states, partly on a weak conceptual background of the experimental procedure. The rôle of a particular belief system shared by the participants and experimenters is critically discussed.

  6. Correlation between muscle electrophysiology and strength after fibular nerve injury.

    PubMed

    Won, Yu Hui; Kim, Kang-Won; Choi, Jun Tak; Ko, Myoung-Hwan; Park, Sung-Hee; Seo, Jeong-Hwan

    2016-08-01

    Muscle strength measurement is important when evaluating the degree of impairment in patients with nerve injury. However, accurate and objective evaluation may be difficult in patients with severe pain or those who intentionally try to avoid full exertion. We investigated the usefulness of the affected-to-unaffected side electrophysiological parameter ratios as a measure of objective ankle dorsiflexion (ADF) strength in patients with unilateral fibular nerve injury (FNI). ADF strength was measured in patients with FNI via handheld dynamometer and manual muscle test (MMT). Fibular nerve compound muscle action potential (CMAP) amplitude and latency and ADF strength of the affected side were presented as ratios to the corresponding measurements of the unaffected side. We analysed the correlation of the CMAP ratio with the ADF strength ratio using a dynamometer and compared the CMAP ratios according to MMT grade. Fifty-two patients with FNI were enrolled. The mean CMAP latency ratio did not differ between MMT groups (p = 0.573). The CMAP amplitude ratio proportionally increased with the quantified ADF strength ratio via dynamometer increase (ρ = 0.790; p < 0.001), but the CMAP latency ratio and the quantified ADF strength ratio did not significantly correlate (ρ = 0.052; p = 0.713). The average CMAP amplitude ratio significantly differed between MMT groups (p < 0.001), and post hoc tests showed significant differences in all paired comparisons except of Fair and Good grades (p = 0.064). Electrophysiological parameter ratio, such as the affected-to-unaffected side CMAP amplitude ratio, might be sensitive parameters for ADF power estimation after FNI.

  7. Payload missions integration

    NASA Technical Reports Server (NTRS)

    Mitchell, R. A. K.

    1983-01-01

    Highlights of the Payload Missions Integration Contract (PMIC) are summarized. Spacelab Missions no. 1 to 3, OSTA partial payloads, Astro-1 Mission, premission definition, and mission peculiar equipment support structure are addressed.

  8. Characteristics of the electrophysiological activity of muscles attached to the transverse carpal ligament in carpal tunnel syndrome.

    PubMed

    Horiguchi, Gen; Aoki, Takafumi; Ito, Hiromoto

    2011-01-01

    The main cause of carpal tunnel syndrome (CTS) remains unknown. Stiffness of the subcutaneous area of the volar aspect of the carpal tunnel is present in many patients and suggests that the stiffness of muscles attached to the transverse carpal ligament is increased. We performed an electrophysiological study to investigate muscle activities and to clarify whether the stiffness of muscles attached to the transverse carpal ligament is involved in the pathogenesis of CTS. The subjects of this study included 16 patients with early CTS showing no motor dysfunction. Both thenar muscles (opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis) and hypothenar muscles (opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis) were investigated. Surface electrodes were placed on each muscle, and maximum voluntary contractions with the thumb and little finger in opposition were maintained for 3 seconds in all patients and in 7 control subjects. Electromyographs were subjected to fast Fourier transform analysis, and the root mean square (RMS) and the mean power frequency (MPF) were determined for each muscle. The RMS of the opponens pollicis was significantly less in hands affected by CTS (292.8 µV) than in healthy hands (405.9 µV). The RMS did not differ between affected hands and healthy hands for the other 2 thenar muscles but did differ significantly for the hypothenar muscles. The MPF did not differ between affected hands and healthy hands for any muscle. The results show that electrophysiological differences are present among muscles innervated by the median nerve and that hypothenar muscles originally unrelated to median nerve dysfunction are also affected in early CTS. These results suggest that modulation of muscles attached to the transverse carpal ligament is involved in the pathogenesis of CTS.

  9. 48 CFR 1335.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 1335.006 Contracting methods and... research involving human subjects to be carried out in performance of the award is exempt from 15 CFR part... Subjects, that the research involving human subjects is not exempt from the requirements of 15 CFR part...

  10. 48 CFR 17.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... that are not available in the fiscal year in which the contract would otherwise be completed. (e... CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 17.204 Contracts. (a) The contract shall specify limits... contract, including any extension. (b) The contract shall state the period within which the option may...

  11. 48 CFR 16.302 - Cost contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Cost contracts. 16.302... AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 16.302 Cost contracts. (a) Description. A cost contract is a cost-reimbursement contract in which the contractor receives no fee....

  12. 48 CFR 16.302 - Cost contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Cost contracts. 16.302... AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 16.302 Cost contracts. (a) Description. A cost contract is a cost-reimbursement contract in which the contractor receives no fee....

  13. 48 CFR 217.7406 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF DEFENSE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Undefinitized Contract Actions 217.7406 Contract clauses. (a) Use the clause at FAR 52.216-24, Limitation of Government Liability...) Indefinite-delivery contracts; (5) Any other type of contract providing for the use of UCAs; and (6)...

  14. 48 CFR 217.7406 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF DEFENSE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Undefinitized Contract Actions 217.7406 Contract clauses. (a) Use the clause at FAR 52.216-24, Limitation of Government Liability...) Indefinite-delivery contracts; (5) Any other type of contract providing for the use of UCAs; and (6)...

  15. 48 CFR 217.7406 - Contract clauses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF DEFENSE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Undefinitized Contract Actions 217.7406 Contract clauses. (a) Use the clause at FAR 52.216-24, Limitation of Government Liability...) Indefinite-delivery contracts; (5) Any other type of contract providing for the use of UCAs; and (6)...

  16. 48 CFR 217.7406 - Contract clauses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OF DEFENSE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Undefinitized Contract Actions 217.7406 Contract clauses. (a) Use the clause at FAR 52.216-24, Limitation of Government Liability...) Indefinite-delivery contracts; (5) Any other type of contract providing for the use of UCAs; and (6)...

  17. 48 CFR 217.7406 - Contract clauses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OF DEFENSE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Undefinitized Contract Actions 217.7406 Contract clauses. (a) Use the clause at FAR 52.216-24, Limitation of Government Liability...) Indefinite-delivery contracts; (5) Any other type of contract providing for the use of UCAs; and (6)...

  18. Conduction velocity of quiescent muscle fibers decreases during sustained contraction.

    PubMed

    Gazzoni, Marco; Camelia, Federico; Farina, Dario

    2005-07-01

    We tested the hypothesis that conduction velocity of quiescent muscle fibers decreases during sustained contraction due to the activity of the active motor units in the muscle. Ten subjects trained for the identification of a target motor unit in the abductor pollicis brevis with feedback on surface EMG signals detected with a two-dimensional array of 61 electrodes. The subjects activated the target motor unit in two 10-s long contractions, before (contraction C1) and after (C3) a 3-min contraction (C2), all in ischemic condition. The target motor unit was not activated during C2. Eight of the 10 subjects (control group) performed a second experimental session identical to the first but with a resting period of 3 min instead of the contraction C2. Exerted force and target motor unit discharge rate were not different between the two subject groups and between C1 and C3 (mean +/- SD, over C1 and C3; C2 group: 15.8 +/- 10.4% maximal voluntary contractions and 13.1 +/- 1.9 pps; control group: 15.6 +/- 22.1% maximal voluntary contractions and 14.5 +/- 1.9 pps, respectively). Muscle fiber conduction velocity of the target motor unit decreased in C3 with respect to C1 in the C2 group (3.59 +/- 0.57 and 3.34 +/- 0.47 m/s for C1 and C3, respectively; P < 0.05) but not in the control group (3.47 +/- 0.68 and 3.46 +/- 0.73 m/s). In the C2 group, the percent decrease in conduction velocity of the target motor unit between C1 and C3 (6.4 +/- 7.1%) was not significantly different from the percent decrease in the average conduction velocity of the motor units active during C2 (9.6 +/- 5.4%). In conclusion, the contraction-induced modifications in electrophysiological membrane properties of muscle fibers are partly independent on fiber activation.

  19. Utility Energy Services Contracts Guide

    SciTech Connect

    2013-09-01

    The UESC Guide is a compilation of samples and templates developed as a resource to help contracting officers implement task orders for UESCs under existing U.S. General Services Administration areawide contracts.

  20. Performance Contracting: Making It Legal

    ERIC Educational Resources Information Center

    Martin, Reed

    1971-01-01

    Discusses the possible limits on the legal authority of a school to contract with private enterprise for instructional services. The proper procedure for entering into such a contract is discussed. (JF)

  1. Convergence of circuit dysfunction in ASD: a common bridge between diverse genetic and environmental risk factors and common clinical electrophysiology

    PubMed Central

    Port, Russell G.; Gandal, Michael J.; Roberts, Timothy P. L.; Siegel, Steven J.; Carlson, Gregory C.

    2014-01-01

    Most recent estimates indicate that 1 in 68 children are affected by an autism spectrum disorder (ASD). Though decades of research have uncovered much about these disorders, the pathological mechanism remains unknown. Hampering efforts is the seeming inability to integrate findings over the micro to macro scales of study, from changes in molecular, synaptic and cellular function to large-scale brain dysfunction impacting sensory, communicative, motor and cognitive activity. In this review, we describe how studies focusing on neuronal circuit function provide unique context for identifying common neurobiological disease mechanisms of ASD. We discuss how recent EEG and MEG studies in subjects with ASD have repeatedly shown alterations in ensemble population recordings (both in simple evoked related potential latencies and specific frequency subcomponents). Because these disease-associated electrophysiological abnormalities have been recapitulated in rodent models, studying circuit differences in these models may provide access to abnormal circuit function found in ASD. We then identify emerging in vivo and ex vivo techniques, focusing on how these assays can characterize circuit level dysfunction and determine if these abnormalities underlie abnormal clinical electrophysiology. Such circuit level study in animal models may help us understand how diverse genetic and environmental risks can produce a common set of EEG, MEG and anatomical abnormalities found in ASD. PMID:25538564

  2. Convergence of circuit dysfunction in ASD: a common bridge between diverse genetic and environmental risk factors and common clinical electrophysiology.

    PubMed

    Port, Russell G; Gandal, Michael J; Roberts, Timothy P L; Siegel, Steven J; Carlson, Gregory C

    2014-01-01

    Most recent estimates indicate that 1 in 68 children are affected by an autism spectrum disorder (ASD). Though decades of research have uncovered much about these disorders, the pathological mechanism remains unknown. Hampering efforts is the seeming inability to integrate findings over the micro to macro scales of study, from changes in molecular, synaptic and cellular function to large-scale brain dysfunction impacting sensory, communicative, motor and cognitive activity. In this review, we describe how studies focusing on neuronal circuit function provide unique context for identifying common neurobiological disease mechanisms of ASD. We discuss how recent EEG and MEG studies in subjects with ASD have repeatedly shown alterations in ensemble population recordings (both in simple evoked related potential latencies and specific frequency subcomponents). Because these disease-associated electrophysiological abnormalities have been recapitulated in rodent models, studying circuit differences in these models may provide access to abnormal circuit function found in ASD. We then identify emerging in vivo and ex vivo techniques, focusing on how these assays can characterize circuit level dysfunction and determine if these abnormalities underlie abnormal clinical electrophysiology. Such circuit level study in animal models may help us understand how diverse genetic and environmental risks can produce a common set of EEG, MEG and anatomical abnormalities found in ASD.

  3. Cloudwave: Distributed Processing of “Big Data” from Electrophysiological Recordings for Epilepsy Clinical Research Using Hadoop

    PubMed Central

    Jayapandian, Catherine P.; Chen, Chien-Hung; Bozorgi, Alireza; Lhatoo, Samden D.; Zhang, Guo-Qiang; Sahoo, Satya S.

    2013-01-01

    Epilepsy is the most common serious neurological disorder affecting 50–60 million persons worldwide. Multi-modal electrophysiological data, such as electroencephalography (EEG) and electrocardiography (EKG), are central to effective patient care and clinical research in epilepsy. Electrophysiological data is an example of clinical “big data” consisting of more than 100 multi-channel signals with recordings from each patient generating 5–10GB of data. Current approaches to store and analyze signal data using standalone tools, such as Nihon Kohden neurology software, are inadequate to meet the growing volume of data and the need for supporting multi-center collaborative studies with real time and interactive access. We introduce the Cloudwave platform in this paper that features a Web-based intuitive signal analysis interface integrated with a Hadoop-based data processing module implemented on clinical data stored in a “private cloud”. Cloudwave has been developed as part of the National Institute of Neurological Disorders and Strokes (NINDS) funded multi-center Prevention and Risk Identification of SUDEP Mortality (PRISM) project. The Cloudwave visualization interface provides real-time rendering of multi-modal signals with “montages” for EEG feature characterization over 2TB of patient data generated at the Case University Hospital Epilepsy Monitoring Unit. Results from performance evaluation of the Cloudwave Hadoop data processing module demonstrate one order of magnitude improvement in performance over 77GB of patient data. (Cloudwave project: http://prism.case.edu/prism/index.php/Cloudwave) PMID:24551370

  4. Contracts for dispatchable power

    SciTech Connect

    Kahn, E.P.; Stoft, S.; Marnay, C.; Berman, D.

    1990-10-01

    Competitive bidding for electric power is maturing. Increasing numbers of utilities are soliciting proposals from private suppliers. The amount of capacity being sought is increasing, and potential suppliers appear to be abundant. Analysis of these developments still remains limited. Evidence on the behavior of this market is scarce and sketchy. The underlying economic principles that are shaping the market have not clearly been articulated. In this report we examine the economics of competitive bidding both empirically and analytically. Previous study of this market has focused on the evaluation criteria specified in Requests for Proposals (RFPs), and highly aggregated summary statistics on participation and results. We continue the examination of RFPs, but also survey the details of long term contracts that have emerged from competitive bidding. Contracts provide a new level of specific detail that has not been previously available. 68 refs., 13 figs., 25 tabs.

  5. Russian Contract Procurement Document

    SciTech Connect

    Tobin, J G

    2010-03-29

    This contract supports the enhancement of physical protection or nuclear material control and accounting systems at institutes or enterprises of the newly independent states under the material protection control and accounting (MPC&A) program. The contract is entered into pursuant to the MPC&A Program, a gratuitous technical assistance program, in accordance with the bilateral Agreements between the Russian Federation and the United States of America concerning the Safe and Secure Transportation, Storage and Destruction of Weapons and the Prevention of Weapons Proliferation of June 1992, as extended and amended by Protocol signed of June 1999, Agreement between the Government of the Russian Federation regarding Cooperation in the Area of Nuclear Materials Physical Protection, Control and Accounting of October 1999 and the Russian Federation law of May 1999 on the taxation exemption of gratuitous technical assistance with Russian Federation under registration No.DOE001000.

  6. Elements of gas contracts

    SciTech Connect

    O`Neal, J.

    1995-12-01

    The gas marketing scene has taken on a new look from the days of the {open_quotes}Long Term{close_quotes} or {open_quotes}Life of Lease{close_quotes} Contracts. In the past natural gas was of ten sold direct from the wellhead or a producer-owned facility to a pipeline company at a flat rate price and the only parties involved were producer or seller and buyer. Today, the parties involved in the marketing process might include a gathering entity to gather gas at a central point and provide gathering, compression and/or dehydration services; multiple pipeline companies for transportation; sales representatives or marketing brokers to negotiate a sale of the available gas on a monthly basis; and purchasers or end users. New terms have also been introduced in the process such as: {open_quotes}LDC{close_quotes} (local distribution company), {open_quotes}FERC Order 636{close_quotes}, {open_quotes}Price Delivered-to-Pipeline{close_quotes} and the various {open_quotes}levels of Service{close_quotes} under Gas Sales and Purchase Agreements. Four common levels of service are: {open_quotes}Firm{close_quotes}, {open_quotes}Baseload{close_quotes}, {open_quotes}Swing{close_quotes} and {open_quotes}Baseload/Operational{close_quotes}. It is evident that current marketing plans often require a separate contract for each service or commitment. Contract contents vary greatly, but most contain the following elements.

  7. Health Contract in the Classroom

    ERIC Educational Resources Information Center

    Haber, David

    2007-01-01

    A health contract is a technique used by health professionals to help clients achieve a health goal. This article describes a course, "Changing Health Behaviors," in which a health contract strategy is taught and practiced with older adults. The health contract can also be included as a smaller educational component within a gerontology course…

  8. 48 CFR 1842.7202 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT MANAGEMENT CONTRACT ADMINISTRATION AND AUDIT SERVICES NASA Contractor Financial Management... Contractor Financial Management Reporting, in solicitations and contracts when any of the NASA Form...

  9. 48 CFR 1842.7202 - Contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTRACT MANAGEMENT CONTRACT ADMINISTRATION AND AUDIT SERVICES NASA Contractor Financial Management... Contractor Financial Management Reporting, in solicitations and contracts when any of the NASA Form...

  10. Auditory Cortical Maturation in a Child with Cochlear Implant: Analysis of Electrophysiological and Behavioral Measures.

    PubMed

    Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Tsuji, Robinson Koji; Bento, Ricardo Ferreira; de Carvalho, Ana Claudia Martinho; Matas, Carla Gentile

    2015-01-01

    The purpose of this study was to longitudinally assess the behavioral and electrophysiological hearing changes of a girl inserted in a CI program, who had bilateral profound sensorineural hearing loss and underwent surgery of cochlear implantation with electrode activation at 21 months of age. She was evaluated using the P1 component of Long Latency Auditory Evoked Potential (LLAEP); speech perception tests of the Glendonald Auditory Screening Procedure (GASP); Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS); and Meaningful Use of Speech Scales (MUSS). The study was conducted prior to activation and after three, nine, and 18 months of cochlear implant activation. The results of the LLAEP were compared with data from a hearing child matched by gender and chronological age. The results of the LLAEP of the child with cochlear implant showed gradual decrease in latency of the P1 component after auditory stimulation (172 ms-134 ms). In the GASP, IT-MAIS, and MUSS, gradual development of listening skills and oral language was observed. The values of the LLAEP of the hearing child were expected for chronological age (132 ms-128 ms). The use of different clinical instruments allow a better understanding of the auditory habilitation and rehabilitation process via CI. PMID:26881163

  11. Nouns and verbs in the brain: a review of behavioural, electrophysiological, neuropsychological and imaging studies.

    PubMed

    Vigliocco, Gabriella; Vinson, David P; Druks, Judit; Barber, Horacio; Cappa, Stefano F

    2011-01-01

    In the past 30 years there has been a growing body of research using different methods (behavioural, electrophysiological, neuropsychological, TMS and imaging studies) asking whether processing words from different grammatical classes (especially nouns and verbs) engage different neural systems. To date, however, each line of investigation has provided conflicting results. Here we present a review of this literature, showing that once we take into account the confounding in most studies between semantic distinctions (objects vs. actions) and grammatical distinction (nouns vs. verbs), and the conflation between studies concerned with mechanisms of single word processing and those studies concerned with sentence integration, the emerging picture is relatively clear-cut: clear neural separability is observed between the processing of object words (nouns) and action words (typically verbs), grammatical class effects emerge or become stronger for tasks and languages imposing greater processing demands. These findings indicate that grammatical class per se is not an organisational principle of knowledge in the brain; rather, all the findings we review are compatible with two general principles described by typological linguistics as underlying grammatical class membership across languages: semantic/pragmatic, and distributional cues in language that distinguish nouns from verbs. These two general principles are incorporated within an emergentist view which takes these constraints into account.

  12. A scalable neuroinformatics data flow for electrophysiological signals using MapReduce

    PubMed Central

    Jayapandian, Catherine; Wei, Annan; Ramesh, Priya; Zonjy, Bilal; Lhatoo, Samden D.; Loparo, Kenneth; Zhang, Guo-Qiang; Sahoo, Satya S.

    2015-01-01

    Data-driven neuroscience research is providing new insights in progression of neurological disorders and supporting the development of improved treatment approaches. However, the volume, velocity, and variety of neuroscience data generated from sophisticated recording instruments and acquisition methods have exacerbated the limited scalability of existing neuroinformatics tools. This makes it difficult for neuroscience researchers to effectively leverage the growing multi-modal neuroscience data to advance research in serious neurological disorders, such as epilepsy. We describe the development of the Cloudwave data flow that uses new data partitioning techniques to store and analyze electrophysiological signal in distributed computing infrastructure. The Cloudwave data flow uses MapReduce parallel programming algorithm to implement an integrated signal data processing pipeline that scales with large volume of data generated at high velocity. Using an epilepsy domain ontology together with an epilepsy focused extensible data representation format called Cloudwave Signal Format (CSF), the data flow addresses the challenge of data heterogeneity and is interoperable with existing neuroinformatics data representation formats, such as HDF5. The scalability of the Cloudwave data flow is evaluated using a 30-node cluster installed with the open source Hadoop software stack. The results demonstrate that the Cloudwave data flow can process increasing volume of signal data by leveraging Hadoop Data Nodes to reduce the total data processing time. The Cloudwave data flow is a template for developing highly scalable neuroscience data processing pipelines using MapReduce algorithms to support a variety of user applications. PMID:25852536

  13. Auditory Cortical Maturation in a Child with Cochlear Implant: Analysis of Electrophysiological and Behavioral Measures

    PubMed Central

    Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Tsuji, Robinson Koji; Bento, Ricardo Ferreira; de Carvalho, Ana Claudia Martinho; Matas, Carla Gentile

    2015-01-01

    The purpose of this study was to longitudinally assess the behavioral and electrophysiological hearing changes of a girl inserted in a CI program, who had bilateral profound sensorineural hearing loss and underwent surgery of cochlear implantation with electrode activation at 21 months of age. She was evaluated using the P1 component of Long Latency Auditory Evoked Potential (LLAEP); speech perception tests of the Glendonald Auditory Screening Procedure (GASP); Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS); and Meaningful Use of Speech Scales (MUSS). The study was conducted prior to activation and after three, nine, and 18 months of cochlear implant activation. The results of the LLAEP were compared with data from a hearing child matched by gender and chronological age. The results of the LLAEP of the child with cochlear implant showed gradual decrease in latency of the P1 component after auditory stimulation (172 ms–134 ms). In the GASP, IT-MAIS, and MUSS, gradual development of listening skills and oral language was observed. The values of the LLAEP of the hearing child were expected for chronological age (132 ms–128 ms). The use of different clinical instruments allow a better understanding of the auditory habilitation and rehabilitation process via CI. PMID:26881163

  14. Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

    PubMed Central

    Israel, Jean-Marc; Oliet, Stéphane H.; Ciofi, Philippe

    2016-01-01

    Hypothalamic neurohormones are released in a pulsatile manner. The mechanisms of this pulsatility remain poorly understood and several hypotheses are available, depending upon the neuroendocrine system considered. Among these systems, hypothalamo-neurohypophyseal magnocellular neurons have been early-considered models, as they typically display an electrical activity consisting of bursts of action potentials that is optimal for the release of boluses of the neurohormones oxytocin and vasopressin. The cellular mechanisms underlying this bursting behavior have been studied in vitro, using either acute slices of the adult hypothalamus, or organotypic cultures of neonatal hypothalamic tissue. We have recently proposed, from experiments in organotypic cultures, that specific central pattern generator networks, upstream of magnocellular neurons, determine their bursting activity. Here, we have tested whether a similar hypothesis can be derived from in vitro experiments in acute slices of the adult hypothalamus. To this aim we have screened our electrophysiological recordings of the magnocellular neurons, previously obtained from acute slices, with an analysis of autocorrelation of action potentials to detect a rhythmic drive as we recently did for organotypic cultures. This confirmed that the bursting behavior of magnocellular neurons is governed by central pattern generator networks whose rhythmic drive, and thus probably integrity, is however less satisfactorily preserved in the acute slices from adult brains. PMID:27065780

  15. Materials for Multifunctional Balloon Catheters With Capabilities in Cardiac Electrophysiological Mapping and Ablation Therapy

    PubMed Central

    Kim, Dae-Hyeong; Lu, Nanshu; Ghaffari, Roozbeh; Kim, Yun-Soung; Lee, Stephen P.; Xu, Lizhi; Wu, Jian; Kim, Rak-Hwan; Song, Jizhou; Liu, Zhuangjian; Viventi, Jonathan; de Graff, Bassel; Elolampi, Brian; Mansour, Moussa; Slepian, Marvin J.; Hwang, Sukwon; Moss, Joshua D.; Won, Sang-Min; Huang, Younggang; Litt, Brian; Rogers, John A.

    2011-01-01

    Development of advanced surgical tools for minimally invasive procedures represents an activity of central importance to improvements in human health. A key materials challenge is in the realization of bio-compatible interfaces between the classes of semiconductor and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on biocompatible materials and devices that integrate directly with the thin elastic membranes of otherwise conventional balloon catheters, to provide multimodal functionality suitable for clinical use. We present sensors for measuring temperature, flow, tactile, optical and electrophysiological data, together with radio frequency (RF) electrodes for controlled, local ablation of tissue. These components connect together in arrayed layouts designed to decouple their operation from large strain deformations associated with deployment and repeated inflation/deflation. Use of such ‘instrumented’ balloon catheter devices in live animal models and in vitro tests illustrates their operation in cardiac ablation therapy. These concepts have the potential for application in surgical systems of the future, not only those based on catheters but also on other platforms, such as surgical gloves. PMID:21378969

  16. Central administration of ghrelin alters emotional responses in rats: behavioural, electrophysiological and molecular evidence.

    PubMed

    Hansson, C; Haage, D; Taube, M; Egecioglu, E; Salomé, N; Dickson, S L

    2011-04-28

    The orexigenic and pro-obesity hormone ghrelin targets key hypothalamic and mesolimbic circuits involved in energy balance, appetite and reward. Given that such circuits are closely integrated with those regulating mood and cognition, we sought to determine whether chronic (>2 weeks) CNS exposure to ghrelin alters anxiety- and depression-like behaviour in rats as well as some physiological correlates. Rats bearing chronically implanted i.c.v. catheters were treated with ghrelin (10 μg/d) or vehicle for 4 weeks. Tests used to assess anxiety- and depression-like behaviour were undertaken during weeks 3-4 of the infusion. These revealed an increase in anxiety- and depression-like behaviour in the ghrelin-treated rats relative to controls. At the end of the 4-week infusion, brains were removed and the amygdala dissected for subsequent qPCR analysis that revealed changes in expression of a number of genes representing key systems implicated in these behavioural changes. Finally, given the key role of the dorsal raphe serotonin system in emotional reactivity, we examined the electrophysiological response of dorsal raphe neurons after a ghrelin challenge, and found mainly inhibitory responses in this region. We demonstrate that the central ghrelin signalling system is involved in emotional reactivity in rats, eliciting pro-anxiety and pro-depression effects and have begun to explore novel target systems for ghrelin that may be of importance for these effects.

  17. Closed-Loop, Multichannel Experimentation Using the Open-Source NeuroRighter Electrophysiology Platform

    PubMed Central

    Newman, Jonathan P.; Zeller-Townson, Riley; Fong, Ming-Fai; Arcot Desai, Sharanya; Gross, Robert E.; Potter, Steve M.

    2013-01-01

    Single neuron feedback control techniques, such as voltage clamp and dynamic clamp, have enabled numerous advances in our understanding of ion channels, electrochemical signaling, and neural dynamics. Although commercially available multichannel recording and stimulation systems are commonly used for studying neural processing at the network level, they provide little native support for real-time feedback. We developed the open-source NeuroRighter multichannel electrophysiology hardware and software platform for closed-loop multichannel control with a focus on accessibility and low cost. NeuroRighter allows 64 channels of stimulation and recording for around US $10,000, along with the ability to integrate with other software and hardware. Here, we present substantial enhancements to the NeuroRighter platform, including a redesigned desktop application, a new stimulation subsystem allowing arbitrary stimulation patterns, low-latency data servers for accessing data streams, and a new application programming interface (API) for creating closed-loop protocols that can be inserted into NeuroRighter as plugin programs. This greatly simplifies the design of sophisticated real-time experiments without sacrificing the power and speed of a compiled programming language. Here we present a detailed description of NeuroRighter as a stand-alone application, its plugin API, and an extensive set of case studies that highlight the system’s abilities for conducting closed-loop, multichannel interfacing experiments. PMID:23346047

  18. A scalable neuroinformatics data flow for electrophysiological signals using MapReduce.

    PubMed

    Jayapandian, Catherine; Wei, Annan; Ramesh, Priya; Zonjy, Bilal; Lhatoo, Samden D; Loparo, Kenneth; Zhang, Guo-Qiang; Sahoo, Satya S

    2015-01-01

    Data-driven neuroscience research is providing new insights in progression of neurological disorders and supporting the development of improved treatment approaches. However, the volume, velocity, and variety of neuroscience data generated from sophisticated recording instruments and acquisition methods have exacerbated the limited scalability of existing neuroinformatics tools. This makes it difficult for neuroscience researchers to effectively leverage the growing multi-modal neuroscience data to advance research in serious neurological disorders, such as epilepsy. We describe the development of the Cloudwave data flow that uses new data partitioning techniques to store and analyze electrophysiological signal in distributed computing infrastructure. The Cloudwave data flow uses MapReduce parallel programming algorithm to implement an integrated signal data processing pipeline that scales with large volume of data generated at high velocity. Using an epilepsy domain ontology together with an epilepsy focused extensible data representation format called Cloudwave Signal Format (CSF), the data flow addresses the challenge of data heterogeneity and is interoperable with existing neuroinformatics data representation formats, such as HDF5. The scalability of the Cloudwave data flow is evaluated using a 30-node cluster installed with the open source Hadoop software stack. The results demonstrate that the Cloudwave data flow can process increasing volume of signal data by leveraging Hadoop Data Nodes to reduce the total data processing time. The Cloudwave data flow is a template for developing highly scalable neuroscience data processing pipelines using MapReduce algorithms to support a variety of user applications. PMID:25852536

  19. Culturing and Electrophysiology of Cells on NRCC Patch-clamp Chips

    PubMed Central

    Py, Christophe; Martina, Marzia; Monette, Robert; Comas, Tanya; Denhoff, Mike W.; Luk, Collin; Syed, Naweed I.; Mealing, Geoff

    2012-01-01

    Due to its exquisite sensitivity and the ability to monitor and control individual cells at the level of ion channels, patch-clamping is the gold standard of electrophysiology applied to disease models and pharmaceutical screens alike 1. The method traditionally involves gently contacting a cell with a glass pipette filled by a physiological solution in order to isolate a patch of the membrane under its apex 2. An electrode inserted in the pipette captures ion-channel activity within the membrane patch or, when ruptured, for the whole cell. In the last decade, patch-clamp chips have been proposed as an alternative 3, 4: a suspended film separates the physiological medium from the culture medium, and an aperture microfabricated in the film replaces the apex of the pipette. Patch-clamp chips have been integrated in automated systems and commercialized for high-throughput screening 5. To increase throughput, they include the fluidic delivery of cells from suspension, their positioning on the aperture by suction, and automated routines to detect cell-to-probe seals and enter into whole cell mode. We have reported on the fabrication of a silicon patch-clamp chip with optimized impedance and orifice shape that permits the high-quality recording of action potentials in cultured snail neurons 6; recently, we have also reported progress towards interrogating mammalian neurons 7. Our patch-clamp chips are fabricated at the Canadian Photonics Fabrication Centre 8, a commercial foundry, and are available in large series. We are eager to engage in collaborations with electrophysiologists to validate the use of the NRCC technology in different models. The chips are used according to the general scheme represented in Figure 1: the silicon chip is at the bottom of a Plexiglas culture vial and the back of the aperture is connected to a subterranean channel fitted with tubes at either end of the package. Cells are cultured in the vial and the cell on top of the probe is monitored by

  20. Active Contraction of Microtubule Networks

    NASA Astrophysics Data System (ADS)

    Foster, Peter; Fürthauer, Sebastian; Shelley, Michael; Needleman, Daniel

    Many cellular processes are driven by cytoskeletal assemblies. It remains unclear how cytoskeletal filaments and motor proteins organize into cellular scale structures and how molecular properties of cytoskeletal components affect the large scale behaviors of these systems. Here we investigate the self-organization of stabilized microtubules in Xenopus oocyte extracts and find that they can form macroscopic networks that spontaneously contract. We propose that these contractions are driven by the clustering of microtubule minus ends by dynein. Based on this idea, we construct an active fluid theory of network contractions which predicts a dependence of the timescale of contraction on initial network geometry, a development of density inhomogeneities during contraction, a constant final network density, and a strong influence of dynein inhibition on the rate of contraction, all in quantitative agreement with experiments. These results demonstrate that the motor-driven clustering of filament ends is a generic mechanism leading to contraction.

  1. Effect of phenylephrine infusion on atrial electrophysiological properties.

    PubMed Central

    Leitch, J. W.; Basta, M.; Fletcher, P. J.

    1997-01-01

    OBJECTIVE: To determine the effect of changes in autonomic tone induced by phenylephrine infusion on atrial refractoriness and conduction. DESIGN: Left and right atrial electrophysiological properties were measured before and after a constant phenylephrine infusion designed to increase sinus cycle length by 25%. SUBJECTS: 20 patients, aged 53 (SD 6) years, undergoing electrophysiological study for investigation of idiopathic paroxysmal atrial fibrillation (seven patients) or for routine follow up after successful catheter ablation of supraventricular tachycardia (13 patients). MAIN OUTCOME MEASURES: Changes in left and right atrial effective refractory periods, atrial activation times, and frequency of induction of atrial fibrillation. RESULTS: Phenylephrine (mean dose 69 (SD 18) mg/min) increased mean blood pressure by 22 (12) mm Hg (range 7 to 44) and lengthened sinus cycle length by 223 (94) ms (20 to 430). Left atrial effective refractory period lengthened following phenylephrine infusion from 250 (25) to 264 (21) ms (P < 0.001) but there was no significant change in right atrial effective refractory period: 200 (20) v 206 (29), P = 0.11. There was a significant relation between the effect of phenylephrine on sinus cycle length and on right atrial refractoriness (r = 0.6, P = 0.005) with shortening of right atrial refractoriness in patients with the greatest prolongation in sinus cycle length. During phenylephrine infusion, the right atrial stimulus to left atrial activation time at the basic pacing cycle length of 600 ms was unchanged, at 130 (18) v 131 (17) ms, but activation delay with a premature extrastimulus increased: 212 (28) v 227 (38) ms, P = 0.002. Atrial fibrillation was induced by two of 58 refractory period measurements at baseline and by 12 of 61 measurements during phenylephrine infusion (P < 0.01). Phenylephrine increased the difference between left and right atrial refractory periods by 22.8 (19.4) ms in the five patients with induced atrial

  2. 42 CFR 434.6 - General requirements for all contracts and subcontracts. P>(a) Contracts. All contracts under...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... contracts and subcontracts.P>(a) Contracts. All contracts under this part must include all of the following: (1) Include provisions that define a sound and complete procurement contract, as required by 45 CFR... subcontracts. P>(a) Contracts. All contracts under this part must include all of the following: 434.6...

  3. Swelling and Contraction of Phaseolus Hypocotyl Mitochondria 1

    PubMed Central

    Earnshaw, M. J.; Truelove, B.

    1968-01-01

    Isolated Phaseolus mitochondria will swell spontaneously in buffered KCl and contract with an oxidizable substrate or ATP + Mg2+. The conditions under which the mitochondria are swollen affect subsequent contraction, substrate oxidation and ion accumulation, but not their oxidative phosphorylation ability. Bovine serum albumin reduces the rate of swelling and promotes substrate oxidation, contraction and ion accumulation. Swelling of these mitochondria is associated with the release of malic dehydrogenase and a loss of membrane integrity. The beneficial effects of bovine serum albumin in preserving the energy linked functions of Phaseolus mitochondria is discussed. PMID:16656729

  4. The Lanthanide Contraction Revisited

    SciTech Connect

    Seitz, Michael; Oliver, Allen G.; Raymond, Kenneth N.

    2007-04-19

    A complete, isostructural series of lanthanide complexes (except Pm) with the ligand TREN-1,2-HOIQO has been synthesized and structurally characterized by means of single-crystal X-ray analysis. All complexes are 1D-polymeric species in the solid state, with the lanthanide being in an eight-coordinate, distorted trigonal-dodecahedral environment with a donor set of eight unique oxygen atoms. This series constitutes the first complete set of isostructural lanthanide complexes with a ligand of denticity greater than two. The geometric arrangement of the chelating moieties slightly deviates across the lanthanide series, as analyzed by a shape parameter metric based on the comparison of the dihedral angles along all edges of the coordination polyhedron. The apparent lanthanide contraction in the individual Ln-O bond lengths deviates considerably from the expected quadratic decrease that was found previously in a number of complexes with ligands of low denticity. The sum of all bond lengths around the trivalent metal cation, however, is more regular, showing an almost ideal quadratic behavior across the entire series. The quadratic nature of the lanthanide contraction is derived theoretically from Slater's model for the calculation of ionic radii. In addition, the sum of all distances along the edges of the coordination polyhedron show exactly the same quadratic dependency as the Ln-X bond lengths. The universal validity of this coordination sphere contraction, concomitant with the quadratic decrease in Ln-X bond lengths, was confirmed by reexamination of four other, previously published, almost complete series of lanthanide complexes. Due to the importance of multidentate ligands for the chelation of rare-earth metals, this result provides a significant advance for the prediction and rationalization of the geometric features of the corresponding lanthanide complexes, with great potential impact for all aspects of lanthanide coordination.

  5. 48 CFR 3035.7000 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SECURITY ACQUISITION REGULATION (HSAR) SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Information Dissemination by Educational Institutions 3035.7000 Contract clause. The contracting officer may use the clause at (HSAR) 48 CFR 3052.235-70, Dissemination of...

  6. 48 CFR 2442.1107 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACT MANAGEMENT CONTRACT ADMINISTRATION Production Surveillance and Reporting 2442.1107 Contract clause... value of $500,000 or less. (d) The clause shall not be used in contracts for information...

  7. 48 CFR 39.107 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING ACQUISITION OF INFORMATION TECHNOLOGY General 39.107 Contract clause. The contracting officer..., in solicitations and contracts for information technology which require security of information... information technology services or support services....

  8. 48 CFR 2415.204 - Contract format.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING METHODS AND CONTRACTING TYPES CONTRACTING BY NEGOTIATION Solicitation and Receipt of Proposals and Information 2415.204 Contract format. (e) The cognizant HCA shall be responsible for making...

  9. 48 CFR 517.109 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Multiyear Contracting 517.109 Contract clauses. Use of... by 40 U.S.C. 490(a)(14) for maintenance and repair of fixed equipment in federally-owned...

  10. 48 CFR 2417.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Options 2417.204 Contracts. (e) The Senior Procurement Executive shall approve any solicitation or contract which exceeds the five (5) year maximum...

  11. 48 CFR 2132.617 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... GROUP LIFE INSURANCE FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Debts 2132.617 Contract clause. The clause at FAR 52.232-17 is modified in FEGLI Program...

  12. 48 CFR 1632.617 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HEALTH BENEFITS ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Debts 1632.617 Contract clause. The clause at (FAR) 48 CFR 52.232-17 will be modified in all FEHBP...

  13. A wearable chemical-electrophysiological hybrid biosensing system for real-time health and fitness monitoring.

    PubMed

    Imani, Somayeh; Bandodkar, Amay J; Mohan, A M Vinu; Kumar, Rajan; Yu, Shengfei; Wang, Joseph; Mercier, Patrick P

    2016-05-23

    Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices.

  14. A wearable chemical–electrophysiological hybrid biosensing system for real-time health and fitness monitoring

    PubMed Central

    Imani, Somayeh; Bandodkar, Amay J.; Mohan, A. M. Vinu; Kumar, Rajan; Yu, Shengfei; Wang, Joseph; Mercier, Patrick P.

    2016-01-01

    Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices. PMID:27212140

  15. Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis

    PubMed Central

    Molina, Cristina E; Heijman, Jordi; Dobrev, Dobromir

    2016-01-01

    A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca2+ handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis. PMID:27403288

  16. Retinal Electrophysiology Is a Viable Preclinical Biomarker for Drug Penetrance into the Central Nervous System

    PubMed Central

    Charng, Jason; He, Zheng; Vingrys, Algis J.; Fish, Rebecca L.; Gurrell, Rachel; Bui, Bang V.; Nguyen, Christine T.

    2016-01-01

    Objective. To examine whether retinal electrophysiology is a useful surrogate marker of drug penetrance into the central nervous system (CNS). Materials and Methods. Brain and retinal electrophysiology were assessed with full-field visually evoked potentials and electroretinograms in conscious and anaesthetised rats following systemic or local administrations of centrally penetrant (muscimol) or nonpenetrant (isoguvacine) compounds. Results. Local injections into the eye/brain bypassed the blood neural barriers and produced changes in retinal/brain responses for both drugs. In conscious animals, systemic administration of muscimol resulted in retinal and brain biopotential changes, whereas systemic delivery of isoguvacine did not. General anaesthesia confounded these outcomes. Conclusions. Retinal electrophysiology, when recorded in conscious animals, shows promise as a viable biomarker of drug penetration into the CNS. In contrast, when conducted under anaesthetised conditions confounds can be induced in both cortical and retinal electrophysiological recordings. PMID:27239335

  17. CONTRACTING AND ERUPTING COMPONENTS OF SIGMOIDAL ACTIVE REGIONS

    SciTech Connect

    Liu Rui; Wang Yuming; Liu Chang; Wang Haimin; Toeroek, Tibor

    2012-10-01

    It has recently been noted that solar eruptions can be associated with the contraction of coronal loops that are not involved in magnetic reconnection processes. In this paper, we investigate five coronal eruptions originating from four sigmoidal active regions, using high-cadence, high-resolution narrowband EUV images obtained by the Solar Dynamic Observatory (SDO). The magnitudes of the flares associated with the eruptions range from GOES class B to class X. Owing to the high-sensitivity and broad temperature coverage of the Atmospheric Imaging Assembly (AIA) on board SDO, we are able to identify both the contracting and erupting components of the eruptions: the former is observed in cold AIA channels as the contracting coronal loops overlying the elbows of the sigmoid, and the latter is preferentially observed in warm/hot AIA channels as an expanding bubble originating from the center of the sigmoid. The initiation of eruption always precedes the contraction, and in the energetically mild events (B- and C-flares), it also precedes the increase in GOES soft X-ray fluxes. In the more energetic events, the eruption is simultaneous with the impulsive phase of the nonthermal hard X-ray emission. These observations confirm that loop contraction is an integrated process in eruptions with partially opened arcades. The consequence of contraction is a new equilibrium with reduced magnetic energy, as the contracting loops never regain their original positions. The contracting process is a direct consequence of flare energy release, as evidenced by the strong correlation of the maximal contracting speed, and strong anti-correlation of the time delay of contraction relative to expansion, with the peak soft X-ray flux. This is also implied by the relationship between contraction and expansion, i.e., their timing and speed.

  18. 48 CFR 315.209 - Solicitation provisions and contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICES CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Solicitation and Receipt of Proposals and Information 315.209 Solicitation provisions and contract clauses. (a) The Contracting...

  19. 48 CFR 15.204-1 - Uniform contract format.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Solicitation and Receipt of Proposals and Information 15.204-1 Uniform contract format. (a) Contracting officers shall prepare solicitations...

  20. [Collective versus selective contracts from a legal point of view].

    PubMed

    Schirmer, Horst Dieter

    2006-01-01

    The historically proven organisational model of service relations between sickness funds and healthcare providers are collective contracts. A collective contract as a standards treaty ("Normenvertrag") is particularly pronounced concerning the panel doctor law ("Vertragsarztrecht") defining medical care on the basis of the principle of benefits in kind governing benefit claims of the insured in case of illness. The collective contract is a suitable instrument for ensuring both consistent and exhaustive provision of care and for organising the conditions of care, especially the quality and reimbursement of professional medical services. For several years the legislator has been "experimenting" with parallel contract design patterns such as the contract of integrated care in the form of selective contracts between health insurances or their associations and healthcare providers or groups of healthcare providers. More recently, allowances for conclusion of such contracts have been supposed to lead to competition between the contractual systems. It is doubtful whether this "push-start" will contribute to overcoming the systematic legal disadvantages of selective contracting as an organisational model for the provision of healthcare services to the insured.

  1. Moment-angle relations in the initial time of contraction.

    PubMed

    Rousanoglou, E N; Herzog, W; Boudolos, K D

    2010-09-01

    Standard moment-angle relations are typically obtained for values at maximum of contraction. Muscle properties for contraction times, similar to the short times of powerful athletic activities, may be more important than muscle properties that are obtained at maximum (TMAX) of contraction. The research question was whether moment-angle relations obtained during the initial time course of contraction are linearly scaled reflections of moment-angle relations obtained at maximum of contraction. The isometric moment of the knee extensor and the electromyographic activity (EMG) of the knee extensor and flexor muscles were measured at 9 knee angles in 22 elite female track and field jumpers. Absolute moments (Nm), relative moments (%TMAX) and EMG integrals were determined at 30 ms, 50 ms, 150 ms and 200 ms from the onset of contraction and at maximum. For moment-angle relations obtained during the initial time course of contraction, there was a shift of the optimum knee angle to a more extended knee. During the initial time course of the contraction, %TMAX moment was greater near full knee extension. The EMG activity was the same across knee angles. The results may have important practical implications for muscular force evaluation for activities where maximum force production is coupled to a short activation time.

  2. Pitting binding against selection: electrophysiological measures of feature-based attention are attenuated by Gestalt object grouping

    PubMed Central

    Snyder, Adam C.; Fiebelkorn, Ian C.; Foxe, John J.

    2012-01-01

    Humans have limited cognitive resources to process the nearly limitless information available in the environment. Endogenous, or “top-down”, selective attention to basic visual features such as color or motion is a common strategy for biasing resources in favor of the most relevant information sources in a given context. Opposing this top-down separation of features is a “bottom-up” tendency to integrate, or bind, the various features that constitute objects. We pitted these two processes against each other in an electrophysiological experiment to test if top-down selective attention can overcome constitutive binding processes. Our results demonstrate that bottom-up binding processes can dominate top-down feature-based attention even when explicitly detrimental to task performance. PMID:22429245

  3. TraceContract

    NASA Technical Reports Server (NTRS)

    Kavelund, Klaus; Barringer, Howard

    2012-01-01

    TraceContract is an API (Application Programming Interface) for trace analysis. A trace is a sequence of events, and can, for example, be generated by a running program, instrumented appropriately to generate events. An event can be any data object. An example of a trace is a log file containing events that a programmer has found important to record during a program execution. Trace - Contract takes as input such a trace together with a specification formulated using the API and reports on any violations of the specification, potentially calling code (reactions) to be executed when violations are detected. The software is developed as an internal DSL (Domain Specific Language) in the Scala programming language. Scala is a relatively new programming language that is specifically convenient for defining such internal DSLs due to a number of language characteristics. This includes Scala s elegant combination of object-oriented and functional programming, a succinct notation, and an advanced type system. The DSL offers a combination of data-parameterized state machines and temporal logic, which is novel. As an extension of Scala, it is a very expressive and convenient log file analysis framework.

  4. 48 CFR 1517.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contracts. 1517.204 Section 1517.204 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1517.204 Contracts. The SCM may approve a contract...

  5. 48 CFR 817.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 817.204 Contracts. (a) The contracting officer must obtain the approval of the DSPE before awarding a contract that includes options exceeding the 5-year limitation specified in FAR 17.204(e). This requirement does not apply to contracts to be awarded by or...

  6. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract files. 4.802... MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract file, that documents the basis for the acquisition and the...

  7. 48 CFR 1846.470 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Government Contract Quality Assurance 1846.470 Contract clause. The contracting officer may insert a clause substantially as stated at 1852.246-71, Government Contract Quality... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Contract clause....

  8. 48 CFR 1846.470 - Contract clause.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Government Contract Quality Assurance 1846.470 Contract clause. The contracting officer may insert a clause substantially as stated at 1852.246-71, Government Contract Quality... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Contract clause....

  9. 48 CFR 1846.470 - Contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Government Contract Quality Assurance 1846.470 Contract clause. The contracting officer may insert a clause substantially as stated at 1852.246-71, Government Contract Quality... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Contract clause....

  10. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract file, that documents the basis for the acquisition and the award... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Contract files....

  11. 48 CFR 1846.470 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Government Contract Quality Assurance 1846.470 Contract clause. The contracting officer may insert a clause substantially as stated at 1852.246-71, Government Contract Quality... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contract clause....

  12. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract file, that documents the basis for the acquisition and the award... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Contract files....

  13. 48 CFR 32.611 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract clause. 32.611 Section 32.611 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Debts 32.611 Contract clause. (a) The contracting officer shall...

  14. 48 CFR 3416.307 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Section 3416.307 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 3416.307 Contract clauses. (a) If the clause in FAR 52.216-7, Allowable cost and Payment, is used in a contract with...

  15. 48 CFR 1316.406 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 1316.406 Section 1316.406 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Incentive Contracts 1316.406 Contract clauses. Insert a...

  16. 48 CFR 716.406 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 716.406 Section 716.406 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost Reimbursement Contracts 716.406 Contract clauses....

  17. Effects of context on electrophysiological response to musical accents.

    PubMed

    Palmer, Caroline; Jewett, Lisa R; Steinhauer, Karsten

    2009-07-01

    Listeners' aesthetic and emotional responses to music typically occur in the context of long musical passages that contain structures defined in terms of the events that precede them. We describe an electrophysiological study of listeners' brain responses to musical accents that coincided in longer musical sequences. Musically trained listeners performed a timbre-change detection task in which a single-tone timbre change was positioned within 4-bar melodies composed of 350-ms tones to coincide or not with melodic contour accents and temporal accents (induced with temporal gaps). Event-related potential responses to (task-relevant) attended timbre changes elicited an early negativity (MMN/N2b) around 200 ms and a late positive component around 350 ms (P300), reflecting updating of the timbre change in working memory. The amplitudes of both components changed systematically across the sequence, consistent with expectancy-based context effects. Furthermore, melodic contour changes modulated the MMN/N2b response (but not the P300) to timbre changes in later sequence positions. In contrast, task-irrelevant temporal gaps elicited an MMN that was not modulated by position within the context; absence of a P300 indicated that temporal-gap accents were not updated in working memory. Listeners' neural responses to musical structure changed systematically as sequential predictability and listeners' expectations changed across the melodic context. PMID:19673825

  18. Electrophysiological properties of cultured hippocampal neurons from Wistar Audiogenic Rats.

    PubMed

    Mesquita, Fernando; Aguiar, José F; Oliveira, José A; Garcia-Cairasco, Norberto; Varanda, Wamberto A

    2005-03-15

    The main goal of this work was to analyze the electrophysiological properties of cultured hippocampal neurons from a particular epileptic rat strain, called Wistar Audiogenic Rats (WAR). The whole-cell patch-clamp technique was used to record both active and passive membrane responses in an attempt to detect alterations in their characteristics in relation to controls from Wistar rats. Neurons from WARs show a significant reduction in the magnitude of the inhibitory GABAergic currents ( approximately 45%), in spite of maintaining a normal level of the excitatory glutamatergic currents. In addition, the magnitude of potassium currents, measured at +80 mV, is reduced by about 30% in comparison to controls. Surprisingly, we also found important changes in the passive cellular properties in WAR neurons such as membrane potential (-50.0 mV in WARs and -63.1 mV in controls) and input resistance (647 MOmega in WARs and 408 MOmega in controls). The changes described here, could be the basis of the neurophysiological and behavioral alterations present in these hyperexcitable animals, contributing to a better understanding of epileptogenesis in this particular animal model.

  19. Application of Parallel Factor Analysis (PARAFAC) to electrophysiological data

    PubMed Central

    Schmitz, S. Katharina; Hasselbach, Philipp P.; Ebisch, Boris; Klein, Anja; Pipa, Gordon; Galuske, Ralf A. W.

    2015-01-01

    The identification of important features in multi-electrode recordings requires the decomposition of data in order to disclose relevant features and to offer a clear graphical representation. This can be a demanding task. Parallel Factor Analysis (PARAFAC; Hitchcock, 1927; Carrol and Chang, 1970; Harshman, 1970) is a method to decompose multi-dimensional arrays in order to focus on the features of interest, and provides a distinct illustration of the results. We applied PARAFAC to analyse spatio-temporal patterns in the functional connectivity between neurons, as revealed in their spike trains recorded in cat primary visual cortex (area 18). During these recordings we reversibly deactivated feedback connections from higher visual areas in the pMS (posterior middle suprasylvian) cortex in order to study the impact of these top-down signals. Cross correlation was computed for every possible pair of the 16 electrodes in the electrode array. PARAFAC was then used to reveal the effects of time, stimulus, and deactivation condition on the correlation patterns. Our results show that PARAFAC is able to reliably extract changes in correlation strength for different experimental conditions and display the relevant features. Thus, PARAFAC proves to be well-suited for the use in the context of electrophysiological (action potential) recordings. PMID:25688205

  20. A recording chamber for small volume slice electrophysiology.

    PubMed

    Dondzillo, Anna; Quinn, Kevin D; Cruickshank-Quinn, Charmion I; Reisdorph, Nichole; Lei, Tim C; Klug, Achim

    2015-09-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. PMID:26203105

  1. Electrophysiology of turgor regulation in marine siphonous green algae.

    PubMed

    Bisson, M A; Beilby, M J; Shepherd, V A

    2006-05-01

    We review electrophysiological measures of turgor regulation in some siphonous green algae, primarily the giant-celled marine algae, Valonia and Ventricaria, with particular comparison to the well studied charophyte algae Chara and Lamprothamnium. The siphonous green algae have a less negative plasma membrane potential, and are unlikely to have a proton-based chemiosmotic transport system, dominated by active electrogenic K(+) uptake. We also make note of the unusual cellular structure of the siphonous green algae. Hypertonic stress, due to increased external osmotic pressure, is accompanied by positive-going potential difference (PD), increase in conductance, and slow turgor regulation. The relationship between these is not yet resolved, but may involve changes in K(+ )conductance (G (K)) or active K(+) transport at both membranes. Hypotonic turgor regulation, in response to decreased external osmotic pressure, is approximately 3 times faster than hypertonic turgor regulation. It is accompanied by a negative-going PD, although conductance also increases. The conductance increase and the magnitude of the PD change are strongly correlated with the magnitude of hypotonic stress.

  2. Distinct morphological and electrophysiological properties of an elk prion peptide.

    PubMed

    Glaves, John Paul; Gorski, Przemek A; Alier, Kwai; Ma, Li; Renault, Ludovic; Primeau, Joseph O; Jhamandas, Jack H; Young, Howard S

    2013-02-01

    A key event in prion diseases is the conversion of the prion protein (PrP) from its native α-helical conformation to a misfolded, β-sheet rich conformation. Thus, preventing or reversing PrP misfolding could provide a means to disrupt prion disease progression and transmission. However, determining the structure of misfolded PrP has been notoriously difficult due to its inherent heterogeneity and aggregation behavior. For these reasons, simplified peptide fragments have been used as models that recapitulate characteristics of full-length PrP, such as amyloid-like aggregation and fibril formation, and in vitro toxicity. We provide a biochemical and structural comparison of PrP(127-147) peptides from elk, bovine and hamster using electrophysiology, electron microscopy and fluorescence. Our results demonstrate that the PrP(127-147) peptides adopt distinct populations of fibril structures. In addition, the elk PrP(127-147) peptide is unique in its ability to enhance Thioflavin T fluorescence and its ability to modulate neuronal ion channel conductances. PMID:23262353

  3. Electrophysiological CNS-processes related to associative learning in humans.

    PubMed

    Christoffersen, Gert R J; Schachtman, Todd R

    2016-01-01

    The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli.

  4. Electrophysiological correlates of morphological processing in Chinese compound word recognition

    PubMed Central

    Du, Yingchun; Hu, Weiping; Fang, Zhuo; Zhang, John X.

    2013-01-01

    The present study investigated the electrophysiological correlates of morphological processing in Chinese compound word reading using a delayed repetition priming paradigm. Participants were asked to passively view lists of two-character compound words containing prime-target pairs separated by a few items. In a Whole Word repetition condition, the prime and target were the same real words (e.g., , manager-manager). In a Constituent repetition condition, the prime and target were swapped in terms of their constituent position (e.g., , the former is a pseudo-word and the later means nurse). Two ERP components including N200 and N400 showed repetition effects. The N200 showed a negative shift upon repetition in the Whole Word condition but this effect was delayed for the Constituent condition. The N400 showed comparable amplitude reduction across the two priming conditions. The results reveal different aspects of morphological processing with an early stage associated with N200 and a late stage with N400. There was also a possibility that the N200 effect reflect general cognitive processing, i.e., the detection of low-probability stimuli. PMID:24068994

  5. [Facial emotion recognition in schizophrenia: an electrophysiological review].

    PubMed

    Komlósi, Sarolta; Csukly, Gábor; Czobor, Pál

    2010-01-01

    Deficits in social cognition in schizophrenia have been shown to be among the main factors predicting functional impairment. Facial emotion perception is a basic component of social cognition and other higher-level social cognitive processes. In our review we aim to give an overview of findings investigating the electrophysiological correlates of facial emotion recognition, and summarize previous findings relating to the nature of the deficit in schizophrenia as compared to healthy controls. Disentangling early and late components of emotion processing as indexed by event-related brain potentials allows for a better understanding of whether impairment of facial emotion processing is due to deficits in the early structural encoding of faces, or whether it is related to later deficits associated with the encoding of the emotional content. Findings in the field of social cognition in schizophrenia are of both clinical and pharmacological importance, as on one side they carry the potential to improve cognitive therapeutic interventions, and on the other to develop targets aiming at the improvement of social deficits in schizophrenia.

  6. Audiological and electrophysiological assessment of professional pop/rock musicians.

    PubMed

    Samelli, Alessandra G; Matas, Carla G; Carvallo, Renata M M; Gomes, Raquel F; de Beija, Carolina S; Magliaro, Fernanda C L; Rabelo, Camila M

    2012-01-01

    In the present study, we evaluated peripheral and central auditory pathways in professional musicians (with and without hearing loss) compared to non-musicians. The goal was to verify if music exposure could affect auditory pathways as a whole. This is a prospective study that compared the results obtained between three groups (musicians with and without hearing loss and non-musicians). Thirty-two male individuals participated and they were assessed by: Immittance measurements, pure-tone air conduction thresholds at all frequencies from 0.25 to 20 kHz, Transient Evoked Otoacoustic Emissions, Auditory Brainstem Response (ABR), and Cognitive Potential. The musicians showed worse hearing thresholds in both conventional and high frequency audiometry when compared to the non-musicians; the mean amplitude of Transient Evoked Otoacoustic Emissions was smaller in the musicians group, but the mean latencies of Auditory Brainstem Response and Cognitive Potential were diminished in the musicians when compared to the non-musicians. Our findings suggest that the population of musicians is at risk for developing music-induced hearing loss. However, the electrophysiological evaluation showed that latency waves of ABR and P300 were diminished in musicians, which may suggest that the auditory training to which these musicians are exposed acts as a facilitator of the acoustic signal transmission to the cortex.

  7. The Electrophysiological Underpinnings of Processing Gender Stereotypes in Language

    PubMed Central

    Siyanova-Chanturia, Anna; Pesciarelli, Francesca; Cacciari, Cristina

    2012-01-01

    Despite the widely documented influence of gender stereotypes on social behaviour, little is known about the electrophysiological substrates engaged in the processing of such information when conveyed by language. Using event-related brain potentials (ERPs), we examined the brain response to third-person pronouns (lei “she” and lui “he”) that were implicitly primed by definitional (passeggeraFEM “passenger”, pensionatoMASC “pensioner”), or stereotypical antecedents (insegnante “teacher”, conducente “driver”). An N400-like effect on the pronoun emerged when it was preceded by a definitionally incongruent prime (passeggeraFEM – lui; pensionatoMASC – lei), and a stereotypically incongruent prime for masculine pronouns only (insegnante – lui). In addition, a P300-like effect was found when the pronoun was preceded by definitionally incongruent primes. However, this effect was observed for female, but not male participants. Overall, these results provide further evidence for on-line effects of stereotypical gender in language comprehension. Importantly, our results also suggest a gender stereotype asymmetry in that male and female stereotypes affected the processing of pronouns differently. PMID:23226494

  8. Differential Electrophysiological Responses to Odorant Isotopologues in Drosophilid Antennae.

    PubMed

    Drimyli, Efstathia; Gaitanidis, Alexandros; Maniati, Klio; Turin, Luca; Skoulakis, Efthimios M C

    2016-01-01

    Olfaction presents the ultimate challenge to molecular recognition as thousands of molecules have to be recognized by far fewer olfactory receptors. We have presented evidence that Drosophila readily distinguish odorants based on their molecular vibrations using a battery of behavioral assays suggesting engagement of a molecular vibration-sensing component. Here we interrogate electrophysiologically the antennae of four Drosophilids and demonstrate conserved differential response amplitudes to aldehydes, alcohols, ketones, nitriles, and their deuterated isotopologues. Certain deuterated odorants evoked larger electroantennogram (EAG) amplitudes, while the response to the normal odorant was elevated in others. Significantly, benzonitrile isotopologues were not distinguishable as predicted. This suggests that isotopologue-specific EAG amplitudes result from differential activation of specific olfactory receptors. In support of this, odorants with as few as two deuteria evoke distinct EAG amplitudes from their normal isotopologues, and this is independent of the size of the deuterated molecule. Importantly, we find no evidence that these isotopologue-specific amplitudes depend on perireceptor mechanisms or other pertinent physical property of the deuterated odorants. Rather, our results strongly suggest that Drosophilid olfactory receptors are activated by molecular vibrations differentiating similarly sized and shaped odorants in vivo, yielding sufficient differential information to drive behavioral choices. PMID:27351023

  9. Electrophysiological measurement of interest during walking in a simulated environment.

    PubMed

    Takeda, Yuji; Okuma, Takashi; Kimura, Motohiro; Kurata, Takeshi; Takenaka, Takeshi; Iwaki, Sunao

    2014-09-01

    A reliable neuroscientific technique for objectively estimating the degree of interest in a real environment is currently required in the research fields of neuroergonomics and neuroeconomics. Toward the development of such a technique, the present study explored electrophysiological measures that reflect an observer's interest in a nearly-real visual environment. Participants were asked to walk through a simulated shopping mall and the attractiveness of the shopping mall was manipulated by opening and closing the shutters of stores. During the walking task, participants were exposed to task-irrelevant auditory probes (two-stimulus oddball sequence). The results showed a smaller P2/early P3a component of task-irrelevant auditory event-related potentials and a larger lambda response of eye-fixation-related potentials in an interesting environment (i.e., open-shutter condition) than in a boring environment (i.e., closed-shutter condition); these findings can be reasonably explained by supposing that participants allocated more attentional resources to visual information in an interesting environment than in a boring environment, and thus residual attentional resources that could be allocated to task-irrelevant auditory probes were reduced. The P2/early P3a component and the lambda response may be useful measures of interest in a real visual environment.

  10. Perception of Chinese poem and its electrophysiological effects.

    PubMed

    Li, W; Yang, Y

    2010-07-14

    A neural correlate for phrase boundary perception in language has recently been identified as a reliable and replicable brain effect. It is called the closure positive shift (CPS) and has an equivalent in the perception of music (music CPS). Nevertheless, either in language or in music, this component is elicited by phrase boundary embedded in sentence or melody. Poetry, as the interlude of language and music, is a special kind of discourse and promising material to explore prosodic boundary processing beyond sentence level. The aim of the present study was to investigate the cognitive processing of hierarchical prosodic boundaries in Chinese Tang poem using rhythm matching task. There are generally four hierarchical levels in each poem, including foot boundary, phonological phrase boundary, intonational phrase boundary, and couplet boundary. The electrophysiological results indicated that all the prosodic boundaries of different levels in poems could give rise to the CPS reflecting prosodic phrasing. Furthermore, as the prosodic hierarchical level became higher, the onset latency of the CPS got longer, suggesting the influence of retrospective processing of former information. With regard to the amplitude, we analyzed the CPS amplitude in every 100 ms time window. It was showed that phonological phrase boundary elicited higher CPS amplitude as compared to that evoked by couplet boundary in an earlier time window, whereas in a later time window both of them were lower than the CPS correlated to intonational phrase boundary. The present results further shape our understanding of the CPS component and its relation to the processes involved in prosodic phrasing.

  11. Comparison of the cardiac electrophysiological effects between doxazosin and bunazosin.

    PubMed

    Lee, An-Sheng; Chen, Wen-Pin; Su, Ming-Jai

    2008-07-01

    In Langendorff-perfused adult rat heart with constant pressure at 80 mmHg, we found doxazosin, an alpha(1) adrenoceptor blocker, at 10 muM prolonged PR interval and induced occasional arrhythmia followed by complete inhibition of the sinus rhythm, whereas bunazosin, another alpha(1)-blocker, at same concentration did not. The results of voltage-clamp study showed that, at the concentration of 10 muM, doxazosin inhibited I (Na), I ( (Ca,L) ), I (to), and Iss without changing I (k1) but bunazosin only inhibited I ( (Ca,L) ) about 30%. Doxazosin also caused markedly negative shift of the I (Na) inactivation curve. In current-clamp study, doxazosin prolonged action potential duration in association with the decreased action potential amplitude and upstroke velocity, whereas bunazosin did not. We hypothesize that doxazosin-induced arrhythmia may result from the heterogeneous or different level of I ( (Ca,L) ) blockade of AV nodal tissue. In conclusion, the present study suggests that bunazosin is safer than doxazosin for long-term treatment in view of electrophysiological effect. However, the underlying mechanism of doxazosin induced nodal arrhythmia is still needed to be determined.

  12. First steps towards initial registration for electrophysiology procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Bourier, Felix; Yatziv, Liron; Koch, Martin; Hornegger, Joachim; Strobel, Norbert; Kurzidim, Klaus

    2011-03-01

    Atrial fibrillation is the most common heart arrhythmia and a leading cause of stroke. The treatment option of choice is radio-frequency catheter ablation, which is performed in electrophysiology labs using C-Arm X-ray systems for navigation and guidance. The goal is to electrically isolate the pulmonary vein-left atrial junction thereby rendering myocardial fibers responsible for induction and maintenance of AF inactive. The use of overlay images for fluoroscopic guidance may improve the quality of the ablation procedure, and can reduce procedure time. Overlay images, acquired using CT, MRI, or C-arm CT, can add soft-tissue information, otherwise not visible under X-ray. MRI can be used to image a wide variety of anatomical details without ionizing radiation. In this paper, we present a method to register a 3-D MRI volume to 2-D biplane X-ray images using the coronary sinus. Current approaches require registration of the overlay images to the fluoroscopic images to be performed after the trans-septal puncture, when contast agent can be administered. We present a new approach for registration to align overlay images before the trans-septal puncture. To this end, we manually extract the coronary sinus from pre-operative MRI and register it to a multi-electorde catheter placed in the coronary sinus.

  13. Behavioral and electrophysiological correlates of sleep and sleep homeostasis.

    PubMed

    Deboer, Tom

    2015-01-01

    The definition of what sleep is depends on the method that is applied to record sleep. Behavioral and (electro)-physiological measures of sleep clearly overlap in mammals and birds , but it is often unclear how these two relate in other vertebrates and invertebrates. Homeostatic regulation of sleep, where the amount of sleep depends on the amount of previous waking, can be observed in physiology and behavior in all animals this was tested in. In mammals and birds, sleep is generally subdivided into two states, non-rapid eye movement (NREM) sleep and REM sleep. In mammals the combination of behavioral sleep and the changes in the slow-wave range of the NREM sleep electroencephalogram (EEG) can explain and predict the occurrence and depth of sleep in great detail. For REM sleep this is far less clear. Finally, the discovery that slow-waves in the NREM sleep EEG are influenced locally on the cortex depending on prior waking behavior is an interesting new development that asks for an adaptation of the concept of homeostatic regulation of sleep. Incorporating local sleep into models of sleep regulation is needed to obtain a comprehensive picture.

  14. Automatically Generated, Anatomically Accurate Meshes for Cardiac Electrophysiology Problems

    PubMed Central

    Prassl, Anton J.; Kickinger, Ferdinand; Ahammer, Helmut; Grau, Vicente; Schneider, Jürgen E.; Hofer, Ernst; Vigmond, Edward J.; Trayanova, Natalia A.

    2010-01-01

    Significant advancements in imaging technology and the dramatic increase in computer power over the last few years broke the ground for the construction of anatomically realistic models of the heart at an unprecedented level of detail. To effectively make use of high-resolution imaging datasets for modeling purposes, the imaged objects have to be discretized. This procedure is trivial for structured grids. However, to develop generally applicable heart models, unstructured grids are much preferable. In this study, a novel image-based unstructured mesh generation technique is proposed. It uses the dual mesh of an octree applied directly to segmented 3-D image stacks. The method produces conformal, boundary-fitted, and hexahedra-dominant meshes. The algorithm operates fully automatically with no requirements for interactivity and generates accurate volume-preserving representations of arbitrarily complex geometries with smooth surfaces. The method is very well suited for cardiac electrophysiological simulations. In the myocardium, the algorithm minimizes variations in element size, whereas in the surrounding medium, the element size is grown larger with the distance to the myocardial surfaces to reduce the computational burden. The numerical feasibility of the approach is demonstrated by discretizing and solving the monodomain and bidomain equations on the generated grids for two preparations of high experimental relevance, a left ventricular wedge preparation, and a papillary muscle. PMID:19203877

  15. Differential Electrophysiological Responses to Odorant Isotopologues in Drosophilid Antennae123

    PubMed Central

    Drimyli, Efstathia; Gaitanidis, Alexandros; Maniati, Klio; Turin, Luca

    2016-01-01

    Abstract Olfaction presents the ultimate challenge to molecular recognition as thousands of molecules have to be recognized by far fewer olfactory receptors. We have presented evidence that Drosophila readily distinguish odorants based on their molecular vibrations using a battery of behavioral assays suggesting engagement of a molecular vibration-sensing component. Here we interrogate electrophysiologically the antennae of four Drosophilids and demonstrate conserved differential response amplitudes to aldehydes, alcohols, ketones, nitriles, and their deuterated isotopologues. Certain deuterated odorants evoked larger electroantennogram (EAG) amplitudes, while the response to the normal odorant was elevated in others. Significantly, benzonitrile isotopologues were not distinguishable as predicted. This suggests that isotopologue-specific EAG amplitudes result from differential activation of specific olfactory receptors. In support of this, odorants with as few as two deuteria evoke distinct EAG amplitudes from their normal isotopologues, and this is independent of the size of the deuterated molecule. Importantly, we find no evidence that these isotopologue-specific amplitudes depend on perireceptor mechanisms or other pertinent physical property of the deuterated odorants. Rather, our results strongly suggest that Drosophilid olfactory receptors are activated by molecular vibrations differentiating similarly sized and shaped odorants in vivo, yielding sufficient differential information to drive behavioral choices. PMID:27351023

  16. A recording chamber for small volume slice electrophysiology.

    PubMed

    Dondzillo, Anna; Quinn, Kevin D; Cruickshank-Quinn, Charmion I; Reisdorph, Nichole; Lei, Tim C; Klug, Achim

    2015-09-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products.

  17. A low-cost, open-source, wireless electrophysiology system.

    PubMed

    Ghomashchi, A; Zheng, Z; Majaj, N; Trumpis, M; Kiorpes, L; Viventi, J

    2014-01-01

    Many experiments in neuroscience require or would benefit tremendously from a wireless neural recording system. However, commercially available wireless systems are expensive, have moderate to high noise and are often not customizable. Academic wireless systems present impressive capabilities, but are not available for other labs to use. To overcome these limitations, we have developed an ultra-low noise 8 channel wireless electrophysiological data acquisition system using standard, commercially available components. The system is capable of recording many types of neurological signals, including EEG, ECoG, LFP and unit activity. With a diameter of just 25 mm and height of 9 mm, including a CR2032 Lithium coin cell battery, it is designed to fit into a small recording chamber while minimizing the overall implant height (Fig. 1 and 3). Using widely available parts we were able to keep the material cost of our system under $100 dollars. The complete design, including schematic, PCB layout, bill of materials and source code, will be released through an open source license, allowing other labs to modify the design to fit their needs. We have also developed a driver to acquire data using the BCI2000 software system. Feedback from the community will allow us to improve the design and create a more useful neuroscience research tool. PMID:25570656

  18. [Electrophysiologic and other objective tests in pediatric cochlear implantation].

    PubMed

    Bordure, P; O'Donoghue, G M; Mason, S

    1996-01-01

    Various electrophysiological procedures have been developed and utilized in pediatric cochlear implant patients. During surgery and just before implantation, recording of Electrically-Evoked Auditory Brainstem Responses (EABR) by electrical stimulation via a promontory needle electrode is a useful tool to select the suitable ear for implantation in the absence of other criteria. After implantation, peroperative assessment of the Electrically-Evoked Stapedius Reflex thresholds allows an estimation of the comfort levels not to be exceeded during the first tuning sessions. Recording of Averaged Electrode Voltages (AEV) provides assurance against general device failure, and can localize defectives electrodes which will be disactivated. Finally EABR obtained by electrical stimulation via the implant is the last control showing objective auditory responses. Furthermore there is a strong correlation between EABR thresholds and behavioral thresholds which will be obtained during the first tuning session. When a device malfunction is suspected after implantation, recording of AEV and EABR are performed, and the results are compared with the preoperative data.

  19. Electrophysiological correlates of long-term Soto Zen meditation.

    PubMed

    Pasquini, Henrique Adam; Tanaka, Guaraci Ken; Basile, Luis Fernando Hindi; Velasques, Bruna; Lozano, Mirna Delposo; Ribeiro, Pedro

    2015-01-01

    This study aimed to verify the electrophysiological correlates of the changes in long-term regular meditators. We use modern techniques of high-resolution electroencephalography applied to slow potentials, power spectra, and potencies related to the events. To obtain encephalographic records, we use an assembly of 128 channels in 31 subjects (17 Soto Zen Buddhist meditators). The motivation of this study was to determine whether the induced beta power would present an increase in meditators as well as a decrease in induced theta/beta ratio in absolute and relative values. However, opposite to what we expected, no significant change was found in the beta frequency. In contrast, the main findings of the study were correlations between the frequency of weekly meditation practice and the increased theta induced relative power, increase of induced power ratio (ratio theta/beta), and increase of the ratio of induced relative powers (theta/beta ratio) during our task that featured an "adapted meditation," suggesting that the meditative state of "mindfulness" is much more related to the permittivity of "distractions" by the meditators, with a deliberate reduction of attention.

  20. Myokit: A simple interface to cardiac cellular electrophysiology.

    PubMed

    Clerx, Michael; Collins, Pieter; de Lange, Enno; Volders, Paul G A

    2016-01-01

    Myokit is a new powerful and versatile software tool for modeling and simulation of cardiac cellular electrophysiology. Myokit consists of an easy-to-read modeling language, a graphical user interface, single and multi-cell simulation engines and a library of advanced analysis tools accessible through a Python interface. Models can be loaded from Myokit's native file format or imported from CellML. Model export is provided to C, MATLAB, CellML, CUDA and OpenCL. Patch-clamp data can be imported and used to estimate model parameters. In this paper, we review existing tools to simulate the cardiac cellular action potential to find that current tools do not cater specifically to model development and that there is a gap between easy-to-use but limited software and powerful tools that require strong programming skills from their users. We then describe Myokit's capabilities, focusing on its model description language, simulation engines and import/export facilities in detail. Using three examples, we show how Myokit can be used for clinically relevant investigations, multi-model testing and parameter estimation in Markov models, all with minimal programming effort from the user. This way, Myokit bridges a gap between performance, versatility and user-friendliness. PMID:26721671

  1. Electrophysiological Determination of Submembrane Na(+) Concentration in Cardiac Myocytes.

    PubMed

    Hegyi, Bence; Bányász, Tamás; Shannon, Thomas R; Chen-Izu, Ye; Izu, Leighton T

    2016-09-20

    In the heart, Na(+) is a key modulator of the action potential, Ca(2+) homeostasis, energetics, and contractility. Because Na(+) currents and cotransport fluxes depend on the Na(+) concentration in the submembrane region, it is necessary to accurately estimate the submembrane Na(+) concentration ([Na(+)]sm). Current methods using Na(+)-sensitive fluorescent indicators or Na(+) -sensitive electrodes cannot measure [Na(+)]sm. However, electrophysiology methods are ideal for measuring [Na(+)]sm. In this article, we develop patch-clamp protocols and experimental conditions to determine the upper bound of [Na(+)]sm at the peak of action potential and its lower bound at the resting state. During the cardiac cycle, the value of [Na(+)]sm is constrained within these bounds. We conducted experiments in rabbit ventricular myocytes at body temperature and found that 1) at a low pacing frequency of 0.5 Hz, the upper and lower bounds converge at 9 mM, constraining the [Na(+)]sm value to ∼9 mM; 2) at 2 Hz pacing frequency, [Na(+)]sm is bounded between 9 mM at resting state and 11.5 mM; and 3) the cells can maintain [Na(+)]sm to the above values, despite changes in the pipette Na(+) concentration, showing autoregulation of Na(+) in beating cardiomyocytes. PMID:27653489

  2. Simulating Cardiac Electrophysiology Using Unstructured All-Hexahedra Spectral Elements

    PubMed Central

    Cuccuru, Gianmauro; Fotia, Giorgio; Maggio, Fabio; Southern, James

    2015-01-01

    We discuss the application of the spectral element method to the monodomain and bidomain equations describing propagation of cardiac action potential. Models of cardiac electrophysiology consist of a system of partial differential equations coupled with a system of ordinary differential equations representing cell membrane dynamics. The solution of these equations requires solving multiple length scales due to the ratio of advection to diffusion that varies among the different equations. High order approximation of spectral elements provides greater flexibility in resolving multiple length scales. Furthermore, spectral elements are extremely efficient to model propagation phenomena on complex shapes using fewer degrees of freedom than its finite element equivalent (for the same level of accuracy). We illustrate a fully unstructured all-hexahedra approach implementation of the method and we apply it to the solution of full 3D monodomain and bidomain test cases. We discuss some key elements of the proposed approach on some selected benchmarks and on an anatomically based whole heart human computational model. PMID:26583112

  3. Myokit: A simple interface to cardiac cellular electrophysiology.

    PubMed

    Clerx, Michael; Collins, Pieter; de Lange, Enno; Volders, Paul G A

    2016-01-01

    Myokit is a new powerful and versatile software tool for modeling and simulation of cardiac cellular electrophysiology. Myokit consists of an easy-to-read modeling language, a graphical user interface, single and multi-cell simulation engines and a library of advanced analysis tools accessible through a Python interface. Models can be loaded from Myokit's native file format or imported from CellML. Model export is provided to C, MATLAB, CellML, CUDA and OpenCL. Patch-clamp data can be imported and used to estimate model parameters. In this paper, we review existing tools to simulate the cardiac cellular action potential to find that current tools do not cater specifically to model development and that there is a gap between easy-to-use but limited software and powerful tools that require strong programming skills from their users. We then describe Myokit's capabilities, focusing on its model description language, simulation engines and import/export facilities in detail. Using three examples, we show how Myokit can be used for clinically relevant investigations, multi-model testing and parameter estimation in Markov models, all with minimal programming effort from the user. This way, Myokit bridges a gap between performance, versatility and user-friendliness.

  4. Describing relevant indices from the resting state electrophysiological networks.

    PubMed

    Toppi, J; Petti, M; De Vico Fallani, F; Vecchiato, G; Maglione, A G; Cincotti, F; Salinari, S; Mattia, D; Babiloni, F; Astolfi, L

    2012-01-01

    The "Default Mode Network" concept was defined, in fMRI field, as a consistent pattern, involving some regions of the brain, which is active during resting state activity and deactivates during attention demanding or goal-directed tasks. Several fMRI studies described its features also correlating the deactivations with the attentive load required for the task execution. Despite the efforts in EEG field, aiming at correlating the spectral features of EEG signals with DMN, an electrophysiological correlate of the DMN hasn't yet been found. In this study we used advanced techniques for functional connectivity estimation for describing the neuroelectrical properties of DMN. We analyzed the connectivity patterns elicited during the rest condition by 55 healthy subjects by means of Partial Directed Coherence. We extracted some graph indexes in order to describe the properties of the resting network in terms of local and global efficiencies, symmetries and influences between different regions of the scalp. Results highlighted the presence of a consistent network, elicited by more than 70% of analyzed population, involving mainly frontal and parietal regions. The properties of the resting network are uniform among the population and could be used for the construction of a normative database for the identification of pathological conditions.

  5. Spectrally resolved fast transient brain states in electrophysiological data

    PubMed Central

    Vidaurre, Diego; Quinn, Andrew J.; Baker, Adam P.; Dupret, David; Tejero-Cantero, Alvaro; Woolrich, Mark W.

    2016-01-01

    The brain is capable of producing coordinated fast changing neural dynamics across multiple brain regions in order to adapt to rapidly changing environments. However, it is non-trivial to identify multiregion dynamics at fast sub-second time-scales in electrophysiological data. We propose a method that, with no knowledge of any task timings, can simultaneously identify and describe fast transient multiregion dynamics in terms of their temporal, spectral and spatial properties. The approach models brain activity using a discrete set of sequential states, with each state distinguished by its own multiregion spectral properties. This can identify potentially very short-lived visits to a brain state, at the same time as inferring the state's properties, by pooling over many repeated visits to that state. We show how this can be used to compute state-specific measures such as power spectra and coherence. We demonstrate that this can be used to identify short-lived transient brain states with distinct power and functional connectivity (e.g., coherence) properties in an MEG data set collected during a volitional motor task. PMID:26631815

  6. Spectrally resolved fast transient brain states in electrophysiological data.

    PubMed

    Vidaurre, Diego; Quinn, Andrew J; Baker, Adam P; Dupret, David; Tejero-Cantero, Alvaro; Woolrich, Mark W

    2016-02-01

    The brain is capable of producing coordinated fast changing neural dynamics across multiple brain regions in order to adapt to rapidly changing environments. However, it is non-trivial to identify multiregion dynamics at fast sub-second time-scales in electrophysiological data. We propose a method that, with no knowledge of any task timings, can simultaneously identify and describe fast transient multiregion dynamics in terms of their temporal, spectral and spatial properties. The approach models brain activity using a discrete set of sequential states, with each state distinguished by its own multiregion spectral properties. This can identify potentially very short-lived visits to a brain state, at the same time as inferring the state's properties, by pooling over many repeated visits to that state. We show how this can be used to compute state-specific measures such as power spectra and coherence. We demonstrate that this can be used to identify short-lived transient brain states with distinct power and functional connectivity (e.g., coherence) properties in an MEG data set collected during a volitional motor task. PMID:26631815

  7. A recording chamber for small volume slice electrophysiology

    PubMed Central

    Quinn, Kevin D.; Cruickshank-Quinn, Charmion I.; Reisdorph, Nichole; Lei, Tim C.; Klug, Achim

    2015-01-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. PMID:26203105

  8. Contraction mode itself does not determine the level of mTORC1 activity in rat skeletal muscle.

    PubMed

    Ato, Satoru; Makanae, Yuhei; Kido, Kohei; Fujita, Satoshi

    2016-10-01

    Resistance training with eccentric contraction has been shown to augment muscle hypertrophy more than other contraction modes do (i.e., concentric and isometric contraction). However, the molecular mechanisms involved remain unclear. The purpose of this study was to investigate the effect of muscle contraction mode on mammalian target of rapamycin complex 1 (mTORC1) signaling using a standardized force-time integral (load (weight) × contraction time). Male Sprague-Dawley rats were randomly assigned to three groups: eccentric contraction, concentric contraction, and isometric contraction. The right gastrocnemius muscle was exercised via percutaneous electrical stimulation-induced maximal contraction. In experiment 1, different modes of muscle contraction were exerted using the same number of reps in all groups, while in experiment 2, muscle contractions were exerted using a standardized force-time integral. Muscle samples were obtained immediately and 3 h after exercise. Phosphorylation of molecules associated with mTORC1 activity was assessed using western blot analysis. In experiment 1, the force-time integral was significantly different among contraction modes with a higher force-time integral for eccentric contraction compared to that for other contraction modes (P < 0.05). In addition, the force-time integral was higher for concentric contraction compared to that for isometric contraction (P < 0.05). Similarly, p70S6K phosphorylation level was higher for eccentric contraction than for other modes of contraction (P < 0.05), and concentric contraction was higher than isometric contraction (P < 0.05) 3 h after exercise. In experiment 2, under the same force-time integral, p70S6K (Thr389) and 4E-BP1 phosphorylation levels were similar among contraction modes 3 h after exercise. Our results suggest that mTORC1 activity is not determined by differences in muscle contraction mode itself. Instead, mTORC1 activity is determined by differences in the force

  9. Plastic and stable electrophysiological properties of adult avian forebrain song-control neurons across changing breeding conditions.

    PubMed

    Meitzen, John; Weaver, Adam L; Brenowitz, Eliot A; Perkel, David J

    2009-05-20

    Steroid sex hormones drive changes in the nervous system and behavior in many animal taxa, but integrating the former with the latter remains challenging. One useful model system for meeting this challenge is seasonally breeding songbirds. In these species, plasma testosterone levels rise and fall across the seasons, altering song behavior and causing dramatic growth and regression of the song-control system, a discrete set of nuclei that control song behavior. Whereas the cellular mechanisms underlying changes in nucleus volume have been studied as a model for neural growth and degeneration, it is unknown whether these changes in neural structure are accompanied by changes in electrophysiological properties other than spontaneous firing rate. Here we test the hypothesis that passive and active neuronal properties in the forebrain song-control nuclei HVC and RA change across breeding conditions. We exposed adult male Gambel's white-crowned sparrows to either short-day photoperiod or long-day photoperiod and systemic testosterone to simulate nonbreeding and breeding conditions, respectively. We made whole-cell recordings from RA and HVC neurons in acute brain slices. We found that RA projection neuron membrane time constant, capacitance, and evoked and spontaneous firing rates were all increased in the breeding condition; the measured electrophysiological properties of HVC interneurons and projection neurons were stable across breeding conditions. This combination of plastic and stable intrinsic properties could directly impact the song-control system's motor control across seasons, underlying changes in song stereotypy. These results provide a valuable framework for integrating how steroid hormones modulate cellular physiology to change behavior.

  10. Plastic and stable electrophysiological properties of adult avian forebrain song-control neurons across changing breeding conditions.

    PubMed

    Meitzen, John; Weaver, Adam L; Brenowitz, Eliot A; Perkel, David J

    2009-05-20

    Steroid sex hormones drive changes in the nervous system and behavior in many animal taxa, but integrating the former with the latter remains challenging. One useful model system for meeting this challenge is seasonally breeding songbirds. In these species, plasma testosterone levels rise and fall across the seasons, altering song behavior and causing dramatic growth and regression of the song-control system, a discrete set of nuclei that control song behavior. Whereas the cellular mechanisms underlying changes in nucleus volume have been studied as a model for neural growth and degeneration, it is unknown whether these changes in neural structure are accompanied by changes in electrophysiological properties other than spontaneous firing rate. Here we test the hypothesis that passive and active neuronal properties in the forebrain song-control nuclei HVC and RA change across breeding conditions. We exposed adult male Gambel's white-crowned sparrows to either short-day photoperiod or long-day photoperiod and systemic testosterone to simulate nonbreeding and breeding conditions, respectively. We made whole-cell recordings from RA and HVC neurons in acute brain slices. We found that RA projection neuron membrane time constant, capacitance, and evoked and spontaneous firing rates were all increased in the breeding condition; the measured electrophysiological properties of HVC interneurons and projection neurons were stable across breeding conditions. This combination of plastic and stable intrinsic properties could directly impact the song-control system's motor control across seasons, underlying changes in song stereotypy. These results provide a valuable framework for integrating how steroid hormones modulate cellular physiology to change behavior. PMID:19458226

  11. Ion Channel ElectroPhysiology Ontology (ICEPO) – a case study of text mining assisted ontology development

    PubMed Central

    Elayavilli, Ravikumar Komandur; Liu, Hongfang

    2016-01-01

    Background Computational modeling of biological cascades is of great interest to quantitative biologists. Biomedical text has been a rich source for quantitative information. Gathering quantitative parameters and values from biomedical text is one significant challenge in the early steps of computational modeling as it involves huge manual effort. While automatically extracting such quantitative information from bio-medical text may offer some relief, lack of ontological representation for a subdomain serves as impedance in normalizing textual extractions to a standard representation. This may render textual extractions less meaningful to the domain experts. Methods In this work, we propose a rule-based approach to automatically extract relations involving quantitative data from biomedical text describing ion channel electrophysiology. We further translated the quantitative assertions extracted through text mining to a formal representation that may help in constructing ontology for ion channel events using a rule based approach. We have developed Ion Channel ElectroPhysiology Ontology (ICEPO) by integrating the information represented in closely related ontologies such as, Cell Physiology Ontology (CPO), and Cardiac Electro Physiology Ontology (CPEO) and the knowledge provided by domain experts. Results The rule-based system achieved an overall F-measure of 68.93% in extracting the quantitative data assertions system on an independently annotated blind data set. We further made an initial attempt in formalizing the quantitative data assertions extracted from the biomedical text into a formal representation that offers potential to facilitate the integration of text mining into ontological workflow, a novel aspect of this study. Conclusions This work is a case study where we created a platform that provides formal interaction between ontology development and text mining. We have achieved partial success in extracting quantitative assertions from the biomedical text

  12. Uterine Contraction Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Liu, Miao; Belfore, Lee A.; Shen, Yuzhong; Scerbo, Mark W.

    2010-01-01

    Building a training system for medical personnel to properly interpret fetal heart rate tracing requires developing accurate models that can relate various signal patterns to certain pathologies. In addition to modeling the fetal heart rate signal itself, the change of uterine pressure that bears strong relation to fetal heart rate and provides indications of maternal and fetal status should also be considered. In this work, we have developed a group of parametric models to simulate uterine contractions during labor and delivery. Through analysis of real patient records, we propose to model uterine contraction signals by three major components: regular contractions, impulsive noise caused by fetal movements, and low amplitude noise invoked by maternal breathing and measuring apparatus. The regular contractions are modeled by an asymmetric generalized Gaussian function and least squares estimation is used to compute the parameter values of the asymmetric generalized Gaussian function based on uterine contractions of real patients. Regular contractions are detected based on thresholding and derivative analysis of uterine contractions. Impulsive noise caused by fetal movements and low amplitude noise by maternal breathing and measuring apparatus are modeled by rational polynomial functions and Perlin noise, respectively. Experiment results show the synthesized uterine contractions can mimic the real uterine contractions realistically, demonstrating the effectiveness of the proposed algorithm.

  13. A microfluidic device for whole-animal drug screening using electrophysiological measures in the nematode C. elegans

    PubMed Central

    Hulme, S. Elizabeth; Roberts, William M.; Robinson, Kristin J.; Laromaine, Anna; Lindsay, Theodore H.; Whitesides, George M.; Weeks, Janis C.

    2012-01-01

    This paper describes the fabrication and use of a microfluidic device for performing whole-animal chemical screens using non-invasive electrophysiological readouts of neuromuscular function in the nematode worm, C. elegans. The device consists of an array of microchannels to which electrodes are attached to form recording modules capable of detecting the electrical activity of the pharynx, a heart-like neuromuscular organ involved in feeding. The array is coupled to a tree-like arrangement of distribution channels that automatically delivers one nematode to each recording module. The same channels are then used to perfuse the recording modules with test solutions while recording the electropharyngeogram (EPG) from each worm with sufficient sensitivity to detect each pharyngeal contraction. The device accurately reported the acute effects of known anthelmintics (anti-nematode drugs) and also correctly distinguished a specific drug-resistant mutant strain of C. elegans from wild type. The approach described here is readily adaptable to parasitic species for the identification of novel anthelmintics. It is also applicable in toxicology and drug discovery programs for human metabolic and degenerative diseases for which C. elegans is used as a model. PMID:22588281

  14. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... production option on a development contract for a major weapon system reasonably in advance of the expiration of the option exercise period. (ii) For other than major defense acquisition programs— (A) Do not... permits realistic pricing; (2) The use of a fixed-price type contract permits an equitable and...

  15. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... production option on a development contract for a major weapon system reasonably in advance of the expiration of the option exercise period. (ii) For other than major defense acquisition programs— (A) Do not... permits realistic pricing; (2) The use of a fixed-price type contract permits an equitable and...

  16. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... production option on a development contract for a major weapon system reasonably in advance of the expiration of the option exercise period. (ii) For other than major defense acquisition programs— (A) Do not... permits realistic pricing; (2) The use of a fixed-price type contract permits an equitable and...

  17. Electrophysiology in the eukaryotic model cell Saccharomyces cerevisiae.

    PubMed

    Bertl, A; Bihler, H; Kettner, C; Slayman, C L

    1998-11-01

    Since the mid-1980s, use of the budding yeast, Saccharomyces cerevisiae, for expression of heterologous (foreign) genes and proteins has burgeoned for several major purposes, including facile genetic manipulation, large-scale production of specific proteins, and preliminary functional analysis. Expression of heterologous membrane proteins in yeast has not kept pace with expression of cytoplasmic proteins for two principal reasons: (1) although plant and fungal proteins express and function easily in yeast membranes, animal proteins do not, at least yet; and (2) the yeast plasma membrane is generally regarded as a difficult system to which to apply the standard electrophysiological techniques for detailed functional analysis of membrane proteins. Especially now, since completion of the genome-sequencing project for Saccharomyces, yeast membranes themselves can be seen as an ample source of diverse membrane proteins - including ion channels, pumps, and cotransporters - which lend themselves to electrophysiological analysis, and specifically to patch-clamping. Using some of these native proteins for assay, we report systematic methods to prepare both the yeast plasma membrane and the yeast vacuolar membrane (tonoplast) for patch-clamp experiments. We also describe optimized ambient conditions - such as electrode preparation, buffer solutions, and time regimens - which facilitate efficient patch recording from Saccharomyces membranes. There are two main keys to successful patch-clamping with Saccharomyces. The first is patience; the second is scrupulous cleanliness. Large cells, such as provided by polyploid strains, are also useful in yeast patch recording, especially while the skill required for gigaseal formation is being learned. Cleanliness is aided by (1) osmotic extrusion of protoplasts, after minimal digestion of yeast walls; (2) use of a rather spare suspension of protoplasts in the recording chamber; (3) maintenance of continuous chamber perfusion prior to

  18. Electrophysiology in the eukaryotic model cell Saccharomyces cerevisiae.

    PubMed

    Bertl, A; Bihler, H; Kettner, C; Slayman, C L

    1998-11-01

    Since the mid-1980s, use of the budding yeast, Saccharomyces cerevisiae, for expression of heterologous (foreign) genes and proteins has burgeoned for several major purposes, including facile genetic manipulation, large-scale production of specific proteins, and preliminary functional analysis. Expression of heterologous membrane proteins in yeast has not kept pace with expression of cytoplasmic proteins for two principal reasons: (1) although plant and fungal proteins express and function easily in yeast membranes, animal proteins do not, at least yet; and (2) the yeast plasma membrane is generally regarded as a difficult system to which to apply the standard electrophysiological techniques for detailed functional analysis of membrane proteins. Especially now, since completion of the genome-sequencing project for Saccharomyces, yeast membranes themselves can be seen as an ample source of diverse membrane proteins - including ion channels, pumps, and cotransporters - which lend themselves to electrophysiological analysis, and specifically to patch-clamping. Using some of these native proteins for assay, we report systematic methods to prepare both the yeast plasma membrane and the yeast vacuolar membrane (tonoplast) for patch-clamp experiments. We also describe optimized ambient conditions - such as electrode preparation, buffer solutions, and time regimens - which facilitate efficient patch recording from Saccharomyces membranes. There are two main keys to successful patch-clamping with Saccharomyces. The first is patience; the second is scrupulous cleanliness. Large cells, such as provided by polyploid strains, are also useful in yeast patch recording, especially while the skill required for gigaseal formation is being learned. Cleanliness is aided by (1) osmotic extrusion of protoplasts, after minimal digestion of yeast walls; (2) use of a rather spare suspension of protoplasts in the recording chamber; (3) maintenance of continuous chamber perfusion prior to

  19. Electrophysiological correlates of melodic processing in congenital amusia.

    PubMed

    Omigie, Diana; Pearce, Marcus T; Williamson, Victoria J; Stewart, Lauren

    2013-08-01

    Music listening involves using previously internalized regularities to process incoming musical structures. A condition known as congenital amusia is characterized by musical difficulties, notably in the detection of gross musical violations. However, there has been increasing evidence that individuals with the disorder show preserved musical ability when probed using implicit methods. To further characterize the degree to which amusic individuals show evidence of latent sensitivity to musical structure, particularly in the context of stimuli that are ecologically valid, electrophysiological recordings were taken from a sample of amusic and control participants as they listened to real melodies. To encourage them to pay attention to the music, participants were asked to detect occasional notes in a different timbre. Using a computational model of auditory expectation to identify points of varying levels of expectedness in these melodies (in units of information content (IC), a measure which has an inverse relationship with probability), ERP analysis investigated the extent to which the amusic brain differs from that of controls when processing notes of high IC (low probability) as compared to low IC ones (high probability). The data revealed a novel effect that was highly comparable in both groups: Notes with high IC reliably elicited a delayed P2 component relative to notes with low IC, suggesting that amusic individuals, like controls, found these notes more difficult to evaluate. However, notes with high IC were also characterized by an early frontal negativity in controls that was attenuated in amusic individuals. A correlation of this early negative effect with the ability to make accurate note expectedness judgments (previous data collected from a subset of the current sample) was shown to be present in typical individuals but compromised in individuals with amusia: a finding in line with evidence of a close relationship between the amplitude of such a

  20. Intraoperative electrophysiological evaluations of macular function during peripheral scleral indentation

    PubMed Central

    Akiyama, Goichi; Matsumoto, Celso Soiti; Shinoda, Kei; Terauchi, Gaku; Matsumoto, Harue; Watanabe, Emiko; Iwata, Takeshi; Mizota, Atsushi; Miyake, Yozo

    2016-01-01

    Scleral indentation is widely used to examine the peripheral fundus, however it can increase the intraocular pressure (IOP) to high levels which can then affect retinal function. We evaluated the effects of scleral indentation on the macular function electrophysiologically. Intraoperative focal macular electroretinograms (iFMERGs) were recorded with and without controlling the IOP in 7 eyes. Without IOP control, the IOP increased from 21.7 ± 4.9 to 92.7 ± 20.2 mmHg significantly (P = 0.020) and the amplitudes of the b-wave (from 6.29 ± 1.160 to 3.71 ± 1.98 uV, P = 0.007), on-photopic negative response (from 2.29 ± 0.99 to 0.72 ± 0.47 uV, on-PhNR, P = 0.005), and d-wave (from 2.57 ± 0.41 to 1.64 ± 0.69 uV, P = 0.007) decreased significantly soon after beginning the indentation. All values returned to the baseline levels after releasing the indentation. In the eyes with IOP controlled, the IOP and the amplitude of all components did not change significantly during and after the indentation except the on-PhNR amplitude which was significantly reduced during the indentation. The changes in the iFMERGs and macular function caused by scleral indentation were transient and reversible. The changes can be minimized by controlling the IOP. PMID:27762313

  1. Aldosterone-induced glycoproteins: electrophysiological-biochemical correlation.

    PubMed

    Szerlip, H M; Weisberg, L; Geering, K; Rossier, B C; Cox, M

    1988-05-01

    Aldosterone induces the synthesis of a group of glycoproteins (GP65,70) in toad urinary bladders which are potential effectors of the natriferic action of this hormone. In the present study we have confirmed that aldosterone produces a two-phase electrophysiological response. During the early phase (less than 3 h) short-circuit current and transepithelial conductance increase in parallel, while during the late phase (greater than 3 h) short-circuit current continues to increase without any further change in conductance. By biosynthetically labeling aldosterone-treated toad bladders with [35S]methionine either during the early (h 0-2 or 1-3) or the late (h 4-6 or 7-9) phases of the natriferic response, we have demonstrated that GP65,70 is synthesized as a late effect of aldosterone. Since synthesis of GP65,70 occurs at a time when the electromotive force of the Na+ pump is increasing, and since GP65,70 biochemically resembles the beta subunit of Na+/K+-ATPase, studies were undertaken to examine whether GP65,70 is the beta subunit. Purified amphibian renal beta subunit was analyzed by two-dimensional polyacrylamide gel electrophoresis and was found to have an isoelectric point and Mr value similar to those of GP65,70. However, when nitrocellulose blots containing wheat germ agglutinin-purified proteins from aldosterone-treated bladders were stained with monospecific polyclonal antibodies developed against the beta subunit, GP65,70 was not recognized, whereas a group of slightly more acidic proteins of similar Mr were recognized. Thus, GP65,70 is not the beta subunit of Na+/Ka+-ATPase. Further studies are needed to determine the cellular function of GP65,70. PMID:2835098

  2. Electrophysiological biomarkers in spinal muscular atrophy: proof of concept

    PubMed Central

    David Arnold, W; Porensky, Paul N; McGovern, Vicki L; Iyer, Chitra C; Duque, Sandra; Li, Xiaobai; Meyer, Kathrin; Schmelzer, Leah; Kaspar, Brian K; Kolb, Stephen J; Kissel, John T; Burghes, Arthur H M

    2014-01-01

    Objective Preclinical therapies that restore survival motor neuron (SMN) protein levels can dramatically extend survival in spinal muscular atrophy (SMA) mouse models. Biomarkers are needed to effectively translate these promising therapies to clinical trials. Our objective was to investigate electrophysiological biomarkers of compound muscle action potential (CMAP), motor unit number estimation (MUNE) and electromyography (EMG) using an SMA mouse model. Methods Sciatic CMAP, MUNE, and EMG were obtained in SMNΔ7 mice at ages 3–13 days and at 21 days in mice with SMN selectively reduced in motor neurons (ChATCre). To investigate these measures as biomarkers of treatment response, measurements were obtained in SMNΔ7 mice treated with antisense oligonucleotide (ASO) or gene therapy. Results CMAP was significantly reduced in SMNΔ7 mice at days 6–13 (P < 0.01), and MUNE was reduced at days 7–13 (P < 0.01). Fibrillations were present on EMG in SMNΔ7 mice but not controls (P = 0.02). Similar findings were seen at 21 days in ChATCre mice. MUNE in ASO-treated SMNΔ7 mice were similar to controls at day 12 and 30. CMAP reduction persisted in ASO-treated SMNΔ7 mice at day 12 but was corrected at day 30. Similarly, CMAP and MUNE responses were corrected with gene therapy to restore SMN. Interpretation These studies confirm features of preserved neuromuscular function in the early postnatal period and subsequent motor unit loss in SMNΔ7 mice. SMN restoring therapies result in preserved MUNE and gradual repair of CMAP responses. This provides preclinical evidence for the utilization of CMAP and MUNE as biomarkers in future SMA clinical trials. PMID:24511555

  3. Giant Liposome Preparation for Imaging and Patch-Clamp Electrophysiology

    PubMed Central

    Collins, Marcus D.; Gordon, Sharona E.

    2013-01-01

    The reconstitution of ion channels into chemically defined lipid membranes for electrophysiological recording has been a powerful technique to identify and explore the function of these important proteins. However, classical preparations, such as planar bilayers, limit the manipulations and experiments that can be performed on the reconstituted channel and its membrane environment. The more cell-like structure of giant liposomes permits traditional patch-clamp experiments without sacrificing control of the lipid environment. Electroformation is an efficient mean to produce giant liposomes >10 μm in diameter which relies on the application of alternating voltage to a thin, ordered lipid film deposited on an electrode surface. However, since the classical protocol calls for the lipids to be deposited from organic solvents, it is not compatible with less robust membrane proteins like ion channels and must be modified. Recently, protocols have been developed to electroform giant liposomes from partially dehydrated small liposomes, which we have adapted to protein-containing liposomes in our laboratory. We present here the background, equipment, techniques, and pitfalls of electroformation of giant liposomes from small liposome dispersions. We begin with the classic protocol, which should be mastered first before attempting the more challenging protocols that follow. We demonstrate the process of controlled partial dehydration of small liposomes using vapor equilibrium with saturated salt solutions. Finally, we demonstrate the process of electroformation itself. We will describe simple, inexpensive equipment that can be made in-house to produce high-quality liposomes, and describe visual inspection of the preparation at each stage to ensure the best results. PMID:23851612

  4. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography.

    PubMed

    Giardini, Mario E; Zippo, Antonio G; Valente, Maurizio; Krstajic, Nikola; Biella, Gabriele E M

    2016-01-01

    Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention. PMID:27050096

  5. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography

    PubMed Central

    Valente, Maurizio; Krstajic, Nikola; Biella, Gabriele E. M.

    2016-01-01

    Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention. PMID:27050096

  6. Evolving anatomic and electrophysiologic considerations associated with Fontan conversion.

    PubMed

    Mavroudis, Constantine; Backer, Carl Lewis; Deal, Barbara J; Stewart, Robert D; Franklin, Wayne H; Tsao, Sabrina; Ward, Kendra

    2007-01-01

    The principles of Fontan conversion with arrhythmia surgery are to restore the cardiac anatomy by converting the original atriopulmonary connection to a total cavopulmonary artery extracardiac connection and treat the underlying atrial arrhythmias. Successful outcomes of this procedure are dependent on a thorough understanding of several factors: the patient's fundamental diagnosis of single-ventricle anatomy, the resultant cardiac configuration from the original atriopulmonary Fontan connection, right atrial dilatation that leads to atrial flutter or fibrillation, and associated congenital cardiac anomalies. The purpose of this article is to present some of the more challenging anatomic and electrophysiologic problems we have encountered with Fontan conversion and arrhythmia surgery and the innovative solutions we have used to treat them. The cases reviewed herein include: takedown of a Bjork-Fontan modification, right ventricular hypertension and tricuspid regurgitation after atriopulmonary Fontan for pulmonary atresia and intact ventricular septum, takedown of atrioventricular valve isolation patch for right-sided maze procedure, resultant hemodynamic considerations leading to intraoperative pulmonary vein stenosis after Fontan conversion, unwanted inferior vena cava retraction during the extracardiac connection, right atrial cannulation in the presence of a right atrial clot, distended left superior vena cava causing left pulmonary vein stenosis, dropped atrial septum, and the modified right-sided maze procedure for various single-ventricle pathology. Since 1994 we have performed Fontan conversion with arrhythmia surgery on 109 patients with a 0.9% mortality rate. We attribute our program's success in no small measure to the strong collaborative efforts of the cardiothoracic surgery and cardiology teams.

  7. The Automation of Electrophysiological Experiments and Data Analysis

    NASA Astrophysics Data System (ADS)

    Morton, David L.

    The role of computation in science is continually growing and neuroscience is no exception. Despite this, a severe lack of scientific software infrastructure persists, slowing progress in many domains. In this thesis, we will see how the combination of neuroscience and software engineering can build infrastructure that enables discovery. The first chapter discusses the Turtle Electrophysiology Project, or TEP, an experiment-automation and data-management system. This system has allowed us to automate away some of the most tedious tasks involved in conducting experiments. As a result, we can collect more data in less time, and with fewer errors related to the loss of metadata (information about how the data were collected). Also, since all of the metadata is automatically digitized during the experiment we can now completely automate our analyses. Chapters two and three are examples of research conducted using the ever-evolving TEP system. In the first instance, we used TEP to deliver visual stimuli and handle data-management. In chapter three, the experiments involved delivering electrical stimuli instead of visual stimuli, and much more rigorous analysis. And even though TEP was not specifically designed to handle collecting data this way, the flexible tags system enabled us to do so. Finally, chapter four details the construction of a robust analysis tool called Spikepy. Whereas TEP is specially designed for the turtle preparation we have, Spikepy is a general-purpose spike-sorting application and framework. Spikepy takes flexibility to the extreme by being a plugin-based framework, yet maintaining a very easy to use interface.

  8. Electrophysiological basis of human fallopian tubal fluid formation.

    PubMed

    Downing, S J; Maguiness, S D; Watson, A; Leese, H J

    1997-09-01

    A preparation for the maintenance of human Fallopian tubal epithelial cells as a polarized layer in primary culture was used to study the electrophysiological basis of tubal fluid formation in terms of the movement of Na+, K+ and Cl- ions. Transepithelial potential difference (PD) and short-circuit current (Iscc) were recorded by mounting the epithelial cells in a modified Ussing chamber. Resistance (R) was calculated from the measurements of PD and Iscc. The epithelia, although confluent, formed a 'leaky' electrical system and resistances greater than 300 omega cm-2 were rarely achieved. The sodium channel blocker, amiloride (100 mumol l-1), produced only small effects on PD and Iscc. The potassium channel blocker, tetraethylammonium chloride (TEA) (25 mmol l-1), also produced small, but significant changes in PD, Iscc and R while the chloride channel blocker, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) (1 mmol l-1), induced a marked increase in PD and Iscc, and a fall in R, when added to the basal surface of the cells. Bathing the apical surface of the cells with chloride-free medium also produced a marked increase in PD, Iscc and R: bathing the basal surface of the cells with chloride-free medium produced a marked decrease in PD and Iscc. Extracellular ATP (10 mumol l-1), added to either the apical or the basal surface of the cells, induced a transient increase in PD and Iscc and a decrease in R. Amiloride, TEA or furosemide had no effect on the response of the cells to ATP. SITS, applied to the apical surface, significantly reduced the response of the cells to ATP. We conclude that the major driving force for human tubal fluid formation is the transepithelial secretion of chloride ions into the oviduct lumen and that exogenous ATP is a potential modulator of secretion. PMID:9370964

  9. Electrophysiological Evidence of Attentional Biases in Social Anxiety Disorder

    PubMed Central

    Mueller, E. M.; Hofmann, S. G.; Santesso, D. L.; Meuret, A. E.; Bitran, S.; Pizzagalli, D. A.

    2011-01-01

    Background Previous studies investigating attentional biases in social anxiety disorder (SAD) have yielded mixed results. Recent event-related potential (ERP) studies employing the dot-probe paradigm in non-anxious participants have shown that the P1 component is sensitive to visuospatial attention toward emotional faces. We used a dot-probe task in conjunction with high-density ERPs and source localization to investigate attentional biases in SAD. Method Twelve SAD and 15 control participants performed a modified dot-probe task using angry-neutral and happy-neutral face-pairs. The P1 component elicited by face-pairs was analyzed to test the hypothesis that SAD participants would display early hypervigilance to threat-related cues. The P1 component to probes replacing angry, happy or neutral faces was used to evaluate whether SAD participants show sustained hypervigilance or rather decreased visual processing of threat-related cues at later processing stages. Results Compared to controls, SAD participants showed relatively (a) potentiated P1 amplitudes and fusiform gyrus activation to angry-neutral vs. happy-neutral face-pairs; (b) decreased P1 amplitudes to probes replacing emotional (angry and happy) vs. neutral faces; and (c) higher sensitivity (d′) to probes following angry-neutral vs. happy-neutral face-pairs. SAD participants also showed significantly shorter reaction times to probes replacing angry vs. happy faces, but no group differences emerged for reaction time. Conclusions The results provide electrophysiological support for early hypervigilance to angry faces in SAD with involvement of the fusiform gyrus, and reduced visual processing of emotionally salient locations at later stages of information processing, which might be a manifestation of attentional avoidance. PMID:19079826

  10. Visual adaptation provides objective electrophysiological evidence of facial identity discrimination.

    PubMed

    Retter, Talia L; Rossion, Bruno

    2016-07-01

    Discrimination of facial identities is a fundamental function of the human brain that is challenging to examine with macroscopic measurements of neural activity, such as those obtained with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Although visual adaptation or repetition suppression (RS) stimulation paradigms have been successfully implemented to this end with such recording techniques, objective evidence of an identity-specific discrimination response due to adaptation at the level of the visual representation is lacking. Here, we addressed this issue with fast periodic visual stimulation (FPVS) and EEG recording combined with a symmetry/asymmetry adaptation paradigm. Adaptation to one facial identity is induced through repeated presentation of that identity at a rate of 6 images per second (6 Hz) over 10 sec. Subsequently, this identity is presented in alternation with another facial identity (i.e., its anti-face, both faces being equidistant from an average face), producing an identity repetition rate of 3 Hz over a 20 sec testing sequence. A clear EEG response at 3 Hz is observed over the right occipito-temporal (ROT) cortex, indexing discrimination between the two facial identities in the absence of an explicit behavioral discrimination measure. This face identity discrimination occurs immediately after adaptation and disappears rapidly within 20 sec. Importantly, this 3 Hz response is not observed in a control condition without the single-identity 10 sec adaptation period. These results indicate that visual adaptation to a given facial identity produces an objective (i.e., at a pre-defined stimulation frequency) electrophysiological index of visual discrimination between that identity and another, and provides a unique behavior-free quantification of the effect of visual adaptation.

  11. Electrophysiological correlates of sleep homeostasis in freely behaving rats

    PubMed Central

    Vyazovskiy, Vladyslav V.; Cirelli, Chiara; Tononi, Giulio

    2011-01-01

    The electrical activity of the brain does not only reflect the current level of arousal, ongoing behavior or involvement in a specific task, but is also influenced by what kind of activity, and how much sleep and waking occurred before. The best marker of sleep-wake history is the electroencephalogram (EEG) spectral power in slow frequencies (slow-wave activity, 0.5–4 Hz, SWA) during sleep, which is high after extended wakefulness and low after consolidated sleep. While sleep homeostasis has been well characterized in various species and experimental paradigms, the specific mechanisms underlying homeostatic changes in brain activity or their functional significance remain poorly understood. However, several recent studies in humans, rats and computer simulations shed light on the cortical mechanisms underlying sleep regulation. First, it was found that the homeostatic changes in SWA can be fully accounted for by the variations in amplitude and slope of EEG slow waves, which are in turn determined by the efficacy of cortico-cortical connectivity. Specifically, the slopes of sleep slow waves were steeper in early sleep compared to late sleep. Second, the slope of cortical evoked potentials, which is an established marker of synaptic strength, was steeper after waking and decreased after sleep. Furthermore, cortical long-term potentiation (LTP) was partially occluded if it was induced after a period of waking, but it could again be fully expressed after sleep. Finally, multiunit activity recordings during sleep revealed that cortical neurons fired more synchronously after waking, and less so after a period of consolidated sleep. The decline of all these electrophysiological measures - the slopes of slow waves and evoked potentials and neuronal synchrony – during sleep correlated with the decline of the traditional marker of sleep homeostasis, EEG SWA. Taken together, these data suggest that homeostatic changes in sleep EEG are the result of altered neuronal firing

  12. Electrophysiological evidence for parts and wholes in visual face memory.

    PubMed

    Towler, John; Eimer, Martin

    2016-10-01

    It is often assumed that upright faces are represented in a holistic fashion, while representations of inverted faces are essentially part-based. To assess this hypothesis, we recorded event-related potentials (ERPs) during a sequential face identity matching task where successively presented pairs of upright or inverted faces were either identical or differed with respect to their internal features, their external features, or both. Participants' task was to report on each trial whether the face pair was identical or different. To track the activation of visual face memory representations, we measured N250r components that emerge over posterior face-selective regions during the activation of visual face memory representations by a successful identity match. N250r components to full identity repetitions were smaller and emerged later for inverted as compared to upright faces, demonstrating that image inversion impairs face identity matching processes. For upright faces, N250r components were also elicited by partial repetitions of external or internal features, which suggest that the underlying identity matching processes are not exclusively based on non-decomposable holistic representations. However, the N250r to full identity repetitions was super-additive (i.e., larger than the sum of the two N250r components to partial repetitions of external or internal features) for upright faces, demonstrating that holistic representations were involved in identity matching processes. For inverted faces, N250r components to full and partial identity repetitions were strictly additive, indicating that the identity matching of external and internal features operated in an entirely part-based fashion. These results provide new electrophysiological evidence for qualitative differences between representations of upright and inverted faces in the occipital-temporal face processing system. PMID:27614900

  13. NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig.

    PubMed

    Sahoo, Satya S; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A; Lhatoo, Samden D

    2016-01-01

    The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This "neuroscience Big data" represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability-the ability to efficiently process increasing volumes of data; (b) Adaptability-the toolkit can be deployed across different computing configurations; and (c) Ease of programming-the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that the toolkit

  14. NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig.

    PubMed

    Sahoo, Satya S; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A; Lhatoo, Samden D

    2016-01-01

    The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This "neuroscience Big data" represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability-the ability to efficiently process increasing volumes of data; (b) Adaptability-the toolkit can be deployed across different computing configurations; and (c) Ease of programming-the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that the toolkit

  15. NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig

    PubMed Central

    Sahoo, Satya S.; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A.; Lhatoo, Samden D.

    2016-01-01

    The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This “neuroscience Big data” represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability—the ability to efficiently process increasing volumes of data; (b) Adaptability—the toolkit can be deployed across different computing configurations; and (c) Ease of programming—the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that

  16. Two Views on Performance Contracting.

    ERIC Educational Resources Information Center

    Lurie, Sylvia; Smith, Kenneth

    1996-01-01

    North Chicago, Illinois, District 187, received a districtwide overhaul of lighting, heating, ventilation, and security systems through a 10-year performance contract with the Honeywell Corporation. The Briarcliff Manor Union-Free School District, New York, has a contract with Johnson Controls that guarantees a portion of the energy savings…

  17. CONTRACT ADMINISTRATIVE TRACKING SYSTEM (CATS)

    EPA Science Inventory

    The Contract Administrative Tracking System (CATS) was developed in response to an ORD NHEERL, Mid-Continent Ecology Division (MED)-recognized need for an automated tracking and retrieval system for Cost Reimbursable Level of Effort (CR/LOE) Contracts. CATS is an Oracle-based app...

  18. Contract Education: A Background Paper.

    ERIC Educational Resources Information Center

    California Community Colleges, Sacramento. Academic Senate.

    Today contract education is generally thought of as a program or course for which an employer is paying the full cost of instruction for customized training. Contract education can help faculty remain current, encourage industry to make equipment available to the college that might otherwise be too expensive, and provide employment opportunities…

  19. Teaching History via Learning Contracts.

    ERIC Educational Resources Information Center

    Burke, Jack D.; And Others

    Contract learning is particularly suitable for teaching both the content and methodology of history in a college level, learner-centered, individualized format. Typically, a learning contract has three components. The first deals with the student's goals and objectives. The second component involves identification of the learning resources and…

  20. Contract Schools. Trends and Issues.

    ERIC Educational Resources Information Center

    Hadderman, Margaret

    This article examines contract schools and their influence on U.S. education. Schools that are contracted out may be viewed as a privatization development that both parallels and builds upon the charter-school movement. They can be defined as publicly funded schools operated by an independent group of teachers and administrators under a contract…

  1. Policing Mechanisms in Agricultural Contracts

    ERIC Educational Resources Information Center

    Wolf, Steven; Hueth, Brent; Ligon, Ethan

    2001-01-01

    In this paper we focus on mechanisms of coordination in agricultural contracts. Our approach is intended to advance understanding of social relations of production and distribution of power in agrofood systems. Through an analysis of contracts between farmers and intermediaries (e.g., processors, shippers, consignment agents) for California fruits…

  2. Contracting Arrangements in Children's Services.

    ERIC Educational Resources Information Center

    Ainsworth, Frank

    1994-01-01

    Reports on the results of a study undertaken in Pennsylvania and Massachusetts in 1992 of the use of contracting arrangements in children's services. Highlights the positive and negative aspects of contracting for both contractors and providers, and discusses the impact of this approach for the traditional differentiation between nongovernmental…

  3. Contractive multifunctions, fixed point inclusions and iterated multifunction systems

    NASA Astrophysics Data System (ADS)

    Kunze, H. E.; La Torre, D.; Vrscay, E. R.

    2007-06-01

    We study the properties of multifunction operators that are contractive in the Covitz-Nadler sense. In this situation, such operators T possess fixed points satisfying the relation x[set membership, variant]Tx. We introduce an iterative method involving projections that guarantees convergence from any starting point x0[set membership, variant]X to a point x[set membership, variant]XT, the set of all fixed points of a multifunction operator T. We also prove a continuity result for fixed point sets XT as well as a "generalized collage theorem" for contractive multifunctions. These results can then be used to solve inverse problems involving contractive multifunctions. Two applications of contractive multifunctions are introduced: (i) integral inclusions and (ii) iterated multifunction systems.

  4. A longitudinal perspective on health plan-provider risk contracting.

    PubMed

    Hurley, Robert; Grossman, Joy; Lake, Timothy; Casalino, Lawrence

    2002-01-01

    During the past decade many health plans adopted risk-contracting arrangements that transferred substantial financial risk and care management responsibility to physician groups and hospital-sponsored integrated delivery systems. Risk transfer arrangements are now believed to be in steep decline, but there is little empirical evidence on this topic, particularly at the local-market level. Data from the Community Tracking Study were used to examine changes in risk contracting from 1996 to 2000. A decline in reliance on risk contracting is evident in nearly all markets. However, retrenchment in risk contracting has followed different patterns ranging from refinements in the scope of risk transfer to reduced use of risk arrangements to total rejection of risk-sharing arrangements. Modified risk-transfer agreements remain viable in several markets, but continued refinement in the nature and scope of risk sharing will be necessary.

  5. Strategies and Lessons-Learned for the Successful Alignment of Contract Cost with the Contract Budget Base (CBB) within the First Year of Contract Award - 13154

    SciTech Connect

    Mullis, Jay; Rueter, Ken

    2013-07-01

    In order to provide a sound basis and foundation for integrated Project and Contract change management, it is imperative to ensure the alignment of the Negotiated Contract Costs (NCC) with the Contract Budget Base (CBB), where CBB is defined as the Performance Measurement Baseline (PMB) plus Management Reserve (MR). The achievement of this alignment assures customer and contractor agreement on scope, requirements, quantities, schedule and cost, which facilitates the identification of change conditions and ultimate agreement on the value of changes to the NCC and the CBB. Delays in contract/CBB true up/reconciliation can negatively effect measurement of project progress, limiting owner understanding of liability, and may result in increased contract disagreements and potential claims. The Department of Energy Oak Ridge Office of Environmental Management (OR-EM) and URS - CH2M Oak Ridge LLC (UCOR) achieved alignment of the NCC with the CBB within 10 months of UCOR taking over work on the East Tennessee Technology Park (ETTP) cleanup contract by: 1. Managing as a discrete project; 2. Establishing expectations and setting tone of interactions; 3. Using personnel experienced with Federal Acquisition Regulation (FAR); 4. Partnering; 5. Establishing ombudsmen. (authors)

  6. Cartographic services contract...for everything geographic

    USGS Publications Warehouse

    ,

    2003-01-01

    The U.S. Geological Survey's (USGS) Cartographic Services Contract (CSC) is used to award work for photogrammetric and mapping services under the umbrella of Architect-Engineer (A&E) contracting. The A&E contract is broad in scope and can accommodate any activity related to standard, nonstandard, graphic, and digital cartographic products. Services provided may include, but are not limited to, photogrammetric mapping and aerotriangulation; orthophotography; thematic mapping (for example, land characterization); analog and digital imagery applications; geographic information systems development; surveying and control acquisition, including ground-based and airborne Global Positioning System; analog and digital image manipulation, analysis, and interpretation; raster and vector map digitizing; data manipulations (for example, transformations, conversions, generalization, integration, and conflation); primary and ancillary data acquisition (for example, aerial photography, satellite imagery, multispectral, multitemporal, and hyperspectral data); image scanning and processing; metadata production, revision, and creation; and production or revision of standard USGS products defined by formal and informal specification and standards, such as those for digital line graphs, digital elevation models, digital orthophoto quadrangles, and digital raster graphics.

  7. [Contracts including performance and management of uncertainty].

    PubMed

    Duru, G; Garassus, P; Auray, J-P

    2013-09-01

    Since many decades in France, the most important part of ambulatory health care expenditure is represented by drug consumption. By the fact, French patient is indeed the greatest world consumer of pharmaceuticals treatments. Therefore, the regulation authorities by successive strategies, attempt to limit or even restrict market access for new drugs in the health care sector secured by public social insurance coverage. Common objectives are to assess the reimbursement to scientific studies and to fix the price of therapeutics at an acceptable level for both industries and government. New trends try then to determine recently the drug price in a dual approach, as a component of global and effective contract, including performance and outcome. The first diffusion authorization is diffusion concerned, but this concept takes into account the eventual success of new produces in long-term survey. Signed for a fixed period as reciprocal partnership between regulation authorities and pharmaceutics industries, the contract integrates two dimensions of incertitude. The first one is represented by the strategy of new treatments development according to efficacy and adapted price, and the second one is linked to the result of diffusion and determines adapted rules if eventual non-respects of the previous engagement are registered. This paper discusses problems related to this new dimension of incertitude affected by conditional drug prices in market access strategy and the adapted follow-up of new treatment diffusion fixed by "outcome" contract between French regulation administration and pharmaceutics industries in our recent economic context. PMID:24075704

  8. [Contracts including performance and management of uncertainty].

    PubMed

    Duru, G; Garassus, P; Auray, J-P

    2013-09-01

    Since many decades in France, the most important part of ambulatory health care expenditure is represented by drug consumption. By the fact, French patient is indeed the greatest world consumer of pharmaceuticals treatments. Therefore, the regulation authorities by successive strategies, attempt to limit or even restrict market access for new drugs in the health care sector secured by public social insurance coverage. Common objectives are to assess the reimbursement to scientific studies and to fix the price of therapeutics at an acceptable level for both industries and government. New trends try then to determine recently the drug price in a dual approach, as a component of global and effective contract, including performance and outcome. The first diffusion authorization is diffusion concerned, but this concept takes into account the eventual success of new produces in long-term survey. Signed for a fixed period as reciprocal partnership between regulation authorities and pharmaceutics industries, the contract integrates two dimensions of incertitude. The first one is represented by the strategy of new treatments development according to efficacy and adapted price, and the second one is linked to the result of diffusion and determines adapted rules if eventual non-respects of the previous engagement are registered. This paper discusses problems related to this new dimension of incertitude affected by conditional drug prices in market access strategy and the adapted follow-up of new treatment diffusion fixed by "outcome" contract between French regulation administration and pharmaceutics industries in our recent economic context.

  9. Hyperosmolar Tears Induce Functional and Structural Alterations of Corneal Nerves: Electrophysiological and Anatomical Evidence Toward Neurotoxicity

    PubMed Central

    Hirata, Harumitsu; Mizerska, Kamila; Marfurt, Carl F.; Rosenblatt, Mark I.

    2015-01-01

    Purpose In an effort to elucidate possible neural mechanisms underlying diminished tearing in dry eye disease, this study sought to determine if hyperosmolar tears, a ubiquitous sign of dry eye disease, produce functional changes in corneal nerve responses to drying of the cornea and if these changes correlate with alterations in corneal nerve morphology. Methods In vivo extracellular electrophysiological recordings were performed in rat trigeminal ganglion neurons that innervated the cornea before, and up to 3 hours after, the ocular application of continuous hyperosmolar tears or artificial tears. In corollary experiments, immunohistochemical staining was performed to compare corneal nerve morphology in control and in eyes treated with hyperosmolar solutions. Results Our previous studies identified a population of corneal afferents, dry-sensitive neurons that are strongly excited by corneal dessication (“dry response”), a response thought to trigger the lacrimation reflex. In the present study, we found that the dry responses of corneal dry-sensitive neurons were depressed or even completely abolished by hyperosmolar tears in a time- (30 minutes to 3 hours) and dose (450- to 1000-mOsm solutions)-dependent manner. Furthermore, eyes treated with hyperosmolar tears for 3 hours contained large numbers of morphologically abnormal (granular, fragmented, or prominently beaded) subbasal nerves that appeared to be undergoing degeneration. Conclusions These results demonstrate that tear hyperosmolarity, considered to be a “core” mechanism of dry eye disease, significantly decreases physiological sensitivity and morphologic integrity of the corneal nerves important in tear production. These alterations might contribute to the diminished tearing seen clinically in dry eye patients. PMID:26720465

  10. A theoretical formulation of the electrophysiological inverse problem on the sphere

    NASA Astrophysics Data System (ADS)

    Riera, Jorge J.; Valdés, Pedro A.; Tanabe, Kunio; Kawashima, Ryuta

    2006-04-01

    The construction of three-dimensional images of the primary current density (PCD) produced by neuronal activity is a problem of great current interest in the neuroimaging community, though being initially formulated in the 1970s. There exist even now enthusiastic debates about the authenticity of most of the inverse solutions proposed in the literature, in which low resolution electrical tomography (LORETA) is a focus of attention. However, in our opinion, the capabilities and limitations of the electro and magneto encephalographic techniques to determine PCD configurations have not been extensively explored from a theoretical framework, even for simple volume conductor models of the head. In this paper, the electrophysiological inverse problem for the spherical head model is cast in terms of reproducing kernel Hilbert spaces (RKHS) formalism, which allows us to identify the null spaces of the implicated linear integral operators and also to define their representers. The PCD are described in terms of a continuous basis for the RKHS, which explicitly separates the harmonic and non-harmonic components. The RKHS concept permits us to bring LORETA into the scope of the general smoothing splines theory. A particular way of calculating the general smoothing splines is illustrated, avoiding a brute force discretization prematurely. The Bayes information criterion is used to handle dissimilarities in the signal/noise ratios and physical dimensions of the measurement modalities, which could affect the estimation of the amount of smoothness required for that class of inverse solution to be well specified. In order to validate the proposed method, we have estimated the 3D spherical smoothing splines from two data sets: electric potentials obtained from a skull phantom and magnetic fields recorded from subjects performing an experiment of human faces recognition.

  11. A Quantitative Comparison of the Behavior of Human Ventricular Cardiac Electrophysiology Models in Tissue

    PubMed Central

    Elshrif, Mohamed M.; Cherry, Elizabeth M.

    2014-01-01

    Numerical integration of mathematical models of heart cell electrophysiology provides an important computational tool for studying cardiac arrhythmias, but the abundance of available models complicates selecting an appropriate model. We study the behavior of two recently published models of human ventricular action potentials, the Grandi-Pasqualini-Bers (GPB) and the O'Hara-Virág-Varró-Rudy (OVVR) models, and compare the results with four previously published models and with available experimental and clinical data. We find the shapes and durations of action potentials and calcium transients differ between the GPB and OVVR models, as do the magnitudes and rate-dependent properties of transmembrane currents and the calcium transient. Differences also occur in the steady-state and S1–S2 action potential duration and conduction velocity restitution curves, including a maximum conduction velocity for the OVVR model roughly half that of the GPB model and well below clinical values. Between single cells and tissue, both models exhibit differences in properties, including maximum upstroke velocity, action potential amplitude, and minimum diastolic interval. Compared to experimental data, action potential durations for the GPB and OVVR models agree fairly well (although OVVR epicardial action potentials are shorter), but maximum slopes of steady-state restitution curves are smaller. Although studies show alternans in normal hearts, it occurs only in the OVVR model, and only for a narrow range of cycle lengths. We find initiated spiral waves do not progress to sustained breakup for either model. The dominant spiral wave period of the GPB model falls within clinically relevant values for ventricular tachycardia (VT), but for the OVVR model, the dominant period is longer than periods associated with VT. Our results should facilitate choosing a model to match properties of interest in human cardiac tissue and to replicate arrhythmia behavior more closely. Furthermore, by

  12. Mathematical Modeling of Heterogeneous Electrophysiological Responses in Human β-Cells

    PubMed Central

    Riz, Michela; Braun, Matthias; Pedersen, Morten Gram

    2014-01-01

    Electrical activity plays a pivotal role in glucose-stimulated insulin secretion from pancreatic -cells. Recent findings have shown that the electrophysiological characteristics of human -cells differ from their rodent counterparts. We show that the electrophysiological responses in human -cells to a range of ion channels antagonists are heterogeneous. In some cells, inhibition of small-conductance potassium currents has no effect on action potential firing, while it increases the firing frequency dramatically in other cells. Sodium channel block can sometimes reduce action potential amplitude, sometimes abolish electrical activity, and in some cells even change spiking electrical activity to rapid bursting. We show that, in contrast to L-type -channels, P/Q-type -currents are not necessary for action potential generation, and, surprisingly, a P/Q-type -channel antagonist even accelerates action potential firing. By including SK-channels and dynamics in a previous mathematical model of electrical activity in human -cells, we investigate the heterogeneous and nonintuitive electrophysiological responses to ion channel antagonists, and use our findings to obtain insight in previously published insulin secretion measurements. Using our model we also study paracrine signals, and simulate slow oscillations by adding a glycolytic oscillatory component to the electrophysiological model. The heterogenous electrophysiological responses in human -cells must be taken into account for a deeper understanding of the mechanisms underlying insulin secretion in health and disease, and as shown here, the interdisciplinary combination of experiments and modeling increases our understanding of human -cell physiology. PMID:24391482

  13. Electrophysiological Motor Unit Number Estimation (MUNE) Measuring Compound Muscle Action Potential (CMAP) in Mouse Hindlimb Muscles.

    PubMed

    Arnold, W David; Sheth, Kajri A; Wier, Christopher G; Kissel, John T; Burghes, Arthur H; Kolb, Stephen J

    2015-09-25

    Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diagnostic and clinical human studies. We present electrophysiological techniques similar to those employed in humans to allow recordings of mouse sciatic nerve function. The CMAP response represents the electrophysiological output from a muscle or group of muscles following supramaximal stimulation of a peripheral nerve. MUNE is an electrophysiological technique that is based on modifications of the CMAP response. MUNE is a calculated value that represents the estimated number of motor neurons or axons (motor control input) supplying the muscle or group of muscles being tested. We present methods for recording CMAP responses from the proximal leg muscles using surface recording electrodes following the stimulation of the sciatic nerve in mice. An incremental MUNE technique is described using submaximal stimuli to determine the average single motor unit potential (SMUP) size. MUNE is calculated by dividing the CMAP amplitude (peak-to-peak) by the SMUP amplitude (peak-to-peak). These electrophysiological techniques allow repeated measures in both neonatal and adult mice in such a manner that facilitates rapid analysis and data collection while reducing the number of animals required for experimental testing. Furthermore, these measures are similar to those recorded in human studies allowing more direct comparisons.

  14. Electrophysiological Motor Unit Number Estimation (MUNE) Measuring Compound Muscle Action Potential (CMAP) in Mouse Hindlimb Muscles.

    PubMed

    Arnold, W David; Sheth, Kajri A; Wier, Christopher G; Kissel, John T; Burghes, Arthur H; Kolb, Stephen J

    2015-01-01

    Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diagnostic and clinical human studies. We present electrophysiological techniques similar to those employed in humans to allow recordings of mouse sciatic nerve function. The CMAP response represents the electrophysiological output from a muscle or group of muscles following supramaximal stimulation of a peripheral nerve. MUNE is an electrophysiological technique that is based on modifications of the CMAP response. MUNE is a calculated value that represents the estimated number of motor neurons or axons (motor control input) supplying the muscle or group of muscles being tested. We present methods for recording CMAP responses from the proximal leg muscles using surface recording electrodes following the stimulation of the sciatic nerve in mice. An incremental MUNE technique is described using submaximal stimuli to determine the average single motor unit potential (SMUP) size. MUNE is calculated by dividing the CMAP amplitude (peak-to-peak) by the SMUP amplitude (peak-to-peak). These electrophysiological techniques allow repeated measures in both neonatal and adult mice in such a manner that facilitates rapid analysis and data collection while reducing the number of animals required for experimental testing. Furthermore, these measures are similar to those recorded in human studies allowing more direct comparisons. PMID:26436455

  15. Electrophysiological Motor Unit Number Estimation (MUNE) Measuring Compound Muscle Action Potential (CMAP) in Mouse Hindlimb Muscles

    PubMed Central

    Arnold, W. David; Sheth, Kajri A.; Wier, Christopher G.; Kissel, John T.; Burghes, Arthur H.; Kolb, Stephen J.

    2015-01-01

    Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diagnostic and clinical human studies. We present electrophysiological techniques similar to those employed in humans to allow recordings of mouse sciatic nerve function. The CMAP response represents the electrophysiological output from a muscle or group of muscles following supramaximal stimulation of a peripheral nerve. MUNE is an electrophysiological technique that is based on modifications of the CMAP response. MUNE is a calculated value that represents the estimated number of motor neurons or axons (motor control input) supplying the muscle or group of muscles being tested. We present methods for recording CMAP responses from the proximal leg muscles using surface recording electrodes following the stimulation of the sciatic nerve in mice. An incremental MUNE technique is described using submaximal stimuli to determine the average single motor unit potential (SMUP) size. MUNE is calculated by dividing the CMAP amplitude (peak-to-peak) by the SMUP amplitude (peak-to-peak). These electrophysiological techniques allow repeated measures in both neonatal and adult mice in such a manner that facilitates rapid analysis and data collection while reducing the number of animals required for experimental testing. Furthermore, these measures are similar to those recorded in human studies allowing more direct comparisons. PMID:26436455

  16. Landsat 6 contract signed

    NASA Astrophysics Data System (ADS)

    Maggs, William Ward

    A new agreement provides $220 million for development and construction of the Landsat 6 remote sensing satellite and its ground systems. The contract, signed on March 31, 1988, by the Department of Commerce (DOC) and the Earth Observation Satellite (EOSAT) Company of Lanham, Md., came just days after approval of DOC's Landsat commercialization plan by subcommittees of the House and Senate appropriations committees.The Landsat 6 spacecraft is due to be launched into orbit on a Titan II rocket in June 1991 from Vandenburg Air Force Base, Calif. The satellite will carry an Enhanced Thematic Mapper (ETM) sensor, an instrument sensitive to electromagnetic radiation in seven ranges or bands of wavelengths. The satellite's payload will also include the Sea Wide Field Sensor (Sea-WiFS), designed to provide information on sea surface temperature and ocean color. The sensor is being developed in a cooperative effort by EOSAT and the National Aeronautics and Space Administration (NASA). A less certain passenger is a proposed 5-m resolution, three-band sensor sensitive to visible light. EOSAT is trying to find both private financing for the device and potential buyers of the high-resolution imagery that it could produce. The company has been actively courting U.S. television networks, which have in the past used imagery from the European Système Probatoire d'Observation de la Terre (SPOT) satellite for news coverage.

  17. INFINITY construction contract signed

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Key state and community leaders celebrated April 6 with the signing of a construction contract for the state-of-the-art INFINITY Science Center planned near John C. Stennis Space Center in south Mississippi. Gulfport Mayor George Schloegel (l to r), chair of non-profit INFINITY Science Center Inc., was joined for the signing ceremony at the Hancock Bank in Gulfport by Virginia Wagner, sister of late Hancock Bank President Leo Seal Jr.; and Roy Anderson III, president and CEO of Roy Anderson Corp. Seal was the first chair of INFINITY Science Center Inc., which has led in development of the project. Roy Anderson Corp. plans to begin construction on the 72,000-square-foot, $28 million science and education center in May. The Mississippi Department of Transportation (MDOT) also is set to begin construction of a $2 million access road to the new center. The April 6 ceremony was attended by numerous officials, including former Stennis Space Center Directors Jerry Hlass and Roy Estess; Mississippi Senate President Pro Tempore Billy Hewes, R-Gulfport; Mississippi Rep. Diane Peranich, D-Pass Christian; and MDOT Southern District Commissioner Wayne Brown.

  18. 48 CFR 3443.106 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Contract clause. 3443.106 Section 3443.106 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION CONTRACT MANAGEMENT CONTRACT MODIFICATIONS 3443.106 Contract clause. The contracting officer shall...

  19. 48 CFR 1532.908 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contract clauses. 1532.908 Section 1532.908 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Prompt Payment 1532.908 Contract clauses. The Contracting...

  20. 48 CFR 1516.603 - Letter Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Letter Contracts. 1516.603 Section 1516.603 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts...

  1. 48 CFR 1532.111 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contract clauses. 1532.111 Section 1532.111 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING General 1532.111 Contract clauses. The Contracting Officer...

  2. 29 CFR 4.190 - Contract cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., the contract is subject upon written notice to cancellation by the contracting agency, whereupon the... contract is similarly subject upon written notice to immediate cancellation by the contracting agency and... in paragraph (a). Such contract is without warrant of law and has no force and effect and is void...

  3. 7 CFR 1780.61 - Construction contracts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Construction contracts. 1780.61 Section 1780.61..., Constructing and Inspections § 1780.61 Construction contracts. Contract documents must be sufficiently.... (a) Standard construction contract documents. If the construction contract documents utilized are...

  4. 25 CFR 502.15 - Management contract.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Management contract. 502.15 Section 502.15 Indians... CHAPTER § 502.15 Management contract. Management contract means any contract, subcontract, or collateral... contract or agreement provides for the management of all or part of a gaming operation....

  5. 25 CFR 502.15 - Management contract.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Management contract. 502.15 Section 502.15 Indians... CHAPTER § 502.15 Management contract. Management contract means any contract, subcontract, or collateral... contract or agreement provides for the management of all or part of a gaming operation....

  6. 25 CFR 502.15 - Management contract.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Management contract. 502.15 Section 502.15 Indians... CHAPTER § 502.15 Management contract. Management contract means any contract, subcontract, or collateral... contract or agreement provides for the management of all or part of a gaming operation....

  7. 48 CFR 317.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Contracts. 317.204 Section 317.204 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 317.204 Contracts. (e) The total of the basic and...

  8. 48 CFR 46.314 - Transportation contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Transportation contracts... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.314 Transportation contracts. The contracting officer shall insert the clause at 52.246-14, Inspection of Transportation, in solicitations and contracts for...

  9. 48 CFR 46.314 - Transportation contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Transportation contracts... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.314 Transportation contracts. The contracting officer shall insert the clause at 52.246-14, Inspection of Transportation, in solicitations and contracts for...

  10. 48 CFR 46.314 - Transportation contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Transportation contracts... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.314 Transportation contracts. The contracting officer shall insert the clause at 52.246-14, Inspection of Transportation, in solicitations and contracts for...

  11. 48 CFR 46.314 - Transportation contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Transportation contracts... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.314 Transportation contracts. The contracting officer shall insert the clause at 52.246-14, Inspection of Transportation, in solicitations and contracts for...

  12. 48 CFR 46.314 - Transportation contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Transportation contracts... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.314 Transportation contracts. The contracting officer shall insert the clause at 52.246-14, Inspection of Transportation, in solicitations and contracts for...

  13. 48 CFR 1235.7000 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Research Misconduct 1235.7000 Contract clause. The contracting officer shall insert the clause at (TAR) 48 CFR 1252.235-70, Research Misconduct, in all solicitations and contracts for research and development. For further information, see...

  14. 48 CFR 46.312 - Construction contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Construction contracts. 46... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.312 Construction contracts. The contracting officer shall insert the clause at 52.246-12, Inspection of Construction, in solicitations and contracts...

  15. 7 CFR 631.14 - Contract violations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Contract violations. 631.14 Section 631.14 Agriculture... AGRICULTURE LONG TERM CONTRACTING GREAT PLAINS CONSERVATION PROGRAM Contracts § 631.14 Contract violations. Contract violations, determinations and appeals will be handled in accordance with the terms of...

  16. 7 CFR 631.14 - Contract violations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Contract violations. 631.14 Section 631.14 Agriculture... AGRICULTURE LONG TERM CONTRACTING GREAT PLAINS CONSERVATION PROGRAM Contracts § 631.14 Contract violations. Contract violations, determinations and appeals will be handled in accordance with the terms of...

  17. 7 CFR 631.14 - Contract violations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Contract violations. 631.14 Section 631.14 Agriculture... AGRICULTURE LONG TERM CONTRACTING GREAT PLAINS CONSERVATION PROGRAM Contracts § 631.14 Contract violations. Contract violations, determinations and appeals will be handled in accordance with the terms of...

  18. 25 CFR 502.15 - Management contract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Management contract. 502.15 Section 502.15 Indians... CHAPTER § 502.15 Management contract. Management contract means any contract, subcontract, or collateral... contract or agreement provides for the management of all or part of a gaming operation....

  19. 48 CFR 1235.7000 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Research Misconduct 1235.7000 Contract clause. The contracting officer shall insert the clause at (TAR) 48 CFR 1252.235-70, Research Misconduct, in all solicitations and contracts for research and development. For further information, see...

  20. 48 CFR 1832.705 - Contract clauses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Contract clauses. 1832.705 Section 1832.705 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Funding 1832.705 Contract clauses....

  1. 48 CFR 1832.705 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Contract clauses. 1832.705 Section 1832.705 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Funding 1832.705 Contract clauses....

  2. 48 CFR 1832.705 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contract clauses. 1832.705 Section 1832.705 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Funding 1832.705 Contract clauses....

  3. 48 CFR 1832.705 - Contract clauses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Contract clauses. 1832.705 Section 1832.705 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Funding 1832.705 Contract clauses....

  4. 48 CFR 1832.705 - Contract clauses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Contract clauses. 1832.705 Section 1832.705 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Funding 1832.705 Contract clauses....

  5. 48 CFR 1817.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... discuss planned future assessment of continued performance either prior to exercise of options or at the... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1817.204 Contracts. (e)(i) The 5-year limitation (basic plus option periods) applies to all NASA contracts regardless of type and...

  6. 48 CFR 546.312 - Construction contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Construction contracts... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.312 Construction contracts. Insert the clause at 552.246-72, Final Inspection and Tests, in solicitations and contracts for construction that...

  7. 7 CFR 1780.61 - Construction contracts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Construction contracts. 1780.61 Section 1780.61..., Constructing and Inspections § 1780.61 Construction contracts. Contract documents must be sufficiently.... (a) Standard construction contract documents. If the construction contract documents utilized are...

  8. 7 CFR 1780.61 - Construction contracts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Construction contracts. 1780.61 Section 1780.61..., Constructing and Inspections § 1780.61 Construction contracts. Contract documents must be sufficiently.... (a) Standard construction contract documents. If the construction contract documents utilized are...

  9. 48 CFR 546.312 - Construction contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Construction contracts... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.312 Construction contracts. Insert the clause at 552.246-72, Final Inspection and Tests, in solicitations and contracts for construction that...

  10. 48 CFR 46.312 - Construction contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Construction contracts. 46... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.312 Construction contracts. The contracting officer shall insert the clause at 52.246-12, Inspection of Construction, in solicitations and contracts...

  11. 48 CFR 46.312 - Construction contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Construction contracts. 46... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.312 Construction contracts. The contracting officer shall insert the clause at 52.246-12, Inspection of Construction, in solicitations and contracts...

  12. 48 CFR 546.312 - Construction contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Construction contracts... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.312 Construction contracts. Insert the clause at 552.246-72, Final Inspection and Tests, in solicitations and contracts for construction that...

  13. 48 CFR 546.312 - Construction contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Construction contracts... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.312 Construction contracts. Insert the clause at 552.246-72, Final Inspection and Tests, in solicitations and contracts for construction that...

  14. 7 CFR 1780.61 - Construction contracts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 12 2011-01-01 2011-01-01 false Construction contracts. 1780.61 Section 1780.61..., Constructing and Inspections § 1780.61 Construction contracts. Contract documents must be sufficiently.... (a) Standard construction contract documents. If the construction contract documents utilized are...

  15. 48 CFR 46.312 - Construction contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Construction contracts. 46... MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.312 Construction contracts. The contracting officer shall insert the clause at 52.246-12, Inspection of Construction, in solicitations and contracts...

  16. Improving Contract Performance by Corrective Actions Plans

    SciTech Connect

    Dowd, A.S., jr.

    2002-06-23

    Corrective Action Plans (CAPs) are required to be developed, submitted, and reported upon by the prime contractors for the U.S. Department of Energy (U.S. DOE) Management and Operations (M and O) contracts. The best known CAP ''type,'' and there are many, is for Price-Anderson Amendments Act (PAAA) ''potential noncompliances.'' The M and O contractor fines for PAAA problems have increased from approximately $100,000 in 1996 to almost $2,000,000 in 2000. In order to improve CAP performance at the National Nuclear Security Administration (NNSA) site at Y-12 in Oak Ridge, Tennessee, the contractor chose to centralize the company-wide processes of problem identification and reporting with the PAAA (and other) CAP processes. This directly integrates these functional reports to the contractor General Manager. The functions contained in the M and O contractor central organization, called ''Performance Assurance,'' are: PAAA; Defense Nuclear Facilities Safety Board (DNFSB) Liaison; Contract Requirements Management; Issues Management (including the CAP processes); Lessons Learned; Independent and Management Assessments; Internal Audits; and Ethics. By centrally locating and managing these problem identification and problem correction functions, the contractor, BWXT Y-12, L.L.C., has improved PAAA (and other) CAP performance more than 200 percent in the first year of the contract. Much of this improvement (see Table 1 for examples) has been achieved by increasing the knowledge and experience of management and workers in the specific contract and company requirements for CAPs. The remainder of this paper will describe some of the many CAP processes at Y-12 to show the reader the non-trivial scope of the CAP process. Improvements in CAP management will be discussed. In addition, a specific recommendation for CAP management, in a major capital construction project, will be presented.

  17. Active contraction of microtubule networks

    PubMed Central

    Foster, Peter J; Fürthauer, Sebastian; Shelley, Michael J; Needleman, Daniel J

    2015-01-01

    Many cellular processes are driven by cytoskeletal assemblies. It remains unclear how cytoskeletal filaments and motor proteins organize into cellular scale structures and how molecular properties of cytoskeletal components affect the large-scale behaviors of these systems. Here, we investigate the self-organization of stabilized microtubules in Xenopus oocyte extracts and find that they can form macroscopic networks that spontaneously contract. We propose that these contractions are driven by the clustering of microtubule minus ends by dynein. Based on this idea, we construct an active fluid theory of network contractions, which predicts a dependence of the timescale of contraction on initial network geometry, a development of density inhomogeneities during contraction, a constant final network density, and a strong influence of dynein inhibition on the rate of contraction, all in quantitative agreement with experiments. These results demonstrate that the motor-driven clustering of filament ends is a generic mechanism leading to contraction. DOI: http://dx.doi.org/10.7554/eLife.10837.001 PMID:26701905

  18. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... contracts as designs become more firmly established, risks are reduced, and production tooling, equipment... cost estimate for price negotiations. (See 16.207.) (e) Projects having production requirements as...

  19. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... contracts as designs become more firmly established, risks are reduced, and production tooling, equipment... cost estimate for price negotiations. (See 16.207.) (e) Projects having production requirements as...

  20. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... contracts as designs become more firmly established, risks are reduced, and production tooling, equipment... cost estimate for price negotiations. (See 16.207.) (e) Projects having production requirements as...