《International journal of radiation biology》2013,89(10):833-840

Abstract

Purpose: The behavioral responses of planaria to the exposures of a range of concentrations of morphine (μM to attoM) or the μ-opiate antagonist naloxone or to either of these compounds and a burst-firing magnetic field (5 μT) were studied.

Material and methods: The locomotor velocity (LMV) of planaria was measured after individual worms were exposed to increasing concentrations from attomolar to micromolar of morphine or naloxone, physiologically patterned magnetic fields or a combination of the two.

Results: Compared to spring water controls, the 2-hour exposure to the patterned magnetic field before measurement reduced activity by about 50% which was comparable to the non-specific effects of morphine and naloxone across all dosages except 1 attomolar that did not differ from spring water. The specific dosage of 100 nM produced additional marked reduction in activity for planaria exposed to either morphine or naloxone while only 1 pM of morphine produced this effect.

Conclusion: The results support the presence of at least two receptor subtypes that mediate the diminished activity effects elicited by morphine specifically and suggests that exposure to the specifically patterned magnetic field produces a behavioral suppression whose magnitude is similar to the ‘dose independent’ effects from this opiate.  相似文献   

    

Hans Weber  Gerrit Schultz  Daniel Gallichan  Jürgen Hennig  Maxim Zaitsev 《Magnetic resonance in medicine》2014,71(3):1002-1014

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Hans Weber  Martin Haas  Denis Kokorin  Daniel Gallichan  Jürgen Hennig  Maxim Zaitsev 《Magnetic resonance in medicine》2014,72(1):112-123

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M. Haas  P. Ullmann  J. T. Schneider  H. Post  W. Ruhm  J. Hennig  M. Zaitsev 《Magnetic resonance in medicine》2013,70(5):1220-1228

With the recent proposal of using magnetic fields that are nonlinear by design for spatial encoding, new flexibility has been introduced to MR imaging. The new degrees of freedom in shaping the spatially encoding magnetic fields (SEMs) can be used to locally adapt the imaging resolution to features of the imaged object, e.g., anatomical structures, to reduce peripheral nerve stimulation during in vivo experiments or to increase the gradient switching speed by reducing the inductance of the coils producing the SEMs and thus accelerate the imaging process. In this work, the potential of nonlinear and nonbijective SEMs for spatial encoding during transmission in multidimensional spatially selective excitation is explored. Methods for multidimensional spatially selective excitation radiofrequency pulse design based on nonlinear encoding fields are introduced, and it is shown how encoding ambiguities can be resolved using parallel transmission. In simulations and phantom experiments, the feasibility of selective excitation using nonlinear, nonbijective SEMs is demonstrated, and it is shown that the spatial resolution with which the target distribution of the transverse magnetization can be realized varies locally. Thus, the resolution of the target pattern can be increased in some regions compared with conventional linear encoding. Furthermore, experimental proof of principle of accelerated two‐dimensional spatially selective excitation using nonlinear SEMs is provided in this study. Magn Reson Med 70:1220–1228, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

    

David F. Nichols  Lisa R. Betts  Hugh R. Wilson 《Brain and Behavior》2016,6(11)

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Mae Maskit Lord  Carole Stone 《Contemporary psychoanalysis》2013,49(4):526-539

In this discussion I attempt to link some of Tennes's ideas with those preexisting in psychoanalysis, in particular those of Loewald, Matte-Bianco, and Bion; I also elaborate on some of the connections with modern physics. I believe that by going beyond intersubjectivity, it is important to integrate the transpersonal with the intersubjective so that intuition and intimations remain connected with the psychic reality of other people.  相似文献   

    

《Clinical neurophysiology》2014,125(9):1764-1773

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W. Gaetz  H. Otsubo  E.W. Pang   《Clinical neurophysiology》2008,119(8):1923-1933

OBJECTIVE: At present, whole-head MEG systems are designed to accommodate adult heads, thereby introducing a technical issue unique to pediatric MEG. It is known that magnetic field strength decreases as a function of 1/distance(2). For pediatric patients, we questioned whether re-positioning the head to minimize the distance between the expected source location and the MEG sensor array would significantly improve source measurement. METHODS: Somatosensory-evoked fields (SEFs) were recorded in 17 children (mean=4.96 years) with their head placed centrally in the MEG, and then re-positioned laterally to reduce the distance between the cortical source and sensors. Equivalent current dipole (ECD) source models were evaluated for changes in residual variance (RV), signal-to-noise ratio (SNR), moment (strength), and location. RESULTS: Re-positioning the head closer to the sensors resulted in a significant shift in the mediolateral dipole coordinate location, accompanied by a significant increase in the SNR, decrease in the dipole RV, and a reduction in size of ECD confidence volumes. CONCLUSIONS: We conclude that for clinical pediatric measurement of the SEF, repositioning of the head to minimize the distance between the expected SEF source location and the sensor array will significantly improve SEF source measurement and concomitant ECD source modeling. SIGNIFICANCE: These issues are relevant to all pediatric MEG settings involving healthy or clinical populations and underscores the need for future development of a MEG helmet specifically designed for pediatric populations.  相似文献   

    

Donald J. Bernardini MD  Stephen D. Pratt MD  Tamara C. Takoudes MD  Thomas T. Simopoulos MD  MA 《Neuromodulation》2010,13(4):270-274

Objectives: The use of spinal cord stimulation (SCS) is a form of neuromodulation used to treat chronic pain in those patients who are refractory to conventional medical management. Not uncommonly, SCS can dramatically improve a patient's quality of life, and those who are in the childbearing years may go on to become pregnant. The purpose of this case series is to describe: 1) implantation considerations in women of childbearing age; 2) use of rechargeable systems; 3) the obstetric and anesthetic concerns in patients with spinal cord stimulators; 4) risks of using SCS in the peripartum period. Materials and Methods: Two female patients with complex regional pain syndrome I (CRPS I) who were well managed with SCS became pregnant. In both patients, the leads were placed through the T12/L1 interspace and the generator was placed in the buttock region. In the first patient, the device was deactivated prior to conception and maintained off for the duration of the pregnancy. The second patient became pregnant on two separate occasions, with active SCS for a portion of the first trimester. During her second pregnancy, the patient elected to use of SCS at 30 weeks' gestation. Results: The developing fetuses with intrauterine exposure to SCS were followed out for a minimum of two years and are developmentally normal. The physical presence of the device did not complicate obstetric or anesthetic care. Rechargeable SCS systems were not adversely affected when turned off for the duration of the pregnancy. Conclusion: Implantation of SCS devices in women of childbearing years should take into account the future needs of both obstetric and anesthetic care by avoiding the abdomen and lower lumbar spine whenever possible. There was no appreciable decline of battery capacity in present day constant current rechargeable generators when deactivated for the duration of pregnancy.  相似文献   

    

Felix Carbonell  Keith J. Worsley  Nelson J. Trujillo‐Barreto  Roberto C. Sotero 《Human brain mapping》2009,30(8):2477-2486

Electrophysiological (EEG/MEG) imaging challenges statistics by providing two views of the same underlying spatio‐temporal brain activity: a topographic view (EEG/MEG) and tomographic view (EEG/MEG source reconstructions). It is a common practice that statistical parametric mapping (SPM) for these two situations is developed separately. In particular, assessing statistical significance of functional connectivity is a major challenge in these types of studies. This work introduces statistical tests for assessing simultaneously the significance of spatio‐temporal correlation structure between ERP/ERF components as well as that of their generating sources. We introduce a greatest root statistic as the multivariate test statistic for detecting functional connectivity between two sets of EEG/MEG measurements at a given time instant. We use some new results in random field theory to solve the multiple comparisons problem resulting from the correlated test statistics at each time instant. In general, our approach using the union‐intersection (UI) principle provides a framework for hypothesis testing about any linear combination of sensor data, which allows the analysis of the correlation structure of both topographic and tomographic views. The performance of the proposed method is illustrated with real ERP data obtained from a face recognition experiment. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.  相似文献