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1.
Gynecol Obstet Fertil Senol ; 50(1): 33-39, 2022 Jan.
Article in French | MEDLINE | ID: mdl-34509670

ABSTRACT

OBJECTIVE: To demonstrate the feasibility of outpatient laparoscopic hysterectomy using the assessment of post-operative quality of life. METHODS: A prospective randomized single-center trial was performed in France between 2013 and 2016. A total of 42 patients needed laparoscopic hysterectomy was included. Postoperative quality of life was assessed using the standardized Euroquol questionnaire. Patients filled the score before the operation and then on the 3rd and 30th postoperative day. Secondary outcomes were assessment of postoperative pain, overall quality of life, analgesic use, and anxiety. The patients were randomized into two groups, group A with a conventional hospital stay of 2 to 3 days and group B with a short stay and a discharge the day after the intervention. RESULTS: Twenty-one patients were randomized to group A as well as group B. We did not find any significant differences between the two groups in our study either on our primary outcome or in the seconds ones. On day 3, the average of Euroquol score was 0.68 for group A against 0.50 for group B (P=0.05). Likewise, the scores for postoperative pain were similar with 70.6 in group A and 61.8 in group B (P=0.21). The trend was the same for quality of life score or anxiety. CONCLUSION: Our study shows the possibility and the safety of outpatient laparoscopic hysterectomy.


Subject(s)
Laparoscopy , Outpatients , Female , Humans , Hysterectomy/adverse effects , Laparoscopy/adverse effects , Prospective Studies , Quality of Life
2.
J Phys Condens Matter ; 29(49): 494002, 2017 Dec 13.
Article in English | MEDLINE | ID: mdl-29047449

ABSTRACT

In addition to the chemical and physical properties of nanostructures their successful utilization for applications is strongly triggered by economic aspects. Electrospinning of nanowires from solution followed by subsequent annealing steps is a comparably cheap technique to fabricate conductive carbon nanofibers (CNF) made from polyacrylonitrile (PAN) molecules in large quantities. In this work, we investigated the microscopic properties of the CNFs with diameters of 100-300 nm by means of Raman and x-ray photoelectron spectroscopy and correlated these results with transport measurements done with a 4-tip STM. In particular, we investigated the effect of fiber alignment and knot densities, which can be controlled by applying constant creep due to stress during the stabilization process. The comparison of the conductivity obtained from single CNFs revealed further that the fiber crossings within the ensemble structure act as scattering centers and proofs that the transport is along the surfaces of the CNFs.

3.
J Neurophysiol ; 102(4): 2554-62, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19692509

ABSTRACT

The mammalian brain is an enormously complex set of circuits composed of interconnected neuronal cell types. The analysis of central neural circuits will be greatly served by the ability to turn off specific neuronal cell types while recording from others in intact brains. Because drug delivery cannot be restricted to specific cell types, this can only be achieved by putting "silencer" transgenes under the control of neuron-specific promoters. Towards this end we have created a line of transgenic mice putting the Drosophila allatostatin (AL) neuropeptide receptor (AlstR) under the control of the tetO element, thus enabling its inducible expression when crossed to tet-transactivator lines. Mammals have no endogenous AL or AlstR, but activation of exogenously expressed AlstR in mammalian neurons leads to membrane hyperpolarization via endogenous G-protein-coupled inward rectifier K(+) channels, making the neurons much less likely to fire action potentials. Here we show that this tetO/AlstR line is capable of broadly expressing AlstR mRNA in principal neurons throughout the forebrain when crossed to a commercially-available transactivator line. We electrophysiologically characterize this cross in hippocampal slices, demonstrating that bath application of AL leads to hyperpolarization of CA1 pyramidal neurons, making them refractory to the induction of action potentials by injected current. Finally, we demonstrate the ability of AL application to silence the sound-evoked spiking responses of auditory cortical neurons in intact brains of AlstR/tetO transgenic mice. When crossed to other transactivator lines expressing in defined neuronal cell types, this AlstR/tetO line should prove a very useful tool for the analysis of intact central neural circuits.


Subject(s)
Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Gene Silencing , Neurons/physiology , Prosencephalon/physiology , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Receptors, Neuropeptide/genetics , Receptors, Neuropeptide/metabolism , Acoustic Stimulation , Action Potentials/physiology , Animals , Auditory Perception/physiology , CA1 Region, Hippocampal/physiology , Drosophila , Evoked Potentials, Auditory/physiology , In Vitro Techniques , Membrane Potentials/physiology , Mice , Mice, Transgenic , Neuropeptides/metabolism , Potassium Channels, Inwardly Rectifying/metabolism , Pyramidal Cells/physiology , RNA, Messenger/metabolism
4.
Neuroscience ; 163(4): 1302-15, 2009 Nov 10.
Article in English | MEDLINE | ID: mdl-19628023

ABSTRACT

The recent characterization of excitatory and inhibitory synaptic receptive fields in rat auditory cortex laid the basis for further investigation of the roles of synaptic excitation and inhibition in cortical computation and plasticity. The mouse is an increasingly important model system because of the wide range of genetic tools available for it. Here we present the first in vivo whole-cell voltage-clamp measurements of synaptic excitation and inhibition in the mouse cortex. We find that a substantial population of auditory cortical neurons receives balanced synaptic excitation and inhibition, whose amplitude ratios and relative time courses remain approximately constant across tone frequency. We conclude that the synaptic mechanisms underlying tone-evoked auditory cortical responses in mice closely resemble those in rats, supporting the mouse as a suitable model for synaptic processing in auditory cortex.


Subject(s)
Auditory Cortex/physiology , Auditory Perception/physiology , Evoked Potentials, Auditory , Neural Inhibition/physiology , Neurons/physiology , Synapses/physiology , Acoustic Stimulation , Animals , Linear Models , Membrane Potentials , Mice , Mice, Inbred C57BL , Patch-Clamp Techniques , Time Factors
5.
Internist (Berl) ; 49(9): 1061-7, 2008 Sep.
Article in German | MEDLINE | ID: mdl-18651117

ABSTRACT

Although there are accepted guidelines for treatment of acute coronary syndromes and ST-segment elevation myocardial infarction, elderly patients may have a variety of conditions that can complicate the decision making process about the best therapy. For fear of adverse effects many elderly patients do not receive potentially lifesaving treatments, such as percutaneous coronary intervention or thrombolytic therapy. Appropriate revascularisation therapy also often will be received too late in the course of the infarct, when irreversible myocardial damage has occurred. Many studies, however, show that older patients will benefit substantially from these therapies and early treatment improves outcome in this population, despite a higher risk of complications. In this review, the evidence regarding medical and revascularisation therapies in acute coronary syndromes in the elderly is critically examined.


Subject(s)
Acute Coronary Syndrome/diagnosis , Acute Coronary Syndrome/therapy , Geriatric Assessment/methods , Myocardial Revascularization/methods , Risk Assessment/methods , Aged , Aged, 80 and over , Female , Humans , Male , Risk Factors
6.
Z Kardiol ; 93(9): 671-8, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15365734

ABSTRACT

BACKGROUND: Results of studies concerning prevention of cardiovascular disease by treatment with macrolide antibiotics targeting C. pneumoniae infection are still controversial. This study describes the results of different tests for infection with C. pneumoniae as well as the effect of treatment with roxithromycin in patients with acute myocardial infarction (AMI) in relation to their serostatus against C. pneumoniae. METHODS: We analysed blood of 160 patients who came from the ANTIBIOtic therapy after an AMI ( ANTIBIO-) study, a prospective, randomised, placebo-controlled, double-blind study to investigate the effect of roxithromycin 300 mg/OD for 6 weeks in patients with an AMI. Anti- Chlamydia IgG-, IgA-, and IgM-antibodies of these patients were analysed by means of different test systems. RESULTS: There was a good correlation between the two IgG and IgA methods (r = 0.900, p < 0.001 and r = 0.878, p < 0.001, respectively), but marked differences in the prevalence of positive tests. This resulted in only moderate concordance values, as expressed by the Kappa coefficients, for IgG kappa = 0.611 (95% CI = 0.498-0.724, p < 0.001) and for IgA kappa = 0.431 (95% CI: 0.322-0.540, p < 0.001). No significant association between positive C. pneumonia titers and the combined clinical endpoint during the 12 month follow-up could be found. In all test systems used, patients with positive anti- C. pneumoniae titers did not benefit from roxithromycin therapy (p = ns). CONCLUSION: Depending on the test system used, there are large differences in the prevalence of anti- C. pneumoniae seropositive patients. Clinical events during the 12 month follow-up after AMI did not depend on serostatus against C. pneumoniae and treatment with roxithromycin did not influence these events, independently of the serostatus against C. pneumoniae. However, the power of this subgroup analysis was low to detect small but significant differences.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Antibodies, Bacterial/blood , Chlamydophila Infections , Chlamydophila pneumoniae/immunology , Myocardial Infarction/drug therapy , Roxithromycin/therapeutic use , Anti-Bacterial Agents/administration & dosage , Chi-Square Distribution , Chlamydophila Infections/diagnosis , Chlamydophila Infections/drug therapy , Chlamydophila Infections/immunology , Complement Fixation Tests , Data Interpretation, Statistical , Double-Blind Method , Electrocardiography , Follow-Up Studies , Humans , Immunoenzyme Techniques , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Myocardial Infarction/complications , Myocardial Infarction/mortality , Placebos , Prospective Studies , Randomized Controlled Trials as Topic , Recurrence , Roxithromycin/administration & dosage , Time Factors , Treatment Outcome
10.
Clin Cardiol ; 23(3): 181-6, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10761806

ABSTRACT

BACKGROUND: Episodes of stress-induced myocardial ischemia in patients with coronary artery disease (CAD) may cause increases of QT dispersion (QTd). HYPOTHESIS: Aim of this study was to analyze the effect of increasing heart rates on QTd and to compare the effect of different methods of stress induction in patients with varying degrees of CAD when estimating QTd. METHODS: We studied 58 patients, 22 with prior myocardial infarction (MI), 25 without MI or wall motion disturbances at rest, and 11 patients without evidence of CAD. Prior to coronary angiography, standard 12-lead ECGs were obtained at rest as well as during dynamic exercise and pharmacologic stress using arbutamine simultaneously with echocardiography. QTd was determined at each stress level by subtracting minimal from maximal QT interval duration. RESULTS: QTd values at rest were not consistently higher in the patients with CAD. At maximal heart rate, QTd was statistically significantly higher in patients with CAD with a better discrimination between groups for pharmacologic stress (p < 0.005 for exercise, p < 0.0001 for arbutamine). Patients after MI had higher QTd values under all conditions than did the groups without MI. As in patients with CAD, the values of this group changed more radically as a result of pharmacologic stress. CONCLUSION: Patients with CAD can be identified on the basis of QTd under stress. These changes were not as marked in patients with MI as their rest values were already increased. Overall, drug-induced stress produced greater differences than dynamic exercise, suggesting that the ischemic threshold might be lower in the former.


Subject(s)
Coronary Disease/physiopathology , Heart Conduction System/physiopathology , Myocardial Ischemia/physiopathology , Adrenergic beta-Agonists/pharmacology , Aged , Catecholamines/pharmacology , Coronary Angiography , Electrocardiography , Exercise Test , Female , Heart Rate , Humans , Male , Middle Aged
11.
Heart ; 83(1): 58-63, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10618337

ABSTRACT

OBJECTIVE: To expand the benefits of the minimally invasive direct coronary artery bypass (MIDCAB) concept to patients with multivessel disease, a hybrid procedure combining surgical revascularisation of the left anterior descending artery with interventional procedures for additional coronary lesions has recently been introduced. Preliminary results in patients undergoing this hybrid procedure are presented. DESIGN AND PATIENTS: Since December 1996, 35 patients (29 male, 6 female, mean (SD) age 56.7 (17) years) underwent a hybrid revascularisation performed as a primary MIDCAB procedure for grafting of the left anterior descending artery with the left internal mammary artery, followed by staged angioplasty and stenting of additional coronary lesions. RESULTS: After MIDCAB grafting the postoperative course was uneventful in all patients. Coronary reangiography after a median of seven days revealed patent and functioning left internal mammary artery grafts in all patients. Applying subsequent percutaneous transluminal coronary angioplasty and occasional stenting (n = 14), a total of 47 lesions were treated successfully. Procedure related complications did not occur. All patients remained free from angina and no stress ECG changes were recorded. CONCLUSIONS: The preliminary results of this hybrid approach to myocardial revascularisation suggest that this is a safe and effective procedure for complete revascularisation in selected patients with multivessel disease. Elderly and reoperative patients with significant comorbidity may benefit especially from such hybrid procedures by avoiding cardiopulmonary bypass and mid sternotomy.


Subject(s)
Angioplasty, Balloon, Coronary , Coronary Disease/surgery , Internal Mammary-Coronary Artery Anastomosis/methods , Myocardial Revascularization/methods , Adult , Aged , Comorbidity , Coronary Angiography , Female , Humans , Male , Middle Aged , Minimally Invasive Surgical Procedures , Stents
12.
Z Kardiol ; 88(7): 481-8, 1999 Jul.
Article in German | MEDLINE | ID: mdl-10467647

ABSTRACT

BACKGROUND: Minimally invasive direct coronary artery bypass (MIDCAB) grafting without cardiopulmonary bypass (CPB) through an anterolateral minithoracotomy has become a promising therapeutical option especially in multimorbid, elderly and reoperative patients with single vessel disease. However, this procedure precludes complete revascularization in multivessel disease because the minithoracotomy limits the surgical access either to anterior or lateral or posterior vessels of the beating heart. To expand the benefits of the MIDCAB concept to patients with multivessel disease, new interdisciplinary approaches have recently been introduced. METHODS: Since December 1996, 26 patients (21 male, 5 female, mean age 56.6 +/- 18.8 years) underwent a "hybrid" revascularization performed as a primary MIDCAB procedure for grafting of the left anterior descending artery (LAD) with the left internal mammary artery (LIMA) followed by staged angioplasty and stenting of additional coronary lesions. RESULTS: After MIDCAB grafting, the postoperative course was uneventful in all patients. Coronary re-angiography after a median of 7 days revealed patent and functioning LIMA grafts in all patients. Applying subsequent percutaneous transluminal coronary angioplasty (PTCA) and occasional stenting (n = 8), a total of 31 lesions were treated successfully. Procedure related complications did not occur. All patients remained angina-free and no stress electrocardiographic changes were recorded. CONCLUSION: Our preliminary results of a "hybrid" approach to myocardial revascularization suggest that this concept is a safe and effective approach of complete revascularization for selected patients with multivessel involvement. Especially elderly and reoperative patients with significant comorbidity may benefit from hybrid procedures avoiding cardiopulmonary bypass and midsternotomy.


Subject(s)
Angioplasty, Balloon, Coronary/instrumentation , Coronary Disease/surgery , Endoscopes , Myocardial Revascularization/instrumentation , Adult , Aged , Combined Modality Therapy , Coronary Angiography , Coronary Disease/diagnostic imaging , Female , Humans , Internal Mammary-Coronary Artery Anastomosis/instrumentation , Male , Middle Aged , Minimally Invasive Surgical Procedures/instrumentation , Patient Care Team , Postoperative Complications/diagnostic imaging , Stents
13.
J Electrocardiol ; 32(3): 207-16, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10465564

ABSTRACT

This study investigated changes in spatial distribution of QT duration in patients with and without coronary artery disease (CAD) using magnetocardiography. Thirty-six-channel magnetocardiograms (MCGs) were registered at rest and under stress in 15 patients with chest pain, seven of whom had significant coronary stenosis. QT dispersion (QTd) was calculated for MCG and 12-lead electrocardiogram (ECG) under both conditions. For MCG, homogeneity of repolarization was measured using a smoothness index (SI). Also, at each registration site, the intraindividual difference between QT at rest and under stress was determined (deltaQT). QTd values as determined by standard 12-lead configurations were not significantly different between groups. MCG QTd values were significantly higher in the CAD group at rest only when all available channels were taken into consideration (P < .05); SI values differed significantly between groups under both conditions (rest, P < .005; stress, P < .01). Good separation between groups was possible using the range of deltaQT (P < .05) and SI (deltaQT) (P < .005). Consideration of the spatial distribution of QTd increases its sensitivity in the detection of CAD, suggesting that CAD involves complex changes in repolarization, not apparent in limited lead sets such as standard 12-lead configurations.


Subject(s)
Coronary Disease/physiopathology , Electrocardiography/methods , Magnetics , Adrenergic beta-Agonists , Catecholamines , Coronary Disease/diagnosis , Echocardiography , Female , Humans , Male , Middle Aged
14.
J Neurosci ; 19(1): 381-90, 1999 Jan 01.
Article in English | MEDLINE | ID: mdl-9870967

ABSTRACT

Odors evoke synchronized oscillations and slow temporal patterns in antennal lobe neurons and fast oscillations in the mushroom body local field potential (LFP) of the locust. What is the contribution of primary afferents in the generation of these dynamics? We addressed this question in two ways. First, we recorded odor-evoked afferent activity in both isolated antennae and intact preparations. Odor-evoked population activity in the antenna and the antennal nerve consisted of a slow potential deflection, similar for many odors. This deflection contained neither oscillatory nor odor-specific slow temporal patterns, whereas simultaneously recorded mushroom body LFPs exhibited clear 20-30 Hz oscillations. This suggests that the temporal patterning of antennal lobe and mushroom body neurons is generated downstream of the olfactory receptor axons. Second, we electrically stimulated arrays of primary afferents in vivo. A brief shock to the antennal nerve produced compound PSPs in antennal lobe projection neurons, with two peaks at an approximately 50 msec interval. Prolonged afferent stimulation with step, ramp, or slow sine-shaped voltage waveforms evoked sustained 20-30 Hz oscillations in projection neuron membrane potential and in the mushroom body LFP. Projection neuron and mushroom body oscillations were phase-locked and reliable across trials. Synchronization of projection neurons was seen directly in paired intracellular recordings. Pressure injection of picrotoxin into the antennal lobe eliminated the oscillations evoked by electrical stimulation. Different projection neurons could express different temporal patterns in response to the same electrical stimulus, as seen for odor-evoked responses. Conversely, individual projection neurons could express different temporal patterns of activity in response to step stimulation of different spatial arrays of olfactory afferents. These patterns were reliable and remained distinct across different stimulus intensities. We conclude that oscillatory synchronization of olfactory neurons originates in the antennal lobe and that slow temporal patterns in projection neurons can arise in the absence of temporal patterning of the afferent input.


Subject(s)
Grasshoppers/physiology , Odorants , Afferent Pathways/physiology , Animals , Axons/physiology , Central Nervous System Stimulants/pharmacology , Electric Stimulation , Female , Olfactory Pathways/physiology , Oscillometry , Picrotoxin/pharmacology , Time Factors
15.
Learn Mem ; 5(1-2): 124-32, 1998.
Article in English | MEDLINE | ID: mdl-10454377

ABSTRACT

A requirement to understand mushroom body (MB) function is to characterize the operations (or transformations) that they impose on incoming signals. Understanding the nature of these integrative operations requires an understanding of the inputs from other brain areas. By inputs we mean not only the anatomical pathways leading to the MBs, but also the dynamic structure of the inflow of sensory (and other) signals. Neurons are complex, capacitative, and generally nonlinear devices that transform barrages of neurochemical packets into electrical waveforms. Their modes of operation are intrinsically time dependent and therefore, their functions or roles in a circuit cannot be inferred only from structural data. Thanks to elegant anatomical, behavioral, genetic, and molecular (for review, see Crittenden et al. 1998; Hammer and Menzel 1998; Heisenberg 1998; Wolf et al. 1998) studies, there is convincing evidence that MB circuits are involved, at least in fruit flies and honeybees, in some forms of odor integration and learning. In vivo electrophysiological studies of MB neurons, however, are rare and mainly restricted to individual (or small populations of) so-called extrinsic neurons, that is, those whose processes link MBs with other brain areas (Schildberger 1983, 1984; Homberg 1984; Hammer 1993; Mauelshagen 1993; Li and Strausfeld 1997). Kaulen et al. (1984) examined extracellular potentials in the MBs of bees, using current source density analysis, and more recently, Laurent and Naraghi (1994) provided a description of stimulus-evoked activity in Kenyon cells (KCs), the intrinsic neurons of the MBs, using intracellular recordings. In this short review we will summarize the recent results from our laboratory in an attempt to provide a description of the spatiotemporal structure of olfactory inputs to the MBs and their intrinsic neurons. We will focus only on the encoding of odor quality. We will then speculate on the possible role of MB circuits for olfactory processing.


Subject(s)
Brain Mapping/methods , Grasshoppers/physiology , Animals , Neurons/physiology , Neuropil/physiology , Odorants , Olfactory Pathways/physiology , Time Factors
17.
Herzschrittmacherther Elektrophysiol ; 8(2): 118-23, 1997 Jun.
Article in German | MEDLINE | ID: mdl-19484523

ABSTRACT

Patients who need an implantable Cardioverter/Defibrillator (ICD) often require a cardiac pacemaker (PM) to treat underlying symptomatic bradycardia. In some cases the simultaneous therapy has caused interactions between the systems with defaults on both sides.Four patients with an ICD of the newer generation received a single or dual chamber pacemaker system. In all cases bipolar pacemaker electrodes were used. They were positioned together with the ICD-electrode in the right ventricular apex without regard to the distance between them. In order to exclude possible interference between systems special tests were performed during the operative procedure with respect to the system implanted first. In a follow-up period of 4-14 months all patients had episodes of ventricular tachycardia or ventricular fibrillation that were terminated successfully. Two patients with a bradycardia related arrhythmia after shock delivery showed a correct pacemaker stimulation. Subsequent to the start of pacemaker therapy improvement in stress capacity could be documented, partly on the basis of echocardiography.Combined ICD and PM therapy can thus be generally regarded as compatible. For AV-sequential pacing at least three electrodes and two aggregates are necessary. The development of an ICD with the option for a dual-chamber stimulation would simplify the therapy, along with a greater acceptance on part of the patients.

18.
Nature ; 384(6605): 162-6, 1996 Nov 14.
Article in English | MEDLINE | ID: mdl-8906790

ABSTRACT

Stimulus-evoked oscillatory synchronization of activity has been observed in many neural systems, including the cerebral cortex of mammals and the brain of insects. The possible functions of such rhythmic synchronization in neural coding, however, remain largely speculative. In the locust, odours evoke activity in dynamic (evolving) ensembles of transiently synchronized neurons. We report here that the active neurons composing these ensembles change in a stimulus-specific manner and with a high degree of reliability on a cycle-by-cycle basis during an odour response. Hence, information about an odour is contained not only in the neural assembly active at each oscillation cycle, but also in the precise temporal sequence in which these assemblies are updated during an odour response. Neural coding with oscillations thus allows combinatorial representations in time as well as in space.


Subject(s)
Cortical Synchronization , Neurons/physiology , Smell/physiology , Action Potentials , Animals , Electrophysiology , Female , Grasshoppers , Male , Odorants
19.
Pacing Clin Electrophysiol ; 19(11 Pt 2): 1894-9, 1996 Nov.
Article in English | MEDLINE | ID: mdl-8945064

ABSTRACT

QT dispersion (QTd) describes the heterogeneity of ventricular repolarization on the basis of the temporal range of QT intervals as measured in the 12-lead ECG. We examined the spatial distribution of QTd using multichannel magnetocardiograms (MCGs), which noninvasively register changes in magnetic field strength at 37 sites over the heart. As in ECG, the MCG signal in each channel may be used to measure QT interval. By calculating QT deviation from QTmin at each site, one can reconstruct the spatial distribution of QTd. Analysis of spatial QTd in ten healthy subjects and ten patients after acute myocardial infarction (MI) showed clear differences in spatial distribution. The healthy subjects generally displayed shorter QT intervals along a line corresponding to the approximate position of the septum with longer intervals in plateaus in the upper right and lower left. Spatial QTd of the post-MI patients deviated from this pattern, often displaying a sharp rise in QT duration over specific areas, which could be related to functional and morphological disturbances. The quantification of local irregularities as well as the overall pattern on the basis of a smoothness index allowed better discrimination between healthy subjects and post-MI patients than QTd. Distribution patterns of QTd which reflect local repolarization alterations may thus represent a more differentiated marker for pathology and risk.


Subject(s)
Electrocardiography/methods , Adult , Aged , Body Surface Potential Mapping , Coronary Disease/physiopathology , Electrocardiography/instrumentation , Female , Heart Septum/physiology , Humans , Magnetics , Male , Middle Aged , Myocardial Infarction/physiopathology , Risk Factors , Signal Processing, Computer-Assisted , Time Factors , Ventricular Function
20.
J Neurosci ; 16(12): 3837-47, 1996 Jun 15.
Article in English | MEDLINE | ID: mdl-8656278

ABSTRACT

The responses of projection neurons in the antennal lobe of the locust brain (the functional analog of mitral-tufted cells in the vertebrate olfactory bulb) to natural blends and simple odors were studied with multiple intra- and extracellular recordings in vivo. Individual odors evoked complex temporal response patterns in many neurons. These patterns differed across odors for a given neuron and across neurons for a given odor, but were stable for each neuron over repeated presentations (separated by seconds to minutes) of the same odor. The response of individual neurons to an odor was superimposed on an odor-specific coherent oscillatory population activity. Each neuron usually participated in the coherent oscillations during one or more specific epochs of the ensemble activity. These epochs of phase locking were reliable for each neuron over tens of repeated presentations of one odor. The timing of these epochs of synchronization differed across neurons and odors. Correlated activity of specific pairs of neurons, hence, generally occurred transiently during the population response, at times that were specific to these pairs and to the odor smelled. The field potential oscillations, therefore, fail to reveal a progressive transformation of the synchronized ensemble as the response to the odor unfolds. We propose that (1) odors are represented by spatially and temporally distributed ensembles of coherently firing neurons, and (2) the field potential oscillations that characterize odor responses in the olfactory system occur, at least in this animal, in parallel with a slower dynamic odor representation.


Subject(s)
Grasshoppers/physiology , Smell/physiology , Animals , Electrophysiology , Ganglia, Invertebrate/cytology , Ganglia, Invertebrate/physiology , Nervous System/cytology , Nervous System Physiological Phenomena , Neurons, Afferent/cytology , Neurons, Afferent/physiology , Odorants , Periodicity , Time Factors
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