Slow Late Component in Conditioned Stimulus-Evoked Potentials From the Amygdala After Fear Conditioning in the Rat

Male Wistar rats were subjected to a differential Pavlovian fear conditioning procedure in which one of two tones (6 or 10 kHz) was followed by an electric shock (CS+) and the other was not (CS-). Before and after fear conditioning, we recorded the evoked potentials elicited byCS+andCS-from electrodes aimed at the lateral nucleus of the amygdala. Before conditioning, a slow, negative component with peak amplitude around 150 ms was present in the evoked potentials. This component was sensitive to habituation. After fear conditioning, bothCS+andCS-elicited the same late component, albeit with a larger amplitude. This enhancement was temporary: decreasing amplitude was observed in the course of CS test presentations under extinction. Prior research revealed a comparable slow component in the amygdala of the cat under similar experimental conditions. The collective results indicate that the large late component in the amygdala is enhanced by fear conditioning, suggesting that such enhancement reflects the anticipation of a biologically significant event.

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Isoflurane Causes Anterograde but Not Retrograde Amnesia for Pavlovian Fear Conditioning

Anesthesiology ◽

10.1097/00000542-200205000-00027 ◽

2002 ◽

Vol 96 (5) ◽

pp. 1223-1229 ◽

Cited By ~ 25

Author(s):

Robert C. Dutton ◽

Anya J. Maurer ◽

James M. Sonner ◽

Michael S. Fanselow ◽

Michael J. Laster ◽

...

Keyword(s):

Fear Conditioning ◽

Retrograde Amnesia ◽

Minimum Alveolar Concentration ◽

Conditioned Fear ◽

Pavlovian Fear Conditioning ◽

Conditioning Procedure ◽

Trial Procedure ◽

Learning Procedure ◽

The One ◽

Dose Dependent

Background Production of retrograde amnesia by anesthetics would indicate that these drugs can disrupt mechanisms that stabilize memory. Such disruption would allow suppression of memory of previous untoward events. The authors examined whether isoflurane provides retrograde amnesia for classic (Pavlovian) fear conditioning. Methods Rats were trained to fear tone by applying three (three-trial) or one (one-trial) tone-shock pairs while breathing various constant concentrations of isoflurane. Immediately after training, isoflurane administration was either discontinued, maintained unchanged, or rapidly increased to 1.0 minimum alveolar concentration for 1 h longer. Groups of rats were similarly trained to fear context while breathing isoflurane by applying shocks (without tones) in a distinctive environment. The next day, memory for the conditioned stimuli was determined by presenting the tone or context (without shock) and measuring the proportion of time each rat froze (appeared immobile). For each conditioning procedure, the effects of the three posttraining isoflurane treatments were compared. Results Rapid increases in posttraining isoflurane administration did not suppress conditioned fear for any of the training procedures. In contrast, isoflurane administration during conditioning dose-dependently suppressed conditioning (P < 0.05). Training to tone was more resistant to the effects of isoflurane than training to context (P < 0.05), and the three-trial learning procedure was more was more resistant than the one-trial procedure (P < 0.05). Conclusions Isoflurane provided intense dose-dependent anterograde but not retrograde amnesia for classic fear conditioning. Isoflurane appears to disrupt memory processes that occur at or within a few minutes of the conditioning procedure.

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Structural and functional renal alterations in five-sixth nephrectomized rats on unrestricted diet

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014333x ◽

1986 ◽

Vol 44 ◽

pp. 342-343

Author(s):

I. Stachura ◽

M. Pardo ◽

J. Costello ◽

D.M. Landwehr

Keyword(s):

Wistar Rats ◽

Renal Damage ◽

Standard Diet ◽

Experimental Conditions ◽

Phosphate Intake ◽

Dietary Restrictions ◽

Severe Reduction ◽

Male Wistar Rats ◽

Unrestricted Diet ◽

Progressive Renal Insufficiency

Under experimental conditions severe reduction of renal mass results in the hyperfiltration of the remaining nephrons leading to a progressive renal insufficiency. Similar changes are observed in patients with various renal disorders associated with a loss of the functioning nephrons. The progression of renal damage is accelerated by high protein and phosphate intake, and may be modified by the dietary restrictions.We studied 50 five-sixth nephrectarrized male Wistar rats on a standard diet (Rodent Laboratory Chow 5001 Ralston Purina Co., Richmond, Indiana; containing 23.4% protein) over a 20 week period.

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Preliminary Evaluation of a Weibull Function for Fitting Slow-Component Eye Velocity over the Time Course of Caloric-Induced Nystagmus

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.3203.681 ◽

1989 ◽

Vol 32 (3) ◽

pp. 681-687 ◽

Cited By ~ 1

Author(s):

C. Formby ◽

B. Albritton ◽

I. M. Rivera

Keyword(s):

Time Course ◽

Slow Component ◽

Weibull Function ◽

Preliminary Evaluation ◽

Mathematical Function ◽

Before And After ◽

Best Fitting ◽

Eye Velocity ◽

Fitting Parameters ◽

Weibull Equation

We describe preliminary attempts to fit a mathematical function to the slow-component eye velocity (SCV) over the time course of caloric-induced nystagmus. Initially, we consider a Weibull equation with three parameters. These parameters are estimated by a least-squares procedure to fit digitized SCV data. We present examples of SCV data and fitted curves to show how adjustments in the parameters of the model affect the fitted curve. The best fitting parameters are presented for curves fit to 120 warm caloric responses. The fitting parameters and the efficacy of the fitted curves are compared before and after the SCV data were smoothed to reduce response variability. We also consider a more flexible four-parameter Weibull equation that, for 98% of the smoothed caloric responses, yields fits that describe the data more precisely than a line through the mean. Finally, we consider advantages and problems in fitting the Weibull function to caloric data.

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The Effects of MRNA synthesis in the Amygdala on the Acquisition and Reconsolidation of Pavlovian Fear Conditioning

PsycEXTRA Dataset ◽

10.1037/e413812005-447 ◽

2002 ◽

Author(s):

Ryan G. Parsons ◽

Georgette M. Gafford ◽

Fred J. Helmstetter

Keyword(s):

Fear Conditioning ◽

Pavlovian Fear Conditioning ◽

Mrna Synthesis

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The evaluation of Teucrium persicum methanolic extract and its fractions in Pavlovian Fear Conditioning

Planta Medica ◽

10.1055/s-0031-1282962 ◽

2011 ◽

Vol 77 (12) ◽

Author(s):

H Monsef Esfahani ◽

M Sharifzadeh ◽

M Moattari ◽

A Miri ◽

E Nasireslami

Keyword(s):

Fear Conditioning ◽

Methanolic Extract ◽

Pavlovian Fear Conditioning

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Faculty Opinions recommendation of Auditory-evoked spike firing in the lateral amygdala and Pavlovian fear conditioning: mnemonic code or fear bias?

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1017805.207445 ◽

2004 ◽

Author(s):

Wendy Suzuki

Keyword(s):

Fear Conditioning ◽

Pavlovian Fear Conditioning ◽

Lateral Amygdala ◽

Spike Firing

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Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters

Water ◽

10.3390/w13131757 ◽

2021 ◽

Vol 13 (13) ◽

pp. 1757

Author(s):

Yesica Vicente-Martínez ◽

Manuel Caravaca ◽

Antonio Soto-Meca ◽

Miguel Ángel Martín-Pereira ◽

María del Carmen García-Onsurbe

Keyword(s):

Magnetic Nanoparticles ◽

Nitrate Content ◽

Adsorption Efficiency ◽

Experimental Conditions ◽

Dependent Behavior ◽

Before And After ◽

Naoh Solution ◽

High Concentrations ◽

Interference Studies

This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe3O4@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe3O4@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increases. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.

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Experimental Study on the Water Selective Dense Membrane under an Absolute Pressure Difference with Simplified Test Method

Applied Sciences ◽

10.3390/app11041710 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1710

Author(s):

Jinwook Lee ◽

Hyo-Sun Kim ◽

Donik Ku ◽

Jihun Lim ◽

Minkyu Jung ◽

...

Keyword(s):

Measurement Methods ◽

Test Method ◽

Coefficient Of Performance ◽

Absolute Pressure ◽

Air Conditioner ◽

Experimental Conditions ◽

Simple Method ◽

Performance Factors ◽

Dense Membrane ◽

Before And After

Membrane-based vacuum dehumidification technology is currently being actively studied. In most studies, the performance of the membrane-based systems is evaluated under the assumption that the membrane can achieve ideal separation, which results in ideal coefficient of performance (COP) values. However, the performance factors for membranes vary depending on the experimental conditions and measurement methods. Therefore, relevant values can only be calculated if the data are measured in an environment close to that of the application conditions. The cup measurement method is a simple method to measure the permeability, however, there are limitations regarding adding variables during the experiment. To overcome these limitations, a new experimental device was constructed that combines pressurized cell with the cup method. Using the device, the performance of polyethylene-amide-bonded dense membranes was evaluated under conditions where absolute pressure differentials occurred before and after the membrane, such as in air conditioner dehumidification systems.

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