Neurobehavioral Effects of Acute Exposure to Normal (n-) Paraffins

2011 ◽  
Vol 30 (1) ◽  
pp. 47-58 ◽  
Author(s):  
J. H. C. M. Lammers ◽  
H. Muijser ◽  
D. E. Owen ◽  
B.M. Kulig ◽  
R. H. McKee
Keyword(s):  
Molecular Weight ◽  
Central Nervous System ◽  
Visual Discrimination ◽  
Discrimination Performance ◽  
Clinical Effects ◽  
Compelling Evidence ◽  
Effect Level ◽  
Neurobehavioral Effects ◽  
Cns Effects ◽  
Metabolic Induction

This article reports the results of neurobehavioral tests on C5-C10 normal paraffinic constituents (n-paraffins). Shortly after exposure, effects were evaluated in several domains including clinical effects, motor activity, functional observations, and visual discrimination performance. The representative C5 n-paraffin, n-pentane, did not produce any evidence of acute central nervous system (CNS) effects at levels up to 20 000 mg/m3. Similarly, there was no compelling evidence that n-octane (C8) produced CNS effects at 14 000 mg/m3, the highest concentration tested. n-decane (C10) produced minor, reversible acute CNS effects at 5000 mg/m3, with 1500 mg/m3 as the no-effect level. Consistent with literature data, there seemed to be a relationship between increasing molecular weight up to C10 and acute CNS effects. However, the CNS effects were reversible. Repeated exposures did not provide evidence of metabolic induction.

Neurobehavioral Effects of Acute Exposure to Isoparaffinic and Cycloparaffinic Hydrocarbons

2011 ◽  
Vol 30 (6) ◽  
pp. 715-734 ◽  
Author(s):  
Richard H. McKee ◽  
J. H. C. M. Lammers ◽  
H. Muijser ◽  
David E. Owen
Keyword(s):  
Central Nervous System ◽  
Visual Discrimination ◽  
Discrimination Performance ◽  
Clinical Effects ◽  
Occupational Exposure Limits ◽  
Exposure Limits ◽  
Discrimination Testing ◽  
Effect Level ◽  
Neurobehavioral Effects ◽  
Cns Effects

This article reports neurobehavioral tests in rats with C5-C11 isoparaffinic and cycloparaffinic hydrocarbons. Testing, conducted shortly after exposure, evaluated the effects in several domains including clinical effects, motor activity, functional observations, and visual discrimination performance. Isopentane and cyclopentane did not produce any evidence of acute central nervous system (CNS) effects at levels up to 20 000 mg/m3. A C6/C7 mixed cycloparaffinic solvent produced minor, reversible changes in latency to response in visual discrimination testing at 14 000 mg/m3; the no-effect level was 4200 mg/m3. A C8 isoparaffin produced no effects at 14 000 mg/m3, the highest level tested. A C9/C11 isoparaffinic solvent produced minor acute CNS effects at 5000 mg/m3, with 1500 mg/m3 as the no-effect level. A C10 cycloparaffinic solvent did not produce any statistically significant CNS effects at 5000 mg/m3. These studies were designed to provide data that may be useful in setting occupational exposure limits for C5-C11 isoparaffinic and cycloparaffinic hydrocarbons.

Neurobehavioral Effects of Acute Exposure to Aromatic Hydrocarbons

2010 ◽  
Vol 29 (3) ◽  
pp. 277-290 ◽  
Author(s):  
Richard H. McKee ◽  
J. H. C. M. Lammers ◽  
H. Muijser ◽  
D. E. Owen ◽  
B. M. Kulig
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance ◽  
Clinical Effects ◽  
High Exposure ◽  
Molecular Weights ◽  
Trimethyl Benzene ◽  
The Central Nervous System ◽  
Exposure Levels ◽  
Alkyl Benzenes ◽  
Neurobehavioral Effects

This article reports the results of neurobehavioral tests on representative aromatic constituents, specifically C9 to C11 species. The testing evaluated effects in several domains including clinical effects, motor activity, functional observations, and visual discrimination performance. Exposures ranging from 600 to 5000 mg/m3, depending on the molecular weights of the specific aromatic constituents, produced minor, reversible effects on the central nervous system (CNS), particularly in the domains of gait and visual discrimination. There was little evidence of effects at lower exposure levels. There was some evidence of respiratory effects at 5000 mg/m3 in 1 study, and there were also minor changes in body weight and temperature. The CNS effects became less pronounced with repeated exposures, corresponding to lower concentrations in the brain of 1 representative substance, 1,2,4-trimethyl benzene (TMB). At high exposure levels, the alkyl benzenes apparently induced their own metabolism, increasing elimination rates.

Neurobehavioral Effects of Cyclohexane in Rat and Human

2009 ◽  
Vol 28 (6) ◽  
pp. 488-497 ◽  
Author(s):  
J. H. C. M. Lammers ◽  
H. H. Emmen ◽  
H. Muijser ◽  
E. M. G. Hoogendijk ◽  
R. H. McKee ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Discrimination Performance ◽  
Internal Exposure ◽  
Psychomotor Speed ◽  
Significant Treatment ◽  
High Exposure ◽  
Observational Measures ◽  
Human Volunteers ◽  
Neurobehavioral Effects

The neurobehavioral effects of inhaled cyclohexane in rats and humans are investigated to define relationships between internal doses and acute central nervous system effects. Rats are exposed for 3 consecutive days at target concentrations of 0, 1.4, 8, and 28 g/m3, 8 h/d. Measurements include standardized observational measures, spontaneous motor activity assessments, and learned visual discrimination performance. Cyclohexane concentrations in blood and brain are measured to assess internal exposure. Human volunteers are exposed for 4 hours to 86 or 860 mg/m3 in 2 test sessions. Neurobehavioral effects are measured using a computerized neurobehavioral test battery. In rats, there are slight reductions in psychomotor speed in the high-exposure group but minimal central nervous system effects. In humans, there are no significant treatment-related effects at the levels tested.

scholarly journals Confidence in perceptual decision-making is preserved in schizophrenia

2019 ◽  
Author(s):  
Nathan Faivre ◽  
Matthieu Roger ◽  
Michael Pereira ◽  
Vincent de Gardelle ◽  
Jean-Christophe Vergnaud ◽  
...  
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance ◽  
Perceptual Decision Making ◽  
Task Execution ◽  
Bayesian Analyses ◽  
Functional Deficits ◽  
Evidence Accumulation ◽  
Narrative Assessment ◽  
Mental Operations ◽  
Healthy Participants

AbstractMetacognition is the set of reflexive processes allowing humans to evaluate the accuracy of their mental operations. Deficits in synthetic metacognition have been described in schizophrenia using mostly narrative assessment and linked to several key symptoms. Here, we assessed metacognitive performance by asking individuals with schizophrenia or schizoaffective disorder (N=20) and matched healthy participants (N = 21) to perform a visual discrimination task and subsequently report confidence in their performance. Metacognitive performance was defined as the adequacy between visual discrimination performance and confidence. Bayesian analyses revealed equivalent metacognitive performance in the two groups despite a weaker association between confidence and trajectory tracking during task execution among patients. These results were reproduced using a bounded evidence accumulation model which showed similar decisional processes in the two groups. The inability to accurately attune confidence to perceptual decisions in schizophrenia remains to be experimentally demonstrated, along with the way such impairments may underpin functional deficits.

scholarly journals Training protocol for touchscreen-based visual discrimination in mice

2020 ◽  
Author(s):  
Kazuhiro Goto ◽  
Yuya Hataji
Keyword(s):  
Visual Discrimination ◽  
Reinforcement Schedule ◽  
Discrimination Performance ◽  
Magazine Training ◽  
Stimulus Position ◽  
Continuous Reinforcement Schedule ◽  
Continuous Reinforcement ◽  
Contrast Discrimination ◽  
And Behavior ◽  
Training Protocol

Automated touchscreen-based tasks are increasingly being used to explore a broad range of issues in learning and behavior in mice. Researchers usually report how they train mice before acquiring the target task concisely, and shaping protocols at this stage are typically flexible. In this report, we described a training protocol, developed in our laboratory, for mice acquiring a simultaneous discrimination performance using visual stimuli. C57BL/6N mice were first given magazine training. Nosepoke responses were then authoshaped and maintained on a continuous reinforcement schedule. Self-start response was then introduced in order to measure response time to complete each trial. The stimulus position was also varied across trials. We finally examined the contrast discrimination performance. Mice were tested with four different contrast ratios. Target stimuli were white and black targets and the brightness of distractors had values between targets and background. All mice successfully went through all training stages, confirming that this training protocol is promising for shaping appropriate discriminative behaviors in mice.

Elucidating the Phytochemical and Pharmacological Potential of Myristica fragrans (Nutmeg)

2020 ◽  
pp. 52-61 ◽  
Author(s):  
Ena Gupta
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Daily Intake ◽  
Low Doses ◽  
Acceptable Daily Intake ◽  
Bioactive Constituents ◽  
Myristica Fragrans ◽  
The Family ◽  
Pharmacological Potential ◽  
Cns Effects

Myristica fragrans or nutmeg is a ground spice of the family Myristicaceae. Its tree has dark leaves mainly cultivated in Grenada, Malaysia, and Kerala. It is majorly a source of two spices derived from its fruit: nutmeg (jaiphal) from its seed and mace (javitri) from the covering of seed. The important bioactive constituents present in nutmeg include macelignan, carvacrol, myristicin, β-caryophyllene, β-pinene, α-pinene, p-cymene, and eugenol. Low doses of nutmeg do not cause any side effects whereas after consuming 5g toxic overdose occurs, and central nervous system (CNS) effects were induced after consuming 1 to 2 mg/kg b.wt. of nutmeg. Various therapeutic or medicinal applications were shown by nutmeg such as antioxidant, antimicrobial, aphrodisiac, anticancer, hepatoprotective, anti-inflammatory, antidepressant, and cardioprotective activity. This review chapter focuses on ethnobotany, phytochemistry, acceptable daily intake, and different pharmacological actions of this medicinal plant.

scholarly journals Snake Venom Hemotoxic Enzymes: Biochemical Comparison between Crotalus Species from Central Mexico

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1489 ◽  
Author(s):  
Octavio Roldán-Padrón ◽  
José Luis Castro-Guillén ◽  
José Alejandro García-Arredondo ◽  
Martha Sandra Cruz-Pérez ◽  
Luis Fernando Díaz-Peña ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Snake Venom ◽  
Serine Proteases ◽  
Biochemical Characterization ◽  
Protein Pattern ◽  
Medical Problem ◽  
Enzymatic Activities ◽  
Clinical Effects ◽  
Pla2 Activity ◽  
Biochemical Comparison

Snakebite envenoming is a serious medical problem in different areas of the world. In Latin America, the major prevalence is due to snakes of the family Viperidae, where rattlesnakes (Crotalus) are included. They produce hemotoxic venom which causes bleeding, tissue degradation and necrosis. Each venom has several enzymatic activities, producing different effects in the envenoming, doing its clinical effects difficult to study. Comparison between venom molecules is also difficult when different techniques are used, and therefore, their identification/characterization using the same methodology is necessary. In this work, a general biochemical characterization in snake venom of serine proteases (SVSP), phospholipases A2 (PLA2), metalloproteases (SVMP) and hyaluronidases (SVH) of Crotalus aquilus (Ca), Crotalus polystictus (Cp) and Crotalus molossus nigrescens (Cmn) was done. Differences in protein pattern, enzyme content and enzymatic activities were observed. All the venoms showed high PLA2 activity, high molecular weight SVSP, and a wide variety of SVMP and SVH forms. Ca and Cp showed the highest enzymatic activities of SVMP and SVSP trypsin-like and chymotrypsin-like, whereas Cmn showed the highest SVH and similar PLA2 activity with Ca. All the venoms showed peptides with similar molecular weight to crotamine-like myotoxins. No previous biochemical characterization of C. aquilus has been reported and there are no previous analyses that include these four protein families in these Crotalus venoms.

Varying Deficits in Visual Discrimination Performance Associated with Different Forms of Malnutrition in Rats

1980 ◽  
Vol 110 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Janina R. Galler ◽  
Susan F. Fleischer ◽  
Gerald Turkewitz ◽  
Michael Manes
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance
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