Defecation follows digestion, and is a necessary process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces from the digestive tract via the anus or cloaca. The act has a variety of names ranging from the common, like pooping or crapping, to the technical, e.g. bowel movement, to the obscene (shitting), to the euphemistic, to the juvenile. The topic, usually avoided in polite company, can become the basis for some potty humor.
5-HT receptors, 5-hydroxytryptamine receptors, or serotonin receptors, are a group of G protein-coupled receptor and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission. The serotonin receptors are activated by the neurotransmitter serotonin, which acts as their natural ligand.
The laboratory mouse or lab mouse is a small mammal of the order Rodentia which is bred and used for scientific research or feeders for certain pets. Laboratory mice are usually of the species Mus musculus. They are the most commonly used mammalian research model and are used for research in genetics, physiology, psychology, medicine and other scientific disciplines. Mice belong to the Euarchontoglires clade, which includes humans. This close relationship, the associated high homology with humans, their ease of maintenance and handling, and their high reproduction rate, make mice particularly suitable models for human-oriented research. The laboratory mouse genome has been sequenced and many mouse genes have human homologues. Lab mice are sold at pet stores for snake food and can also be kept as pets.
The Morris water navigation task, also known as the Morris water maze, is a behavioral procedure mostly used with rodents. It is widely used in behavioral neuroscience to study spatial learning and memory. It enables learning, memory, and spatial working to be studied with great accuracy, and can also be used to assess damage to particular cortical regions of the brain. It is used by neuroscientists to measure the effect of neurocognitive disorders on spatial learning and possible neural treatments, to test the effect of lesions to the brain in areas concerned with memory, and to study how age influences cognitive function and spatial learning. The task is also used as a tool to study drug-abuse, neural systems, neurotransmitters, and brain development.
The radial arm maze was designed by Olton and Samuelson in 1976 to measure spatial learning and memory in rats. The original apparatus consists of eight equidistantly spaced arms, each about 4 feet long, and all radiating from a small circular central platform. At the end of each arm there is a food site, the contents of which are not visible from the central platform.
The Barnes maze is a tool used in psychological laboratory experiments to measure spatial learning and memory. The test was first developed by Dr. Carol Barnes in 1979. The test subjects are usually rodents such as mice or lab rats, which either serve as a control or may have some genetic variable or deficiency present in them which will cause them to react to the maze differently. The basic function of Barnes maze is to measure the ability of a mouse to learn and remember the location of a target zone using a configuration of distal visual cues located around the testing area. This noninvasive task is useful for evaluating novel chemical entities for their effects on cognition as well as identifying cognitive deficits in transgenic strains of rodents that model for disease such as Alzheimer's disease. It is also used by neuroscientists to determine whether there is a causative effect after mild traumatic brain injury on learning deficits and spatial memory retention (probe) at acute and chronic time points. This task is dependent on the intrinsic inclination of the subjects to escape from an aversive environment and on hippocampal-dependent spatial reference memory.
The behavioural despair test is a test, centered on a rodent's response to the threat of drowning, whose result has been interpreted as measuring susceptibility to negative mood. It is commonly used to measure the effectiveness of antidepressants, although significant criticisms of its interpretation have been made.
C57BL/6, often referred to as "C57 black 6", "B6", "C57" or "black 6", is a common inbred strain of laboratory mouse.
Genes, Brain and Behavior is a bimonthly peer-reviewed open access scientific journal covering research in the fields of behavioral, neural, and psychiatric genetics. It is published by Wiley on behalf of the International Behavioural and Neural Genetics Society. The journal was established in 2002 as a quarterly and is currently published bimonthly.
The elevated plus maze (EPM) is a test measuring anxiety in laboratory animals that usually uses rodents as a screening test for putative anxiolytic or anxiogenic compounds and as a general research tool in neurobiological anxiety research such as PTSD and TBI. The model is based on the test animal's aversion to open spaces and tendency to be thigmotaxic. In the EPM, this anxiety is expressed by the animal spending more time in the enclosed arms. The validity of the model has been criticized as non-classical clinical anxiolytics produce mixed results in the EPM test. Despite this, the model is still commonly used for screening putative anxiolytics and for general research into the brain mechanisms of anxiety.
Ambidirectional dominance occurs in a situation where multiple genes influence a phenotype and dominance is in different directions depending on the gene. For example, for gene A increased height is dominant, while for gene B decreased height is dominant. The opposite situation, where all genes show dominance in the same direction, is called directional dominance. In the same example, for both genes A and B increased height is dominant. According to Broadhurst, ambidirectional dominance is the result of stabilising selection in the evolutionary past. Ambidirectional dominance has been found for exploratory behaviours in mice and paradise fish.
Wim E. Crusio is a Dutch behavioral neurogeneticist and a directeur de recherche with the French National Centre for Scientific Research in Talence, France.
Jacqueline N. Crawley is an American behavioral neuroscientist and an expert on rodent behavioral analysis. Since July 2012, she is the Robert E. Chason Chair in Translational Research in the MIND Institute and professor of psychiatry and behavioral sciences at the University of California, Davis School of Medicine in Sacramento. Previously, from 1983–2012, she was chief of the Laboratory of Behavioral Neuroscience in the intramural program of the National Institute of Mental Health. Her translational research program focuses on testing hypotheses about the genetic causes of autism spectrum disorders and discovering treatments for the diagnostic symptoms of autism, using mouse models. She has published more than 275 peer-reviewed articles in scientific journals and 110 review articles and book chapters. According to Scopus, her works have been cited over 36,000 times, giving her an h-index of 99. She has co-edited 4 books and is the author of What's Wrong With my Mouse? Behavioral Phenotyping of Transgenic and Knockout Mice, which was very well received.
Animal models of depression are research tools used to investigate depression and action of antidepressants. They are used as a simulation to investigate the symptomatology and pathophysiology of depressive illness and to screen novel antidepressants. These models provide insights into molecular, genetic, and epigenetic factors associated with depression. Criteria for valid animal models include face, construct, and predictive validity. Endophenotypes, such as anhedonia, behavioral despair, changes in appetite, neuroanatomical alterations, neuroendocrine disturbances, alterations in sleep architecture, and anxiety-related behaviors, are evaluated in these models. Antidepressant screening tests are employed to assess the effects of genetic, pharmacological, or environmental manipulations. Stress models including learned helplessness, chronic mild stress, and social defeat stress simulate the impact of stressors on depression. Early life stress models, psychostimulant withdrawal models, olfactory bulbectomy, and genetically engineered mice contribute to a comprehensive understanding of depression's etiology and potential therapeutic interventions.
In animal behaviour, stereotypy, stereotypic or stereotyped behaviour has several meanings, leading to ambiguity in the scientific literature. A stereotypy is a term for a group of phenotypic behaviours that are repetitive, morphologically identical and which possess no obvious goal or function. These behaviours have been defined as "abnormal", as they exhibit themselves solely in animals subjected to barren environments, scheduled or restricted feedings, social deprivation and other cases of frustration, but do not arise in "normal" animals in their natural environments. These behaviours may be maladaptive, involving self-injury or reduced reproductive success, and in laboratory animals can confound behavioural research. Stereotypical behaviours are thought to be caused ultimately by artificial environments that do not allow animals to satisfy their normal behavioural needs. Rather than refer to the behaviour as abnormal, it has been suggested that it be described as "behaviour indicative of an abnormal environment".
A knockout mouse, or knock-out mouse, is a genetically modified mouse in which researchers have inactivated, or "knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are important animal models for studying the role of genes which have been sequenced but whose functions have not been determined. By causing a specific gene to be inactive in the mouse, and observing any differences from normal behaviour or physiology, researchers can infer its probable function.
Research into the mental disorder of schizophrenia, involves multiple animal models as a tool, including in the preclinical stage of drug development.
The hole-board test (HBT) is an experimental method used in scientific research to measure anxiety, stress, neophilia and emotionality in animals. Because of its ability to measure multiple behaviors it is a popular test in behavioral pharmacology, but the results are controversial.
Marble burying is an animal model used in scientific research to depict anxiety or obsessive–compulsive disorder (OCD) behavior. It is based on the observation that rats and mice will bury either harmful or harmless objects in their bedding. While widely used there is significant controversy over the interpretation of its results.
The light-dark box test (LDB) is a popular animal model used in pharmacology to assay unconditioned anxiety responses in rodents. The extent to which behavior in the LDB measures anxiety is controversial.
