Conditioning, Operant: Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced.Conditioning, Classical: Learning that takes place when a conditioned stimulus is paired with an unconditioned stimulus.Conditioning (Psychology): A general term referring to the learning of some particular response.Conditioning, Eyelid: Reflex closure of the eyelid occurring as a result of classical conditioning.Transplantation Conditioning: Preparative treatment of transplant recipient with various conditioning regimens including radiation, immune sera, chemotherapy, and/or immunosuppressive agents, prior to transplantation. Transplantation conditioning is very common before bone marrow transplantation.Fear: The affective response to an actual current external danger which subsides with the elimination of the threatening condition.Reinforcement (Psychology): The strengthening of a conditioned response.Extinction, Psychological: The procedure of presenting the conditioned stimulus without REINFORCEMENT to an organism previously conditioned. It refers also to the diminution of a conditioned response resulting from this procedure.Association Learning: The principle that items experienced together enter into a connection, so that one tends to reinstate the other.Behavior, Animal: The observable response an animal makes to any situation.Reinforcement Schedule: A schedule prescribing when the subject is to be reinforced or rewarded in terms of temporal interval in psychological experiments. The schedule may be continuous or intermittent.Electroshock: Induction of a stress reaction in experimental subjects by means of an electrical shock; applies to either convulsive or non-convulsive states.Appetitive Behavior: Animal searching behavior. The variable introductory phase of an instinctive behavior pattern or sequence, e.g., looking for food, or sequential courtship patterns prior to mating.Self Administration: Administration of a drug or chemical by the individual under the direction of a physician. It includes administration clinically or experimentally, by human or animal.Blinking: Brief closing of the eyelids by involuntary normal periodic closing, as a protective measure, or by voluntary action.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.Avoidance Learning: A response to a cue that is instrumental in avoiding a noxious experience.Freezing Reaction, Cataleptic: An induced response to threatening stimuli characterized by the cessation of body movements, except for those that are involved with BREATHING, and the maintenance of an immobile POSTURE.Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Amygdala: Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.Discrimination Learning: Learning that is manifested in the ability to respond differentially to various stimuli.Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.Reward: An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.Air Conditioning: The maintenance of certain aspects of the environment within a defined space to facilitate the function of that space; aspects controlled include air temperature and motion, radiant heat level, moisture, and concentration of pollutants such as dust, microorganisms, and gases. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Busulfan: An alkylating agent having a selective immunosuppressive effect on BONE MARROW. It has been used in the palliative treatment of chronic myeloid leukemia (MYELOID LEUKEMIA, CHRONIC), but although symptomatic relief is provided, no permanent remission is brought about. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), busulfan is listed as a known carcinogen.Transplantation, Homologous: Transplantation between individuals of the same species. Usually refers to genetically disparate individuals in contradistinction to isogeneic transplantation for genetically identical individuals.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Psychology, Experimental: The branch of psychology which seeks to learn more about the fundamental causes of behavior by studying various psychologic phenomena in controlled experimental situations.Consummatory Behavior: An act which constitutes the termination of a given instinctive behavior pattern or sequence.Hematopoietic Stem Cell Transplantation: Transfer of HEMATOPOIETIC STEM CELLS from BONE MARROW or BLOOD between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). Hematopoietic stem cell transplantation has been used as an alternative to BONE MARROW TRANSPLANTATION in the treatment of a variety of neoplasms.Aplysia: An opisthobranch mollusk of the order Anaspidea. It is used frequently in studies of nervous system development because of its large identifiable neurons. Aplysiatoxin and its derivatives are not biosynthesized by Aplysia, but acquired by ingestion of Lyngbya (seaweed) species.Galvanic Skin Response: A change in electrical resistance of the skin, occurring in emotion and in certain other conditions.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Columbidae: Family in the order COLUMBIFORMES, comprised of pigeons or doves. They are BIRDS with short legs, stout bodies, small heads, and slender bills. Some sources call the smaller species doves and the larger pigeons, but the names are interchangeable.Lymnaea: A genus of dextrally coiled freshwater snails that includes some species of importance as intermediate hosts of parasitic flukes.Ethanol: A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.Vidarabine: A nucleoside antibiotic isolated from Streptomyces antibioticus. It has some antineoplastic properties and has broad spectrum activity against DNA viruses in cell cultures and significant antiviral activity against infections caused by a variety of viruses such as the herpes viruses, the VACCINIA VIRUS and varicella zoster virus.Motivation: Those factors which cause an organism to behave or act in either a goal-seeking or satisfying manner. They may be influenced by physiological drives or by external stimuli.Myeloablative Agonists: Agents that destroy bone marrow activity. They are used to prepare patients for BONE MARROW TRANSPLANTATION or STEM CELL TRANSPLANTATION.Whole-Body Irradiation: Irradiation of the whole body with ionizing or non-ionizing radiation. It is applicable to humans or animals but not to microorganisms.Graft vs Host Disease: The clinical entity characterized by anorexia, diarrhea, loss of hair, leukopenia, thrombocytopenia, growth retardation, and eventual death brought about by the GRAFT VS HOST REACTION.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Central Nervous System Depressants: A very loosely defined group of drugs that tend to reduce the activity of the central nervous system. The major groups included here are ethyl alcohol, anesthetics, hypnotics and sedatives, narcotics, and tranquilizing agents (antipsychotics and antianxiety agents).Smell: The ability to detect scents or odors, such as the function of OLFACTORY RECEPTOR NEURONS.Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Odors: The volatile portions of substances perceptible by the sense of smell. (Grant & Hackh's Chemical Dictionary, 5th ed)H-Reflex: A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.Reaction Time: The time from the onset of a stimulus until a response is observed.Cocaine: An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Rats, Hairless: Mutant strains of rats that produce little or no hair. Several different homozygous recessive mutations can cause hairlessness in rats including rnu/rnu (Rowett nude), fz/fz (fuzzy), shn/shn (shorn), and nznu/nznu (New Zealand nude). Note that while NUDE RATS are often hairless, they are most characteristically athymic.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Sucrose: A nonreducing disaccharide composed of GLUCOSE and FRUCTOSE linked via their anomeric carbons. It is obtained commercially from SUGARCANE, sugar beet (BETA VULGARIS), and other plants and used extensively as a food and a sweetener.Transplantation Chimera: An organism that, as a result of transplantation of donor tissue or cells, consists of two or more cell lines descended from at least two zygotes. This state may result in the induction of donor-specific TRANSPLANTATION TOLERANCE.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Choice Behavior: The act of making a selection among two or more alternatives, usually after a period of deliberation.Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Bone Marrow Transplantation: The transference of BONE MARROW from one human or animal to another for a variety of purposes including HEMATOPOIETIC STEM CELL TRANSPLANTATION or MESENCHYMAL STEM CELL TRANSPLANTATION.Habituation, Psychophysiologic: The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.Discrimination (Psychology): Differential response to different stimuli.Startle Reaction: A complex involuntary response to an unexpected strong stimulus usually auditory in nature.Memory, Long-Term: Remembrance of information from 3 or more years previously.Nucleus Accumbens: Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA.Hematologic Neoplasms: Neoplasms located in the blood and blood-forming tissue (the bone marrow and lymphatic tissue). The commonest forms are the various types of LEUKEMIA, of LYMPHOMA, and of the progressive, life-threatening forms of the MYELODYSPLASTIC SYNDROMES.Taste: The ability to detect chemicals through gustatory receptors in the mouth, including those on the TONGUE; the PALATE; the PHARYNX; and the EPIGLOTTIS.Facial Pain: Pain in the facial region including orofacial pain and craniofacial pain. Associated conditions include local inflammatory and neoplastic disorders and neuralgic syndromes involving the trigeminal, facial, and glossopharyngeal nerves. Conditions which feature recurrent or persistent facial pain as the primary manifestation of disease are referred to as FACIAL PAIN SYNDROMES.Ganglia, Invertebrate: Clusters of neuronal cell bodies in invertebrates. Invertebrate ganglia may also contain neuronal processes and non-neuronal supporting cells. Many invertebrate ganglia are favorable subjects for research because they have small numbers of functional neuronal types which can be identified from one animal to another.Food Preferences: The selection of one food over another.Sweetening Agents: Substances that sweeten food, beverages, medications, etc., such as sugar, saccharine or other low-calorie synthetic products. (From Random House Unabridged Dictionary, 2d ed)Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Generalization (Psychology): The phenomenon of an organism's responding to all situations similar to one in which it has been conditioned.Nictitating Membrane: A fold of the mucous membrane of the CONJUNCTIVA in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the CORNEA.Mice, Inbred C57BLSaccharin: Flavoring agent and non-nutritive sweetener.Exploratory Behavior: The tendency to explore or investigate a novel environment. It is considered a motivation not clearly distinguishable from curiosity.Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Drinking Behavior: Behaviors associated with the ingesting of water and other liquids; includes rhythmic patterns of drinking (time intervals - onset and duration), frequency and satiety.Generalization, Stimulus: The tendency to react to stimuli that are different from, but somewhat similar to, the stimulus used as a conditioned stimulus.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Methylergonovine: A homolog of ERGONOVINE containing one more CH2 group. (Merck Index, 11th ed)Alcohol-Induced Disorders, Nervous System: Acute and chronic neurologic disorders associated with the various neurologic effects of ETHANOL. Primary sites of injury include the brain and peripheral nerves.Food: Any substances taken in by the body that provide nourishment.Substance Withdrawal Syndrome: Physiological and psychological symptoms associated with withdrawal from the use of a drug after prolonged administration or habituation. The concept includes withdrawal from smoking or drinking, as well as withdrawal from an administered drug.Retention (Psychology): The persistence to perform a learned behavior (facts or experiences) after an interval has elapsed in which there has been no performance or practice of the behavior.Behavior, Addictive: The observable, measurable, and often pathological activity of an organism that portrays its inability to overcome a habit resulting in an insatiable craving for a substance or for performing certain acts. The addictive behavior includes the emotional and physical overdependence on the object of habit in increasing amount or frequency.Maze Learning: Learning the correct route through a maze to obtain reinforcement. It is used for human or animal populations. (Thesaurus of Psychological Index Terms, 6th ed)Antilymphocyte Serum: Serum containing GAMMA-GLOBULINS which are antibodies for lymphocyte ANTIGENS. It is used both as a test for HISTOCOMPATIBILITY and therapeutically in TRANSPLANTATION.Cerebellar Nuclei: Four clusters of neurons located deep within the WHITE MATTER of the CEREBELLUM, which are the nucleus dentatus, nucleus emboliformis, nucleus globosus, and nucleus fastigii.Cerebellum: The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Nicotine: Nicotine is highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke.Ethology: The discipline pertaining to the study of animal behavior.Transfer (Psychology): Change in learning in one situation due to prior learning in another situation. The transfer can be positive (with second learning improved by first) or negative (where the reverse holds).Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Graft Survival: The survival of a graft in a host, the factors responsible for the survival and the changes occurring within the graft during growth in the host.Colinus: A genus of QUAIL, in the family Odontophoridae, comprised of at least four different species of bobwhites.Muscimol: A neurotoxic isoxazole isolated from species of AMANITA. It is obtained by decarboxylation of IBOTENIC ACID. Muscimol is a potent agonist of GABA-A RECEPTORS and is used mainly as an experimental tool in animal and tissue studies.Prefrontal Cortex: The rostral part of the frontal lobe, bounded by the inferior precentral fissure in humans, which receives projection fibers from the MEDIODORSAL NUCLEUS OF THE THALAMUS. The prefrontal cortex receives afferent fibers from numerous structures of the DIENCEPHALON; MESENCEPHALON; and LIMBIC SYSTEM as well as cortical afferents of visual, auditory, and somatic origin.Dopamine Uptake Inhibitors: Drugs that block the transport of DOPAMINE into axon terminals or into storage vesicles within terminals. Most of the ADRENERGIC UPTAKE INHIBITORS also inhibit dopamine uptake.Escape Reaction: Innate response elicited by sensory stimuli associated with a threatening situation, or actual confrontation with an enemy.Spatial Behavior: Reactions of an individual or groups of individuals with relation to the immediate surrounding area including the animate or inanimate objects within that area.Dopamine: One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.Motor Neurons: Neurons which activate MUSCLE CELLS.Melphalan: An alkylating nitrogen mustard that is used as an antineoplastic in the form of the levo isomer - MELPHALAN, the racemic mixture - MERPHALAN, and the dextro isomer - MEDPHALAN; toxic to bone marrow, but little vesicant action; potential carcinogen.Psychological Theory: Principles applied to the analysis and explanation of psychological or behavioral phenomena.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Nicotinic Agonists: Drugs that bind to and activate nicotinic cholinergic receptors (RECEPTORS, NICOTINIC). Nicotinic agonists act at postganglionic nicotinic receptors, at neuroeffector junctions in the peripheral nervous system, and at nicotinic receptors in the central nervous system. Agents that function as neuromuscular depolarizing blocking agents are included here because they activate nicotinic receptors, although they are used clinically to block nicotinic transmission.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Microinjections: The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.Hermissenda: A genus of marine sea slugs in the family Glaucidae, superorder GASTROPODA, found on the Pacific coast of North America. They are used in behavioral and neurological laboratory studies.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Transplantation, Autologous: Transplantation of an individual's own tissue from one site to another site.Food Deprivation: The withholding of food in a structured experimental situation.Trigeminal Nerve Injuries: Traumatic injuries to the TRIGEMINAL NERVE. It may result in extreme pain, abnormal sensation in the areas the nerve innervates on face, jaw, gums and tongue and can cause difficulties with speech and chewing. It is sometimes associated with various dental treatments.GABA Agonists: Endogenous compounds and drugs that bind to and activate GAMMA-AMINOBUTYRIC ACID receptors (RECEPTORS, GABA).Cycloserine: Antibiotic substance produced by Streptomyces garyphalus.Flupenthixol: A thioxanthene neuroleptic that, unlike CHLORPROMAZINE, is claimed to have CNS-activating properties. It is used in the treatment of psychoses although not in excited or manic patients. (From Martindale, The Extra Pharmacopoeia, 30th ed, p595)Cocaine-Related Disorders: Disorders related or resulting from use of cocaine.Drug-Seeking Behavior: Activities performed to obtain licit or illicit substances.Cyclophosphamide: Precursor of an alkylating nitrogen mustard antineoplastic and immunosuppressive agent that must be activated in the LIVER to form the active aldophosphamide. It has been used in the treatment of LYMPHOMA and LEUKEMIA. Its side effect, ALOPECIA, has been used for defleecing sheep. Cyclophosphamide may also cause sterility, birth defects, mutations, and cancer.Bees: Insect members of the superfamily Apoidea, found almost everywhere, particularly on flowers. About 3500 species occur in North America. They differ from most WASPS in that their young are fed honey and pollen rather than animal food.Mental Recall: The process whereby a representation of past experience is elicited.Long-Term Potentiation: A persistent increase in synaptic efficacy, usually induced by appropriate activation of the same synapses. The phenomenological properties of long-term potentiation suggest that it may be a cellular mechanism of learning and memory.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Mollusca: A phylum of the kingdom Metazoa. Mollusca have soft, unsegmented bodies with an anterior head, a dorsal visceral mass, and a ventral foot. Most are encased in a protective calcareous shell. It includes the classes GASTROPODA; BIVALVIA; CEPHALOPODA; Aplacophora; Scaphopoda; Polyplacophora; and Monoplacophora.Recurrence: The return of a sign, symptom, or disease after a remission.Chimerism: The occurrence in an individual of two or more cell populations of different chromosomal constitutions, derived from different individuals. This contrasts with MOSAICISM in which the different cell populations are derived from a single individual.Aversive Therapy: A treatment that suppresses undesirable behavior by simultaneously exposing the subject to unpleasant consequences.Cheek: The part of the face that is below the eye and to the side of the nose and mouth.Histocompatibility Testing: Identification of the major histocompatibility antigens of transplant DONORS and potential recipients, usually by serological tests. Donor and recipient pairs should be of identical ABO blood group, and in addition should be matched as closely as possible for HISTOCOMPATIBILITY ANTIGENS in order to minimize the likelihood of allograft rejection. (King, Dictionary of Genetics, 4th ed)Peripheral Blood Stem Cell Transplantation: Transplantation of stem cells collected from the peripheral blood. It is a less invasive alternative to direct marrow harvesting of hematopoietic stem cells. Enrichment of stem cells in peripheral blood can be achieved by inducing mobilization of stem cells from the BONE MARROW.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Piperidines: A family of hexahydropyridines.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Evoked Potentials: Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.Ibogaine: One of several indole alkaloids extracted from Tabernanthe iboga, Baill. It has a complex pharmacological profile, and interacts with multiple systems of neurotransmission. Ibogaine has psychoactive properties and appears to modulate tolerance to opiates.Self Stimulation: Stimulation of the brain, which is self-administered. The stimulation may result in negative or positive reinforcement.Narcotic Antagonists: Agents inhibiting the effect of narcotics on the central nervous system.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Immunosuppressive Agents: Agents that suppress immune function by one of several mechanisms of action. Classical cytotoxic immunosuppressants act by inhibiting DNA synthesis. Others may act through activation of T-CELLS or by inhibiting the activation of HELPER CELLS. While immunosuppression has been brought about in the past primarily to prevent rejection of transplanted organs, new applications involving mediation of the effects of INTERLEUKINS and other CYTOKINES are emerging.Tissue Donors: Individuals supplying living tissue, organs, cells, blood or blood components for transfer or transplantation to histocompatible recipients.Behaviorism: A psychologic theory, developed by John Broadus Watson, concerned with studying and measuring behaviors that are observable.TurtlesHistocompatibility: The degree of antigenic similarity between the tissues of different individuals, which determines the acceptance or rejection of allografts.Physical Conditioning, Animal: Diet modification and physical exercise to improve the ability of animals to perform physical activities.Models, Animal: Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.Drinking: The consumption of liquids.Compulsive Behavior: The behavior of performing an act persistently and repetitively without it leading to reward or pleasure. The act is usually a small, circumscribed behavior, almost ritualistic, yet not pathologically disturbing. Examples of compulsive behavior include twirling of hair, checking something constantly, not wanting pennies in change, straightening tilted pictures, etc.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.Central Nervous System Stimulants: A loosely defined group of drugs that tend to increase behavioral alertness, agitation, or excitation. They work by a variety of mechanisms, but usually not by direct excitation of neurons. The many drugs that have such actions as side effects to their main therapeutic use are not included here.Laboratory Animal Science: The science and technology dealing with the procurement, breeding, care, health, and selection of animals used in biomedical research and testing.Receptors, N-Methyl-D-Aspartate: A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.Tongue Habits: Acquired responses regularly manifested by tongue movement or positioning.Thermosensing: The sensation of cold, heat, coolness, and warmth as detected by THERMORECEPTORS.Cord Blood Stem Cell Transplantation: Transplantation of STEM CELLS collected from the fetal blood remaining in the UMBILICAL CORD and the PLACENTA after delivery. Included are the HEMATOPOIETIC STEM CELLS.Memory, Short-Term: Remembrance of information for a few seconds to hours.Auditory Perception: The process whereby auditory stimuli are selected, organized, and interpreted by the organism.Punishment: The application of an unpleasant stimulus or penalty for the purpose of eliminating or correcting undesirable behavior.Appetite: Natural recurring desire for food. Alterations may be induced by APPETITE DEPRESSANTS or APPETITE STIMULANTS.Behavior Therapy: The application of modern theories of learning and conditioning in the treatment of behavior disorders.Neck Muscles: The neck muscles consist of the platysma, splenius cervicis, sternocleidomastoid(eus), longus colli, the anterior, medius, and posterior scalenes, digastric(us), stylohyoid(eus), mylohyoid(eus), geniohyoid(eus), sternohyoid(eus), omohyoid(eus), sternothyroid(eus), and thyrohyoid(eus).Alcohol Drinking: Behaviors associated with the ingesting of alcoholic beverages, including social drinking.Excitatory Amino Acid Antagonists: Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.Stereotyped Behavior: Relatively invariant mode of behavior elicited or determined by a particular situation; may be verbal, postural, or expressive.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Chlordiazepoxide: An anxiolytic benzodiazepine derivative with anticonvulsant, sedative, and amnesic properties. It has also been used in the symptomatic treatment of alcohol withdrawal.Token Economy: A practice whereby tokens representing money, toys, candy, etc., are given as secondary reinforcers contingent upon certain desired behaviors or performances.Synapses: Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.Naltrexone: Derivative of noroxymorphone that is the N-cyclopropylmethyl congener of NALOXONE. It is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. The FDA has approved naltrexone for the treatment of alcohol dependence.Narcotics: Agents that induce NARCOSIS. Narcotics include agents that cause somnolence or induced sleep (STUPOR); natural or synthetic derivatives of OPIUM or MORPHINE or any substance that has such effects. They are potent inducers of ANALGESIA and OPIOID-RELATED DISORDERS.Helplessness, Learned: Learned expectation that one's responses are independent of reward and, hence, do not predict or control the occurrence of rewards. Learned helplessness derives from a history, experimentally induced or naturally occurring, of having received punishment/aversive stimulation regardless of responses made. Such circumstances result in an impaired ability to learn. Used for human or animal populations. (APA, Thesaurus of Psychological Index Terms, 1994)Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Amnesia, Retrograde: Loss of the ability to recall information that had been previously encoded in memory prior to a specified or approximate point in time. This process may be organic or psychogenic in origin. Organic forms may be associated with CRANIOCEREBRAL TRAUMA; CEREBROVASCULAR ACCIDENTS; SEIZURES; DEMENTIA; and a wide variety of other conditions that impair cerebral function. (From Adams et al., Principles of Neurology, 6th ed, pp426-9)Models, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Neurobiology: The study of the structure, growth, activities, and functions of NEURONS and the NERVOUS SYSTEM.Microdialysis: A technique for measuring extracellular concentrations of substances in tissues, usually in vivo, by means of a small probe equipped with a semipermeable membrane. Substances may also be introduced into the extracellular space through the membrane.Dextroamphetamine: The d-form of AMPHETAMINE. It is a central nervous system stimulant and a sympathomimetic. It has also been used in the treatment of narcolepsy and of attention deficit disorders and hyperactivity in children. Dextroamphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulating release of monamines, and inhibiting monoamine oxidase. It is also a drug of abuse and a psychotomimetic.Reversal Learning: Any situation where an animal or human is trained to respond differentially to two stimuli (e.g., approach and avoidance) under reward and punishment conditions and subsequently trained under reversed reward values (i.e., the approach which was previously rewarded is punished and vice versa).Graft vs Tumor Effect: Immunological rejection of tumor tissue/cells following bone marrow transplantation.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Inhibition (Psychology): The interference with or prevention of a behavioral or verbal response even though the stimulus for that response is present; in psychoanalysis the unconscious restraining of an instinctual process.Mouth: The oval-shaped oral cavity located at the apex of the digestive tract and consisting of two parts: the vestibule and the oral cavity proper.Animals, Newborn: Refers to animals in the period of time just after birth.Head: The upper part of the human body, or the front or upper part of the body of an animal, typically separated from the rest of the body by a neck, and containing the brain, mouth, and sense organs.Stem Cell Transplantation: The transfer of STEM CELLS from one individual to another within the same species (TRANSPLANTATION, HOMOLOGOUS) or between species (XENOTRANSPLANTATION), or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). The source and location of the stem cells determines their potency or pluripotency to differentiate into various cell types.Models, Psychological: Theoretical representations that simulate psychological processes and/or social processes. These include the use of mathematical equations, computers, and other electronic equipment.Pain Threshold: Amount of stimulation required before the sensation of pain is experienced.Pons: The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.Methamphetamine: A central nervous system stimulant and sympathomimetic with actions and uses similar to DEXTROAMPHETAMINE. The smokable form is a drug of abuse and is referred to as crank, crystal, crystal meth, ice, and speed.BenzoxazolesAnemia, Aplastic: A form of anemia in which the bone marrow fails to produce adequate numbers of peripheral blood elements.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Scopolamine Hydrobromide: An alkaloid from SOLANACEAE, especially DATURA and SCOPOLIA. Scopolamine and its quaternary derivatives act as antimuscarinics like ATROPINE, but may have more central nervous system effects. Among the many uses are as an anesthetic premedication, in URINARY INCONTINENCE, in MOTION SICKNESS, as an antispasmodic, and as a mydriatic and cycloplegic.Cerebellar Cortex: The superficial GRAY MATTER of the CEREBELLUM. It consists of two main layers, the stratum moleculare and the stratum granulosum.Environment: The external elements and conditions which surround, influence, and affect the life and development of an organism or population.Alcohol Deterrents: Substances interfering with the metabolism of ethyl alcohol, causing unpleasant side effects thought to discourage the drinking of alcoholic beverages. Alcohol deterrents are used in the treatment of alcoholism.