Reward: An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.Choice Behavior: The act of making a selection among two or more alternatives, usually after a period of deliberation.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.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.Anticipation, Psychological: The ability to foresee what is likely to happen on the basis of past experience. It is largely a frontal lobe function.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.Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.Behavior, Animal: The observable response an animal makes to any situation.Reinforcement (Psychology): The strengthening of a conditioned response.Self Stimulation: Stimulation of the brain, which is self-administered. The stimulation may result in negative or positive reinforcement.Punishment: The application of an unpleasant stimulus or penalty for the purpose of eliminating or correcting undesirable behavior.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.Impulsive Behavior: An act performed without delay, reflection, voluntary direction or obvious control in response to a stimulus.Reaction Time: The time from the onset of a stimulus until a response is observed.Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Decision Making: The process of making a selective intellectual judgment when presented with several complex alternatives consisting of several variables, and usually defining a course of action or an idea.Probability Learning: Usually refers to the use of mathematical models in the prediction of learning to perform tasks based on the theory of probability applied to responses; it may also refer to the frequency of occurrence of the responses observed in the particular study.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Basal Ganglia: Large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.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.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.Conditioning (Psychology): A general term referring to the learning of some particular response.Ventral Tegmental Area: A region in the MESENCEPHALON which is dorsomedial to the SUBSTANTIA NIGRA and ventral to the RED NUCLEUS. The mesocortical and mesolimbic dopaminergic systems originate here, including an important projection to the NUCLEUS ACCUMBENS. Overactivity of the cells in this area has been suspected to contribute to the positive symptoms of SCHIZOPHRENIA.Feedback, Psychological: A mechanism of information stimulus and response that may control subsequent behavior, cognition, perception, or performance. (From APA Thesaurus of Psychological Index Terms, 8th ed.)Conditioning, Classical: Learning that takes place when a conditioned stimulus is paired with an unconditioned stimulus.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.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.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.Drive: A state of internal activity of an organism that is a necessary condition before a given stimulus will elicit a class of responses; e.g., a certain level of hunger (drive) must be present before food will elicit an eating response.Association Learning: The principle that items experienced together enter into a connection, so that one tends to reinstate the other.Gambling: An activity distinguished primarily by an element of risk in trying to obtain a desired goal, e.g., playing a game of chance for money.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.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.Food Preferences: The selection of one food over another.Corpus Striatum: Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.Games, Experimental: Games designed to provide information on hypotheses, policies, procedures, or strategies.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.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.Anhedonia: Inability to experience pleasure due to impairment or dysfunction of normal psychological and neurobiological mechanisms. It is a symptom of many PSYCHOTIC DISORDERS (e.g., DEPRESSIVE DISORDER, MAJOR; and SCHIZOPHRENIA).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.Limbic System: A set of forebrain structures common to all mammals that is defined functionally and anatomically. It is implicated in the higher integration of visceral, olfactory, and somatic information as well as homeostatic responses including fundamental survival behaviors (feeding, mating, emotion). For most authors, it includes the AMYGDALA; EPITHALAMUS; GYRUS CINGULI; hippocampal formation (see HIPPOCAMPUS); HYPOTHALAMUS; PARAHIPPOCAMPAL GYRUS; SEPTAL NUCLEI; anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, (September 2, 1998)).Economics, Behavioral: The combined discipline of psychology and economics that investigates what happens in markets in which some of the agents display human limitations and complications.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.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.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.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.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Gyrus Cinguli: One of the convolutions on the medial surface of the CEREBRAL HEMISPHERES. It surrounds the rostral part of the brain and CORPUS CALLOSUM and forms part of the LIMBIC SYSTEM.Macaca mulatta: A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.Pleasure: Sensation of enjoyment or gratification.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.Caudate Nucleus: Elongated gray mass of the neostriatum located adjacent to the lateral ventricle of the brain.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.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.Mesencephalon: The middle of the three primitive cerebral vesicles of the embryonic brain. Without further subdivision, midbrain develops into a short, constricted portion connecting the PONS and the DIENCEPHALON. Midbrain contains two major parts, the dorsal TECTUM MESENCEPHALI and the ventral TEGMENTUM MESENCEPHALI, housing components of auditory, visual, and other sensorimoter systems.Frontal Lobe: The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus.Goals: The end-result or objective, which may be specified or required in advance.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)Plant Nectar: Sugar-rich liquid produced in plant glands called nectaries. It is either produced in flowers or other plant structures, providing a source of attraction for pollinating insects and animals, as well as being a nutrient source to animal mutualists which provide protection of plants against herbivores.Food: Any substances taken in by the body that provide nourishment.Models, Psychological: Theoretical representations that simulate psychological processes and/or social processes. These include the use of mathematical equations, computers, and other electronic equipment.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Task Performance and Analysis: The detailed examination of observable activity or behavior associated with the execution or completion of a required function or unit of work.Functional Neuroimaging: Methods for visualizing REGIONAL BLOOD FLOW, metabolic, electrical, or other physiological activities in the CENTRAL NERVOUS SYSTEM using various imaging modalities.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Dopamine Antagonists: Drugs that bind to but do not activate DOPAMINE RECEPTORS, thereby blocking the actions of dopamine or exogenous agonists. Many drugs used in the treatment of psychotic disorders (ANTIPSYCHOTIC AGENTS) are dopamine antagonists, although their therapeutic effects may be due to long-term adjustments of the brain rather than to the acute effects of blocking dopamine receptors. Dopamine antagonists have been used for several other clinical purposes including as ANTIEMETICS, in the treatment of Tourette syndrome, and for hiccup. Dopamine receptor blockade is associated with NEUROLEPTIC MALIGNANT SYNDROME.Discrimination (Psychology): Differential response to different stimuli.Cocaine-Related Disorders: Disorders related or resulting from use of cocaine.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.Neostriatum: The phylogenetically newer part of the CORPUS STRIATUM consisting of the CAUDATE NUCLEUS and PUTAMEN. It is often called simply the striatum.Dopaminergic Neurons: Neurons whose primary neurotransmitter is DOPAMINE.Receptors, Dopamine D2: A subfamily of G-PROTEIN-COUPLED RECEPTORS that bind the neurotransmitter DOPAMINE and modulate its effects. D2-class receptor genes contain INTRONS, and the receptors inhibit ADENYLYL CYCLASES.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.Behavior: The observable response of a man or animal to a situation.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.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).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)Medial Forebrain Bundle: A complex group of fibers arising from the basal olfactory regions, the periamygdaloid region, and the septal nuclei, and passing to the lateral hypothalamus. Some fibers continue into the tegmentum.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.Amphetamine: A powerful central nervous system stimulant and sympathomimetic. Amphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulation of release of monamines, and inhibiting monoamine oxidase. Amphetamine is also a drug of abuse and a psychotomimetic. The l- and the d,l-forms are included here. The l-form has less central nervous system activity but stronger cardiovascular effects. The d-form is DEXTROAMPHETAMINE.Saccharin: Flavoring agent and non-nutritive sweetener.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.

Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits. (1/3403)

Association between Y chromosome haplotype variation and alcohol dependence and related personality traits was investigated in a large sample of psychiatrically diagnosed Finnish males. Haplotypes were constructed for 359 individuals using alleles at eight loci (seven microsatellite loci and a nucleotide substitution in the DYZ3 alphoid satellite locus). A cladogram linking the 102 observed haplotype configurations was constructed by using parsimony with a single-step mutation model. Then, a series of contingency tables nested according to the cladogram hierarchy were used to test for association between Y haplotype and alcohol dependence. Finally, using only alcohol-dependent subjects, we tested for association between Y haplotype and personality variables postulated to define subtypes of alcoholism-antisocial personality disorder, novelty seeking, harm avoidance, and reward dependence. Significant association with alcohol dependence was observed at three Y haplotype clades, with significance levels of P = 0.002, P = 0.020, and P = 0.010. Within alcohol-dependent subjects, no relationship was revealed between Y haplotype and antisocial personality disorder, novelty seeking, harm avoidance, or reward dependence. These results demonstrate, by using a fully objective association design, that differences among Y chromosomes contribute to variation in vulnerability to alcohol dependence. However, they do not demonstrate an association between Y haplotype and the personality variables thought to underlie the subtypes of alcoholism.  (+info)

An analysis of choice making in the assessment of young children with severe behavior problems. (2/3403)

We examined how positive and negative reinforcement influenced time allocation, occurrence of problem behavior, and completion of parent instructions during a concurrent choice assessment with 2 preschool-aged children who displayed severe problem behavior in their homes. The children were given a series of concurrent choice options that varied availability of parent attention, access to preferred toys, and presentation of parent instructions. The results showed that both children consistently allocated their time to choice areas that included parent attention when no instructions were presented. When parent attention choice areas included the presentation of instructions, the children displayed differential patterns of behavior that appeared to be influenced by the presence or absence of preferred toys. The results extended previous applications of reinforcer assessment procedures by analyzing the relative influence of both positive and negative reinforcement within a concurrent-operants paradigm.  (+info)

Delay or probability discounting in a model of impulsive behavior: effect of alcohol. (3/3403)

Little is known about the acute effects of drugs of abuse on impulsivity and self-control. In this study, impulsivity was assessed in humans using a computer task that measured delay and probability discounting. Discounting describes how much the value of a reward (or punisher) is decreased when its occurrence is either delayed or uncertain. Twenty-four healthy adult volunteers ingested a moderate dose of ethanol (0.5 or 0.8 g/kg ethanol: n = 12 at each dose) or placebo before completing the discounting task. In the task the participants were given a series of choices between a small, immediate, certain amount of money and $10 that was either delayed (0, 2, 30, 180, or 365 days) or probabilistic (i.e., certainty of receipt was 1.0, .9, .75, .5, or .25). The point at which each individual was indifferent between the smaller immediate or certain reward and the $10 delayed or probabilistic reward was identified using an adjusting-amount procedure. The results indicated that (a) delay and probability discounting were well described by a hyperbolic function; (b) delay and probability discounting were positively correlated within subjects; (c) delay and probability discounting were moderately correlated with personality measures of impulsivity; and (d) alcohol had no effect on discounting.  (+info)

Sodium depletion and aldosterone decrease dopamine transporter activity in nucleus accumbens but not striatum. (4/3403)

Motivated behaviors, including sodium (Na) appetite, are correlated with increased dopamine (DA) transmission in the nucleus accumbens (NAc). DA transporter (DAT) modulation affects DA transmission and may play a role in motivated behaviors. In vivo Na depletion, which reliably induces Na appetite, was correlated with robust decreases in DA uptake via the DAT in the rat NAc with rotating disk electrode voltammetry [1,277 +/- 162 vs. 575 +/- 89 pmol. s-1. g-1; Vmax of transport for control vs. Na-depleted tissue]. Plasma aldosterone (Aldo) levels increase after in vivo Na depletion and contribute to Na appetite. Decreased DAT activity in the NAc was observed after in vitro Aldo treatment (428 +/- 28 vs. 300 +/- 25 pmol. s-1. g-1). Neither treatment affected DAT activity in the striatum. These results suggest that a direct action of Aldo is one possible mechanism by which Na depletion induces a reduction in DAT activity in the NAc. Reduced DAT activity may play a role in generating increased NAc DA transmission during Na appetite, which may underlie the motivating properties of Na for the Na-depleted rat.  (+info)

Dopamine fluctuations in the nucleus accumbens during maintenance, extinction, and reinstatement of intravenous D-amphetamine self-administration. (5/3403)

Moment-to-moment fluctuations of nucleus accumbens dopamine (DA) were determined in rats self-administering or passively receiving "yoked" intravenous infusions of D-amphetamine. The initial lever presses of each session caused elevations in DA concentration, usually to an initial peak that was not maintained throughout the rest of the session. As the initial ("loading") injections were metabolized, DA levels dropped toward baseline but were sustained at elevated plateaus by subsequent lever pressing that was spaced throughout the remainder of the 3 hr sessions. During this period, DA levels fluctuated phasically, time-locked to the cycle of periodic lever pressing. Consistent with the known pharmacological actions and dynamics of amphetamine, peak DA elevations were seen approximately 10-15 min after each injection, and the mean DA level was at a low point in the phasic cycle at the time of each new lever press. During extinction periods when saline was substituted for amphetamine, DA levels dropped steadily toward baseline levels despite a dramatic increase in (now-unrewarded) lever pressing. Noncontingent injections during extinction reinstated lever-pressing behavior and increased nucleus accumbens DA concentrations. These data are consistent with the hypothesis that under the conditions of this experiment-during periods of amphetamine intoxication in well-trained animals-the timing of amphetamine self-administration comes primarily under the control of extracellular DA concentrations. The probability of lever pressing during the maintenance phase is highest when DA concentrations fall near a characteristic trigger point, a trigger point that is significantly elevated above baseline, and falls as DA concentrations fall below or increase above that trigger point.  (+info)

Enhancement of locomotor activity and conditioned reward to cocaine by brain-derived neurotrophic factor. (6/3403)

The mesolimbic dopamine (DA) system has been implicated in drug reward, locomotor sensitization, and responding for reward-related stimuli [termed conditioned reinforcers (CR)]. Here, we investigated the effect of brain-derived neurotrophic factor (BDNF), which enhances the survival and function of dopaminergic neurons, on stimulant-induced locomotor sensitization and responding for CR. In experiment 1, BDNF was infused into the nucleus accumbens (NAc) or ventral tegmental area over 2 weeks via chronically implanted minipumps (1-2.5 microgram/d), and the psychomotor stimulant effects of cocaine (5-15 mg/kg, i.p.) were studied. We found that BDNF enhanced the initial stimulant effects of cocaine and seemed to facilitate the development of sensitization to repeated cocaine doses. In experiment 2, we studied the effects of intra-NAc BDNF infusions on responding for CR. BDNF-treated rats showed twice as many CR responses compared with controls when saline was first administered. BDNF enhanced responding on the CR lever more than four times that seen in control animals after a cocaine injection (10 mg/kg, i.p.). The enhanced response to cocaine in BDNF-treated animals persisted for more than a month after the BDNF infusions had stopped, indicating long-lasting changes in the mesolimbic DA system caused by BDNF administration. In experiment 3, we examined locomotor sensitization to cocaine in heterozygous BDNF knock-out mice and found that the development of sensitization was delayed compared with wild-type littermates. These results demonstrate the profound effects of BDNF on the enhancement of both cocaine-induced locomotion and facilitation of CR and suggest a possible role for BDNF in long-term adaptations of the brain to cocaine.  (+info)

High effort, low reward, and cardiovascular risk factors in employed Swedish men and women: baseline results from the WOLF Study. (7/3403)

STUDY OBJECTIVE: To examine associations between measures of work stress (that is, the combination of high effort and low reward) and cardiovascular risk factors. DESIGN: Cross sectional first screening of a prospective cohort study. SETTING AND PARTICIPANTS: The study was conducted among 5720 healthy employed men and women living in the greater Stockholm area aged 19-70 years. All analyses were restricted to subjects with complete data (n = 4958). The investigation of associations between indicators of effort-reward imbalance and cardiovascular risk factors was restricted to the age group 30-55 years (n = 3427). MAIN RESULTS: Subjects reporting high effort and low reward at work had a higher prevalence of well known risk factors for coronary heart disease. After adjustment for relevant confounders, associations between a measure of extrinsic effort and reward (the effort-reward ratio) and hypertension (multivariate prevalence odds ratio (POR) 1.62-1.68), increased total cholesterol (upper tertile 220 mg/dl)(POR = 1.24) and the total cholesterol/high density lipoprotein(HDL)-cholesterol ratio (upper tertile 4.61)(POR 1.26-1.30) were found among men. Among women a measure of high intrinsic effort (immersion) was related to increased low density lipoprotein (LDL)-cholesterol (upper tertile 130 mg/dl)(POR 1.37-1.39). Analyses of variance showed increasing mean values of LDL cholesterol with an increasing degree of the effort-reward ratio among men and increased LDL-cholesterol among women with high levels of intrinsic effort (upper tertile of immersion). CONCLUSIONS: Findings lend support to the hypothesis that effort-reward imbalance represents a specific constellation of stressful experience at work related to cardiovascular risk. The relation was not explained by relevant confounders (for example, lack of physical exercise, body weight, cigarette smoking).  (+info)

Muscimol-induced inactivation of monkey frontal eye field: effects on visually and memory-guided saccades. (8/3403)

Muscimol-induced inactivation of the monkey frontal eye field: effects on visually and memory-guided saccades. Although neurophysiological, anatomic, and imaging evidence suggest that the frontal eye field (FEF) participates in the generation of eye movements, chronic lesions of the FEF in both humans and monkeys appear to cause only minor deficits in visually guided saccade generation. Stronger effects are observed when subjects are tested in tasks with more cognitive requirements. We tested oculomotor function after acutely inactivating regions of the FEF to minimize the effects of plasticity and reallocation of function after the loss of the FEF and gain more insight into the FEF contribution to the guidance of eye movements in the intact brain. Inactivation was induced by microinjecting muscimol directly into physiologically defined sites in the FEF of three monkeys. FEF inactivation severely impaired the monkeys' performance of both visually guided and memory-guided saccades. The monkeys initiated fewer saccades to the retinotopic representation of the inactivated FEF site than to any other location in the visual field. The saccades that were initiated had longer latencies, slower velocities, and larger targeting errors than controls. These effects were present both for visually guided and for memory-guided saccades, although the memory-guided saccades were more disrupted. Initially, the effects were restricted spatially, concentrating around the retinotopic representation at the center of the inactivated site, but, during the course of several hours, these effects spread to flanking representations. Predictability of target location and motivation of the monkey also affected saccadic performance. For memory-guided saccades, increases in the time during which the monkey had to remember the spatial location of a target resulted in further decreases in the accuracy of the saccades and in smaller peak velocities, suggesting a progressive loss of the capacity to maintain a representation of target location in relation to the fovea after FEF inactivation. In addition, the monkeys frequently made premature saccades to targets in the hemifield ipsilateral to the injection site when performing the memory task, indicating a deficit in the control of fixation that could be a consequence of an imbalance between ipsilateral and contralateral FEF activity after the injection. There was also a progressive loss of fixation accuracy, and the monkeys tended to restrict spontaneous visual scanning to the ipsilateral hemifield. These results emphasize the strong role of the FEF in the intact monkey in the generation of all voluntary saccadic eye movements, as well as in the control of fixation.  (+info)

  • Here, we examined neural activation in SZ and HC participants during the anticipatory phase of stimuli that predicted immediate upcoming reward and punishment, and during the feedback/outcome phase, in relation to trait measures of hedonic pleasure and real-world functional capacity. (
  • In their study of 45 subjects, Ahmad Hariri, PhD, and colleagues at the University of Pittsburgh and collaborators at Mount Sinai School of Medicine and the University of Chicago showed that activity in the ventral striatum, a core component of the brain's reward circuitry, correlated with individuals' impulsiveness. (
  • Choice central The striatum is a key structure in the brain involved in representing reward values of actions and picking one. (
  • The model, developed by Frank, Cockburn, and co-author Anne Collins, a postdoctoral researcher, was based on prior research on the function of the striatum, a part of the brain's basal ganglia (BG) that is principally involved in representing reward values of actions and picking one. (
  • When a rewarding choice has been made, the substantia nigra pars compacta (SNc) releases dopamine into the striatum to reinforce connections between cortex and striatum, so that rewarded actions are more likely to be repeated. (
  • TEHRAN (Tasnim) - A brain reward center, the striatum, may be directly affected by inflammation and that striatal change is related to the emergence of illness behaviors, scientists report. (
  • SZ patients showed hypoactivation in ventral striatum during reward anticipation. (
  • HC participants recruited reward-related regions in striatum that significantly correlated with subjective consummatory pleasure, while SZ patients revealed activation in attention-related regions, such as the IPL, which correlated with consummatory pleasure and functional capacity. (
  • Dissociable reward and timing signals in human midbrain and ventral striatum. (
  • By contrast, BOLD activity in ventral striatum (VS) does not reflect a TD RPE, but instead encodes a signal on the variable relevant for behavior, here timing but not magnitude of reward. (
  • Additionally, we found distinct differences between HC and SZ groups in their association between reward-related immediate anticipatory neural activity and their reported experience of pleasure. (
  • To address this question, we recorded neural activity in a prefrontal sensorimotor area while monkeys naturally switched between exploring and exploiting rewarding options. (
  • When the SNr decides that striatal valuation signals are strong enough for one action, it releases the brakes not only on downstream structures that allow actions to be executed, but also on the SNc dopamine system, so any unexpected rewards are amplified. (
  • Reward prediction error (RPE) signals are central to current models of reward-learning. (
  • Temporal difference (TD) learning models posit that these signals should be modulated by predictions, not only of magnitude but also timing of reward. (
  • A Vanderbilt University team recently described how error and reward signals are organized within the cerebral cortex, which is only as thick as a nickel. (
  • This study highlights that the brain regions central to reward and motivation are directly altered by inflammation in ways that that appear to predispose or protect against developing fatigue but not depression. (
  • Nucleus accumbens corticotropin-releasing factor increases cue-triggered motivation for sucrose reward: paradoxical positive incentive effects in stress? (
  • Performance-dependent (contingent) reward is instrumental, relying on an internal action-outcome model, whereas motivation by guaranteed reward may serve to minimise opportunity cost in reward-rich environments. (
  • We posit that dopamine is necessary for goal-directed motivation, but dampens reward-driven vigour, challenging the theory that tonic dopamine encodes reward expectation. (
  • Less convincing or more constrained bug submissions will likely qualify for reduced reward amounts, as chosen at the discretion of the reward panel. (
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  • Every 1,000 Rewards Points awarded to your Zappos Rewards Program account ("Rewards Program Account") can be redeemed for a $1 Rewards Code. (
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  • Welcome to iHerb Rewards, an easy-to-use referral program for customers and everyone they know. (
  • The iHerb Rewards program is a customer referral program to share with friends and family via your email or your social media accounts. (
  • Extending this idea, the marriage of personalization and loyalty programs begets an entirely new type of reward program, one users actually have a stake in. (
  • A more interesting program, one that might actually build loyalty, offers personalized rewards. (
  • A poorly designed reward program can feel like a slap in the face. (
  • Providing us with an accurate email address and phone number is critical to keeping you in the AutoZone Rewards program loop and providing you with exclusive member discounts. (
  • Your information is used solely for administering the benefits of the AutoZone Rewards program. (
  • Must be 21 years of age or older to register or participate in the Rock Rewards program. (
  • Rock Bottom reserves the right to disqualify entrants who fail to follow these official rules and regulations or who make any misrepresentations relative to the program and redemption of rewards. (
  • Sponsor and each of its affiliates are not responsible for any negligence, claims, liability, injury, property loss or other damages of participants and/or winners arising from, or in connection with the use/misuse of rewards awarded or participation in program. (
  • b. " 8x8 Referral Program " or "Program" means the program described on the website located at (or such successor site as designated by 8x8) and to which these Terms and Conditions apply. (
  • My big favorite is my the Fuel Rewards program offered at my local grocery store. (
  • Important Information about the RCI Elite Rewards Credit Card Program: Offers may vary. (
  • Please review the below and the Terms and Conditions , which include the Reward Rules for full information about the Reward program, interest rates and account fees and terms for this particular offer before applying. (
  • Refer to the FAQs and Reward Rules within the Terms and Conditions for additional information about the rewards program. (
  • WOONSOCKET, R.I. - CVS/pharmacy's ExtraCare Rewards program, which has more than 67 million active cardholders and this year celebrates its 10-year anniversary, announced on Friday the launch of a new interactive digital campaign that encourages cardholders to take advantage of their earned rewards, as well as a new look for the ExtraBucks rewards receipt. (
  • Rewards for qualifying bugs typically range from $500 to $100,000. (
  • We have a standing $100,000 reward for participants that can compromise a Chromebook or Chromebox with device persistence in guest mode (i.e. guest to guest persistence with interim reboot, delivered via a web page). (
  • A new imaging study shows that our brains react with varying sensitivity to reward and suggests that people most susceptible to impulse are those who need to buy it, eat it, or have it, now - show the greatest activity in a reward center of the brain . (
  • Errors in reward prediction are reflected in the event-related brain potential. (
  • Individuals with obesity are often characterized by alterations in reward processing. (
  • Amotivation in schizophrenia is a central predictor of poor functioning, and is thought to occur due to deficits in anticipating future rewards, suggesting that impairments in anticipating pleasure can contribute to functional disability in schizophrenia. (
  • We will typically focus on critical, high and medium impact bugs , but any clever vulnerability at any severity might get a reward. (
  • Summary We can be motivated when reward depends on performance, or merely by the prospect of a guaranteed reward. (
  • Here we show that BOLD activity in the VTA conforms to such TD predictions: responses to unexpected rewards are modulated by a temporal hazard function and activity between a predictive stimulus and reward is depressed in proportion to predicted reward. (
  • When PD patients were ON dopamine, they had greater response vigour (peak saccadic velocity) for contingent rewards, whereas when PD patients were OFF medication, they had greater vigour for guaranteed rewards. (