Pavlovian-instrumental transfer (PIT) is a psychological phenomenon that occurs when a conditioned stimulus (CS, also known as a "cue") that has been associated with rewarding or aversive stimuli via classical conditioning alters motivational salience and operant behavior. [1] [2] [3] [4] Two distinct forms of Pavlovian-instrumental transfer have been identified in humans and other animals – specific PIT and general PIT – with unique neural substrates mediating each type. [1] [5] [6] In relation to rewarding stimuli, specific PIT occurs when a CS is associated with a specific rewarding stimulus through classical conditioning and subsequent exposure to the CS enhances an operant response that is directed toward the same reward with which it was paired (i.e., it promotes approach behavior). [1] [5] [6] General PIT occurs when a CS is paired with one reward and it enhances an operant response that is directed toward a different rewarding stimulus. [1] [5] [6]
An example of specific PIT, as described by a neuroscience review on Pavlovian-instrumental transfer from 2013, [1] is as follows:
In a typical experimental scenario a rat is trained to associate a sound (CS) with the delivery of food. Later, the rat undergoes an instrumental training where it learns to press a lever to get some food (without the sound being present). Finally, the rat is presented again with the opportunity to press the lever, this time both in the presence and absence of the sound. The results show that the rat will press the lever more in the presence of the sound than without, even if the sound has not been previously paired with lever pressing. The Pavlovian sound-food association learned in the first phase has somehow transferred to the instrumental situation, hence the name 'Pavlovian-instrumental transfer'. [1]
In relation to rewarding stimuli, specific PIT occurs when a CS is associated with a specific rewarding stimulus through classical conditioning and subsequent exposure to the CS enhances an operant response that is directed toward the same reward with which it was paired (i.e., it promotes approach behavior). [1] [5] [6] General PIT occurs when a CS is paired with one reward and it enhances an operant response that is directed toward a different rewarding stimulus. [1] [5] [6] Neurobiological state factors (e.g., appetite and satiety states, stress level, drug states such as intoxication and withdrawal, etc.), and particularly the motivational state of an animal, strongly affect the amount of appetitive motivational salience (i.e., incentive salience) that a reward cue [note 1] confers to an associated rewarding stimulus via Pavlovian-instrumental transfer. [1] [4] [5] Acute stress amplifies the motivational salience that reward cues confer to rewarding stimuli through both specific and general PIT; [5] however, chronic stress reduces the motivational impact reward cues. [5]
Specific PIT and general PIT also occur with aversive stimuli and are defined analogously. [2] [5] Specific PIT with an aversive stimulus occurs when a CS is paired with an aversive stimulus and subsequent exposure to the CS enhances an operant response that is directed away from the aversive stimulus with which it was paired (i.e., it promotes escape and avoidance behavior). [2] [5] General PIT with an aversive stimulus occurs when a CS is paired with one aversive stimulus and it enhances an operant response that is directed away from a different aversive stimulus. [2] [5]
Based on studies of rats that involved PIT with rewards, it has been found that specific PIT is mediated by the nucleus accumbens shell and basolateral amygdala, while general PIT is mediated by the nucleus accumbens core and central amygdala. [1] [6] Studies on humans, which employed neuroimaging during PIT experiments with rewards, appear to be consistent with these findings. [1]
Due to the effect of reward cues and Pavlovian-instrumental transfer on the amplification of incentive salience for rewarding stimuli, PIT is believed to be one of the mechanisms responsible for producing "cue-triggered wanting", or craving, for a drug that occurs when an individual with a drug addiction is exposed to drug cues [note 2] even after long periods of abstinence. [4] [5] [7] For example, anti-drug agencies previously used posters with images of drug paraphernalia – which is a type of drug cue – as an attempt to show the dangers of drug use. However, such posters are no longer used because of the effect of incentive salience in causing cravings and relapse upon sight of the stimuli illustrated in the posters.
The sight or smell of food which one has consumed and enjoyed in the past can elicit hunger (i.e., the motivation to eat) in humans, an effect which is presumably mediated through PIT. [3] [4] [6] In PIT experiments with rats, the presentation of a conditioned stimulus which has been paired with food has been shown to increase instrumental actions that have been reinforced by food, such as pressing a lever which leads to the delivery of a food pellet. [6]
Conditioning may refer to:
Operant conditioning, also called instrumental conditioning, is a learning process where behaviors are modified through the association of stimuli with reinforcement or punishment. In it, operants—behaviors that affect one's environment—are conditioned to occur or not occur depending on the environmental consequences of the behavior.
Classical conditioning is a behavioral procedure in which a biologically potent physiological stimulus is paired with a neutral stimulus. The term classical conditioning refers to the process of an automatic, conditioned response that is paired with a specific stimulus.
In reinforcement theory, it is argued that human behavior is a result of "contingent consequences" to human actions. The publication pushes forward the idea that "you get what you reinforce". This means that behavior, when given the right types of reinforcers, can be changed for the better and negative behavior can be reinforced away.
The experimental analysis of behavior is a science that studies the behavior of individuals across a variety of species. A key early scientist was B. F. Skinner who discovered operant behavior, reinforcers, secondary reinforcers, contingencies of reinforcement, stimulus control, shaping, intermittent schedules, discrimination, and generalization. A central method was the examination of functional relations between environment and behavior, as opposed to hypothetico-deductive learning theory that had grown up in the comparative psychology of the 1920–1950 period. Skinner's approach was characterized by observation of measurable behavior which could be predicted and controlled. It owed its early success to the effectiveness of Skinner's procedures of operant conditioning, both in the laboratory and in behavior therapy.
The mesolimbic pathway, sometimes referred to as the reward pathway, is a dopaminergic pathway in the brain. The pathway connects the ventral tegmental area in the midbrain to the ventral striatum of the basal ganglia in the forebrain. The ventral striatum includes the nucleus accumbens and the olfactory tubercle.
The nucleus accumbens is a region in the basal forebrain rostral to the preoptic area of the hypothalamus. The nucleus accumbens and the olfactory tubercle collectively form the ventral striatum. The ventral striatum and dorsal striatum collectively form the striatum, which is the main component of the basal ganglia. The dopaminergic neurons of the mesolimbic pathway project onto the GABAergic medium spiny neurons of the nucleus accumbens and olfactory tubercle. Each cerebral hemisphere has its own nucleus accumbens, which can be divided into two structures: the nucleus accumbens core and the nucleus accumbens shell. These substructures have different morphology and functions.
Motivational salience is a cognitive process and a form of attention that motivates or propels an individual's behavior towards or away from a particular object, perceived event or outcome. Motivational salience regulates the intensity of behaviors that facilitate the attainment of a particular goal, the amount of time and energy that an individual is willing to expend to attain a particular goal, and the amount of risk that an individual is willing to accept while working to attain a particular goal.
An avoidance response is a natural adaptive behavior performed in response to danger. Excessive avoidance has been suggested to contribute to anxiety disorders, leading psychologists and neuroscientists to study how avoidance behaviors are learned using rat or mouse models. Avoidance learning is a type of operant conditioning.
Salience is that property by which some thing stands out. Salient events are an attentional mechanism by which organisms learn and survive; those organisms can focus their limited perceptual and cognitive resources on the pertinent subset of the sensory data available to them.
Kent C. Berridge is an American academic, currently working as a professor of psychology (biopsychology) and neuroscience at the University of Michigan. Berridge was a joint winner of the 2018 Grawemeyer Award for Psychology.
Brain stimulation reward (BSR) is a pleasurable phenomenon elicited via direct stimulation of specific brain regions, originally discovered by James Olds and Peter Milner. BSR can serve as a robust operant reinforcer. Targeted stimulation activates the reward system circuitry and establishes response habits similar to those established by natural rewards, such as food and sex. Experiments on BSR soon demonstrated that stimulation of the lateral hypothalamus, along with other regions of the brain associated with natural reward, was both rewarding as well as motivation-inducing. Electrical brain stimulation and intracranial drug injections produce robust reward sensation due to a relatively direct activation of the reward circuitry. This activation is considered to be more direct than rewards produced by natural stimuli, as those signals generally travel through the more indirect peripheral nerves. BSR has been found in all vertebrates tested, including humans, and it has provided a useful tool for understanding how natural rewards are processed by specific brain regions and circuits, as well the neurotransmission associated with the reward system.
The reward system is a group of neural structures responsible for incentive salience, associative learning, and positively-valenced emotions, particularly ones involving pleasure as a core component. Reward is the attractive and motivational property of a stimulus that induces appetitive behavior, also known as approach behavior, and consummatory behavior. A rewarding stimulus has been described as "any stimulus, object, event, activity, or situation that has the potential to make us approach and consume it is by definition a reward". In operant conditioning, rewarding stimuli function as positive reinforcers; however, the converse statement also holds true: positive reinforcers are rewarding.
In operant conditioning, punishment is any change in a human or animal's surroundings which, occurring after a given behavior or response, reduces the likelihood of that behavior occurring again in the future. As with reinforcement, it is the behavior, not the human/animal, that is punished. Whether a change is or is not punishing is determined by its effect on the rate that the behavior occurs. This is called motivating operations (MO), because they alter the effectiveness of a stimulus. MO can be categorized in abolishing operations, decrease the effectiveness of the stimuli and establishing, increase the effectiveness of the stimuli. For example, a painful stimulus which would act as a punisher for most people may actually reinforce some behaviors of masochistic individuals.
The basolateral amygdala, or basolateral complex, consists of the lateral, basal and accessory-basal nuclei of the amygdala. The lateral nuclei receives the majority of sensory information, which arrives directly from the temporal lobe structures, including the hippocampus and primary auditory cortex. The basolateral amygdala also receives dense neuromodulatory inputs from ventral tegmental area (VTA), locus coeruleus (LC), and basal forebrain, whose integrity are important for associative learning. The information is then processed by the basolateral complex and is sent as output to the central nucleus of the amygdala. This is how most emotional arousal is formed in mammals.
Conditioned place preference (CPP) is a form of Pavlovian conditioning used to measure the motivational effects of objects or experiences. This motivation comes from the pleasurable aspect of the experience, so that the brain can be reminded of the context that surrounded the "encounter". By measuring the amount of time an animal spends in an area that has been associated with a stimulus, researchers can infer the animal's liking for the stimulus. This paradigm can also be used to measure conditioned place aversion with an identical procedure involving aversive stimuli instead. Both procedures usually involve mice or rats as subjects. This procedure can be used to measure extinction and reinstatement of the conditioned stimulus. Certain drugs are used in this paradigm to measure their reinforcing properties. Two different methods are used to choose the compartments to be conditioned, and these are biased vs. unbiased. The biased method allows the animal to explore the apparatus, and the compartment they least prefer is the one that the drug is administered in and the one they most prefer is the one where the vehicle is injected. This method allows the animal to choose the compartment they get the drug and vehicle. In comparison, the unbiased method does not allow the animal to choose what compartment they get the drug and vehicle in. Instead, the researcher chooses the compartments.
Self-administration is, in its medical sense, the process of a subject administering a pharmacological substance to themself. A clinical example of this is the subcutaneous "self-injection" of insulin by a diabetic patient.
Addiction is a neuropsychological disorder characterized by a persistent and intense urge to use a drug or engage in a behaviour that produces natural reward, despite substantial harm and other negative consequences. Repetitive drug use often alters brain function in ways that perpetuate craving, and weakens self-control. This phenomenon – drugs reshaping brain function – has led to an understanding of addiction as a brain disorder with a complex variety of psychosocial as well as neurobiological factors that are implicated in addiction's development. Classic signs of addiction include compulsive engagement in rewarding stimuli, preoccupation with substances or behavior, and continued use despite negative consequences. Habits and patterns associated with addiction are typically characterized by immediate gratification, coupled with delayed deleterious effects.
Association in psychology refers to a mental connection between concepts, events, or mental states that usually stems from specific experiences. Associations are seen throughout several schools of thought in psychology including behaviorism, associationism, psychoanalysis, social psychology, and structuralism. The idea stems from Plato and Aristotle, especially with regard to the succession of memories, and it was carried on by philosophers such as John Locke, David Hume, David Hartley, and James Mill. It finds its place in modern psychology in such areas as memory, learning, and the study of neural pathways.
Kate Wassum is an American neuroscientist and professor of behavioral neuroscience at the University of California, Los Angeles. Wassum probes the neural circuits underlying appetitive associative learning the circuit dynamics that give rise to diverse motivated behaviors.
This paper reviews one of the experimental paradigms used to study the effects of cues, the Pavlovian to Instrumental Transfer paradigm. In this paradigm, cues associated with rewards through Pavlovian conditioning alter motivation and choice of instrumental actions. ... Predictive cues are an important part of our life that continuously influence and guide our actions. Hearing the sound of a horn makes us stop before we attempt to cross the street. Seeing an advertisement for fast food might make us hungry and lead us to seek out a specific type and source of food. In general, cues can both prompt us towards or stop us from engaging in a certain course of action. They can be adaptive (saving our life in crossing the street) or maladaptive, leading to suboptimal choices, e.g. making us eat when we are not really hungry (Colagiuri and Lovibond, 2015). In extreme cases they can even play a part in pathologies such as in addiction, where drug associated cues produce craving and provoke relapse (Belin et al., 2009).
Incentive salience or 'wanting' is a specific form of Pavlovian-related motivation for rewards mediated by mesocorticolimbic brain systems ...Incentive salience integrates two separate input factors: (1) current physiological neurobiological state; (2) previously learned associations about the reward cue, or Pavlovian CS ...
Cue-triggered 'wanting' for the UCS
A brief CS encounter (or brief UCS encounter) often primes a pulse of elevated motivation to obtain and consume more reward UCS. This is a signature feature of incentive salience. In daily life, the smell of food may make you suddenly feel hungry, when you hadn't felt that way a minute before. In animal neuroscience experiments, a CS for reward may trigger a more frenzied pulse of increased instrumental efforts to obtain that associated UCS reward in situations that purify the measurement of incentive salience, such as in Pavlovian-Instrumental Transfer (PIT) experiments ... Similarly, including a CS can often spur increased consumption of a reward UCS by rats or people, compared to consumption of the same UCS when CSs are absent ... Thus Pavlovian cues can elicit pulses of increased motivation to consume their UCS reward, whetting and intensifying the appetite. However, the motivation power is never simply in the cues themselves or their associations, since cue-triggered motivation can be easily modulated and reversed by drugs, hungers, satieties, etc., as discussed below.
Such effects suggest that specific motivational states gate the arousing effects of Pavlovian incentives processes on instrumental performance ... Behavioral findings are supported by evidence that distinct neural circuits centered on the NAc core and shell mediate the general and specific forms of transfer, respectively ... Finally, stress has been shown to increase the magnitude of transfer effects, particularly general transfer, suggesting a shift in cognitive control under stress conditions. ... corticotropin-releasing factor (CRF) administered directly into the NAc shell enhances transfer in a dose-dependent fashion without affecting baseline lever-press performance (Pecina et al. 2006), suggesting that CRF amplifies the motivational impact of cued rewards in much the same manner as dopamine. ... In general, acute treatments seem to enhance transfer effects, whereas chronic treatments decrease transfer
{{cite book}}
: |journal=
ignored (help)Considerable evidence indicates that accumbens DA is important for Pavlovian approach and Pavlovian-to-instrumental transfer [(PIT)] ... PIT is a behavioral process that reflects the impact of Pavlovian-conditioned stimuli (CS) on instrumental responding. For example, presentation of a Pavlovian CS paired with food can increase output of food-reinforced instrumental behaviors, such as lever pressing. Outcome-specific PIT occurs when the Pavlovian unconditioned stimulus (US) and the instrumental reinforcer are the same stimulus, whereas general PIT is said to occur when the Pavlovian US and the reinforcer are different. ... More recent evidence indicates that accumbens core and shell appear to mediate different aspects of PIT; shell lesions and inactivation reduced outcome-specific PIT, while core lesions and inactivation suppressed general PIT (Corbit and Balleine 2011). These core versus shell differences are likely due to the different anatomical inputs and pallidal outputs associated with these accumbens subregions (Root et al. 2015). These results led Corbit and Balleine (2011) to suggest that accumbens core mediates the general excitatory effects of reward-related cues. PIT provides a fundamental behavioral process by which conditioned stimuli can exert activating effects upon instrumental responding
{{cite book}}
: |journal=
ignored (help)Pavlovian learning plays a central role in many theories of addiction, particularly with regard to relapse. In broad terms, encountering drug-paired CSs are hypothesized to precipitate relapse, often, though not always, by increasing motivation to take drugs. Presumably, if a drug-paired CS increases motivation to take drugs, then a drug-paired CS should increase drug consumption.