Inhibitory Cerebello-Olivary Projections and Blocking Effect in Classical Conditioning

Kim, Jeansok J.; Krupa, David J.; Thompson, Richard F.

doi:10.1126/science.279.5350.570

Cited by 205 publications

(165 citation statements)

References 28 publications

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“…Consistent with this interpretation, it has been shown that reversible inactivation of the NI-DAO inhibitory pathway disrupts the blocking effect in eyelid conditioning (Kim, Krupa, & Thompson, 1998).…”

Section: Extinction and Blocking Are Also Mediated By The Inhibitory supporting

confidence: 61%

Neuroscience of Pavlovian Conditioning: A Brief Review

Aguado

2003

Span. J. Psychol.

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Current knowledge on the neuronal substrates of Pavlovian conditioning in animals and man is briefly reviewed. First, work on conditioning in aplysia, that has showed amplified pre-synaptic facilitation as the basic mechanism of associative learning, is summarized. Then, two exemplars of associative learning in vertebrates, fear conditioning in rodents and eyelid conditioning in rabbits, are described and research into its neuronal substrates discussed. Research showing the role of the amygdala in fear conditioning and of the cerebellum in eyelid conditioning is reviewed, both at the circuit and cellular plasticity levels. Special attention is given to the parallelism suggested by this research between the neuronal mechanisms of conditioning and the principles of formal learning theory. Finally, recent evidence showing a similar role of the amygdala and of the cerebellum in human Pavlovian conditioning is discussed. Keywords: Pavlovian conditioning, neural mechanisms, learning theoriesEl artículo revisa brevemente los conocimientos actuales acerca de los substratos neuronales del condicionamiento pavloviano en los animales y en el hombre. En primer lugar, se resume la investigación sobre condicionamiento en aplysias, que ha demostrado la importancia de la facilitación sináptica amplificada como mecanismo básico del aprendizaje asociativo. A continuación, se describen dos ejemplos de aprendizaje asociativo en vertebrados, el condicionamiento del miedo en roedores y el condicionamiento del parpadeo en conejos, con referencias a la investigación sobre sus substratos neuronales. Se revisa la investigación que muestra el papel de la amígdala en el condicionamiento del miedo y del cerebelo en el condicionamiento del parpadeo, al nivel tanto de circuitos como de la plasticidad celular. Se presta especial atención a los paralelismos que esta área de investigación sugiere entre los mecanismos neuronales del condicionamiento y los principios de las teorías formales del aprendizaje. Por último, se comentan diversas pruebas recientes que demuestran un papel semejante de la amígdala y del cerebelo en el condicionamiento pavloviano humano. Palabras clave: condicionamiento pavloviano, mecanismos neurales, teorias del aprendizaje

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Section: Extinction and Blocking Are Also Mediated By The Inhibitory supporting

confidence: 61%

Neuroscience of Pavlovian Conditioning: A Brief Review

Aguado

2003

Span. J. Psychol.

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“…7). Neurons carrying prediction errors are also found in brain structures other than the dopamine system 7 , particularly in the climbing ®bre projection to cerebellar Purkinje cells 11,12,14,15 .…”

Section: Discussionmentioning

confidence: 99%

Dopamine responses comply with basic assumptions of formal learning theory

Waelti

Dickinson

Schultz

2001

Nature

941

749

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According to contemporary learning theories, the discrepancy, or error, between the actual and predicted reward determines whether learning occurs when a stimulus is paired with a reward. The role of prediction errors is directly demonstrated by the observation that learning is blocked when the stimulus is paired with a fully predicted reward. By using this blocking procedure, we show that the responses of dopamine neurons to conditioned stimuli was governed differentially by the occurrence of reward prediction errors rather than stimulus±reward associations alone, as was the learning of behavioural reactions. Both behavioural and neuronal learning occurred predominantly when dopamine neurons registered a reward prediction error at the time of the reward. Our data indicate that the use of analytical tests derived from formal behavioural learning theory provides a powerful approach for studying the role of single neurons in learning.Classic theories assume that predictive learning occurs whenever a stimulus is paired with a reward or punishment 1,2 . However, more recent analyses of associative learning argue that simple temporal contiguity between a stimulus and a reinforcer is not suf®cient for learning and that a discrepancy between the reinforcer that is predicted by a stimulus and the actual reinforcer is also required 3±6 . This discrepancy can be characterized as a`prediction error' 7 . Presentations of surprising or unpredicted reinforcers generate positive prediction errors, and thereby support learning, whereas omissions of predicted reinforcers generate negative prediction errors and lead to reduction or extinction of learned behaviour. Expected reinforcers do not generate prediction errors and therefore fail to support further learning even when the stimulus is consistently paired with the reinforcer. Modelling studies have shown that neuronal messages encoding prediction errors can act as explicit teaching signals for modifying the synaptic connections that underlie associative learning 8±17 .Current research suggests that one of the principal reward systems of the brain involves dopamine neurons 18±21 . Both psychopharmacological manipulations and lesions of the dopamine system impair reward-driven behaviour of animals 18,21 , and drugs of abuse, which provide strong arti®cial rewards, act via dopamine neurons 19,20 . Neurobiological investigations of associative learning have shown that dopamine neurons respond phasically to rewards in a manner compatible with the coding of prediction errors 22±28 , whereas slower dopamine changes are involved in a larger spectrum of motivating events 18,28,29 . Dopamine neurons show short-latency, phasic activations when rewards occur unpredictably, they are not modulated by fully predicted rewards and show phasically reduced activity when predicted rewards are omitted. During initial learning, when rewards occur unpredictably, dopamine neurons are activated by rewards. They gradually lose the response as the reward becomes increasingly predicted 24,25,27 . The co...

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“…In our earlier review, 204 we included a section entitled 'how is nonreinforcement detected,' which noted that the detection of the nonoccurrence of an expected US is a critical feature of extinction training protocols and, as such, an understanding of the mechanisms by which this occurs will be critical to a full understanding of extinction. At that time there was very little information on the so-called 'error signal' involved in Pavlovian fear conditioning, although work in other paradigms including eyeblink conditioning in rabbits 205 and appetitive learning in nonhuman primates 206 held promise that such a signal could be identified and experimentally manipulated. Since then some exciting work by Gavan McNally and co-workers has argued convincingly that a fear error signal exists and involves endogenous opioid signaling within the ventrolateral periaqueductal gray (vlPAG).…”

Section: Neurotransmitter Systemsmentioning

confidence: 99%

Mechanisms of fear extinction

2006

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Excessive fear and anxiety are hallmarks of a variety of disabling anxiety disorders that affect millions of people throughout the world. Hence, a greater understanding of the brain mechanisms involved in the inhibition of fear and anxiety is attracting increasing interest in the research community. In the laboratory, fear inhibition most often is studied through a procedure in which a previously fear conditioned organism is exposed to a fear-eliciting cue in the absence of any aversive event. This procedure results in a decline in conditioned fear responses that is attributed to a process called fear extinction. Extensive empirical work by behavioral psychologists has revealed basic behavioral characteristics of extinction, and theoretical accounts have emphasized extinction as a form of inhibitory learning as opposed to an erasure of acquired fear. Guided by this work, neuroscientists have begun to dissect the neural mechanisms involved, including the regions in which extinction-related plasticity occurs and the cellular and molecular processes that are engaged. The present paper will cover behavioral, theoretical and neurobiological work, and will conclude with a discussion of clinical implications. Molecular Psychiatry (2007) 12, 120-150.

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Inhibitory Cerebello-Olivary Projections and Blocking Effect in Classical Conditioning

Cited by 205 publications

References 28 publications

Neuroscience of Pavlovian Conditioning: A Brief Review

Neuroscience of Pavlovian Conditioning: A Brief Review

Dopamine responses comply with basic assumptions of formal learning theory

Mechanisms of fear extinction

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