The Experts below are selected from a list of 74094 Experts worldwide ranked by ideXlab platform
Michael Davis - One of the best experts on this subject based on the ideXlab platform.
-
using pavlovian higher order Conditioning paradigms to investigate the neural substrates of emotional learning and memory
Learning & Memory, 2000Co-Authors: Jonathan C Gewirtz, Michael DavisAbstract:In first-order Pavlovian Conditioning, learning is acquired by pairing a conditioned stimulus (CS) with an intrinsically motivating unconditioned stimulus (US; e.g., food or shock). In higher-order Pavlovian Conditioning (sensory preConditioning and Second-Order Conditioning), the CS is paired with a stimulus that has motivational value that is acquired rather than intrinsic. This review describes some of the ways higher-order Conditioning paradigms can be used to elucidate substrates of learning and memory, primarily focusing on fear Conditioning. First-order Conditioning, Second-Order Conditioning, and sensory preConditioning allow for the controlled demonstration of three distinct forms of memory, the neural substrates of which can thus be analyzed. Higher-order Conditioning phenomena allow one to distinguish more precisely between processes involved in transmission of sensory or motor information and processes involved in the plasticity underlying learning. Finally, higher-order Conditioning paradigms may also allow one to distinguish between processes involved in behavioral expression of memory retrieval versus processes involved in memory retrieval itself. By reducing learning to its most rudimentary components, the influence of undefined and uncontrollable confounding variables can be minimized. Consequently, much of the progress that has been achieved in searching for the neural substrates of learning and memory has been made using some of the simplest forms of learning. In one such paradigm, first-order Pavlovian Conditioning, a conditioned stimulus (CS, such as a tone or light) acquires motivational significance by being paired with an intrinsically aversive or rewarding unconditioned stimulus (US, such as foot shock or food). Learning is evaluated by the ability of the CS to elicit a conditioned response (CR) in anticipation of the occurrence of the US. The use of first-order Conditioning has revealed genetic and cellular mechanisms underlying learning and memory in species ranging from the fruit fly and sea snail to the mouse and rat. Thus far, less attention has been paid by neurobiologists to the potential uses of higher-order Pavlovian Conditioning, learning phenomena in which a CS (S2) acquires associative strength by being paired with another CS (S1) rather than with a US. The pairing of S2 with S1 may occur before S1 is paired with the US (sensory preConditioning) or after S1 has been paired with the US (Second-Order Conditioning; see Table 1). The cardinal feature of both sensory preConditioning and Second-Order Conditioning—and that which recommends these paradigms to the service of neurobiologists interested in learning and memory—is that S2 acquires associative strength even though it is never paired directly with a US. This article will describe two promising avenues of research in higher-order Conditioning. First, the fact that reinforcing value is acquired makes higher-order Conditioning well suited to investigating the neural substrates of different forms of reinforcement. Second, the absence of direct pairings between the CS and US allows one to characterize the roles played by molecular, genetic, pharmacological, and anatomical mechanisms in different stages of learning or memory more precisely than could be achieved using other Conditioning paradigms.
-
application of pavlovian higher order Conditioning to the analysis of the neural substrates of fear Conditioning
Neuropharmacology, 1998Co-Authors: Jonathan C Gewirtz, Michael DavisAbstract:Abstract In Pavlovian first-order Conditioning, a conditioned response is acquired by pairing a neutral stimulus (S1) with a stimulus that has innate motivational value. In higher-order Conditioning, a neutral stimulus (S2) is paired with S1 either after (Second-Order Conditioning) or before (sensory preConditioning) first-order Conditioning has been acquired. Thus, in higher-order Conditioning the motivational value of the reinforcer is acquired rather than innate. This review describes some of the potential uses of higher-order Conditioning in investigating the neural substrates of fearful memories. First, because in Second-Order fear Conditioning S2 is not paired directly with a painful stimulus, any effect of a treatment on the acquisition of fear cannot be attributed to the treatment’s possible effects on transmission of nociceptive information. Second, higher-order Conditioning provides opportunities for analyzing where and how different types of events, or different aspects of the same events, are represented in the brain.
-
second order fear Conditioning prevented by blocking nmda receptors in amygdala
Nature, 1997Co-Authors: Jonathan C Gewirtz, Michael DavisAbstract:Antagonists of NMDA (N-methyl-D-aspartate)-type glutamate receptors disrupt several forms of learning1,2,3,4,5,6,7,8. Although this might indicate that NMDA-receptor-mediated processes are critical for synaptic plasticity, there may be other mechanisms by which NMDA-receptor antagonism could interfere with learning1,9,10,11,12. For instance, fear Conditioning would be blocked by microinfusion of the NMDA-receptor antagonist AP5 (D,L-2-amino-5-phosphonovalerate) into the basolateral amygdala6,13,14 if AP5 inhibited routine synaptic transmission, thereby reducing the ability of stimuli to activate amygdala neurons15,16. In Second-Order fear Conditioning17,18, the reinforcer is a fear-eliciting conditioned stimulus rather than an unconditioned stimulus. Expression of conditioned fear is amygdala-dependent19,20 and so provides a behavioural assessment of the ability of the reinforcer to activate amygdala neurons in the presence of AP5. We report here that intra-amygdala AP5 actually enhances expression of conditioned fear to the conditioned stimulus that provides the reinforcement signal for Second-Order Conditioning. Nevertheless, acquisition of Second-Order fear Conditioning is completely blocked. Our findings strongly support the view that NMDA receptors are critically involved in synaptic plasticity.
Jonathan C Gewirtz - One of the best experts on this subject based on the ideXlab platform.
-
using pavlovian higher order Conditioning paradigms to investigate the neural substrates of emotional learning and memory
Learning & Memory, 2000Co-Authors: Jonathan C Gewirtz, Michael DavisAbstract:In first-order Pavlovian Conditioning, learning is acquired by pairing a conditioned stimulus (CS) with an intrinsically motivating unconditioned stimulus (US; e.g., food or shock). In higher-order Pavlovian Conditioning (sensory preConditioning and Second-Order Conditioning), the CS is paired with a stimulus that has motivational value that is acquired rather than intrinsic. This review describes some of the ways higher-order Conditioning paradigms can be used to elucidate substrates of learning and memory, primarily focusing on fear Conditioning. First-order Conditioning, Second-Order Conditioning, and sensory preConditioning allow for the controlled demonstration of three distinct forms of memory, the neural substrates of which can thus be analyzed. Higher-order Conditioning phenomena allow one to distinguish more precisely between processes involved in transmission of sensory or motor information and processes involved in the plasticity underlying learning. Finally, higher-order Conditioning paradigms may also allow one to distinguish between processes involved in behavioral expression of memory retrieval versus processes involved in memory retrieval itself. By reducing learning to its most rudimentary components, the influence of undefined and uncontrollable confounding variables can be minimized. Consequently, much of the progress that has been achieved in searching for the neural substrates of learning and memory has been made using some of the simplest forms of learning. In one such paradigm, first-order Pavlovian Conditioning, a conditioned stimulus (CS, such as a tone or light) acquires motivational significance by being paired with an intrinsically aversive or rewarding unconditioned stimulus (US, such as foot shock or food). Learning is evaluated by the ability of the CS to elicit a conditioned response (CR) in anticipation of the occurrence of the US. The use of first-order Conditioning has revealed genetic and cellular mechanisms underlying learning and memory in species ranging from the fruit fly and sea snail to the mouse and rat. Thus far, less attention has been paid by neurobiologists to the potential uses of higher-order Pavlovian Conditioning, learning phenomena in which a CS (S2) acquires associative strength by being paired with another CS (S1) rather than with a US. The pairing of S2 with S1 may occur before S1 is paired with the US (sensory preConditioning) or after S1 has been paired with the US (Second-Order Conditioning; see Table 1). The cardinal feature of both sensory preConditioning and Second-Order Conditioning—and that which recommends these paradigms to the service of neurobiologists interested in learning and memory—is that S2 acquires associative strength even though it is never paired directly with a US. This article will describe two promising avenues of research in higher-order Conditioning. First, the fact that reinforcing value is acquired makes higher-order Conditioning well suited to investigating the neural substrates of different forms of reinforcement. Second, the absence of direct pairings between the CS and US allows one to characterize the roles played by molecular, genetic, pharmacological, and anatomical mechanisms in different stages of learning or memory more precisely than could be achieved using other Conditioning paradigms.
-
application of pavlovian higher order Conditioning to the analysis of the neural substrates of fear Conditioning
Neuropharmacology, 1998Co-Authors: Jonathan C Gewirtz, Michael DavisAbstract:Abstract In Pavlovian first-order Conditioning, a conditioned response is acquired by pairing a neutral stimulus (S1) with a stimulus that has innate motivational value. In higher-order Conditioning, a neutral stimulus (S2) is paired with S1 either after (Second-Order Conditioning) or before (sensory preConditioning) first-order Conditioning has been acquired. Thus, in higher-order Conditioning the motivational value of the reinforcer is acquired rather than innate. This review describes some of the potential uses of higher-order Conditioning in investigating the neural substrates of fearful memories. First, because in Second-Order fear Conditioning S2 is not paired directly with a painful stimulus, any effect of a treatment on the acquisition of fear cannot be attributed to the treatment’s possible effects on transmission of nociceptive information. Second, higher-order Conditioning provides opportunities for analyzing where and how different types of events, or different aspects of the same events, are represented in the brain.
-
second order fear Conditioning prevented by blocking nmda receptors in amygdala
Nature, 1997Co-Authors: Jonathan C Gewirtz, Michael DavisAbstract:Antagonists of NMDA (N-methyl-D-aspartate)-type glutamate receptors disrupt several forms of learning1,2,3,4,5,6,7,8. Although this might indicate that NMDA-receptor-mediated processes are critical for synaptic plasticity, there may be other mechanisms by which NMDA-receptor antagonism could interfere with learning1,9,10,11,12. For instance, fear Conditioning would be blocked by microinfusion of the NMDA-receptor antagonist AP5 (D,L-2-amino-5-phosphonovalerate) into the basolateral amygdala6,13,14 if AP5 inhibited routine synaptic transmission, thereby reducing the ability of stimuli to activate amygdala neurons15,16. In Second-Order fear Conditioning17,18, the reinforcer is a fear-eliciting conditioned stimulus rather than an unconditioned stimulus. Expression of conditioned fear is amygdala-dependent19,20 and so provides a behavioural assessment of the ability of the reinforcer to activate amygdala neurons in the presence of AP5. We report here that intra-amygdala AP5 actually enhances expression of conditioned fear to the conditioned stimulus that provides the reinforcement signal for Second-Order Conditioning. Nevertheless, acquisition of Second-Order fear Conditioning is completely blocked. Our findings strongly support the view that NMDA receptors are critically involved in synaptic plasticity.
Geoffrey Schoenbaum - One of the best experts on this subject based on the ideXlab platform.
-
causal evidence supporting the proposal that dopamine transients function as temporal difference prediction errors
Nature Neuroscience, 2020Co-Authors: Etienne J P Maes, Melissa J Sharpe, Matthew P H Gardner, Chun Yun Chang, Geoffrey Schoenbaum, Alexandra A Usypchuk, Megan Lozzi, Mihaela D IordanovaAbstract:Reward-evoked dopamine transients are well established as prediction errors. However, the central tenet of temporal difference accounts—that similar transients evoked by reward-predictive cues also function as errors—remains untested. In the present communication we addressed this by showing that optogenetically shunting dopamine activity at the start of a reward-predicting cue prevents Second-Order Conditioning without affecting blocking. These results indicate that cue-evoked transients function as temporal-difference prediction errors rather than reward predictions. Maes et al. use Second-Order Conditioning, blocking and optogenetic inhibition to show that cue-evoked dopamine transients function as temporal-difference prediction errors rather than reward predictions.
-
causal evidence supporting the proposal that dopamine transients function as a temporal difference prediction error
bioRxiv, 2019Co-Authors: Etienne J P Maes, Melissa J Sharpe, Matthew P H Gardner, Chun Yun Chang, Geoffrey Schoenbaum, Mihaela D IordanovaAbstract:Reward-evoked dopamine is well-established as a prediction error. However the central tenet of temporal difference accounts - that similar transients evoked by reward-predictive cues also function as errors - remains untested. To address this, we used two phenomena, Second-Order Conditioning and blocking, in order to examine the role of dopamine in prediction error versus reward prediction. We show that optogenetically-shunting dopamine activity at the start of a reward-predicting cue prevents Second-Order Conditioning without affecting blocking. These results support temporal difference accounts by providing causal evidence that cue-evoked dopamine transients function as prediction errors.
Ralph R. Miller - One of the best experts on this subject based on the ideXlab platform.
-
excitatory second order Conditioning using a backward first order conditioned stimulus a challenge for prediction error reduction
Quarterly Journal of Experimental Psychology, 2019Co-Authors: Arthur Prevel, Vinca Riviere, Jeanclaude Darcheville, Gonzalo P Urcelay, Ralph R. MillerAbstract:Prevel and colleagues reported excitatory learning with a backward conditioned stimulus (CS) in a conditioned reinforcement preparation. Their results add to existing evidence of backward CSs sometimes being excitatory and were viewed as challenging the view that learning is driven by prediction error reduction, which assumes that only predictive (i.e., forward) relationships are learned. The results instead were consistent with the assumptions of both Miller's Temporal Coding Hypothesis and Wagner's Sometimes Opponent Processes (SOP) model. The present experiment extended the conditioned reinforcement preparation developed by Prevel et al. to a backward Second-Order Conditioning preparation, with the aim of discriminating between these two accounts. We tested whether a Second-Order CS can serve as an effective conditioned reinforcer, even when the first-order CS with which it was paired is a backward CS that elicits no responding. Evidence of conditioned reinforcement was found, despite no conditioned response (CR) being elicited by the first-order backward CS. The evidence of Second-Order Conditioning in the absence of excitatory Conditioning to the first-order CS is interpreted as a challenge to SOP. In contrast, the present results are consistent with the Temporal Coding Hypothesis and constitute a conceptual replication in humans of previous reports of excitatory Second-Order Conditioning in rodents with a backward CS. The proposal is made that learning is driven by "discrepancy" with prior experience as opposed to " prediction error."
-
excitatory second order Conditioning using a backward first order conditioned stimulus a challenge for prediction error reduction
Quarterly Journal of Experimental Psychology, 2019Co-Authors: Arthur Prevel, Vinca Riviere, Jeanclaude Darcheville, Gonzalo P Urcelay, Ralph R. MillerAbstract:Prevel and colleagues reported excitatory learning with a backward conditioned stimulus (CS) in a conditioned reinforcement preparation. Their results add to existing evidence of backward CSs somet...
-
time as content in pavlovian Conditioning
Behavioural Processes, 1998Co-Authors: Hernan I Savastano, Ralph R. MillerAbstract:Time has played only a limited role within the traditional theories of Pavlovian Conditioning. Although temporal factors certainly contribute to whether Conditioning occurs, the traditional assumption in the associative framework has been that associations lack temporal information. Recently, the temporal coding hypothesis has challenged that view, arguing that animals encode temporal relationships as part of associations. That is, proximal temporal relationships not only foster associative learning, but also are part of the content of learning. The present paper reviews for the nonspecialist the increasing empirical evidence that temporal coding is ubiquitous in Pavlovian paradigms, including simultaneous and backward Conditioning, Second-Order Conditioning, sensory preConditioning, cue competition, Hall-Pearce type CS-preexposure, and conditioned inhibition. The data support the temporal coding hypothesis' view that contiguity is sufficient for associative learning to occur, but challenge the central assumption of the informational hypothesis that predictive relations are necessary for learning to occur (as opposed to predictive relationships only being necessary for the expression of knowledge).
Mihaela D Iordanova - One of the best experts on this subject based on the ideXlab platform.
-
causal evidence supporting the proposal that dopamine transients function as temporal difference prediction errors
Nature Neuroscience, 2020Co-Authors: Etienne J P Maes, Melissa J Sharpe, Matthew P H Gardner, Chun Yun Chang, Geoffrey Schoenbaum, Alexandra A Usypchuk, Megan Lozzi, Mihaela D IordanovaAbstract:Reward-evoked dopamine transients are well established as prediction errors. However, the central tenet of temporal difference accounts—that similar transients evoked by reward-predictive cues also function as errors—remains untested. In the present communication we addressed this by showing that optogenetically shunting dopamine activity at the start of a reward-predicting cue prevents Second-Order Conditioning without affecting blocking. These results indicate that cue-evoked transients function as temporal-difference prediction errors rather than reward predictions. Maes et al. use Second-Order Conditioning, blocking and optogenetic inhibition to show that cue-evoked dopamine transients function as temporal-difference prediction errors rather than reward predictions.
-
causal evidence supporting the proposal that dopamine transients function as a temporal difference prediction error
bioRxiv, 2019Co-Authors: Etienne J P Maes, Melissa J Sharpe, Matthew P H Gardner, Chun Yun Chang, Geoffrey Schoenbaum, Mihaela D IordanovaAbstract:Reward-evoked dopamine is well-established as a prediction error. However the central tenet of temporal difference accounts - that similar transients evoked by reward-predictive cues also function as errors - remains untested. To address this, we used two phenomena, Second-Order Conditioning and blocking, in order to examine the role of dopamine in prediction error versus reward prediction. We show that optogenetically-shunting dopamine activity at the start of a reward-predicting cue prevents Second-Order Conditioning without affecting blocking. These results support temporal difference accounts by providing causal evidence that cue-evoked dopamine transients function as prediction errors.