Probability of shock in the presence and absence of CS in fear conditioning.
01 Aug 1968-Journal of Comparative and Physiological Psychology (J Comp Physiol Psychol)-Vol. 66, Iss: 1, pp 1-5
TL;DR: 2 experiments indicate that CS-US contingency is an important determinant of fear conditioning and that presentation of US in the absence of CS interferes with fear conditioning.
Abstract: 2 experiments indicate that CS-US contingency is an important determinant of fear conditioning and that presentation of US in the absence of CS interferes with fear conditioning. In Experiment 1, equal probability of a shock US in the presence and absence of a tone CS produced no CER suppression to CS; the same probability of US given only during CS produced substantial conditioning. In Experiment 2, which explored 4 different probabilities of US in the presence and absence of CS, amount of conditioning was higher the greater the probability of US during CS and was lower the greater the probability of US in the absence of CS; when the 2 probabilities were equal, no conditioning resulted. Two conceptions of Pavlovian conditioning have been distinguished by Rescorla (1967). The first, and more traditional, notion emphasizes the role of the number of pairings of CS and US in the formation of a CR. The second notion suggests that it is the contingency between CS and US which is important. The notion of contingency differs from that of pairing in that it includes not only what events are paired but also what events are not paired. As used here, contingency refers to the relative probability of occurrence of US in the presence of CS as contrasted with its probability in the absence of CS. The contingency notion suggests that, in fact, conditioning only occurs when these probabilities differ; when the probability of US is higher during CS than at other times, excitatory conditioning occurs; when the probability is lower, inhibitory conditioning results. Notice that the probability of a US can be the same in the absence and presence of CS and yet there can be a fair number of CS-US pairings. It is this that makes it possible to assess the relative importance of pairing and contingency in the development of a CR. Several experiments have pointed to the usefulness of the contingency notion. Rescorla (1966) reported a Pavlovian 1This research was supported by Grants MH13415-01 from the National Institute of Mental Health and GB-6493 from the National Science Foundation, as well as by funds from Yale University.
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01 Jan 2017
TL;DR: The goal of this dissertation was to determine whether PKM-ζ could modulate EBC in a Kv1.2 dependent manner, and it was found that PKMζ has an important role in regulating the acquisition of EBC.
Abstract: Learning and memory has been a topic that has captured the attention of the scientific and public communities since the dawn of scientific discovery. Without the faculty of memory, mammals cannot experience nor function in the world; among homosapiens specifically, language, relationships, and personal identity cannot be developed (Eysenck, 2012). After all, some philosophers such as John Locke argued we are nothing but a collection of past memories in which we have developed and improved upon (Nimbalkar, 2011). Understanding the cellular mechanisms behind learning, and the subsequent formation of memory, has been a topic that has garnered scientific interest for many decades. One particular kinase that has been at the center of attention in the last decade is the serine/threonine kinase PKM-ζ, an N-terminal truncated form of PKC-ζ that renders it constitutively active (Hernandez et al., 2003). PKM-ζ has long been implicated in a cellular correlate of learning, long-term potentiation (LTP). Inhibition of PKM-ζ with Zeta-inhibitory peptide (ZIP) has been shown in many brain structures to disrupt maintenance of AMPA receptors, irreversibly disrupting numerous forms of learning and memory that have been maintained for weeks. The voltage-gated potassium channel Kv1.2 is a critical modulator of neuronal physiology, including dendritic excitability, action potential propagation, and neurotransmitter release. While expressed in various mammalian tissues, Kv1.2 is most prevalent in the cerebellum where it modulates both dendritic excitability of Purkinje cells (PCs) and basket cell (BC) inhibitory input to PCs. Because PCs are the main computational unit of the cerebellar cortex and provide its sole output (Napper et al., 1988; Harvey et al., 1991), regulation of synaptic Kv1.2 is predicted to have a major role in cerebellar function. Pharmacological inhibition of Kv1.2 in cerebellar PC dendrites increases excitability (Khavandgar et al., 2005), while its inhibition in BC axon terminals increases inhibition to PCs (Southan & Robertson, 1998). Interestingly, two prior studies have demonstrated that PKC-ζ, an atypical Protein Kinase C, is able to phosphorylate and bind cerebellar Kvβ2, a Kv1.2 auxiliary subunit. (Gong et al., 1999; Croci et al., 2003). Delay eyeblink conditioning (EBC) is an established model for the assessment of cerebellar learning. Despite being highly expressed in the cerebellum, no studies have examined how regulation of cerebellar PKM-ζ may affect cerebellar-dependent learning and memory nor have they examined the possible effect PKM-ζ may have on Kv1.2. The goal of this dissertation was to determine whether PKM-ζ could modulate EBC in a Kv1.2 dependent manner. Through the use of microscopy techniques we have shown that PKM-ζ is highly expressed in the cerebellar cortex, primarily in the PC, and by the use of pharmacological manipulations, it was found that PKM-ζ has an important role in regulating the acquisition of EBC. Through the…
Cites background from "Probability of shock in the presenc..."
...In this example, the US may occur in both the presence 27 and absence of the CS, and there is no correlation between the two; hence the tone and shock would be considered “unpaired” and a “truly random” control (Rescorla, 1968)....
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...27 and absence of the CS, and there is no correlation between the two; hence the tone and shock would be considered “unpaired” and a “truly random” control (Rescorla, 1968)....
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TL;DR: In this article , the authors examined whether over-expectation, a phenomenon that supports error-based learning theories, occurs in crickets and found that the response to the odour stimulus was partially recovered after one day.
Abstract: Abstract In associative learning in mammals, it is widely accepted that learning is determined by the prediction error, i.e., the error between the actual reward and the reward predicted by the animal. However, it is unclear whether error-based learning theories are applicable to the learning occurring in other non-mammalian species. Here, we examined whether overexpectation, a phenomenon that supports error-based learning theories, occurs in crickets. Crickets were independently trained with two different conditioned stimuli (CSs), an odour and a visual pattern, that were followed by an appetitive unconditioned stimulus (US). Then the two CSs were presented simultaneously as a compound, followed by the same US. This treatment resulted in a reduced conditioned response to the odour CS when tested immediately after training. However, the response to the CS was partially recovered after 1 day. These results are the first to show overexpectation and its spontaneous recovery in an invertebrate species. While the results showing overexpectation are in agreement with the prediction by the Rescorla-Wagner model, a major form of error-based learning theories, the ones showing spontaneous recovery are not. Our results suggest that conventional error-based learning models account for some, but not for all essential features of Pavlovian conditioning in crickets.
TL;DR: In this paper , interference and non-reinforced trials impaired participants' sensitivity to the contingencies as measured by signal detection theory's d', but they also enhanced detection of positive contingencies through a cue density effect.
Abstract: In a signal detection theory approach to associative learning, the perceived (i.e., subjective) contingency between a cue and an outcome is a random variable drawn from a Gaussian distribution. At the end of the sequence, participants report a positive cue-outcome contingency provided the subjective contingency is above some threshold. Some researchers have suggested that the mean of the subjective contingency distributions and the threshold are controlled by different variables. The present data provide empirical support for this claim. In three experiments, participants were exposed to rapid streams of trials at the end of which they had to indicate whether a target outcome O1 was more likely following a target cue X. Interfering treatments were incorporated in some streams to impend participants' ability to identify the objective X-O1 contingency: interference trials (X was paired with an irrelevant outcome O2), nonreinforced trials (X was presented alone), plus control trials (an irrelevant cue W was paired with O2). Overall, both interference and nonreinforced trials impaired participants' sensitivity to the contingencies as measured by signal detection theory's d', but they also enhanced detection of positive contingencies through a cue density effect, with nonreinforced trials being more susceptible to this effect than interference trials. These results are explicable if one assumes interference and nonreinforced trials impact the mean of the associative strength distribution, while the cue density influences the threshold. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
11 May 2023
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TL;DR: This "truly random" control procedure leads to a new conception of Pavlovian conditioning postulating that the contingency between CS and US, rather than the pairing of CS andUS, is the important event in conditioning.
Abstract: The traditional control procedures for Pavlovian conditioning are examined and each is found wanting. Some procedures introduce nonassociative factors not present in the experimental procedure while others transform the excitatory, experimental CS-US contingency into an inhibitory contingency. An alternative control procedure is suggested in which there is no contingency whatsoever between CS and US. This \"truly random\" control procedure leads to a new conception of Pavlovian conditioning postulating that the contingency between CS and US, rather than the pairing of CS and US, is the important event in conditioning. The fruitfulness of this new conception of Pavlovian conditioning is illustrated by 2 experimental results.
1,328 citations
301 citations
TL;DR: In this paper, three groups of dogs were trained with different kinds of Pavlovian fear conditioning for three different types of dogs: randomly and independently; for a second group, CSs predicted the occurrence of USs; and for a third group, S predicted the absence of the USs.
Abstract: Three groups of dogs were Sidman avoidance trained They then received different kinds of Pavlovian fear conditioning For one group CSs and USs occurred randomly and independently; for a second group, CSs predicted the occurrence of USs; for a third group, CSs predicted the absence of the USs The CSs were subsequently presented while S performed the avoidance response CSs which had predicted the occurrence or the absence of USs produced, respectively, increases and decreases in avoidance rate For the group with random CSs and USs in conditioning, the CS had no effect upon avoidance
160 citations
64 citations
TL;DR: Rats in an experimental group were given 30 trials of differential CER and then the CS+ and CS− were combined during CER extinction, resulting in less suppression for the experimental group than shown by a control group, interpreted as a demonstration of the active inhibitory properties of CS−.
Abstract: Rats in an experimental group were given 30 trials of differential CER and then the CS+ and CS− were combined during CER extinction. The combination resulted in less suppression for the experimental group than shown by a control group which had a CS+ and a formerly random stimulus combined during extinction. This was interpreted as a demonstration of the active inhibitory properties of CS−.
44 citations
"Probability of shock in the presenc..." refers background in this paper
...Although such an account is plausible for the present data, it fails to explain the active inhibition of fear found by Rescorla and LoLordo (1965), Rescorla (1966), and Hammond (1967)....
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