A sensory-enhanced context facilitates learning and multiple measures of unconditioned stimulus processing in the preweanling rat.

Brasser, Susan M.; Spear, Norman E.

doi:10.1037/0735-7044.112.1.126

Cited by 38 publications

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“…However, Spear and his colleagues have proposed a hypothesis that may help to understand this effect (McKinzie and Spear 1995;Spear 1998, 2004). These authors observed that during conditioning, preweanling rats showed an increase in the orientation response to the CS (Kraebel et al 1998) and enhanced responses to the US (Brasser and Spear 1998) when trained in a sensory-enriched context and when the CS and US were contiguous. According to these authors, these changes may favor (particularly during infancy) processing of the events that constitute the conditioning episode, thereby facilitating learning (Brasser and Spear 1998;Kraebel et al 1998).…”

Section: Discussionmentioning

confidence: 99%

“…These authors observed that during conditioning, preweanling rats showed an increase in the orientation response to the CS (Kraebel et al 1998) and enhanced responses to the US (Brasser and Spear 1998) when trained in a sensory-enriched context and when the CS and US were contiguous. According to these authors, these changes may favor (particularly during infancy) processing of the events that constitute the conditioning episode, thereby facilitating learning (Brasser and Spear 1998;Kraebel et al 1998). Given that Spear and his collaborators limited their studies to the acquisition phase of conditioning, it would be interesting to extend these observations to extinction training, in order to explore whether the salience of the context also affects processing of the CS during extinction in preweanling rats.…”

Section: Discussionmentioning

confidence: 99%

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Reinstatement of an extinguished fear conditioned response in infant rats

et al. 2015

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Although it is currently accepted that the extinction effect reflects new context-dependent learning, this is not so clear during infancy, because some studies did not find recovery of the extinguished conditioned response (CR) in rodents during this ontogenetic stage. However, recent studies have shown the return of an extinguished CR in infant rats. The present study analyzes the possibility of recovering an extinguished CR with a reinstatement procedure in a fear conditioning paradigm, on PD17 (Experiments 1 -4) and on PD24 (Experiment 5), while exploring the role of the olfactory content of the context upon the reinstatement effect during the preweanling period. Preweanling rats expressed a previously extinguished CR after a single experience with an unsignaled US. Furthermore, this result was only found when subjects were trained and tested in contexts that included an explicit odor, but not in standard experimental cages. Finally, Experiment 5 demonstrated the reinstatement effect on PD24 in a standard context. These results support the notion that extinction during infancy has the same characteristics as those described for extinction that occurs in adulthood. Instead of postulating a different mechanism for extinction during infancy, we propose that it may be more accurate to view the problem in terms of the variables that may differentially modulate the extinction effect according to the stages of ontogeny.Extinction can be defined as a procedure consisting of repeated presentations of a conditioned stimulus (CS) after conditioning (Pavlov 1927). As a result of this training, the conditioned response (CR) usually decays progressively. It is currently accepted that the extinction effect reflects new learning, because the extinguished CR can be recovered after a retention interval (spontaneous recovery), after the presentation of the unconditioned stimulus-the US, (reinstatement), or after a context changeknown as the renewal effect (Pavlov 1927;Bouton 2002;Quirk and Mueller 2008). All of these findings have been interpreted as evidence that the extinction effect is a context-dependent phenomenon (Bouton 2002(Bouton , 2004.Although extinction has been widely studied in adult organisms, only a few studies have focused on this effect during infancy, and these have yielded inconsistent results. In particular, in some of these studies the authors did not find recovery of the CR once it was extinguished (Kim and Richardson 2010), while others have reported renewal, more rapid reacquisition, and reinstatement in taste aversion learning (Revillo et al. 2014a), and spontaneous recovery (Revillo et al. 2014b) and renewal (Revillo et al. 2013 in fear conditioning. Those authors that did not find recovery of the extinguished CR suggested that in infancy, extinction is a qualitatively different phenomenon to that observed in adulthood, and that during infancy it results in erasure of the CS -US association instead of the production of new learning (Kim and Richardson 2010). However, more recent evidence of recovery a...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Reinstatement of an extinguished fear conditioned response in infant rats

et al. 2015

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“…It should not be a surprise that infant rats --in some cases--show more contextual fear conditioning than adults, given other instances in which infants have seemed more sensitive to context than older animals: CS conditioning is disrupted by a change in olfactory context more extremely for infants than adults (Solheim, Hensler, & Spear, 1980); Pavlovian trace conditioning is regularly facilitated in infant rats by a salient olfactory and visual context but unaffected by the same manipulations in adults (Brasser & Spear, 1998;McKinzie & Spear, 1995); the presence of a familiar context such as odor of the rat's home is more likely to affect infant learning than adult learning (Spear, Kucharski, & Hoffmann, 1985); and infants are more likely than older animals to show enhanced unconditioned responding to visual, auditory and tactile stimuli in the presence of a context rich in novel odor (Brasser & Spear, 1998;Kraebel, Vizvary, & Spear, 1998).…”

Section: Nih Public Accessmentioning

confidence: 99%

“…In these cases, infants have seemed equally or more effective in contextual fear conditioning than older animals, including adults (e.g., Brasser & Spear, 2004;Carew & Rudy, 1991;Lariviere et al, 1990). And when a discrete auditory CS predicts the footshock within a salient olfactory context, contextual fear conditioning in the infant exceeds that in the adult, even when conditioning to the CS is held constant (Brasser & Spear, 2004;Mckinzie & Spear, 1995).It should not be a surprise that infant rats --in some cases--show more contextual fear conditioning than adults, given other instances in which infants have seemed more sensitive to context than older animals: CS conditioning is disrupted by a change in olfactory context more extremely for infants than adults (Solheim, Hensler, & Spear, 1980); Pavlovian trace conditioning is regularly facilitated in infant rats by a salient olfactory and visual context but unaffected by the same manipulations in adults (Brasser & Spear, 1998;McKinzie & Spear, 1995); the presence of a familiar context such as odor of the rat's home is more likely to affect infant learning than adult learning (Spear, Kucharski, & Hoffmann, 1985); and infants are more likely than older animals to show enhanced unconditioned responding to visual, auditory and tactile stimuli in the presence of a context rich in novel odor (Brasser & Spear, 1998;Kraebel, Vizvary, & Spear, 1998).Thus, the goal of the present series of experiments was to examine fear conditioning to an olfactory context, the type of situation where infant rats seem to show the strongest disposition for contextual conditioning. They were intended to replicate and extend previous experiments (viz., Brasser & Spear, 2004) suggesting that contextual fear conditioning in infants may exceed that of adults, particularly when an auditory CS within an olfactory context also predicts the US.…”

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Contextual fear conditioning differs for infant, adolescent, and adult rats

Esmoris-Arranz¹,

Méndez²,

Spear³

2008

Behavioural Processes

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Contextual fear conditioning was tested in infant, adolescent, and adult rats in terms of Pavlovian conditioned suppression. When a discrete auditory conditioned stimulus (CS) was paired with footshock (unconditioned stimulus, US) within the largely olfactory context, infants and adolescents conditioned to the context with substantial effectiveness but adult rats did not. When unpaired presentations of the CS and US occurred within the context, contextual fear conditioning was strong for adults, weak for infants, but about as strong for adolescents as when pairings of CS and US occurred in the context. Nonreinforced presentations of either the CS or context markedly reduced contextual fear conditioning in infants, but, in adolescents, CS extinction had no effect on contextual fear conditioning, although context extinction significantly reduced it. Neither CS extinction nor context extinction affected responding to the CS-context compound in infants, suggesting striking discrimination between the compound and its components. Female adolescents showed the same lack of effect of component extinction on response to the compound as infants, but CS extinction reduced responding to the compound in adolescent males, a sex difference seen also in adults. Theoretical implications are discussed for the development of perceptual-cognitive processing and hippocampus role. Keywordscontextual fear conditioning; fear extinction; learning; olfactory context; hippocampus; ontogeny Contextual fear conditioning has received a lot of attention from behavioral neuroscientists during the last decade (e.g., Anagnostaras, Gale, & Fanselow, 2001;Fanselow & Poulos, 2004;Phillips & LeDoux, 1992). The purpose of this report is to assess the effectiveness of contextual fear conditioning experiments by rats at each of three disparate periods of ontogeny: late infancy, adolescence and early adulthood. The ontogeny of contextual fear conditioning is of interest because --in relation to conditioning of other events within the context--it can Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. provide a window to the ontogeny of encoding and memory organization (e.g., Brasser & Spear, 2004;Lariviere, Chen, & Spear, 1990), and because it has been used as a marker for the development of brain function important for memory (e.g., Pugh & Rudy, 1996;Rudy & Morledge, 1994). NIH Public AccessSeveral experiments led to the conclusion that acquisition of an aversion to a particular context paired with footshock is less effective in rats during late infancy (postnatal days 17-20, P17-20) than in weaned juvenile ...

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“…Rat pups as young as PD 17 can express conditioned fear after explicit-cue fear conditioning (Rudy 1992(Rudy , 1993Stanton 2000;Barnet and Hunt 2005), indicating that the amygdala and output systems are intact. Although PD 17 rats have demonstrated conditioning to an enhanced context (Brasser and Spear 1998), most studies demonstrate that rats younger than PD 23 cannot demonstrate long-term memory for contextual fear conditioning (Rudy 1993(Rudy , 1994Stanton 2000;Raineki et al 2009), which has been interpreted as a delay in the emergence of hippocampus function. This is curious given that rat pups younger than PD 23 can complete many hippocampusdependent tasks (see Stanton 2000), express a fearful response, and show context-dependent effects, such as latent inhibition and renewal following extinction Richardson 2005, 2007).…”

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Evidence for hippocampus-dependent contextual learning at postnatal day 17 in the rat

Foster¹,

Burman²

2010

Learn. Mem.

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Long-term memory for fear of an environment (contextual fear conditioning) emerges later in development (postnatal day; PD 23) than long-term memory for fear of discrete stimuli (PD 17). As contextual, but not explicit cue, fear conditioning relies on the hippocampus; this has been interpreted as evidence that the hippocampus is not fully developed until PD 23. Alternatively, the hippocampus may be functional prior to PD 23, but unable to cooperate with the amygdala for fearful learning. The current experiments investigate this by separating the phases of conditioning across developmental stages. Rats were allowed to learn about the context on one day and to form the fearful association on another. Rats exposed to the context on PD 17 exhibited significant fear only when trained and tested a week later (PD 23, 24), but not on consecutive days (PD 18, 19), demonstrating that rats can learn about a context as early as PD 17. Further experiments clarify that it is associative mechanisms that are developing between PD 18 and 23. Finally, the hippocampus was lesioned prior to training to ensure the task is being solved in a hippocampus-dependent manner. These data provide compelling evidence that the hippocampus is functional for contextual learning as early as PD 17, however, its connection to the amygdala or other relevant brain structures may not yet be fully developed.Research in recent decades has yielded a great deal of information regarding the neural substrates of cognitive processes, such as emotional expression and learning and memory in adult organisms, but relatively little regarding the neural substrates underlying these processes in developing organisms. Pavlovian fear conditioning has proven a useful tool for studying cognition in adult organisms (Malenka and Nicoll 1997;Anagnostaras et al. 2001;Maren 2001) and ought to be an especially powerful tool to help uncover the neural substrates of various cognitive processes in adolescent organisms due to its reliance on relatively basic sensory, motor, and affective systems (Campbell and Spear 1972). Indeed, several behavioral and toxicological studies have already adapted methods pioneered in the adult for use in developing animals with great success (Rudy

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A sensory-enhanced context facilitates learning and multiple measures of unconditioned stimulus processing in the preweanling rat.

Cited by 38 publications

References 57 publications

Reinstatement of an extinguished fear conditioned response in infant rats

Reinstatement of an extinguished fear conditioned response in infant rats

Contextual fear conditioning differs for infant, adolescent, and adult rats

Evidence for hippocampus-dependent contextual learning at postnatal day 17 in the rat

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