Multiple functions of context during conditioning: A developmental analysis

Carew, Maura B.; Rudy, Jerry W.

doi:10.1002/dev.420240305

Cited by 32 publications

(45 citation statements)

References 38 publications

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“…The present findings are consistent with other studies that have examined the role of context in memory retrieval (Carew & Rudy, 1991;Hall & Honey, 1989;Moye et al, 1992;Rosas & Bouton, 1997;Spear et al, 1980). Moye et al (1992) trained rat pups aged PND18, 26, and 35 to acquire and reverse a position habit in an aquatic T-maze.…”

Section: Discussionsupporting

confidence: 92%

Contextual modulation of spatial discrimination reversal in developing rats

2004

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Reversal of discrimination learning is influenced by manipulation of the training context. In adult and developing rats, contextual changes made between acquisition and reversal aid the learning of the new discrimination, possibly by serving to release proactive interference from the originally acquired discrimination (M. E. Bouton & D. C. Brooks, 1993; N. Spear, G. Smith, R. Bryan, & W. Gordon, 1980). The present study sought to examine this effect in an appetitive T-maze task, as a function of different contextual manipulations. Rats of three ages, Postnatal Day (PND) 19, PND23, and PND30, were tested for their ability to acquire and reverse a position habit in a T-maze. Contextual changes were made between acquisition and reversal sessions and consisted of one of three manipulations: (a) texture; the texture of the maze floor was changed via the addition or subtraction of wire mesh; (b) maze; subjects were reversed in a different maze that was identical in construction to the training maze, but differed in spatial location; (c) texture and maze; subjects were shifted to the new maze, the floor of which differed in texture from the training maze but was otherwise identical in construction. Results showed that the texture-maze combination was an effective aid to reversal learning at all ages tested. The texture alone, however, was not effective at any age. The maze alone also was an effective cue for reversal, but proved to have the greatest effect for PND30 subjects. During ontogeny, the contextual modulation of reversal learning is importantly influenced by the nature and the salience of the contextual cue.

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Section: Discussionsupporting

confidence: 92%

Contextual modulation of spatial discrimination reversal in developing rats

2004

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“…Several studies indicate that the theta rhythm is essential for proper memory function in the hippocampal formation, at both the synaptic and the behavioral levels (Huerta and Lisman 1993;Hyman et al 2003;Mitchell et al 1982). Our finding that EC layer II stellate cells develop mature MPOs between P14 and P18 may thus help to explain why many spatial memory functions are poorly developed or absent until the end of week 3 (Carew and Rudy 1991;Carman and Mactutus 2001;Green and Stanton 1987;Raunch and Raskin 1984;Rudy 1993;Rudy et al 1987). However, perhaps the most striking feature of the EC in particular-and thus the feature of most relevance to our study-is the EC representation of space.…”

Section: Functional Consequences Of Developmental Changesmentioning

confidence: 58%

Development of Theta Rhythmicity in Entorhinal Stellate Cells of the Juvenile Rat

Burton

Economo

Lee

et al. 2008

Journal of Neurophysiology

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. Mature stellate cells of the rat medial entorhinal cortex (EC), layer II, exhibit subthreshold membrane potential oscillations (MPOs) at theta frequencies (4 -12 Hz) in vitro. We find that MPOs appear between postnatal days 14 (P14) and 18 (P18) but show little further change by day 28ϩ (P28 -P32). To identify the factors responsible, we examined the electrical responses of developing stellate cells, paying attention to two currents thought necessary for mature oscillation: the h current I h , which provides the slow rectification required for resonance; and a persistent sodium current I NaP , which provides amplification of resonance. Responses to injected current revealed that P14 cells were often nonresonant with a relatively high resistance. Densities of I h and I NaP both rose by about 50% from P14 to P18. However, I h levels fell to intermediate values by P28ϩ. Given the nonrobust trend in I h expression and a previously demonstrated potency of even low levels of I h to sustain oscillation, we propose that resonance and MPOs are limited at P14 more by low levels of I NaP than of I h . The relative importance of I NaP for the development of MPOs is supported by simulations of a conductancebased model, which also suggest that general shunt conductance may influence the precise age when MPOs appear. In addition to our physiological study, we analyzed spine densities at P14, P18, and P28ϩ and found a vigorous synaptogenesis across the whole period. Our data predict that functions that rely on theta rhythmicity in the hippocampal network are limited until at least P18.

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“…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).…”

Section: Nih Public Accessmentioning

confidence: 99%

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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Multiple functions of context during conditioning: A developmental analysis

Cited by 32 publications

References 38 publications

Contextual modulation of spatial discrimination reversal in developing rats

Contextual modulation of spatial discrimination reversal in developing rats

Development of Theta Rhythmicity in Entorhinal Stellate Cells of the Juvenile Rat

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

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