1
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Effects of early social experience on sexual behavior in Japanese quail (Coturnix Japonica). Learn Behav 2022; 50:283-297. [DOI: 10.3758/s13420-022-00527-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2022] [Indexed: 11/08/2022]
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2
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Abstract
Arguably, the most difficult part of learning is deciding what to learn about. Should I associate the positive outcome of safely completing a street-crossing with the situation 'the car approaching the crosswalk was red' or with 'the approaching car was slowing down'? In this Perspective, we summarize our recent research into the computational and neural underpinnings of 'representation learning'-how humans (and other animals) construct task representations that allow efficient learning and decision-making. We first discuss the problem of learning what to ignore when confronted with too much information, so that experience can properly generalize across situations. We then turn to the problem of augmenting perceptual information with inferred latent causes that embody unobservable task-relevant information, such as contextual knowledge. Finally, we discuss recent findings regarding the neural substrates of task representations that suggest the orbitofrontal cortex represents 'task states', deploying them for decision-making and learning elsewhere in the brain.
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3
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Junod A, Opendak M, LeDoux JE, Sullivan RM. Development of Threat Expression Following Infant Maltreatment: Infant and Adult Enhancement but Adolescent Attenuation. Front Behav Neurosci 2019; 13:130. [PMID: 31293397 PMCID: PMC6603125 DOI: 10.3389/fnbeh.2019.00130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/03/2019] [Indexed: 12/21/2022] Open
Abstract
Early life maltreatment by the caregiver constitutes a major risk factor for the development of later-life psychopathologies, including fear-related pathologies. Here, we used an animal model of early life maltreatment induced by the Scarcity-Adversity Model of low bedding (LB) where the mother is given insufficient bedding for nest building while rat pups were postnatal days (PN) 8-12. To assess effects of maltreatment on the expression of threat-elicited defensive behaviors, animals underwent odor-shock threat conditioning at three developmental stages: late infancy (PN18), adolescence (PN45) or adulthood (>PN75) and tested the next day with odor only presentations (cue test). Results showed that in typically developing rats, the response to threat increases with maturation, although experience with maltreatment in early infancy produced enhanced responding to threat in infancy and adulthood, but a decrease in maltreated adolescents. To better understand the unique features of this decreased threat responding in adolescence, c-Fos expression was assessed within the amygdala and ventromedial prefrontal cortex (vmPFC) associated with the cued expression of threat learning. Fos counts across amygdala subregions were lower in LB rats compared to controls, while enhanced c-Fos expression was observed in the vmPFC prelimbic cortex (PL). Correlational analysis between freezing behavior and Fos revealed freezing levels were correlated with CeA in controls, although more global correlations were detected in LB-reared rats, including the BA, LA, and CeA. Functional connectivity analysis between brain regions showed that LB reared rats exhibited more diffuse interconnectivity across amygdala subnuclei, compared the more heterogeneous patterns observed in controls. In addition, functional connectivity between the IL and LA switched from positive to negative in abused adolescents. Overall, these results suggest that in adolescence, the unique developmental decrease in fear expression following trauma is associated with distinct changes in regional function and long-range connectivity, reminiscent of pathological brain function. These results suggest that early life maltreatment from the caregiver perturbs the developmental trajectory of threat-elicited behavior. Indeed, it is possible that this form of trauma, where the infant's safety signal or "safe haven" (the caregiver) is actually the source of the threat, produces distinct outcomes across development.
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Affiliation(s)
- Anouchka Junod
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY, United States
- Child and Adolescent Psychiatry, New York University School of Medicine, New York, NY, United States
| | - Maya Opendak
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY, United States
- Child and Adolescent Psychiatry, New York University School of Medicine, New York, NY, United States
| | - Joseph E. LeDoux
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
| | - Regina M. Sullivan
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY, United States
- Child and Adolescent Psychiatry, New York University School of Medicine, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
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Gill KM, Miller SA, Grace AA. Impaired contextual fear-conditioning in MAM rodent model of schizophrenia. Schizophr Res 2018; 195:343-352. [PMID: 28927551 PMCID: PMC5854517 DOI: 10.1016/j.schres.2017.08.064] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 12/19/2022]
Abstract
The methylazoxymethanol acetate (MAM) rodent neurodevelopmental model of schizophrenia exhibits aberrant dopamine system activation attributed to hippocampal dysfunction. Context discrimination is a component of numerous behavioral and cognitive functions and relies on intact hippocampal processing. The present study explored context processing behaviors, along with dopamine system activation, during fear learning in the MAM model. Male offspring of dams treated with MAM (20mg/kg, i.p.) or saline on gestational day 17 were used for electrophysiological and behavioral experiments. Animals were tested on the immediate shock fear conditioning paradigm, with either different pre-conditioning contexts or varying amounts of context pre-exposure (0-10 sessions). Amphetamine-induced locomotor activity and dopamine neural activity was measured 1-week after fear conditioning. Saline, but not MAM animals, demonstrated enhanced fear responses following a single context pre-exposure in the conditioning context. One week following fear learning, saline rats with 2 or 7min of context pre-exposure prior to fear conditioning also demonstrated enhanced amphetamine-induced locomotor response relative to MAM animals. Dopamine neuron recordings showed fear learning-induced reductions in spontaneous dopamine neural activity in MAM rats that was further reduced by amphetamine. Apomorphine administration confirmed that reductions in dopamine neuron activity in MAM animals resulted from over excitation, or depolarization block. These data show a behavioral insensitivity to contextual stimuli in MAM rats that coincide with a less dynamic dopamine response after fear learning.
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Affiliation(s)
- Kathryn M Gill
- University of Pittsburgh, Pittsburgh, PA 15260, Departments of Neuroscience, Psychiatry and Psychology, USA.
| | - Sarah A Miller
- University of Pittsburgh, Pittsburgh, PA 15260, Departments of Neuroscience, Psychiatry and Psychology, USA
| | - Anthony A Grace
- University of Pittsburgh, Pittsburgh, PA 15260, Departments of Neuroscience, Psychiatry and Psychology, USA
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Revillo D, Cotella E, Paglini M, Arias C. Contextual learning and context effects during infancy: 30years of controversial research revisited. Physiol Behav 2015; 148:6-21. [DOI: 10.1016/j.physbeh.2015.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/25/2014] [Accepted: 02/03/2015] [Indexed: 12/15/2022]
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Miguez G, Soares JS, Miller RR. The role of test context in latent inhibition of conditioned inhibition: Part of a search for general principles of associative interference. Learn Behav 2015; 43:228-42. [PMID: 25875792 PMCID: PMC4515373 DOI: 10.3758/s13420-015-0175-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In two lick suppression experiments with rats, we assessed interference with behavior indicative of conditioned inhibition by a latent inhibition treatment as a function of test context. We asked what effect the test context has, given identical latent inhibition treatments in Phase 1 and identical conditioned inhibition trainings in Phase 2. In Experiment 1, an AAA versus AAB context-shift design determined that the latent inhibition treatment in Phase 1 attenuated behavior indicative of the conditioned inhibition training administered in Phase 2, regardless of the test context, which could reflect a failure to either acquire or express conditioned inhibition. In Experiment 2, an ABA versus ABB design showed that test performance in Contexts A and B reflected the treatments that had been administered in those contexts (i.e., conditioned inhibition was observed in Context B but not A), which could reflect either the context specificity of either latent inhibition or conditioned inhibition. In either case, latent inhibition of conditioned inhibition training in at least some situations was seen to reflect an expression deficit rather than an acquisition deficit. These data, in conjunction with prior reports, suggest that latent inhibition is relatively specific to the context in which it was administered, whereas conditioned inhibition is specific to its training context only when it is the second-learned relationship concerning the target cue. These experiments are part of a larger effort to delineate control by the test context of two-phase associative interference, as a function of the nature of target training and the nature of interference training.
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Affiliation(s)
- Gonzalo Miguez
- State University of New York at Binghamton
- Universidad de Chile
| | - Julia S. Soares
- State University of New York at Binghamton
- University of California, Santa Cruz
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7
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Castello S, Revillo D, Molina J, Arias C. Ethanol-induced tolerance and sex-dependent sensitization in preweanling rats. Physiol Behav 2015; 139:50-8. [DOI: 10.1016/j.physbeh.2014.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/31/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
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8
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Revillo DA, Gaztañaga M, Aranda E, Paglini MG, Chotro MG, Arias C. Context-dependent latent inhibition in preweanling rats. Dev Psychobiol 2014; 56:1507-17. [PMID: 25209712 DOI: 10.1002/dev.21236] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 06/11/2014] [Indexed: 11/10/2022]
Abstract
Preexposure to a conditioned stimulus (CS) usually weakens conditioning, an effect known as latent inhibition. Similar to other learning interference effects, latent inhibition has been characterized as context-dependent, which means that the magnitude of this effect can be attenuated by changing the context between the different phases of the procedure (e.g., preexposure and conditioning). Latent inhibition has been found with a variety of procedures in infant rats, but the few studies that examined the context-dependency of this phenomenon during this ontogenetic period found no context-change effect. The present study explored the context-dependency of latent inhibition during infancy using a conditioned taste aversion preparation and employing contexts enriched with distinctive odors to increase the possible efficacy of the context manipulation. Experiment 1 showed that three preexposures to the CS (saccharin) were sufficient to retard conditioning to the same CS, although this effect was also observed in a control group preexposed to an alternative taste stimulus (saline), in comparison with a non-preexposed control group. In Experiment 2a, the CS-preexposure effect was found to be specific to the preexposed CS when the number of preexposures was increased. This effect was revealed as context-dependent in Experiment 2b, since it was attenuated by changing the context between preexposure and conditioning. The present result is consistent with recent studies showing the context-dependency of extinction in preweanling rats, thus demonstrating these animals' capacity to learn about context early on in their development.
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Affiliation(s)
- D A Revillo
- Instituto de Investigación Médica M. y M. Ferreyra, IMMF-INIMEC-CONICET-UNC, Friuli 2434, Córdoba, Argentina
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9
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Burman MA, Erickson KJ, Deal AL, Jacobson RE. Contextual and auditory fear conditioning continue to emerge during the periweaning period in rats. PLoS One 2014; 9:e100807. [PMID: 24977415 PMCID: PMC4076234 DOI: 10.1371/journal.pone.0100807] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/29/2014] [Indexed: 01/19/2023] Open
Abstract
Anxiety disorders often emerge during childhood. Rodent models using classical fear conditioning have shown that different types of fear depend upon different neural structures and may emerge at different stages of development. For example, some work has suggested that contextual fear conditioning generally emerges later in development (postnatal day 23–24) than explicitly cued fear conditioning (postnatal day 15–17) in rats. This has been attributed to an inability of younger subjects to form a representation of the context due to an immature hippocampus. However, evidence that contextual fear can be observed in postnatal day 17 subjects and that cued fear conditioning continues to emerge past this age raises questions about the nature of this deficit. The current studies examine this question using both the context pre-exposure facilitation effect for immediate single-shock contextual fear conditioning and traditional cued fear conditioning using Sprague-Dawley rats. The data suggest that both cued and contextual fear conditioning are continuing to develop between PD 17 and 24, consistent with development occurring the in essential fear conditioning circuit.
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Affiliation(s)
- Michael A. Burman
- Department of Psychology, Center for Excellence in the Neurosciences, University of New England, Biddeford, Maine, United States of America
- * E-mail:
| | - Kristen J. Erickson
- Department of Psychology, Center for Excellence in the Neurosciences, University of New England, Biddeford, Maine, United States of America
| | - Alex L. Deal
- Department of Psychology, Center for Excellence in the Neurosciences, University of New England, Biddeford, Maine, United States of America
| | - Rose E. Jacobson
- Department of Biology, University of New England, Biddeford, Maine, United States of America
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10
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Revillo D, Molina J, Paglini M, Arias C. A sensory-enhanced context allows renewal of an extinguished fear response in the infant rat. Behav Brain Res 2013; 253:173-7. [DOI: 10.1016/j.bbr.2013.07.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 07/16/2013] [Accepted: 07/18/2013] [Indexed: 10/26/2022]
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11
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Revillo DA, Castello S, Paglini G, Arias C. Reacquisition, reinstatement, and renewal of a conditioned taste aversion in preweanling rats. Dev Psychobiol 2013; 56:713-25. [DOI: 10.1002/dev.21140] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 04/26/2013] [Indexed: 12/17/2022]
Affiliation(s)
- D. A. Revillo
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba; Friuli 2434 Córdoba Argentina
| | - S. Castello
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba; Friuli 2434 Córdoba Argentina
| | - G. Paglini
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba; Friuli 2434 Córdoba Argentina
| | - C. Arias
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba; Friuli 2434 Córdoba Argentina
- Facultad de Psicologia; Universidad del País Vasco-UPV/EHU; Avda Tolosa 70 San Sebastián Spain
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12
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Mickley GA, Hoxha Z, DiSorbo A, Wilson GN, Remus JL, Biesan O, Ketchesin KD, Ramos L, Luchsinger JR, Prodan S, Rogers M, Wiles NR, Hoxha N. Latent inhibition of a conditioned taste aversion in fetal rats. Dev Psychobiol 2013; 56:435-47. [DOI: 10.1002/dev.21110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 02/18/2013] [Indexed: 12/14/2022]
Affiliation(s)
- G. Andrew Mickley
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Zana Hoxha
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Anthony DiSorbo
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Gina N. Wilson
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Jennifer L. Remus
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Orion Biesan
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Kyle D. Ketchesin
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Linnet Ramos
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Joseph R. Luchsinger
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Suzanna Prodan
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Morgan Rogers
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Nathanael R. Wiles
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
| | - Nita Hoxha
- The Neuroscience Program; Baldwin Wallace University; 275 Eastland Rd. Berea OH 44017
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13
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Akers KG, Arruda-Carvalho M, Josselyn SA, Frankland PW. Ontogeny of contextual fear memory formation, specificity, and persistence in mice. Learn Mem 2012; 19:598-604. [PMID: 23161449 DOI: 10.1101/lm.027581.112] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pinpointing the precise age when young animals begin to form memories of aversive events is valuable for understanding the onset of anxiety and mood disorders and for detecting early cognitive impairment in models of childhood-onset disorders. Although these disorders are most commonly modeled in mice, we know little regarding the development of learning and memory in this species because most previous studies have been restricted to rats. Therefore, in the present study, we constructed an ontogenetic timeline of contextual fear memory ranging from infancy to adulthood in mice. We found that the ability of mice to form long-term context-shock associations emerged ∼13-14 d of age, which is several days earlier than previously reported for rats. Although the ability to form contextual fear memories remained stable from infancy into adulthood, infant mice had shorter-lasting memories than adolescent and adult mice. Furthermore, we found that mice subjected to fetal alcohol exposure showed a delay in the developmental emergence of contextual fear memory, illustrating the utility of this ontogenetic approach in detecting developmental delays in cognitive function stemming from maladaptive early life experience.
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Affiliation(s)
- Katherine G Akers
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada, M5G 1X8
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14
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Pisano M, Ferreras S, Krapacher F, Paglini G, Arias C. Re-examining the ontogeny of the context preexposure facilitation effect in the rat through multiple dependent variables. Behav Brain Res 2012; 233:176-90. [DOI: 10.1016/j.bbr.2012.04.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 11/16/2022]
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Revillo DA, Arias C, Spear NE. The unconditioned stimulus pre-exposure effect in preweanling rats in taste aversion learning: role of the training context and injection cues. Dev Psychobiol 2012; 55:193-204. [PMID: 22252883 DOI: 10.1002/dev.21011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 01/02/2012] [Indexed: 01/27/2023]
Abstract
The unconditioned stimulus pre-exposure effect (US-PE) refers to the interference paradigm in which acquisition of the conditioned response is retarded due to prior experience with the US. Most studies analyzing the psychological mechanisms underlying this effect have been conducted with adult rats. The most widely accepted hypothesis explains this effect as a contextual blocking effect. Contextual cues associated with the US block the conditioned stimulus (CS)-US association during conditioning. The modulatory role of a context devoid of distinctive olfactory attributes is not observable until approximately PD23 in rats, including modulation of interference paradigms such as latent inhibition or extinction. In this study, we analyzed US-PE in preweanling rats along with the role of the training context in this effect in terms of conditioned taste aversion preparation. Pre-exposure to LiCl before conditioning retarded the acquisition of taste aversion. The US-PE was observed in preweanling rats when, during pre-exposure, subjects were exposed to the conditioning context, and this effect was not attenuated either by the administration of the US in a familiar environment (Experiment 1a), or by the presence of an alternative, more salient context during pre-exposure (Experiment 1b). Additionally, the US-PE was still observed when the route by which the US was administered was changed between the pre-exposure and conditioning phases (Experiment 2a) as well as when the injection cues were removed during conditioning (Experiment 2b). These experiments show a strong US-PE in preweanling rats and fail to support the contextual blocking hypothesis, at least in this stage of ontogeny.
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Affiliation(s)
- D A Revillo
- Universidad Nacional de Córdoba, Córdoba, CP 5000 Argentina
| | - C Arias
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC - CONICET), Córdoba, C.P 5000, Argentina.,Universidad Nacional de Córdoba, Córdoba, CP 5000 Argentina
| | - N E Spear
- Center for Developmental Psychobiology, Binghamton University, Binghamton, NY 13902-6000, USA
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Castello S, Bobbio A, Orellana E, Arias C. Signaling the unconditioned stimulus during the preexposure phase does not attenuate the unconditioned stimulus preexposure effect in preweanling rats. Dev Psychobiol 2011; 54:808-17. [DOI: 10.1002/dev.21001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/08/2011] [Indexed: 12/17/2022]
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17
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Akers KG, Candelaria-Cook FT, Rice JP, Johnson TE, Hamilton DA. Cued platform training reveals early development of directional responding among preweanling rats in the Morris water task. Dev Psychobiol 2010; 53:1-12. [DOI: 10.1002/dev.20480] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Foster JA, Burman MA. Evidence for hippocampus-dependent contextual learning at postnatal day 17 in the rat. Learn Mem 2010; 17:259-66. [PMID: 20427514 DOI: 10.1101/lm.1755810] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
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.
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Affiliation(s)
- Jennifer A Foster
- Program in Neuroscience, Bates College, Lewiston, Maine 04240-6028, USA
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Manrique T, Gámiz F, Morón I, Ballesteros MA, Gallo M. Peculiar modulation of taste aversion learning by the time of day in developing rats. Dev Psychobiol 2009; 51:147-57. [PMID: 19016240 DOI: 10.1002/dev.20354] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The ontogeny of the temporal context modulation of conditioned taste aversion was studied in male Wistar rats using a palatable 1% NaCl solution. A procedure that included two saline preexposures, a single pairing saline-lithium chloride (0.15 M; 1% b.w.) either at the same or a different time of day of preexposures and a one-bottle test at the same time than preexposure was applied. Four age groups (PN32, PN48, PN64, and PN100) covering the complete range from adolescence to the adult period were tested. The results showed no effect of a temporal context shift in PN32. A peculiar enhancement of temporal context-specific saline aversions was exhibited by PN48 and PN64 rats, while the adult typical temporal context specificity of latent inhibition was only evident in PN100 rats. The results are discussed in terms of the peculiar brain functional organization during a protracted adolescence period.
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Affiliation(s)
- Tatiana Manrique
- Institute of Neurosciences F. Oloriz., University of Granada, Granada, Spain.
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Moustafa AA, Myers CE, Gluck MA. A neurocomputational model of classical conditioning phenomena: a putative role for the hippocampal region in associative learning. Brain Res 2009; 1276:180-95. [PMID: 19379717 DOI: 10.1016/j.brainres.2009.04.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 03/31/2009] [Accepted: 04/09/2009] [Indexed: 10/20/2022]
Abstract
Some existing models of hippocampal function simulate performance in classical conditioning tasks using the error backpropagation algorithm to guide learning (Gluck, M.A., and Myers, C.E., (1993). Hippocampal mediation of stimulus representation: a computational theory. Hippocampus, 3(4), 491-516.). This algorithm is not biologically plausible because it requires information to be passed backward through layers of nodes and assumes that the environment provides information to the brain about what correct outputs should be. Here, we show that the same information-processing function proposed for the hippocampal region in the Gluck and Myers (1993) model can also be implemented in a network without using the backpropagation algorithm. Instead, our newer instantiation of the theory uses only (a) Hebbian learning methods which match more closely with synaptic and associative learning mechanisms ascribed to the hippocampal region and (b) a more plausible representation of input stimuli. We demonstrate here that this new more biologically plausible model is able to simulate various behavioral effects, including latent inhibition, acquired equivalence, sensory preconditioning, negative patterning, and context shift effects. In addition, the newer model is able to address some new phenomena including the effect of the number of training trials on blocking and overshadowing.
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Affiliation(s)
- Ahmed A Moustafa
- Memory Disorders Project and Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, 197 University Avenue, Newark, NJ 07102, USA.
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21
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Yap CSL, Richardson R. Extinction in the developing rat: an examination of renewal effects. Dev Psychobiol 2007; 49:565-75. [PMID: 17680605 DOI: 10.1002/dev.20244] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the present series of experiments the context-specificity of extinction was examined from a developmental perspective. For postnatal day (PN) 23 rats, renewal of freezing to an aversive odor conditioned stimulus (CS) was observed when rats were conditioned in Context A, extinguished in Context B, and tested in Context A (i.e., ABA renewal). This effect was not observed in PN16 rats, which is consistent with previous studies suggesting that rats < approximately PN20 are impaired in encoding contextual information [i.e., Carew and Rudy [1991]. Developmental Psychobiology, 24, 191-209]. Subsequent experiments demonstrated that for rats conditioned at PN16 and tested at PN23, contextual regulation of extinction performance depended on the age at which extinction occurred. Specifically, ABA renewal was observed in rats given extinction training at PN22 but not in rats given extinction training at PN17. These latter results show that whether or not context regulates the expression of an ambiguous memory is determined by the animal's age when the memory becomes ambiguous.
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Affiliation(s)
- Carol S L Yap
- School of Psychology, The University of New South Wales, Sydney 2052, Australia.
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Turnock M, Becker S. A neural network model of hippocampal-striatal-prefrontal interactions in contextual conditioning. Brain Res 2007; 1202:87-98. [PMID: 17889839 DOI: 10.1016/j.brainres.2007.06.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 06/20/2007] [Indexed: 11/26/2022]
Abstract
The hippocampus is thought to be critical for encoding contextually bound memories and setting the context for ongoing behavior. However, the mechanisms by which the hippocampal-cortical system controls behavior are poorly understood. We propose a computational model in which the hippocampus exerts contextual control over motivated behavior by gating prefrontal cortex inputs to the nucleus accumbens. The model integrates the episodic memory functions of the hippocampus, the prefrontal role in representing the motivational stimuli and cognitive control, and the role of striatal regions in conditioned learning within a single theoretical framework. Simulation results are consistent with the hypothesis that hippocampal-prefrontal interactions may act as the neural substrate that allows contextual cues to override conditioned responses at the level of the nucleus accumbens. Prefrontal and hippocampal input overrides the predominant CS-US association if the context is inconsistent, and promotes flexible selection of previously learned associations and behaviors. Simulated transection of the fornix, effectively eliminating hippocampal and prefrontal influence over the nucleus accumbens, abolishes normal contextual modulation of behavior. The model is consistent with a wide range of empirical data.
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Affiliation(s)
- Matthew Turnock
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Building 34, Room 312, 1280 Main Street West, Hamilton, Canada ON L8S 4K1
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