1
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Miller RR. The Illusion of Pure Reason in Science: A Cautionary Note. Behav Processes 2023; 207:104863. [PMID: 36965606 DOI: 10.1016/j.beproc.2023.104863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 03/27/2023]
Abstract
Introspection tells people that their behavior is both consciously reasoned and functional (i.e., rational), at least based on the evidence available to them. In contrast, research has found that much human behavior reported to be consciously determined, is strongly influenced by heuristics and the mechanistic principles of associative learning that usually function unconsciously and are sometimes sub-optimal. Scientists are trained to base their conclusions on a rational analysis of evidence, which enhances the scientific validity of their conclusions. But scientific training appears to do little to constrain the role of unconscious heuristics. The present point is that scientists are humans and, as such, they are subject to the influence of heuristics in their scientific conclusions just as laypeople are in their everyday behavior. As an example, the availability heuristic and how it seemingly feeds the repetition-induced truth effect are described. One consequence of this is that failures to replicate frequently cited papers do little to devalue the irreplicable reports. Although unconscious heuristics influence the scientific thinking of researchers, scientists are typically unaware of the role of these heuristics due to their operating below the horizon of introspection. This appears to explain the persistence, in light of overwhelming evidence to the contrary, of the views by many researchers that 'a prediction error is necessary for learning' and that 'reactivated memories have to be reconsolidated to be retained for future access.'
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2
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LeDoux JE. The day I told Karim Nader, "Don't do the study". Brain Res Bull 2022; 189:1-3. [PMID: 35981628 DOI: 10.1016/j.brainresbull.2022.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/02/2022]
Abstract
Karim Nader changed the course of memory research by reviving interest in the mostly forgotten topic of post-retrieval manipulations of memory. In this paper I summarize the events leading up to his ground-breaking study in my lab on so-called memory reconsolidation, and the effects of that study on the field.
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Affiliation(s)
- Joseph E LeDoux
- Center for Neural Science, New York University, New York, NY, USA; Department of Psychology, New York University, New York, NY, USA; Max-Planck-NYU Center for Language, Music, and Emotion (CLaME), New York University, New York, NY, USA; Department of Psychiatry, New York University Langone Medical School, New York, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical School, New York, NY, USA
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Miller RR. Failures of memory and the fate of forgotten memories. Neurobiol Learn Mem 2021; 181:107426. [PMID: 33794376 DOI: 10.1016/j.nlm.2021.107426] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 03/16/2021] [Accepted: 03/25/2021] [Indexed: 11/28/2022]
Abstract
This review is intended primarily to provide cognitive benchmarks and perhaps a new mindset for behavioral neuroscientists who study memory. Forgetting, defined here broadly as all types of decreases in acquired responding to stimulus-specific eliciting cues, is commonly attributed to one or more of the following families of mechanisms: (1) (4) associative interference by information similar to, but different from the target information, (2) spontaneous decay of memory with increasing retention intervals, (3) displacement from short-term memory by irrelevant information, and (4) inadequate retrieval cues at test. I briefly review each of these families and discuss data suggesting that many apparent instances of spontaneous forgetting and displacement from short-term memory can be viewed as variants of inadequate retrieval cues and associative interference. The potential for recovery of target information from each of these families of forgetting without further relevant training is then reviewed, with a conclusion that most forgetting is due to retrieval failure as opposed to irreversible erasure of memory. The more general point is made that there are logical problems with ever talking about attenuating or erasing a memory as a consequence of conventional forgetting or disrupted consolidation/reconsolidation. Consideration is then given to the frequently overlooked but highly beneficial consequences of most forgetting. Lastly, the major variables that moderate forgetting are summarized, including (a) the similarities of the target information including training context to the explicit retrieval cues and context present at test, (b) the similarities of potentially interfering acquired information to the retrieval cues and context present at test, and (c) the retention interval for the target information relative to that for the potentially interfering information. Appropriate manipulation of these variables can reduce forgetting, and increase forgetting when desired.
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Affiliation(s)
- Ralph R Miller
- Department of Psychology, SUNY-Binghamton, PO Box 6000, Binghamton, NY, USA.
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4
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Kundey SM, Lessard A, Fitz A, Panwar M. Tiger salamanders’ (Ambystoma tigrinum) response retention and usage of visual cues following brumation. Behav Processes 2018; 157:502-508. [DOI: 10.1016/j.beproc.2018.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 12/14/2022]
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5
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Patel U, Perez L, Farrell S, Steck D, Jacob A, Rosiles T, Krause E, Nguyen M, Calin-Jageman RJ, Calin-Jageman IE. Transcriptional changes before and after forgetting of a long-term sensitization memory in Aplysia californica. Neurobiol Learn Mem 2018; 155:474-485. [PMID: 30243850 PMCID: PMC6365195 DOI: 10.1016/j.nlm.2018.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/11/2018] [Accepted: 09/19/2018] [Indexed: 01/06/2023]
Abstract
Most long-term memories are forgotten, becoming progressively less likely to be recalled. Still, some memory fragments may persist, as savings memory (easier relearning) can be detected long after recall has become impossible. What happens to a memory trace during forgetting that makes it inaccessible for recall and yet still effective to spark easier re-learning? We are addressing this question by tracking the transcriptional changes that accompany learning and then forgetting of a long-term sensitization memory in the tail-elicited siphon withdrawal reflex of Aplysia californica. First, we tracked savings memory. We found that even though recall of sensitization fades completely within 1 week of training, savings memory is still detectable at 2 weeks post training. Next, we tracked the time-course of regulation of 11 transcripts we previously identified as potentially being regulated after recall has become impossible. Remarkably, 3 transcripts still show strong regulation 2 weeks after training and an additional 4 are regulated for at least 1 week. These long-lasting changes in gene expression always begin early in the memory process, within 1 day of training. We present a synthesis of our results tracking gene expression changes accompanying sensitization and provide a testable model of how sensitization memory is forgotten.
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Affiliation(s)
- Ushma Patel
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Leticia Perez
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Steven Farrell
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Derek Steck
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Athira Jacob
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Tania Rosiles
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Everett Krause
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Melissa Nguyen
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Robert J Calin-Jageman
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States
| | - Irina E Calin-Jageman
- Neuroscience Program, Dominican University, 7900 West Division Street, River Forest, IL 60305, United States.
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6
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Davis RL, Zhong Y. The Biology of Forgetting-A Perspective. Neuron 2017; 95:490-503. [PMID: 28772119 DOI: 10.1016/j.neuron.2017.05.039] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 01/23/2023]
Abstract
Pioneering research studies, beginning with those using Drosophila, have identified several molecular and cellular mechanisms for active forgetting. The currently known mechanisms for active forgetting include neurogenesis-based forgetting, interference-based forgetting, and intrinsic forgetting, the latter term describing the brain's chronic signaling systems that function to slowly degrade molecular and cellular memory traces. The best-characterized pathway for intrinsic forgetting includes "forgetting cells" that release dopamine onto engram cells, mobilizing a signaling pathway that terminates in the activation of Rac1/Cofilin to effect changes in the actin cytoskeleton and neuron/synapse structure. Intrinsic forgetting may be the default state of the brain, constantly promoting memory erasure and competing with processes that promote memory stability like consolidation. A better understanding of active forgetting will provide insights into the brain's memory management system and human brain disorders that alter active forgetting mechanisms.
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Affiliation(s)
- Ronald L Davis
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, USA.
| | - Yi Zhong
- Tsinghua-Peking Center for Life Sciences, School for Life Sciences, Tsinghua University, Beijing, China.
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7
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Abstract
Recently, the field of animal memory research has seen a resurgence of interest in the mechanisms underlying retrograde amnesia (RA) and in the use of RA as a technique for studying memory processes. A recent report from a major neuroscience lab, which demonstrated RA for an old reactivated memory, revitalized the debate regarding the widely accepted memory-consolidation theory of RA. Here, we discuss a number of the characteristics of RA and consider the findings that led to the development of the memory-consolidation hypothesis, as well as those suggesting an alternative retrieval-deficit explanation.
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Affiliation(s)
- David C. Riccio
- Department of Psychology, Kent State University, Kent, Ohio (D.C.R., P.M.M.), and Laboratoire de Neurobiologie, Université Paris-Sud, Paris, France (P.G.-V.)
| | - Paula M. Millin
- Department of Psychology, Kent State University, Kent, Ohio (D.C.R., P.M.M.), and Laboratoire de Neurobiologie, Université Paris-Sud, Paris, France (P.G.-V.)
| | - Pascale Gisquet-Verrier
- Department of Psychology, Kent State University, Kent, Ohio (D.C.R., P.M.M.), and Laboratoire de Neurobiologie, Université Paris-Sud, Paris, France (P.G.-V.)
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8
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9
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Gisquet-Verrier P, Riccio DC. Memory reactivation effects independent of reconsolidation. Learn Mem 2012; 19:401-9. [PMID: 22904371 DOI: 10.1101/lm.026054.112] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Memory reactivation is an important process resulting from reexposure to salient training-related information whereby a memory is brought from an inactive to an active state. Reactivation is the first stage of memory retrieval but can result from the exposure to salient cues without any behavioral output. Such cue-induced reactivation, although frequently used by neuroscientists to study reconsolidation, has seldom been considered as a process in its own right and studied as such. This review presents arguments indicating that memory reactivation has two main consequences: (1) to enhance the accessibility of the target memory and (2) to make the memory malleable. Accordingly, reactivation creates a transient state during which the content of the memory is easily accessible and can be modified and/or updated. As both of these aspects can be observed shortly after memory reactivation, this review emphasizes that reconsolidation is not necessarily required for these processes and calls attention to reactivation as a factor in the dynamics of the memory.
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Abstract
The predominant view about memory formation states that a consolidation process stabilizes newly acquired traces until they are safely stored in the brain. However, during the last ten years evidence has accumulated to indicate that, upon retrieval, consolidated memories are rendered again vulnerable to the action of metabolic blockers, notably protein synthesis inhibitors. This has led to the hypothesis that memories are reconsolidated at the time of retrieval, and that this requires protein synthesis in different brain regions. Here we will address the consolidation-reconsolidation debate and discuss some controversial issues about the reconsolidation hypothesis, in particular the biological role of this process.
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11
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Abstract
Memory reconsolidation has been argued to be a distinct process that serves to maintain, strengthen or modify memories. Specifically, the retrieval of a previously consolidated memory has been hypothesized to induce an additional activity-dependent labile period during which the memory can be modified. Understanding the molecular mechanisms of reconsolidation could provide crucial insights into the dynamic aspects of normal mnemonic function and psychiatric disorders that are characterized by exceptionally strong and salient emotional memories.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychiatry, Division of Molecular Psychiatry, Center for Genes and Behavior, Yale University School of Medicine, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, 34 Park Street, New Haven, Connecticut 06508, USA
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12
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Riccio DC, Millin PM, Bogart AR. Reconsolidation: A brief history, a retrieval view, and some recent issues. Learn Mem 2006; 13:536-44. [PMID: 17015851 DOI: 10.1101/lm.290706] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This review briefly traces some of the history of the phenomenon of what has come to be called "reconsolidation." The early findings of retrograde amnesia for an old but reactivated memory led to several interesting but largely behaviorally oriented studies. With only a few sporadic exceptions, research in the area languished until about 2000, when several articles caught the attention of the neuroscience community and led to a number of studies examining the phenomenon at several different levels of analysis. We consider several of the current issues generated by those studies, present a retrieval based model that may account for some findings, and indicate some possible new directions on this topic.
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Affiliation(s)
- David C Riccio
- Department of Psychology, Kent State University, Kent, Ohio 44242, USA.
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13
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Martin SJ, de Hoz L, Morris RGM. Retrograde amnesia: neither partial nor complete hippocampal lesions in rats result in preferential sparing of remote spatial memory, even after reminding. Neuropsychologia 2005; 43:609-24. [PMID: 15716151 DOI: 10.1016/j.neuropsychologia.2004.07.007] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 07/07/2004] [Accepted: 07/07/2004] [Indexed: 12/01/2022]
Abstract
Many lesion experiments have provided evidence that the hippocampus plays a time-limited role in memory, consistent with the operation of a systems-level memory consolidation process during which lasting neocortical memory traces become established [see Squire, L. R., Clark, R. E., & Knowlton, B. J. (2001). Retrograde amnesia. Hippocampus 11, 50]. However, large lesions of the hippocampus at different time intervals after acquisition of a watermaze spatial reference memory task have consistently resulted in temporally ungraded retrograde amnesia [Bolhuis, J. J., Stewart, C. A., Forrest, E. M. (1994). Retrograde amnesia and memory reactivation in rats with ibotenate lesions to the hippocampus or subiculum. Quarterly Journal of Experimental Psychology 47B, 129; Mumby, D. G., Astur, R. S., Weisend, M. P., Sutherland, R. J. (1999). Retrograde amnesia and selective damage to the hippocampal formation: memory for places and object discriminations. Behavioural Brain Research 106, 97; Sutherland, R. J., Weisend, M. P., Mumby, D., Astur, R. S., Hanlon, F. M., et al. (2001). Retrograde amnesia after hippocampal damage: recent vs. remote memories in two tasks. Hippocampus 11, 27]. It is possible that spatial memories acquired during such a task remain permanently dependent on the hippocampus, that chance performance may reflect a failure to access memory traces that are initially unexpressed but still present, or that graded retrograde amnesia for spatial information might only be observed following partial hippocampal lesions. This study examined the retrograde memory impairments of rats that received either partial or complete lesions of the hippocampus either 1-2 days, or 6 weeks after training in a watermaze reference memory task. Memory retention was assessed using a novel 'reminding' procedure consisting of a series of rewarded probe trials, allowing the measurement of both free recall and memory reactivation. Rats with complete hippocampal lesions exhibited stable, temporally ungraded retrograde amnesia, and could not be reminded of the correct location. Partially lesioned rats could be reminded of a recently learned platform location, but no recovery of remote memory was observed. These results offer no support for hippocampus-dependent consolidation of allocentric spatial information, and suggest that the hippocampus can play a long-lasting role in spatial memory. The nature of this role--in the storage, retrieval, or expression of memory--is discussed.
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Affiliation(s)
- Stephen J Martin
- Laboratory for Cognitive Neuroscience, Division of Neuroscience, University of Edinburgh, Crichton Street, Edinburgh EH8 9LE, Scotland, UK.
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de Hoz L, Martin SJ, Morris RGM. Forgetting, reminding, and remembering: the retrieval of lost spatial memory. PLoS Biol 2004; 2:E225. [PMID: 15314651 PMCID: PMC509297 DOI: 10.1371/journal.pbio.0020225] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 05/14/2004] [Indexed: 11/19/2022] Open
Abstract
Retrograde amnesia can occur after brain damage because this disrupts sites of storage, interrupts memory consolidation, or interferes with memory retrieval. While the retrieval failure account has been considered in several animal studies, recent work has focused mainly on memory consolidation, and the neural mechanisms responsible for reactivating memory from stored traces remain poorly understood. We now describe a new retrieval phenomenon in which rats' memory for a spatial location in a watermaze was first weakened by partial lesions of the hippocampus to a level at which it could not be detected. The animals were then reminded by the provision of incomplete and potentially misleading information-an escape platform in a novel location. Paradoxically, both incorrect and correct place information reactivated dormant memory traces equally, such that the previously trained spatial memory was now expressed. It was also established that the reminding procedure could not itself generate new learning in either the original environment, or in a new training situation. The key finding is the development of a protocol that definitively distinguishes reminding from new place learning and thereby reveals that a failure of memory during watermaze testing can arise, at least in part, from a disruption of memory retrieval.
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Affiliation(s)
- Livia de Hoz
- Laboratory for Cognitive Neuroscience, Centre and Division of Neuroscience, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
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15
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Santucci AC, Cardiello J. Memory Reactivation in Rats Treated With the 5-HT₁A Agonist 8-OHDP AT: A Case of Gone, but Not Forgotten. Behav Neurosci 2004; 118:248-52. [PMID: 14979803 DOI: 10.1037/0735-7044.118.1.248] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effect of various doses of the serotonin-1A agonist 8-OH-DPAT at training on 72-hr retention of passive avoidance was investigated in rats. Results indicated impaired retention, as measured by latency to avoid shock. However, when total time spent in the nonshock compartment at test was assessed, the performance of drug-treated subjects was not significantly different than that of control animals. It is suggested that although drug treatment produced initial retention impairment, the memory trace for the aversive event was reactivated (i.e., "reminder effect") when subjects entered the shock compartment at test. These data imply that pharmacological treatments, especially those that modulate serotonergic neurotransmission, that appear to disrupt learning per se may interrupt neural circuits involved in retrieval processes.
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Affiliation(s)
- Anthony C Santucci
- Department of Psychology, Manhattanville College, Purchase, NY 10577, USA.
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Szapiro G, Vianna MRM, McGaugh JL, Medina JH, Izquierdo I. The role of NMDA glutamate receptors, PKA, MAPK, and CAMKII in the hippocampus in extinction of conditioned fear. Hippocampus 2003; 13:53-8. [PMID: 12625457 DOI: 10.1002/hipo.10043] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Pavlovian conditioning involves the association of initially neutral conditioned stimuli (CS) with unconditioned stimuli (US) that elicit a response. In contextual fear conditioning in rodents, the CS is the context of a training apparatus and the US is a foot shock. Retrieval of memory of the training is tested by presenting the CS alone. But a retrieval test also initiates extinction of the conditioned response. That is, presentation of the CS alone results in new learning, i.e., the CS no longer predicts the US. Here we report that extinction is triggered by two hippocampal signaling pathways underlying retrieval (the cAMP-dependent protein kinase and the mitogen-activated protein kinase pathways) and two other mechanisms that become activated at the same time and are not necessary for retrieval (N-methyl-D-aspartate glutamatergic receptors and the calcium/calmodulin-dependent protein kinase II signaling pathway). Thus, the molecular mechanisms underlying acquisition and/or consolidation of the memory for extinction are similar to those described for the acquisition and/or consolidation of the original contextual fear.
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Affiliation(s)
- German Szapiro
- Instituto de Biologia Celular y Neurociencias, Facultad de Medicina, Buenos Aires, Argentina
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Santucci AC, Shaw C. Peripheral 8-OH-DPAT and scopolamine infused into the frontal cortex produce passive avoidance retention impairments in rats. Neurobiol Learn Mem 2003; 79:136-41. [PMID: 12591222 DOI: 10.1016/s1074-7427(02)00037-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study determined whether peripheral injections of the 5HT(1A) agonist (8-OH-DPAT), scopolamine infusions into the frontal cortex, or a combination of both drug treatments would produce impairments in rats trained on passive avoidance. Using a 2x2 design, rats were infused with either bacteriostatic water or 30 microg/1 microl of scopolamine HCl into the frontal cortex 30 min before being trained on passive avoidance. This was followed by injections (ip) of either 0.1% ascorbic acid/bacteriostatic water or 30 microg/kg of 8-OH-DPAT 15 min later. All subjects were tested for retention 72h later. At test, the initial latency to enter into the black shocked compartment and the total time spent in the white safe compartment (TTW) were recorded. Analysis of the latency data indicated that scopolamine and 8-OH-DPAT, when administered singly or in combination, produced amnesia for the task. Assessment of TTW scores, however, revealed that of the three drug-treated groups, only animals treated with 8-OH-DPAT alone tended to avoid the previously shocked black compartment and spend more time in the white safe compartment. These data indicate that either stimulating 5-HT(1A) or blocking frontal cortical muscarinic receptors at training impairs passive avoidance performance and that the deficit following the latter treatment is somewhat more extensive. Implications for the role frontal cortical muscarinic and 5HT(1A) receptors play in learning and memory are discussed.
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Affiliation(s)
- Anthony C Santucci
- Department of Psychology, Manhattanville College, 2900 Purchase Street, Purchase, NY 10577, USA.
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18
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Abstract
Certain types of memories are dependent on the hippocampus for a short period of time following training, after which they are no longer susceptible to hippocampal manipulations. Having completed this initial consolidation process, a memory may once again engage the hippocampus (undergo reconsolidation) when recalled. Two studies in the current issue of Neuron make important advances in our understanding of reconsolidation but reach different conclusions about the modifiability of old memories.
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Affiliation(s)
- Karyn M Myers
- Department of Psychology, Emory University, Atlanta, GA 30322, USA
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19
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Abstract
Some of the considerations that led to a consolidation interpretation of retrograde amnesia (RA), which states that RA results from the disruption of memory processing and storage when neural activity is interrupted by a brain insult, are reviewed here. The time-dependent gradient of memory loss (i.e., new memories are more vulnerable to amnesia than old memories) that characterizes RA seemed to fit nicely with the notion of a cascade of cellular events occurring during the immediate post-acquisition period that would transform a labile representation into a more stable form (i.e., consolidate the memory). However, a variety of observations came to challenge the storage-disruption model, and among these was the finding of amnesia for old but reactivated memories. A recent study by Nader, Schafe, and LeDoux (2000) provides an important analytic extension of the work on "reconsolidation" by showing that inhibition of protein synthesis in the lateral and basal nuclei of the amygdala immediately following the reactivation of old memory will induce retrograde amnesia. We offer a retrieval-oriented conceptualization to account for the temporal gradient and the "reconsolidation" phenomena.
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Affiliation(s)
- David C Riccio
- Department of Psychology, Kent State University, OH 44242-0001, USA.
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20
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Abstract
Recent research on the cognitive dysfunctions experienced by human anmesic patients indicates that very long term (multidecade) changes may occur in memory. Flat retrograde amnesia (RA), consisting of a uniform memory deficit for information from all preamnesia time periods, indicates a simple, monolithic retrieval problem, whereas graded RA, with greater memory deficits for information from recent as opposed to remote time periods, suggests the presence of a gradual long-term encoding, or consolidation, process. An evaluation of 247 outcomes from 61 articles provides strong evidence of graded RA across different cerebral injuries, materials, and test procedures, as well as in measures of both absolute and relative (patient vs. control) performance. Future conceptualizations of human memory should address the possibility that memories increase in resistance to forgetting, or reduction in trace fragility, across many decades.
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Affiliation(s)
- Alan S Brown
- Department of Psychology, Southern Methodist University, Dallas, Texas 75275-0442, USA.
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Izquierdo I, Vianna MR, Izquierdo LA, Barros DM, Szapiro G, Coitinho AS, Muller L, Cammarota M, Bevilaqua LR, Medina JH. Memory retrieval and its lasting consequences. Neurotox Res 2002; 4:573-593. [PMID: 12754168 DOI: 10.1080/10298420290031441] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Many, if not all psychiatric diseases are accompanied by memory disturbances, in particular, the dementias, schizophrenia, and, to an extent, mood disorders. Anxiety and stress, on the other hand, cause important alterations of memory, particularly its retrieval. Here we discuss several new findings on the basic mechanisms of consolidation, retrieval and extinction of a prototype form of episodic memory in the rat: conditioned fear. The findings point the way for investigations on the pathology of these aspects of memory in health and disease. Emphasis is placed on the parallel processing of retrieval in several cortical areas, on the links between retrieval and the onset of extinction, on the fact that extinction involves new learning requiring gene expression, and on the differences between the retrieval of recent or remote long-term memories.
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Affiliation(s)
- Iván Izquierdo
- Departamento de Bioquímica, Centro de Memoria, Instituto de Ciencias Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brasil
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22
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Abstract
The observation that retrieval returns a stable memory into a labile state cannot be readily explained by any simple version of consolidation theory. This finding has been interpreted as evidence for the need to reconsolidate a memory after reactivating it. However, as we discuss in this commentary, other behavioural observations indicate that even this modification to consolidation theory may be insufficient to describe the dynamic properties of memory.
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Affiliation(s)
- R R Miller
- Department of Psychology, State University of New York at Binghamton, Binghamton, New York 13902-6000, USA.
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23
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Mickley GA, Cobb BL. Thermal tolerance reduces hyperthermia-induced disruption of working memory: a role for endogenous opiates? Physiol Behav 1998; 63:855-65. [PMID: 9618009 DOI: 10.1016/s0031-9384(98)00010-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Previous reports indicate that microwave-induced hyperthermia can impair learning and memory. Here, we report that preexposure to a single 20-min period of hyperthermia can produce thermal tolerance and, thereby, attenuate future physiological and behavioral reactions to heating. Because endogenous opioids have been implicated in thermoregulation and reactions to microwave exposure, we also determined how opioid receptor antagonism might modulate these effects. In an initial experiment, rats were exposed daily, over 5 successive days, to 600-MHz microwaves (at a whole-body specific absorption rate of 9.3 W/kg) or sham exposed. In animals exposed to microwaves, thermal tolerance was evidenced by declining rectal temperatures over time. Temperature reductions following microwave exposure were prominent after a single previous exposure. Therefore, in a second study, a single hyperthermic episode was used to induce thermal tolerance. On Day 1, rats were either exposed, over a 20-min period, to 600-MHz microwaves (at a whole-body specific absorption rate of 9.3 W/kg) or sham exposed. Just prior to radiation/sham-radiation treatment, rats received either saline or naltrexone (0.1 or 10 mg/kg, intraperitoneally (i.p.)). The following day (Day 2), rats were either microwave or sham exposed and tested on a task which measures the relative time subjects explore a familiar versus a novel stimulus object. Normothermic rats spend significantly more time in contact with new environmental components and less time with familiar objects. Brain (dura) and rectal temperatures were recorded on both days of the study. Microwave exposure produced a reliable hyperthermia which was significantly lower (on Day 2) in rats receiving repeated treatments (tolerant group). On the behavioral test, rats exposed only once to microwave-induced hyperthermia (nontolerant group) exhibited significantly different patterns of object discrimination than did tolerant or sham-exposed animals. Sham-exposed and tolerant animals showed a distinct preference for the new object whereas the nontolerant animals did not. Naltrexone (10 mg/kg) antagonized the hyperthermia-induced disruption of the object discrimination task (in nontolerant rats) and produced patterns of object exploration that were similar to those of sham-irradiated and thermal-tolerant rats, suggesting that endogenous opioids play a role in the organism's response to heating. Taken together, these data are consistent with the conclusions that 1) microwave-induced hyperthermia can cause a dose-dependent disruption of the normal discrimination between new and familiar objects, 2) physiological reactions to a single hyperthermic episode can produce a thermotolerance that expresses itself in both reduced levels of hyperthermia and attenuated behavioral disruptions following microwave exposure, and 3) opioid antagonism can partially reverse some of the behavioral effects of microwave-induced hyperthermia.
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Affiliation(s)
- G A Mickley
- Armstrong Laboratory, Radiofrequency Radiation Division (AL/OER), Brooks AFB, TX 78235-5324, USA.
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Abstract
Infantile amnesia in rats may be attenuated by a wide variety of retrieval cues which reactivate memory for the training episode. The present study investigated the effects of glucose on memory retrieval in infant rats. In Experiment 1, 17-day-old preweanling rats were trained to criterion on passive avoidance conditioning. Twenty-four hours later, each subject received a subcutaneous injection of either saline, 100 mg/kg, or 250 mg/kg of glucose just prior to testing. Saline animals displayed poor retention scores, suggesting infantile amnesia; however, glucose significantly attenuated the 24-hr retention loss. Experiment 2 attempted to replicate the previous experiment, control for age and general drug effects, and extend the dose of glucose to 400 mg/kg. The results of Experiment 2 were consistent with Experiment 1 and also indicated that infant subjects performed significantly worse than adults. Both 100 and 250 mg/kg of glucose significantly attenuated infantile amnesia; however, 400 mg/kg had no effect. These results support a retrieval failure view of infantile amnesia and extend the memory-influencing properties of glucose to infants. Context and neuroendocrine views of memory retrieval are discussed.
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Affiliation(s)
- R W Flint
- Department of Psychology, Mankato State University, MN 56002-8400, USA
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Abstract
Three experiments were conducted to investigate the characteristics of retrograde amnesia (RA) induced by concussion in rats. In Experiment 1, rats receiving experimental concussion shortly after training in a single punishment trial exhibited severe forgetting on a retention test 48 h later. In the second experiment, rats receiving a concussion within 6 h after training showed severe RA, while those receiving concussion one day to five days after training exhibited progressively weaker amnesia. In Experiment 3, amnesic animals in one group received pretest noncontingent foot shock as a reminder treatment. This pretest cue significantly increased the cross-through latency, thus indicating a reduction in the memory deficit resulting from concussion. These results suggest that experimental concussion can be an effective method to induce retrograde memory loss in rats; that the RA caused by concussion is time-dependent; and that concussion-induced RA can be alleviated by a pretest cue indicating that the underlying mechanism of concussion-induced RA is more likely to be a retrieval deficit than a consolidation failure.
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Affiliation(s)
- Y Zhou
- Department of Psychology, Kent State University, OH 44242, USA
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Mickley GA, Cobb BL, Mason PA, Farrell S. Disruption of a putative working memory task and selective expression of brain c-fos following microwave-induced hyperthermia. Physiol Behav 1994; 55:1029-38. [PMID: 8047568 DOI: 10.1016/0031-9384(94)90384-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To discern the effects of hyperthermia on working memory, we recorded the ability of rats to discriminate between objects following microwave radiation exposure. Memory changes were evaluated by measuring relative exploration time of a familiar vs. a new stimulus object. A subject that extensively reexplores a stimulus with which it has previous experience is presumed to exhibit memory loss associated with that object. Between training and testing, rats were exposed to various doses of microwave radiation, were sham irradiated, or remained in their home cage. Brain (dural) and rectal temperatures were recorded. To discern brain regions activated or possibly damaged by microwave exposure, we also used immunocytochemistry techniques to identify sites of c-fos protein expression in the brains of several irradiated/sham-irradiated subjects. Rats exposed to > 5 W/kg exhibited hyperthermia when compared to nonirradiated controls. Normothermic control subjects (sham-irradiated rats and rats exposed to 0.1 W/kg) showed a distinct preference for the new object although other microwave-exposed rats (1, 5, 8.5, 9.3, 10 W/kg) did not. Microwave hyperthermia evoked prominent c-fos expression in periventricular strata, hypothalamic nuclei, amygdala, and several areas of the cortex. These data suggest that performance on a putative working memory task may be disrupted by a sufficiently intense microwave-induced hyperthermia. The pattern of expression of the early proto-oncogene c-fos may suggest candidate brain nuclei that mediate the behavioral changes we observed.
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Affiliation(s)
- G A Mickley
- Radiofrequency Radiation Division (AL/OER), Armstrong Laboratory, Brooks AFB, TX 78235-5324
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Ackil JK, Carman HM, Bakner L, Riccio DC. Reinstatement of latent inhibition following a reminder treatment in a conditioned taste aversion paradigm. BEHAVIORAL AND NEURAL BIOLOGY 1992; 58:232-5. [PMID: 1456944 DOI: 10.1016/0163-1047(92)90524-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Reminder treatments have been shown to facilitate the retrieval of a variety of conditioned responses. Whether or not similar results would occur with an experimental paradigm which involves primarily memory for a stimulus, i.e., where no particular response is specified, is unclear. Accordingly, using Sprague-Dawley rats, we employed a latent inhibition paradigm with a long (10 days) retention interval between sucrose (CS) preexposure and sucrose-illness pairing (training). The results demonstrated a loss of latent inhibition following the 10-day retention interval suggesting "forgetting" of the CS preexposure. However, placing a single reminder exposure to the CS within the preexposure-to-training interval reinstated the preexposure effect. Controls indicated that in the absence of the initial preexposure the reminder per se did not produce latent inhibition. Thus, a reminder can reinstate a stimulus attribute (flavor representation) and explicit conditioned responses.
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Affiliation(s)
- J K Ackil
- Department of Psychology, Kent State University, Ohio 44242
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Santucci AC, Schroeder H, Riccio DC. Homeostatic disruption and memory: effect of insulin administration in rats. BEHAVIORAL AND NEURAL BIOLOGY 1990; 53:321-33. [PMID: 2190550 DOI: 10.1016/0163-1047(90)90184-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The present study examined the effect of insulin-induced hypoglycemia on 24-h retention of passive avoidance in rats. In the initial experiment, rats received either insulin (50 U/kg) or saline injections 30 min prior to training and testing. Impairments in retention were observed when animals were trained with insulin and tested with saline. This anterograde memory loss was attenuated, however, when insulin was administered prior to both training and testing. A subsequent experiment further explored the disruptive effect of hypoglycemia on memory. Data from this study indicated that lower doses of insulin at training (5 and 10 U/rat) yielded impairments in 24-h retention of passive avoidance. It is concluded that disruption of glucoregulation can produce state-dependent anterograde memory losses in rats. Possible implications for the effects of hypoglycemia on cognitive functioning in humans are discussed.
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Affiliation(s)
- A C Santucci
- Department of Psychology, Kent State University, Ohio 44242
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Alleviation of short-term forgetting: Effects of the CS− and other conditioning elements in prior cueing or as context during test. LEARNING AND MOTIVATION 1990. [DOI: 10.1016/0023-9690(90)90006-a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Rauch TM, Welch DI, Gallego L. Hyperthermia impairs retrieval of an overtrained spatial task in the Morris water maze. BEHAVIORAL AND NEURAL BIOLOGY 1989; 52:321-30. [PMID: 2590145 DOI: 10.1016/s0163-1047(89)90442-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Fifteen rats were trained to learn the location of a spatially fixed platform hidden in a Morris water maze (40 +/- 2 degrees C). Then retention of the spatial task was assessed immediately after raising core body temperature (Tc) to 42 or 40 degrees C or stabilizing at 37 degrees C (the normothermic control). The hyperthermic treatment order was counterbalanced according to a Latin-square design. Hyperthermia at 42 degrees C Tc significantly impaired spatial performance. Hyperthermic animals were cooled to normothermia (Tc = 37 degrees C) and spatial performance was tested again approximately 30 min later. Cooling resulted in a complete recovery of spatial performance. These results demonstrate that hyperthermia-induced amnesia can be obtained on an overtrained spatial-mapping strategy and cooling to normothermia initiates recovery of spatial performance.
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Affiliation(s)
- T M Rauch
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760
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Santucci AC, Kanof PD, Haroutunian V. Effect of physostigmine on memory consolidation and retrieval processes in intact and nucleus basalis-lesioned rats. Psychopharmacology (Berl) 1989; 99:70-4. [PMID: 2506606 DOI: 10.1007/bf00634455] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The efficacy of physostigmine on memory enhancement in rats trained on a passive avoidance task was investigated. In experiment 1, the effect of posttraining injections of physostigmine (0.03 mg/kg) in subjects tested at either short (1.25 h or 72 h) or long (3 weeks or 5 weeks) retention intervals was explored. Results indicated drug-induced enhancement of memory at only the two short intervals. Experiment 2 examined the mnemonic consequences of pretest administration of physostigmine. Administration of physostigmine (0.015 mg/kg and 0.03 mg/kg) shortly prior to testing led to a significant potentiation of memory retrieval. The aim of experiment 3 was to determine whether or not an intact cholinergic system is necessary for pretest physostigmine to enhance memory retrieval. Results from this experiment indicated that physostigmine (0.03 mg/kg) was effective in enhancing memory in rats prepared with ibotenic acid-induced lesions of the nucleus basalis of Meynert. Together, these data provide further empirical support for the importance of the cholinergic system in memory processes.
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Affiliation(s)
- A C Santucci
- Psychiatry Service, VA Medical Center, Bronx, NY 10468
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Richardson R, Riccio DC, Axiotis R. Alleviation of infantile amnesia in rats by internal and external contextual cues. Dev Psychobiol 1986; 19:453-62. [PMID: 3019803 DOI: 10.1002/dev.420190506] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A previous study [Richardson, R., Riccio, D.C., and Jonke, T. (1983). Alleviation of infantile amnesia in rats by means of a pharmacological contextual state. Devel. Psychobiol., 16:511-518] found that ontogenetic forgetting ("infantile amnesia") in rats was attenuated by a "contextual matching" manipulation: Subjects trained in a distinct pharmacological state and tested in that state retained learned fear better than saline controls. To determine whether improved retention could be obtained with salient but nonpharmacological contexts, two experiments were conducted employing fear conditioning in preweanling rats. In Experiment 1, an internal context (illness induced by lithium chloride) present at training and testing reduced infantile forgetting. In Experiment 2, matching an exteroceptive context (home nest shavings) at training and testing was also found to be sufficient to alleviate infantile amnesia. In both experiments, retention was not improved in controls exposed to the context at training only or testing only, indicating that the contextual effect is not on acquisition or retrieval processes per se. These findings provide indirect support for views that emphasize the role of contextual cues in retrieval (Spear, 1978). In addition, they indicate that contextual matching is not limited to a state dependent drug, but may include a wide range of "distinctive" stimuli.
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Fekete M, Van Ree JM, De Wied D. The ACTH-(4-9) analog ORG 2766 and desglycinamide9-(Arg8)-vasopressin reverse the retrograde amnesia induced by disrupting circadian rhythms in rats. Peptides 1986; 7:563-8. [PMID: 3020524 DOI: 10.1016/0196-9781(86)90027-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Disrupting circadian organization by exposing rats to a shifted illumination schedule after training for passive avoidance and shuttle box avoidance behavior resulted in retrograde amnesia as evidenced by impaired performance during retention and extinction testing respectively. A single treatment with either the ACTH-(4-9) analog ORG 2766 or desglycinamide9-(Arg8)-vasopressin (DGAVP) 1 hour prior to the retention of passive avoidance or extinction of shuttle box avoidance behavior restored the behavioral impairment. It is suggested that these peptides may be useful to relieve memory deficits induced by disturbances in circadian organization.
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State-dependent retention induced by postacquisition exposure to pentobarbital or shock stress in rats. ACTA ACUST UNITED AC 1986. [DOI: 10.3758/bf03200040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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