Episodic-Like Memory in Rats: Is It Based on When or How Long Ago?

Roberts, William A.; Feeney, Miranda C.; Macpherson, Krista; Petter, Mark; McMillan, Neil; Musolino, Evanya

doi:10.1126/science.1152709

Cited by 147 publications

(133 citation statements)

References 18 publications

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“…Thus, it is difficult to determine if successful performance is based on a memory of the earlier episode or a planned action generated when information was explicitly encoded [1][2][3][4]. Indeed, it is possible that animals may have solved previous tests of episodic memory (e.g., [4][5][6][7]) by using well-learned semantic rules without remembering the episode. Formally, learned rules stored in semantic memory, a non-episodic memory system devoted to storing generic facts [8], could be used to generate a planned action.…”

Section: Resultsmentioning

confidence: 99%

Rats answer an unexpected question after incidental encoding

Zhou¹,

Crystal²

2011

PsycEXTRA Dataset

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SummaryA fundamental aspect of episodic memory is that retrieval of information can occur when encoding is incidental and memory assessment is unexpected [1][2][3][4]. These features are difficult to model in animals because behavioral training likely gives rise to well-learned expectations about the sequence of events. Thus, the possibility remains that animals may solve an episodic-memory test by using well-learned semantic rules without remembering the episode at memory assessment. Here we show that rats can answer an unexpected question after incidental encoding in a hippocampal-dependent manner, consistent with the use of episodic memory. Rats were initially trained to report about a recent event (food vs. no-food) and separately searched for food where there was no expectation of being asked about the presence of food. To test episodic memory, rats were given the opportunity to incidentally encode the presence or absence of food and were unexpectedly asked to report about the recent event. Temporary inactivation of the CA3 region of the hippocampus with bilateral infusions of lidocaine selectively eliminated the ability of rats to answer the unexpected, but not the expected, question. Our studies suggest that rats remember an earlier episode after incidental encoding based upon hippocampal-dependent episodic memory. Results and DiscussionAlthough events are not always known to be important when they occur, people can nonetheless remember details about such events. For example, eyewitness accounts rely on memories for incidental aspects of an earlier episode not known to be important when the episode occurred. Encoding occurs incidentally when apparently unimportant information is stored, but it is not known at the time of encoding that the information may subsequently be useful. By contrast, information is explicitly encoded when it is known that the information is needed later. When information is encoded for use in an upcoming, expected test of retention, it is possible that the explicitly encoded information is used to generate a planned action; according to this view, at the time of the test, the remembered action can occur successfully without remembering the earlier episode. Thus, it is difficult to determine if successful performance is based on a memory of the earlier episode or a planned action generated when information was explicitly encoded [1][2][3][4]. Indeed, it is possible that animals may have solved previous tests of episodic memory (e.g., [4][5][6][7]) by using well-learned semantic rules without remembering the episode. Formally, learned rules stored in semantic 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 conte...

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Section: Resultsmentioning

confidence: 99%

Rats answer an unexpected question after incidental encoding

Zhou¹,

Crystal²

2011

PsycEXTRA Dataset

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“…However, one important consideration here is that there are many ways to think of and define time in relation to memory (Crystal, 2010;Friedman, 1993). In the present study we have used place in a sequence to define time of an event but other studies have utilised measures of time, such as how long ago (Clayton & Dickinson, 1998;Roberts et al, 2008) or what time of day an event took place (Zhou & Crystal, 2009). While it is clear that place in a sequence can be remembered using familiarity it could be that these other measures of time might require recollection for accurate retrieval.…”

Section: Discussionmentioning

confidence: 99%

“…The use of these episodic-like memory paradigms has led to further debate as to whether events are separated in memory using solely temporal information, as suggested by WWWhen memory (Babb & Crystal, 2005Clayton & Dickinson, 1998;Ergorul & Eichenbaum, 2004;Roberts et al, 2008;Zhou & Crystal, 2009) or by the occasion in which they took place using either temporal or non-temporal identifiers, suggested by WWWhich memory (Eacott & Easton, 2010Easton & Eacott, 2008). In spite of their central role within the widely used WWWhen paradigm, humans rarely use specific temporal cues when remembering episodes, relying instead on non-temporal information e.g.…”

Section: Introductionmentioning

confidence: 99%

Disambiguating past events: Accurate source memory for time and context depends on different retrieval processes

Persson

Ainge

O'Connor

2016

Neurobiology of Learning and Memory

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Please cite this article as: Persson, B.M., Ainge, J.A., O'Connor, A.R., Disambiguating past events: Accurate source memory for time and context depends on different retrieval processes, Neurobiology of Learning and Memory (2016), doi: http://dx.doi.org/10. 1016/j.nlm.2016.05.002 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 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. These models aim to capture the testable features of the definition of human episodic memory which stresses the temporal component of the memory as a unique piece of source information that allows us to disambiguate one memory from another. Recently though, it has been suggested that a more accurate model of human episodic memory would include contextual rather than temporal source information, as humans' memory for time is relatively poor. Here, two experiments were carried out investigating human memory for temporal and contextual source information, along with the underlying dual process retrieval processes, using an immersive virtual environment paired with a 'Remember-Know' memory task. Experiment 1 (n = 28) showed that contextual information could only be retrieved accurately using recollection, while temporal information could be retrieved using either recollection or familiarity.Experiment 2 (n = 24), which used a more difficult task, resulting in reduced item recognition rates and therefore less potential for contamination by ceiling effects, replicated the pattern of results from Experiment 1. Dual process theory predicts that it should only be possible to retrieve source context from an event using recollection, and our results are consistent with this prediction. That temporal information can be retrieved using familiarity alone suggests that it may be incorrect to view temporal context as analogous to other typically used source contexts. This latter finding supports the alternative proposal that time since presentation may simply be reflected in the strength of memory trace at retrieval -a measure ideally suited to trace strength interrogation using familiarity, as is typically conceptualised within the dual process framework.

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“…episodic memory) would allow individuals to reciprocate cooperative behaviour and to punish non-cooperators. The existence of episodic memory in animals is still a matter of debate (Clayton et al 2003;Suddendorf & Busby 2003;Roberts et al 2008). Nevertheless, some criteria related to episodic memory have been investigated and confirmed for mammals and birds, including 'what-where-when memory': whether an animal remembers information about a specific event experienced in a given spatial location and at a particular time in the past (e.g.…”

Section: Hormones and The Cognitive Modules Underlying Cooperative Bementioning

confidence: 99%

Hormonal mechanisms of cooperative behaviour

Soares

Bshary

Fusani

et al. 2010

Phil. Trans. R. Soc. B

147

143

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Research on the diversity, evolution and stability of cooperative behaviour has generated a considerable body of work. As concepts simplify the real world, theoretical solutions are typically also simple. Real behaviour, in contrast, is often much more diverse. Such diversity, which is increasingly acknowledged to help in stabilizing cooperative outcomes, warrants detailed research about the proximate mechanisms underlying decision-making. Our aim here is to focus on the potential role of neuroendocrine mechanisms on the regulation of the expression of cooperative behaviour in vertebrates. We first provide a brief introduction into the neuroendocrine basis of social behaviour. We then evaluate how hormones may influence known cognitive modules that are involved in decision-making processes that may lead to cooperative behaviour. Based on this evaluation, we will discuss specific examples of how hormones may contribute to the variability of cooperative behaviour at three different levels: (i) within an individual; (ii) between individuals and (iii) between species. We hope that these ideas spur increased research on the behavioural endocrinology of cooperation.

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Episodic-Like Memory in Rats: Is It Based on When or How Long Ago?

Cited by 147 publications

References 18 publications

Rats answer an unexpected question after incidental encoding

Rats answer an unexpected question after incidental encoding

Disambiguating past events: Accurate source memory for time and context depends on different retrieval processes

Hormonal mechanisms of cooperative behaviour

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