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Reconsolidation: Behavioural and Electrophysiological Sequelae of Context and Stress in Human Episodic Memory

von Dr. Jennifer L. Moore

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[1.] Jm/Fragment 049 01 - Diskussion
Zuletzt bearbeitet: 2014-02-18 23:46:18 Hindemith
Fragment, Gesichtet, Jm, Lee 2009, SMWFragment, Schutzlevel sysop, Verschleierung

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Hindemith
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Untersuchte Arbeit:
Seite: 49, Zeilen: 1-25
Quelle: Lee 2009
Seite(n): 6, 7, Zeilen: 6: 20-42; 7: 1-3
[If the assumption is made that NF-kB activity is reflective of a reconsolidation/updating process,] the extinction-induced inhibition would be consistent with a suppression of memory updating in favour of new extinction learning.

A further boundary condition on memory reconsolidation has recently been termed the ‘predictability of the reactivation stimulus’ (Nader & Hardt, 2009). This condition reflects findings emerging primarily from the crab literature that a mismatch between expected and actual events during reactivation triggers reconsolidation. Pedreira and colleagues (2004) found that reconsolidation only took place, and thus could only be disrupted, when the predictive context ended in the unexpected absence of the aversive outcome. It is not merely the case that memory reactivation must differ in some respect to conditioning, as there are numerous instances whereby reconsolidation impairments have been observed when the reactivation session is operationally identical to training (e.g., using reinforced reactivation procedures in fear conditioning (Eisenberg & Dudai, 2004; Duvarci & Nader, 2004), and in many (Kelly et al., 2003; Akirav & Maroun, 2006), but not all (Rossato et al., 2007) studies of object recognition memories). Instead, reconsolidation is triggered by a violation of expectation based upon prior learning, whether such a violation is qualitative (i.e., the outcome not occurring at all) or quantitative (i.e., the magnitude of the outcome not being fully predicted). It has thus been predicted that further initial training of fear or object memories would render such memories resistant to reconsolidation impairments through the use of reactivation sessions that are identical to training. Such an interpretation suggests that incompletely, but not fully, learned memories are subject to reconsolidation given the requirement for memory updating to optimize further the predictive accuracy of the memory.

Several hypotheses have been put forth regarding the role of reconsolidation in terms of wider memory processes. Two of these (Alberini, 2005; Dudai & Eisenberg, 2004) have adopted the temporal boundary condition to argue that reconsolidation plays a role in an extended process of memory stabilization.

[page 6]

If we make the assumption that NF-κB activity is reflective of a reconsolidation/updating process, the extinction-induced inhibition would be consistent with a suppression of memory updating in favour of new extinction learning.

A further boundary condition on memory reconsolidation has recently been termed the “predictability of the reactivation stimulus” [10]. This reflects the findings emerging primarily from the Chasmagnathus literature that a mismatch between expected and actual events during reactivation triggers reconsolidation. Pedreira et al. [56] found that reconsolidation only took place, and thus could only be disrupted, when the predictive context terminated in the unexpected absence of the aversive outcome. It is not simply that memory reactivation must differ in some manner to conditioning, as there are numerous instances where reconsolidation impairments have been observed when the reactivation session is operationally identical to training (e.g. using reinforced reactivation procedures in fear conditioning [48, 57], and in many [35, 58], but not all [59] studies of object recognition memories). Instead, reconsolidation is triggered by a violation of expectation based upon prior learning, whether such a violation is qualitative (the outcome not occurring at all) or quantitative (the magnitude of the outcome not being fully predicted). It is predicted, then, that more extended initial training of fear or object memories will render those memories resistant to reconsolidation impairments with the use of reactivation sessions that are identical to training. This interpretation, therefore, partially reduces to the prior discussion of memory strength, in that incompletely, but not fully, learned memories are subject to reconsolidation because of the requirement for memory updating in order to optimise further the predictive accuracy of the memory.

[page 7]

Several positions have been advanced regarding the role of reconsolidation in wider memory processes. Two of these [6, 8] have used the apparent temporal boundary condition to argue that reconsolidation plays a part in an extended process of memory stabilisation.


6. Alberini CM. Mechanisms of memory stabilization: are consolidation and reconsolidation similar or distinct processes? Trends Neurosci. 2005; 28:51–56. [PubMed: 15626497]

8. Dudai Y, Eisenberg M. Rites of passage of the engram: reconsolidation and the lingering consolidation hypothesis. Neuron. 2004; 44:93–100. [PubMed: 15450162]

10. Nader K, Hardt O. A Single Standard For Memory: The Case For Reconsolidation. Nature Reviews Neuroscience. 2009; 10:224–234.

35. Kelly A, et al. Activation of mitogen-activated protein kinase/extracellular signal-regulated kinase in hippocampal circuitry is required for consolidation and reconsolidation of recognition memory. J Neurosci. 2003; 23:5354–5360. [PubMed: 12832561]

48. Eisenberg M, Dudai Y. Reconsolidation of fresh, remote, and extinguished fear memory in medaka: old fears don’t die. Eur J Neurosci. 2004; 20:3397–3403. [PubMed: 15610172]

56. Pedreira ME, et al. Mismatch between what is expected and what actually occurs triggers memory reconsolidation or extinction. Learn Mem. 2004; 11:579–585. [PubMed: 15466312]

57. Duvarci S, Nader K. Characterization of fear memory reconsolidation. J Neurosci. 2004; 24:9269– 9275. [PubMed: 15496662]

58. Akirav I, Maroun M. Ventromedial prefrontal cortex is obligatory for consolidation and reconsolidation of object recognition memory. Cereb Cortex. 2006; 16:1759–1765. [PubMed: 16421330]

59. Rossato JI, et al. On the role of hippocampal protein synthesis in the consolidation and reconsolidation of object recognition memory. Learn Mem. 2007; 14:36–46. [PubMed: 17272651]

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