Anterior cingulate cortex in schema assimilation and expression

Abstract

In humans and in animals, mental schemas can store information within an associative framework that enables rapid and efficient assimilation of new information. Using a hippocampal-dependent paired-associate task, we now report that the anterior cingulate cortex is part of a neocortical network of schema storage with NMDA receptor-mediated transmission critical for information updating, and AMPA receptor-mediated transmission required for the expression and updating of stored information.

Systems Reconsolidation Reveals a Selective Role for the Anterior Cingulate Cortex in Generalized Contextual Fear Memory Expression

“…In this paradigm, rats first learn a set of constant place-flavor associations over the course of 6 weeks before being presented with a new association followed by hippocampal lesions afterwards. The findings demonstrate markedly accelerated systems consolidation gradient as recall of the new association was only impaired if rats received lesions within 3 h after learning (Tse et al, 2007), after which the memory became dependent on the ACC (Wang et al, 2012).…”

Building up and knocking down: An emerging role for epigenetics and proteasomal degradation in systems consolidation

“…It is important to note that maintenance is not static and that remote memories may still be subject to reconsolidation, which can result in memories being modified after recall, or updated with the addition of new information (Abraham and Robins, 2005;Graff et al, 2014). Moreover, categorically similar memories may be incorporated into higher order schemas, which rapidly integrate new memories into existing systems of knowledge (Tse et al, 2011;Wang et al, 2012;van Buuren et al, 2014;van Kesteren et al, 2014). Thus, the 'final' stage of memory maintenance does not preclude ongoing plasticity and can be considered as an effective tool for characterizing and understanding various stages of memory formation.…”

“…A number of studies suggest that memory formation immediately involves the PFC and that relative independence of recent memories of the cortex is a byproduct of relatively simple paradigms used to study systems consolidation (Preston and Eichenbaum, 2013). In more complex scenarios, new memories are synthesized with existing knowledge into contextually rich schemas (Tse et al, 2011;Wang et al, 2012;Preston and Eichenbaum, 2013), such that the PFC is immediately engaged in updating existing schemas. In the lab, many single-trial learning tasks, such as contextual fear conditioning, are well-suited for investigating the stimuluslocked molecular events associated with learning and memory, but the relative lack of prior experiences in which to integrate new learning may alter cortical involvement during the recent memory phase (Preston and Eichenbaum, 2013).…”

The Object Space Task shows cumulative memory expression in both mice and rats

“…This task is especially suitable for this as memory conditions tapping into memory accumulation vs. event memory can be presented in the same spatial layout and with very similar overall behavior, as indicated by the lack of difference in total exploration time across conditions. Previous studies have provided evidence that the hippocampus is more involved in the processing of recent experiences that include episodic details, whereas the prefrontal cortex accumulates information from multiple, similar experiences, thereby creating a more stable but also more generalized memory over time (Frankland and Bontempi 2005;Tse, Takeuchi et al 2011;Wang, Tse et al 2012;Preston and Eichenbaum 2013). We can hypothesize that successful performance on the overlapping condition involves the integration of multiple or all events in the prefrontal cortex, thereby creating a stable representation of the overlapping object location in space.…”

“…An example is a modified version of the watermaze, in which evidence accumulation was assessed as mice were trained on multiple platform locations that were drawn stochastically from a specific spatial distribution and retrieval of 'averaged' memory of the learned platform locations was assessed after a 1-day or 30-day delay (Richards, Xia et al 2014). Another example is pairedassociate learning in rodents, in which memory of flavor-place associations is gradually learned with repeated trials (Tse, Langston et al 2007;Tse, Takeuchi et al 2011;Wang, Tse et al 2012). Training procedures in these cumulative memory tasks are often lengthy and labor-intensive.…”