Interplay of Hippocampus and Prefrontal Cortex in Memory

Abstract

Recent studies on the hippocampus and the prefrontal cortex have considerably advanced our understanding of the distinct roles of these brain areas in the encoding and retrieval of memories, and of how they interact in the prolonged process by which new memories are consolidated into our permanent storehouse of knowledge. These studies have led to a new model of how the hippocampus forms and replays memories and how the prefrontal cortex engages representations of the meaningful contexts in which related memories occur, as well as how these areas interact during memory retrieval. Furthermore, they have provided new insights into how interactions between the hippocampus and prefrontal cortex support the assimilation of new memories into pre-existing networks of knowledge, called schemas, and how schemas are modified in this process as the foundation of memory consolidation.

Influence of reward motivation on human declarative memory

“…Data, however, suggest that these two memory systems interact in either a synergistic or competitive manner (Gheysen et al, 2011;Rose et al, 2011;Sadeh et al, 2011;Schott et al, 2006;Seger et al, 2011), depending on task demands (Delgado and Dickerson, 2012;Packard and Goodman, 2012;Poldrack and Foerde, 2008). Specifically, the declarative memory system involves the MTL cooperating with the ventromedial prefrontal cortex (Preston and Eichenbaum, 2013), and enables instance learning, the extraction and application of underlying associative or categorical rules (generalization) to new instances, as well as retrieval of ensuing episodic and semantic memories (Hoscheidt et al, 2010). The second non-declarative learning system allows for rapid, feedback-based learning of patterns predicting reward, via the recruitment of the basal ganglia (Delgado and Dickerson, 2012;Poldrack and Foerde, 2008), and is essential for habit learning (Liljeholm and O'Doherty, 2012;Schwabe and Wolf, 2013;Smith and Graybiel, 2013).…”

“…The role of sleep in memory consolidation as well as generalization is well established (Rasch and Born, 2013;Stickgold and Walker, 2013). In reward memory formation, dopamine, in addition to enabling late-LTP, contributes to offline consolidation processes that continue after a stimulus-stimulus or stimulus-response learning and help better remember the learned association (Shohamy and Adcock, 2010;Wimber et al, 2011).…”

“…This input combines information about current motivational goals and task set from the PFC (mPFC in rats, vmPFC in humans, see Bromberg-Martin et al, 2010b as well as Rushworth et al, 2011 about the role of PFC), sensory stimulus properties from BLA/hippocampus, and the context of the memory from the hippocampus (Pennartz et al, 2011), and serves to either promote or inhibit goal-directed behaviors (Schultz, 2010). PFC participates in memory consolidation by assimilating new information with existing mental schemas (Preston and Eichenbaum, 2013), while emotional arousal can bias memory processing via connections between the amygdala and the hippocampus. The amygdala facilitates responding to Pavlovian stimuli by modulating dopamine signals within the core of the nucleus accumbens (Everitt et al, 1991;Jones et al, 2010;Mahler and Berridge, 2009).…”

“…New memories are often incorporated into existing representations of past experience, so that memory consolidation and retrieval also serve to reactivate and update memory networks (McKenzie and Eichenbaum, 2011;Scimeca and Badre, 2012), some of which may organize into mental schemas (Preston and Eichenbaum, 2013; see also Box 2). As a result, declarative memory representations may also become more abstract, integrating information across multiple sensory and semantic dimensions.…”

Machines Learning - Towards a New Synthetic Autobiographical Memory

“…when experiencing a familiar environment in the dark. This operation follows the idea of a schema [20] [39]. Schemas can be thought of as generative models for a particular basic system [43].…”