Draft:Memory integration

Memory integration is the process whereby similar memories are stored together in the brain, forming a memory network. This network allows individuals to draw upon past experiences or knowledge to make flexible inferences in response to new situations or behaviours. For example, while sitting in a park, you may meet a woman walking her dog, prompting your brain to build an association between the two. Later, if you meet the same dog in the park walked by a man, your brain recognises the dog as a familiar element and recalls its previous association with the woman. By linking these events across time, you might infer that the man and woman are a couple, despite never having seen them together before.

Neural Mechanism
The hippocampus and the medial prefrontal cortex (mPFC) play crucial roles in memory integration. During this process, the mPFC constructs mental models that activate when new information is relevant with prior experiences. Subsequently, the hippocampus, responsible for storing and retrieving episodic memory, reactivates overlapping memories when encountering new information. This process may involve integrating the reactivated knowledge with current perceptions. The mPFC is responsible for keeping the integrated memories.

Role as Opposition to Existing Theory
Memory integration is viewed as an alternative theory to the consolidation/reconsolidation hypothesis in the memory process. The memory consolidation theory represents the initial understanding of the memory process, suggesting that memories solidify over time; interruptions during this consolidation phase may result in memory loss. A primary supporting evidence for the consolidation theory is the occurrence of false memories when treatments are given immediately following the memory process. Therefore, according to the consolidation theory, interference disrupts normal brain function by preventing memory formation, potentially leading to amnesia. Conversely, memories should be permanently stored after this critical period, no longer susceptible to disruption by amnesic treatments.

The memory integration theory leads to a distinct hypothesis in terms of memory. The consolidation theory states that the labile active memory needs time to be consolidated; while the integration theory suggests hat the labile active memory can integrate new information, further leading to update, reinforcement, distortion or disruption of previous memory.

Comparisons between Memory Integration Theory and the Consolidation Theory
The memory integration theory presents a unique hypothesis regarding memory. While the consolidation theory states that labile active memory requires time for consolidation, the integration theory suggests that labile active memory can integrate new information, thereby potentially updating, reinforcing, distorting, or disrupting previous memories.

Protein synthesis
According to the consolidation theory, the process of new protein synthesis is considered crucial for memory formation and retrieval. In contrast, the Memory Integration theory suggests that protein synthesis is not mandatory for memory formation and retrieval, although it may aid in retrieval.

Active memory
Both theories agree on the existence of two states of memory: an active state during training and recall periods, and an inactive state where knowledge exists but is not readily accessible. They also agree that memory in the active state is malleable. For the consolidation theory, this implies that memories are fragile and can be disrupted, while the integration theory views this as the flexibility of memories, allowing for integration.

Memory modification
The consolidation hypothesis believes that memories are lost if interruption takes place during the stabilisation process by preventing memory storage. Conversely, the integration theory suggests that memories are not erased but can be modified and updated by new information, although this modification potentially leads to false memories.

Processing New Information
Both the consolidation and integration theories agree that updating knowledge reactivates prior knowledge. However the consolidation hypothesis suggests that updating needs the reconsolidation process, which is time-dependent. In contrast, the integration theory states that the memory formation is rapid and can occur even in the active state, provided the information is salient enough.

Spatial Navigation
Memory integration can create a map of space by connecting memories of different places and routes traveled. For example, when you explore a new town and learn about different landmarks on separate trips, your brain integrates these experiences into a common map that shows how these landmarks are related to each other on the map. This integrated map allows you to navigate the town more effectively by understanding the connections between the places you have visited. By linking the memories of various locations, memory integration helps to form a mental map of the spaces we have explored.

Creativity and Imagination
Memory integration enables us to build new ideas and picture future scenarios by combining past memories. The involvement of the hippocampus and mPFC during this process further highlights its significance in memory integration.