Memory Reconsolidation Theory

* Consolidation- hypothetical process involving gradual conversion of information into memory codes stored in long term memory.

Memory refers to the persistence of learning in a state that can be revealed at a later time (Squire, 1987). A memory is a network of neocortical neurons and the connections that link them. That network is formed by experience as a result of the concurrent activation of neuronal ensembles that

Among these different processes are encoding, storage, consolidation, and retrieval. This study hypothesized that the hippocampus plays a different role in each of these. The method of this study is especially unique because it used temporary chemical inactivation of the hippocampus, which had not been done before. This temporary inactivation is unique because it lets the researchers selectively assess the role of the hippocampus during each of the processes discussed above. To test encoding, the inactivation occurred during learning of a maze task; to test retrieval, inactivation occurred during a retention task. Results indicate the temporary inactivation of the hippocampus impairs both encoding and retrieval. To test long-term consolidation, rats were trained and then separate groups received hippocampal treatment for different amounts of time between one and five days. Results showed that temporary inactivation during this time period disrupts memory for the already learned task. This study partially supports the result of the study by Eldridge et al. (2000) in that they both show the hippocampus is necessary for memory retrieval. However, it does not address the retrieval of different types of memory. This study also supports the idea from Wang et al. (2012) that the hippocampus may be involved in consolidation and storage of new memories but not necessarily of older

Instead they exist as fragments of information, stored in different parts of our brain. Over time, as the memories are retrieved, or we see news footage about the event or have conversations with others, the story can change as the mind recombines these bits of information and mistakenly stores them as memories.” The meaning of memory retrieval is simply refers to the subsequent re-accessing of events or information from the past, which have been previously encoded and stored in the brain. In common parlance, it is known as remembering.

Consolidation is the process by which an acquired memory is stabilized (Mastin, 2010). It begins when information is “bound into a memory trace by the hippocampus and related structures in the medial temporal lobes and diencephalon” (Nadel & Moscovitch, 1997, p. 217). This involves long term

Additionally, to further support these theories, researchers tend to conduct studies on the famous patient case, HM, to propose the consolidation deficit theory, in which those with amnesia cannot turn short-term memories into long-term memories (Dewar et al., 2010). However, researchers Dewar, Della Sala, Beschin, and Cowan (2010), mentioned that HM’s case does not fully explain why a patient with anterograde amnesia has the ability to get better at cognitive tasks despite being unable to recall having performed those tasks at a previous time. On the same hand, Duff, Wszalek, Tranel, and Cohen (2008) mentioned that most individuals with anterograde amnesia experience heightened intelligence, attention, skill, and reasoning levels (procedural memory).

Extensive research in the field of memory and cognition have provided substantial evidence to prove that the hippocampus is a critical brain mechanism in the role of memory. Although an ongoing debate specifically in memory retrieval is the exact role of this brain structure when extracting memories. There are multiple models of the neural basis of memory retrieval that have posed a hypothesis to answer this exact question. The two theories that are dominant in this debate are the Multiple Trace Theory (MTT) proposed by Nadel and Moscovitch in 1997 and the Standard Model of Systems Consolidation

The formation of new memories requires protein synthesis dependent changes in synaptic structure and plasticity in the hippocampus. Studies in humans and animals suggest that these memories are initially stored in hippocampus but later transferred to cortex for permanent storage. This phenomenon is described as systems consolidation of memories. While the specific role for new protein synthesis in hippocampus in early encoding of memories is established, whether protein synthesis in medial prefrontal cortex play a major role in encoding of memories is unclear. To address this question, we used contextual fear conditioning (CFC) of mouse, a behavior training that induce long lasting memories. A single training session produces robust lifelong memory (8) that can be measured using automated procedures (9). Several studies have used CFC training as a model to study hippocampal-cortical communications and mechanisms underlying systems consolidation of memories. Contextual fear memories are initially stored in hippocampus and then moved to medial prefrontal cortex (mPFC) for long-term storage.

Much psychological research suggests that new memories require time to stabilize and transfer to long-term memory and that these newly acquired memories are disposed to to interference by competing stimuli. Memory consolidation is the processes involved in the stabilization of a long-term memory after it’s initial acquisition (Dudai, 2004). Consolidation is described by two distinct theories: synaptic consolidation, which transpires in the first few hours after learning and systems learning where memories are stabilized over a period of weeks to years (Dudai, 2004).

When forgotten and then remembered, the memory requires some form of restabilization such that the new information can re-incorporate itself with existing memory. Processual memory can be used in this context as well as when given new information or experience, a person’s association with an existing memory can change. No two memories are the same, which is why even the recirculation of memory can become corrupt over time and differ from the truth in relation to a process also known as “Rememory” as seen in Toni Morrison’s Beloved. The act of memory preservation is impossible as over enough time the memory will be muddled and the true context of the event will be forgotten. It is a process that we are unaware of until explicitly focused on because when people remember something that was once forgotten and the original memory is re-written it consolidates the image of that memory as the original. For example, if someone was remembering himself or herself as the star of a child play it could be a reformatted version of a memory of the play that was less than stellar. The idea of memory consolidation is to form coherent memory that people convince themselves to be true even if not recognized as the whole truth by reconstructing past

Hippocampus is a small, curved region, which exists in both hemispheres of the brain and plays a vital role in emotions, learning and acquisition of new information. It also contributes majorly to long term memory, which is permanent information stored in the brain. Although long term memory is the last information that can be forgotten, its impairment has become very common nowadays. The dysfunction is exemplified by many neurological disorders such as amnesia. There are two types of amnesia, anterograde and retrograde. Anterograde amnesia is inability in forming new information, while retrograde refers to the loss of the past memory. As suggested by Cipolotti and Bird (2006), hippocampus’s lesions are

To learn from stressful events, memories of these events must be consolidated into long-term memory in case a similar situation occurs in the future. In the normal process of consolidating a memory, three different processes take place: synaptic long-term potentiation or LTP, systems consolidation, and reconsolidation (Depperman et al., 2014). LTP is a mechanism of neuroplasticity that increases the strength of certain synaptic connections through the stimulation of neurons involved in the connection. After an event happens, the new memory is transmitted to the hippocampus. Systems consolidation is the slow process by which memories are transferred from the hippocampus to the cortex such that memories are no longer hippocampus-dependent. Reconsolidation

Memory is both an essential, yet complex, psychological process that relies on numerous neuroanatomical structures, including parts of the prefrontal cortex, cerebral cortex, temporal lobe, amygdala, cerebellum, basal ganglia, and the hippocampus, just to name a few. However, almost all areas of the human brain are connected to the systematic functioning of memory. According to Okano, Hirano, & Balaban (2000), differentiation between the process of memory and the process of learning is important in order understanding the neurobiological aspects of memory, although both are very closely connected. The researchers define memory as a behavioral modification resulting from innate experiences, while the act of learning is more of a process for

After a new memory is learnt, it enters the process of encoding during which the memory is labile and capable of disruption until it becomes stabilised over a period of time (Nader & Einarsson, 2010; Nader et al, 2000). This process is called consolidation and originally consisted of the theory that once stabilised in the brain, it remains fixed (Suzuki et al, 2004). This theory has been rebutted by the acceptance of reconsolidation, a theory that imposes the ideology that when memories are retrieved, through similar experiences (Lee, 2009), they become labile until,

Loftus and Palmer support the reconstructive memory hypothesis. They believe that information gathered at the time of an icident is