History

What comes to mind when you think of Long-Term Memory? Throughout history a number of researchers have given their insight into the vast topic of human memory. Some of their main questions being: What is it? How is it possible? Where does it occur? There is a variety of definitions for long-term memory that are available today. Cowan describes long-term memory as “a vast store of knowledge and a record of prior events.” (Cowan, 2009)
 * __ History and Key Findings __**

=**__ Early Findings __**= ==== Some of the earliest research available on the topic of long-term memory was found in the writings of William James (1890). James believed that as humans, we use memory as a primary function for survival. Our memory allows us to retain information and recall subject matter that we may find useful later on. James felt that it is inaccurate to imagine our brains holding every piece of information that it ever encounters. This would lead to a great deal of useless information being stored in our heads. Instead, James suggested that the human brain has two systems that are used for memory. The first is the “primary memory”, which is a system that allows people to experience their environment and the world around them. The information stored in the primary system is considered what people are “immediately conscious of”. The second system is the “memory proper” which is where events and information experienced by the person can be stored. James wrote that the primary memory system can be accessed fairly easily, while the secondary memory system would require more effort. Access to the information in the memory proper requires a great deal of recollection. ====

==== In the year 1900, research was conducted on theories for memory consolidation. Müller and Pilzecker were the first to introduce the term “consolidation” as it referred to memory. They published their findings in the Experimental Contributions to the Science of Memory. In these writings, they suggested that the key to consolidating memories is time. Müller and Pilzecker wrote that memories “remain vulnerable to disruption” for a short period of time immediately after learning. Current research supports the idea of time decaying our memories (Lechner, 1999). ====

=__ Later Findings __= As time went on researchers began to achieve a better understanding of memory. In the year 1972, Endel Tulving published his work on human memory. Tulving was a cognitive neuroscientist whose findings would influence the work of psychologists and neuroscientists for generations to come. His work was the first to break down long-term memory into three types: episodic, semantic, and procedural. Episodic memory refers to our recollection of personal experiences from our past. When a person thinks about their childhood or about specific events that have occurred that day, they are using episodic memory. Semantic memory is where facts and general information are stored. When you remember specific rules or problem-solving skills you are utilizing your semantic memory. Finally, procedural memory is where information is stored about remembering tasks or strategies. We employ our procedural memory when we remember the steps that are necessary to perform a specific task (McLeod, 2010).

Another area that Tulving contributed his research to was in implicit and explicit memory. Tulving and his colleagues were the first to propose that these two systems derived from two separate brain systems. They referred to implicit memory as memories that are automatic and implicit memories as memories that must be consciously derived (McLeod, 2010).

Long-term memory has been further broken down into three general processes. These processes include: encoding, storage, and retrieval. In encoding, information that we perceive is “written” into our long-term memory. This information is stored in structures known as schemas. These schemas can be changed as time passes and new information is learned. We assimilate our new experiences with information that we have already stored in our long-term memory. In retrieval, we are actively trying to access the information that we have stored in our long-term memory. Rehearsal of new learned information will help us to remember it for a longer period of time. (McLeod, 2010).

=__ Biology __= Memory is a complex process that involves various areas of the brain. In general, the neural networks that can be found in the cerebrum are responsible for memory and many other complex human interactions. Two brain areas that are involved in long-term memory are the hippocampus and the amygdala. The hippocampus plays a role in the brain's consolidation of memories. The amygdala is not a storage site for long-term memories but it also plays a role in the consolidation of memories. The amygdala has also been linked to the preservation of memories that have strong emotional value (Richter-Levin & Akirav, 2000). In order for long-term memory to occur new proteins must be formed. In particular, the protein PKM has been linked to maintaining long-term memories. However, this subject was researched extensively by Richard Huganir of Hopkins University. Huganir found that although PKM does play a role, it is not solely responsible for the creation of long-term memories. He discovered this through the injection of a molecule known as ZIP into the brains of mice. The ZIP molecule removes the PKM protein from the brain. Huganir noted that there was no type of memory loss or issue with these mice after the injection. These findings have challenged researchers to continue to seek out new information and question concepts that have been around for years (Huganir, 2013).

=__ Current Research __= Currently, research is being done on what causes the storage of long-term memories to occur. In March of 2013, researchers at UC Irvine published findings that implicate a new mechanism in the creation of long-term memories. Marcelo Wood, from UC Irvine’s Center for the Neurobiology of Learning & Memory led a team that identified a protein known as Baf53b. Wood and his team bred mice that had a mutation in the Baf53b proteins, and found that these mice were unable to form long-term memories. These new findings can help pave the way to a new understanding of memory (Irvine, 2013).


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Welcome History & Key Findings Important Contributors Objections References