The Neural Mechanisms Underlying Memory Formation

Since it is close structurally to the hippocampus, the amygdala is involved in controlling memory consolidation, especially emotional memories; when a memory is emotionally charged, it has a better retention rate than one that is not. The hippocampus is generally seen as having an essential role in the creation of new memories about past experiences; it's even responsible for memories that can be verbalized also known as declarative memory. Damage to it result in difficulties in forming new memories and being able to access new memories formed before the

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

Research has shown that there is “greater activation in the left inferior frontal and medial temporal lobes” (Stanford, 2006, p. 208) during the encoding of words which were later remembered as compared to those which were forgotten. The sensations perceived by sensory nerves are decoded in the hippocampus of the brain into a single experience (Mastin, 2010). The hippocampus analyses new information and compares and asssociates it with previously stored memory (Mastin, 2010). Human memory is associative in that new information can be remembered better if it can be associated to previously acquired, firmly consolidated information (Mastin, 2010). The various pieces of information are then stored in different parts of the brain (Mastin, 2010). Though the exact method by which this information is later identified and recalled has yet to be discovered, it is understood that ultra-short term sensory memory is converted into short term memory which can then later be consolidated into long term memory (Mastin, 2010).

Scientists and Practitioners Don't See Eye to Eye on Repressed Memory. (n.d.). Retrieved October 12, 2017, from

The importance of understanding the underlying psychological mechanisms by which both memories are repressed and

The retrieval of a memory can initiate processes in our brain that actively consolidate and strengthen the memory trace, a process known as memory reconsolidation. Memories retrieved are thought to increase their stability once they undergo the process of consolidation. Retrieval of a memory trace may cause another liable phase to require more processing to keep the memory stable after retrieval; the brain systemically acquires cellular mechanisms to initiate a new round of protein synthesis that saves the trace from degradation. (Rudy CITE) There has been recent issues concerning the relationship between post-traumatic stress disorder and reconsolidation of fear memories brought about by individuals who experience the disorder.

Steve Ramirez, Xu Liu, Pei-Ann Lin, Junghyup Suh, Michele Pignatelli, Roger L. Redondo, Tomás J. Ryan, Susumu Tonegawa

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

Anterograde amnesia, as described earlier, is an inability to form lasting memories after some disturbance to the brain, such as a brain injury or degenerative brain disease. The revelation of the H.M. case was the identification of the medial temporal lobes as memory consolidation and storage centers. Within the medial temporal lobes, the hippocampus has been identified specifically as a brain area involved in learning new information (Gluck, 2014). To put it another way, people with damage to the hippocampus will have difficulty forming new memories because they won’t be able to learn new things. The hippocampus helps to integrate objects in a spatial and temporal context. Episodic and semantic memory forming is impaired, otherwise known as declarative memory, though the person can remember declarative memory from the past. The process of encoding, storage consolidation, and retrieval seems to go through the medial temporal lobe with the hippocampus playing a key role. In anterograde amnesia, the consolidation process is damaged. Thus, in the short term new information can be learned, but since it is not consolidated, it can’t be retrieved, so it is forgotten (Webbe slides). Additionally, damage to the basal forebrain can cause anterograde amnesia. This is because the basal forebrain sends neurotransmitters to the hippocampus to tell it whether and when to process and store information (Gluck, 2014). In this way, the hippocampus is the main brain structure involved so

Learning is a very important aspect of humans and creatures alike. Not only is it essential to the survival and adaption into this world but it also defines who we are as individuals (Schiller et al, 2010; Tronson & Taylor, 2007). Memories from past experiences shape the people that we are today. A crucial element to learning is memory, without it we would not be able to retain information. The process of memory is very distinct and consists of several different stages: acquisition of memory, consolidation, retrieval and then either reconsolidation or extinction (Debiec & Ledoux, 2004; Diergaarde, Schoffelmeer & De Vries, 2008). As memory is such a critical aspect of learning, it is no wonder that its distinct process has become the topic of much research in the neurobiological universe (Hupbach et al, 2007; Nader & Hardt, 2009).

Doctors and scientists dispute the exact role of the hippocampus, but agree that it has an essential role in the formation of new memories about personally experienced events. Some researchers prefer to consider the hippocampus as part of a larger medial temporal lobe memory system responsible for declarative memory. When a long-term, declarative memory is made, certain neuronal connections in the temporal lobe are strengthened, and others are weakened. These changes are fairly permanent, however some may take weeks or months before they are complete

Have you ever been trying to NOT think about something? That embarrassing thing you did four years ago, or that spooky picture you saw browsing through a website? If you were successful, congratulations! Your brain has a region, called the prefrontal cortex that does this. However, researchers at Cambridge University have discovered the role of a chemical called GABA that, when released by a nerve cell can stop activity in other cells in the brain from performing functions. Using a functional magnetic resonance imaging and magnetic resonance spectroscopy (they are imaging techniques used to scan the brain), they saw concentrations of GABA in the hippocampus where the brain performs functions like retrieval of memories. The researchers say that

This paper seeks to exploit and explain findings that express the genetic bases of learning and memory. Learning and memory has played a huge evolutionary advantage to animals capable of effectively gathering information of their environment and able to remember and retrieve the information at a different time. The studies covered focused on drosophila because its cognitive functions are very similar to that of higher vertebrates such as humans. The central theme of this paper is to determine the biological bases of learning and memory by observing how disruption of the central nervous system through gene mutations alters the performance of learning and memory thus affecting the organism behavioral responses.

Without the hippocampus, the information from the short-term memory (STM) cannot be stored in long term memory (LTM). The hippocampus is a very important part of the human brain to store our memories. If we lost it, we will lose all our conscious memories. From Henry’s case, it also discovered that there are multiple memory storage areas located at different parts of the brain while the hippocampus is important to consolidate short-term memory to long-term memory. The removal of hippocampus caused Henry to suffer until he died as he lost the ability to make new conscious