Excitatory Synthesis

“The Human Brain”, by myPerspectives, is an informative article that claims that the brain is a complex organ that is truly impressive. The brain is a key part of the central nervous system, that controls the entire body’s activities, to simple things such as breathing. These actions are fired through neurons, that quickly travel through the spinal cord. Surprisingly, the brain transmits these messages at an unimaginable rate, at 150 miles per hour, through 85 billion cells, called neurons. These neurons can form up to 10,000 synapses, or connections to each other. By itself, the brain can create billions of synapses, which change the structure of the brain every time new information is learned. However, there is still much that scientists

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

When you repeat the same task over a long period, your brain constructs specialized neural circuits dedicated to the activity.” (insert page number) In this

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).

Whether aging impair learning related long-term plasticity at LESN-L7MN synapses? (Aim 1). Though several studies have brought insights into the aging associated behavioral, cellular and electrophysiological changes, none of these studies have examined learning related long-term synaptic plasticity at LE SN-L7MN synapses connections of GWR during aging. First, using the semi-intact preparation [6,34], we will measure basal electrophysiological

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.

Chapter five of How People Learn: Brain, Mind, Experience, and School: Expanded Edition explains the two basic procedures in which synaptic connections are added to the brain. One method is synapse overproduction and loss. This method incorporates information from experience at an early age. A second method is synapse addition. This method adds synapses together throughout the entire lifespan, and adds on to create connections between information learned early in one’s life to form complete memories and ideas (nap.edu). Similarly, Donald J. Ford explains in an article titled How the Brain Learns, that through synapses, sensory information gets conveyed through a network of neurons for storing in short-term memory. Then, Ford writes that the information is carried to long-term memory where the information is compared to existing memories to compare and contrast the newly observed information

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

Synaptic plasticity refers to a process through which the brain undergoes neural changes due to alterations in synaptic strength. Many studies have demonstrated that these synapses have the ability to strengthen or weaken on account of synaptic activity. In other words, an increase in synaptic activity will further strengthen that connection, making it more sensitive to a particular stimulus. Conversely, a decrease in synaptic activity will weaken the connection such that it loses its sensitivity to a given stimulus. The neuronal events that result in the strengthening or weakening of a synapse are explained through two mechanisms – Long-Term Potentiation (LTP) and Long-Term Depression (LTD). In fact, scientists believe that the coupling of these two mechanisms essentially contributes to memory and learning of an individual.

Some scientists believe that parts of long term memory are permanent while others will eventually weaken over time. (3) Long term memory can be divided into three sections: procedural memory, declarative memory, and remote memory. Procedural memory includes motor skills such as learning how to ride a bike or how to drive a car. "Such memories are slow to acquire but more resistant to change or loss." (4) Declarative memory is used to remember facts, such as names, dates and places. It is easy to learn but also easy to lose. Finally there is episodic memory, which is the record of events that a person stores throughout his or her experience. Recent studies show that these events, as soon as they occur, are sent to a temporary part of the brain called the hippocampus, and that over time they are moved to the neocortex for permanent storage. (5).

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

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