Psychology

The hippocampus is a curve shaped part of the limbic system situated in the temporal lobe. This structure is involved in sexual and emotional functions of the brain. The hippocampus has got numerous neurons that enable it to carry out various functions effectively. This structure also has a role in learning and memory. It also aids in the development of a three dimensional mental map of the environment. Damage to the hippocampus has got very deteriorating effects to an individual. People with damaged hippocampus have problems in forming new short-term memories. This paper is going to highlight the functions of the hippocampus, the cause and effects of damage to the hippocampus by looking at some peer reviewed journals and published work.

Introduction
The brain is a very important part of the human body. It is one of the most complicated parts of the body whose major role is to control all the functions that a human being undertakes. The brain is subdivided into various sections and parts. Each part of the brain is attributed with different roles. The hippocampus is one of the numerous parts of the brain. The hippocampus, which is part of the limbic system, is situated in the temporal lobe adjacent to the amygdala in the brain (Kalat, 2007). The limbic system is group of structures that surround the brain. The main function of the limbic system is controlling experience of certain emotions such as anger, fear, memory, and motivation (Duvernoy, 2005). There are two hippocampi in human brain each located in each side of the brain (Fortin, Agster  Ichenbaum, 2002). The hippocampus, as stated by Fortin, Agster and Ichenbaum (2002), plays a major role of enabling easy storage and retrieval of stored information. It acts as the path through which memory pass while entering permanent storage. Damage to the hippocampus therefore has got very adverse effects to an individual concerning the ability to store and retrieve information (Taupin, 2007). The hippocampus has been extensively studied to gain insight on the development of various psychological disorders (Hyman, 2001).

Damage to the hippocampus
Damage to the hippocampus can be brought about by various factors including aging, trauma, and infection such as herpes. Oxygen deprivation, according to Duvernoy (2005) is another major cause of hippocampal damage. The other factors that may result in hippocampal damage include heart attack, respiratory failure, and sleep apnea. Hippocampal damage may also result from encephalitis and medial temporal lobe epilepsy (Hyman, 2001). People who have a history of childhood abuse have a reduced volume of  hippocampus. This reduction in volume is related to stress. McClelland (1996), states that the hippocampus is the first region in the brain to suffer damage in Alzheimers disease. Shrinkage of the hippocampus results in severe diseases such as schizophrenia and severe depression. Damage to the hippocampus impairs memory for the order of a series of spatial locations that have recently been visited (Hyman, 2001). Older memories are however not affected by damage to the hippocampus. A person may therefore have a very good memory of childhood experiences and fail to remember anything in adulthood (Andersen, 2007). This is due to the fact that the hippocampus is very crucial to spatial learning in addition to memory in numerous protocols. Patients of hippocampal damage, as asserted by Taupin (2007), therefore become prisoners of the past. Short term memory cannot be processed into long term memory in patients suffering from hippocampal damage.

Patients suffering from Hippocampal damage show extensive deficit in the capability of acquiring novel memories for the content of definite incidents and events. The ability of retrieving memories stored prior to damage is also impaired (McClelland, 1996). The ability to learn arbitrary word pairs is greatly impaired in patients suffering from Hippocampal damage. A normal person has the ability of learning these word pairs with a few trials such that whenever the first word of the pair is presented ,they are able to recall the second word without problems (Duvernoy, 2005). On the other hand, patients whose hippocampus has been damaged may fail even to learn a single word pair from a list, let alone recalling the second word of a pair after the first word has been presented (Kalat, 2007). People who are suffering from Hippocampal damage also cannot remember the order of events that occur in a series (Taupin, 2007). They therefore cannot remember the sequence of events that compose unique episodes. Andersen (2007), agrees that daily memory ability of a person is also greatly impaired. These people cannot learn new names and also cannot remember important events. Damage to the hippocampus however according to Mumby, Gaskin, Glenn, Schramek and Lehmann (2002), does not affect the ability of learning novel skills. People suffering from Hippocampal damage have fragmented memory, disturbing memories, dissociation and pathological emotions, as well as intrusive flashbacks (McClelland, 1996). A person with damaged hippocampus cannot remember spatial layouts. Patients suffering from damage to the parahippocampus, a region located below the hippocampus, as a result of stroke develop topographical disorientation. Their ability of learning new routes or traveling to familiar routes is adversely impaired (Fortin, Agster and Ichenbaum 2002).

Conclusion
The hippocampus is a curve shaped part of the limbic system situated in the temporal lobe. It has got numerous neurons that enable it to carry out various functions effectively. The hippocampus, which is part of the limbic system, is situated in the temporal lobe adjacent to the amygdala in the brain. The hippocampus plays a major role of enabling easy storage and retrieval of stored information. Damage to the hippocampus can be brought about by various factors including aging, trauma, and infection. Damage to the hippocampus has got very deteriorating effects to an individual. Damage to the hippocampus impairs memory for the order of a series of spatial locations that have recently been visited. Patients suffering from Hippocampal damage show extensive deficit in the capability of acquiring novel memories for the content of definite incidents and events. The ability to learn arbitrary word pairs is greatly impaired in patients suffering from Hippocampal damage. Daily memory ability of a person is also greatly impaired.