Have you ever wondered what part of the brain controls memory? Have you ever wondered how it would feel to have no memories – short term or long term – or perhaps not be able to retain or create new memories?
We don’t realize just how important our memories are to us until there comes a time when we have difficulty remembering the simplest things… like where you put your car keys, or what you wore to work yesterday or even what game you were playing only minutes before you were interrupted! But the scariest part is when you start forgetting the names of family members and other people you have known for years.
The part of the brain that is responsible for memory is known as the hippocampus. It is part of the limbic system and can be found in the medial temporal lobe. The functions of the hippocampus go beyond what you think such a small structure in the brain should be capable of.
Believe it or not, this small, curved, tube shaped structure is responsible for not only forming new memories about all your experiences and then processing the new and temporary memories into long term storage… it is also responsible for functions like your emotions, your behavior and your sense of smell.
Whenever you have to remember places, events, people or any important facts… it is because of the hippocampus being able to retrieve this information that this is even possible. If this structure is damaged or removed, your memory will suffer in the process. How do the scientist and doctors know this? Read the next caption of the relationship between the hippocampus and memory.
Relationship Between The Hippocampus And Memory
The relationship between our memory and the hippocampus was realized when a man by the name of Henry Gustav Molaison had two-thirds of his hippocampus removed because of epileptic seizures.
Apparently the surgery was successful for the seizures, but the doctors soon discovered that Mr. Molaison had trouble processing any new events to long-term memory. Neither could he remember most of the things that happened in his life 1 to 2 years prior to the surgery and some things as much as 11 years prior to surgery.
However, it appeared HM as he was called, could still learn new motor skills, even though he couldn’t remember learning them. Needless to say, he became a case study from the late 1950’s until his death, and it was during this time that the doctors and scientists discovered the importance of the link between our brain and our memory, and that if damage or injury occurs to certain parts… it could also affect the memory.
What Happens If The Hippocampus Is Injured
Like any other organ or structure in our bodies, when they are damaged or injured, it causes an impairment. It is no different when the hippocampus is damaged or injured. If the injury is severe enough, a person could have problems forming new memories and problems with memories before the damage. However, older memories, like knowing how to solve puzzles or play an instrument could be intact.
Older memories can be accessed because doctors believe memories that have accumulated over time are transferred and stored in different parts of the brain and doesn’t necessarily rely on the hippocampus for retrieval. However, since it is also believed that the hippocampus helps with our navigation, any damage may disrupt your ability to know where you’ve been and where you’re going.
Other Disorders That Affect The Hippocampus
Alzheimer’s Disease
It has been stated that Alzheimer’s causes memory failure due to cell death in the basal forebrain, which is a group of structures that can be located at the bottom of the front part of your brain. This area is responsible for producing a chemical that helps with the learning process. Alzheimer’s affects the hippocampus by interfering with a person’s ability to form and retain new memories, but it appears memories of events that happened in the past can be remembered.
PTSD
As stated before, the hippocampus is part of the limbic system in the brain, and this system has the ability to store and retrieve memories as well as being responsible for how we experience emotions like anger, fear and motivation.
People with PTSD generally have memory-related problems and they may not be able to remember parts of traumatic events they have suffered. If the hippocampus happens to be damaged, they could also experience fear and have trouble overcoming it if any situations, memories or thoughts about the traumatic event occur.
Temporal Lobe Epilepsy
A temporal lobe seizure begins in the part of the brain that is responsible for your short-term memory, your emotions and how you react to fight or flight situations. Because of this, people who suffer from epilepsy may experience feelings of fear and have hallucinations surrounding their sense of smell or taste. Doctors believe scarring on the hippocampus is responsible for seizures that begin in the temporal lobe, but caution that it can’t always be determined what causes seizures in this area of the brain.
Herpes Encephalitis
Although Herpes simplex 1 is a common virus, it and Herpes simplex 2 can sometimes travel through the sinus cavity to the brain and cause encephalitis. The parts of the brain specifically targeted are one or both temporal lobes – often involving the hippocampus, parahippocampus, and amygdala.
Heart Attack
Hypoxia is your brain starving for oxygen and this can come from having a heart attack . Any time your breathing or oxygen intake is impaired, you run the risk of damaging the hippocampus.
Sleep Apnea
This is another area where your brain doesn’t receive enough oxygen due to airway constriction during sleep. The frequent pauses between breathing causes a lack of oxygen as well as stress on the heart. This can lead to damage of the hippocampus and your heart.
