Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. The hippocampus plays a critical role in the formation, organization, and storage of new memories as well as connecting certain sensations and emotions to these memories. Have you ever noticed how a particular scent might trigger a strong memory?
It is the hippocampus that plays a role in this connection. The hippocampus is a small, curved formation in the brain that plays an important role in the limbic system.
The hippocampus is involved in the formation of new memories and is also associated with learning and emotions. This video has been medically reviewed by Huma Sheikh, MD. Research has also found that different subregions of the hippocampus itself play important roles in certain types of memory. The rear part of the hippocampus is involved in the processing of spatial memories.
Studies of London cab drivers found that navigating complex mazes of big city streets is linked to the growth of the rear region of the hippocampus. The hippocampus also plays a role in consolidating memories during sleep. Studies published in suggest that greater hippocampal activity during sleep following some sort of training or learning experience leads to better memory of the material the following day. Memories are not stored in the hippocampus for the long term.
Instead, it is believed that the hippocampus acts as something of a shipping center, taking in information, registering it, and temporarily storing it before shipping it off to be filed and stored in long-term memory. Sleep is believed to play a critical role in this process. Because the brain is lateralized and symmetrical, you actually have two hippocampi. They are located just above each ear and about an inch-and-a-half inside your head. If the hippocampus is damaged by disease or injury, it can influence a person's memories as well as their ability to form new memories.
Hippocampus damage can particularly affect spatial memory, or the ability to remember directions, locations, and orientations. Because the hippocampus plays such an important role in the formation of new memories, damage to this part of the brain can have a serious long-term impact on certain types of memory. Damage to the hippocampus has been observed upon post-mortem analysis of the brains of individuals with amnesia. We wanted to be sure that any cell we would report would have the distinctive appearance of young neurons; they tend to have a simpler shape that differentiates them from mature neurons, which are usually bigger with long, elaborate branches.
We also looked at overall patterns of gene expression in this region and observed a similar decline in genes associated with young neurons. In addition, we looked for evidence of the stem cells that make young neurons, which have their own protein markers and can be detected when they divide. None of the adult hippocampal tissue we examined with these techniques showed evidence of young neurons or their dividing stem cell parents.
To make sure that our techniques were even capable of detecting young neurons or dividing neural stem cells, we looked at the same region of the hippocampus before birth, when we knew they should be present. In these fetal brain samples, we clearly saw plentiful new neurons. Using the same techniques, we then looked for these cells in brain tissue from people who died in infancy, childhood or early adolescence.
We saw the number of new neurons sharply declined until few remained by the age of 13; by 18 and 19 years, we could not find any. If neurogenesis continues in the adult human hippocampus, it is a very rare phenomenon. Could our inability to see these cells be due to unknown differences between young and old brain tissue?
We knew that there are very rare young neurons in other parts of the adult human brain, so we looked in those regions. When we readily found those rare young neurons, we became more confident that what we were seeing, or not seeing, in the hippocampus was not simply an artifact of aging brain tissue. To convince ourselves that the tissue was as representative of adult brains as possible, we studied brains collected by many different collaborators around the world and saw the same results.
Could the time between death and preservation of the brains lead to our inability to detect young neurons? To test this, we collected more than a dozen tissue samples from patients who were having brain tissue removed as part of surgical treatment for severe epilepsy. These are samples we collected and preserved quickly to maximize their quality.
In addition, we looked at two samples where the brains had been collected and preserved almost immediately at the time of death and saw the same results. In total we examined 59 brains, a collection comparable to previous studies.
In all these cases, we saw the same results: no signs of new neurons in the adult hippocampus. We concluded that if new neurons are being born in the adult human hippocampus, they are extremely rare. So what have other researchers seen that made them believe that new neurons are born in the adult human hippocampus?
Previous studies frequently used only a single protein to identify new neurons. If someone is experiencing dysfunction with their hippocampus, they may be experiencing one or more of the following symptoms:.
As this condition develops, the volume of the hippocampus tends to reduce, and it becomes harder to function in daily life. Hippocampal weakening could simply be the result of aging, leading to this cognitive decline in older adults.
There can however be other causes of weakening or dysfunction. The hippocampus contains high levels of glucocorticoid receptors which makes it more susceptible to long-term stress.
Long-term stress can have a negative impact on the hippocampus and there is evidence that individuals who have experienced severe traumatic stress show atrophy of the hippocampus.
Damage to the hippocampus could also be the result of trauma to this area, oxygen starvation, stroke, or medial temporal lobe epilepsy. There is evidence that links hippocampal atrophy to cognitive disorders such as depression, bipolar disorder, and schizophrenia Weis et al. Similarly, the duration that someone has suffered from depression has been correlated with the severity of hippocampal atrophy. It is suggested that a reason for this could be that depression may be causing prolonged stress because of their depression.
Equally, hippocampal volume reduction has consistently been found to be a major finding in the brains of people who have schizophrenia. Being able to manage stress can reduce the number of stress-related neurotransmitters being taken in by the hippocampus. Some simple methods could be to practise deep breathing exercises, mindfulness, or meditation. As the hippocampus is more concerned with memory, completing memory-based activities can help to keep the hippocampus active. Exercises such as trying to memorize lists of words or reading and writing could all help to keep the hippocampus working properly.
The researchers used electroconvulsive therapy ECT , a procedure in which small electric currents are passed through the brain, deliberately causing a brief seizure. ECT has found to highly effective for the relief of depression. After a series of ECT, there was a significant increase in the hippocampal volume of the patients. As there was an increase in volume, this could imply that the hippocampus may play a key role in the treatment of depression.
The researchers suggest that we use social maps to guide us through social spaces in the same way as cognitive maps can help us physically navigate our way around the environment. Berger and his colleagues were able to mimic the structure of the hippocampus by stimulating the brain in a particular way to form memories in rats and monkeys.
In a small pilot study on humans, people fitted with this implant had improved performance on memory tasks. This implant works by communicating with the brain via electrodes placed on either side of the hippocampus. They found an increase in grey matter in the brains of taxi drivers. There was no difference in the size of the hippocampus but difference in shape was visible.
They concluded that the hippocampus changes in line with demand on spatial memory which supports brain plasticity. Olivia has been working as a support worker for adults with learning disabilities in Bristol for the last four years. Guy-Evans, O. Hippocampus function and location. Simply Psychology. Anand, K. Hippocampus in health and disease: An overview.
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