hippocampus

means "sea horse", and is named for its shape. It is one of the oldest parts of the brain, and is buried deep inside, within the limbic lobe. The hippocampus is important for the forming, and perhaps long-term storage, of associative and episodic memories. Specifically, the hippocampus has been implicated in (among other things) the encoding of face-name associations, the retrieval of face-name associations, the encoding of events, the recall of personal memories in response to smells. It may also be involved in the processes by which memories are consolidated during sleep.

Physical fitness improves memory in children

October, 2010

More evidence for the benefits of physical exercise for cognition, this time involving 9-10 year old children.

Brain imaging of 49 children aged 9-10 has found that those who were physically fit had a hippocampus significantly bigger (around 12%) than those who were not fit. Animal studies and those with older adults have shown that aerobic exercise increases the growth of new brain cells in the hippocampus. Physical fitness was measured by how efficiently the children used oxygen while running on a treadmill. Fitter children also did better on tests of relational (but not item) memory, and this association was directly mediated by hippocampal volume.

Reference: 

Source: 

Topics: 

tags development: 

tags lifestyle: 

tags memworks: 

tags strategies: 

Change in our understanding of memory development

September, 2010

Children’s slowly developing memory for past events may not be due to the slow development of the prefrontal cortex, as was thought, but to changes in the hippocampus.

Children’s ability to remember past events improves as they get older. This has been thought by many to be due to the slow development of the prefrontal cortex. But now brain scans from 60 children (8-year-olds, 10- to 11-year-olds, and 14-year-olds) and 20 young adults have revealed marked developmental differences in the activity of the mediotemporal lobe.

The study involved the participants looking at a series of pictures (while in the scanner), and answering a different question about the image, depending on whether it was drawn in red or green ink. Later they were shown the pictures again, in black ink and mixed with new ones. They were asked whether they had seen them before and whether they had been red or green.

While the adolescents and adults selectively engaged regions of the hippocampus and posterior parahippocampal gyrus to recall event details, the younger children did not, with the 8-year-olds indiscriminately using these regions for both detail recollection and item recognition, and the 10- to 11-year-olds showing inconsistent activation. It seems that the hippocampus and posterior parahippocampal gyrus become increasingly specialized for remembering events, and these changes may partly account for long-term memory improvements during childhood.

Reference: 

Source: 

Topics: 

tags development: 

tags memworks: 

Adolescents with type 2 diabetes have diminished cognitive performance and brain abnormalities

September, 2010

Another study adds to growing evidence that diabetes, or poor glycaemic control, has serious implications for brain function.

A small study comparing 18 obese adolescents with type 2 diabetes and equally obese adolescents without diabetes or pre-diabetes has found that those with diabetes had significantly impaired cognitive performance, as well as clear abnormalities in the integrity of their white matter (specifically, reduced white matter volume, especially in the frontal lobe, as well as impaired integrity in both white and grey matter). Similar abnormalities have previously been found in adults with type 2 diabetes, but the subjects were elderly and, after many years of diabetes, generally had significant vascular disease. One study involving middle-aged diabetics found a reduction in the volume of the hippocampus, which was directly associated with poor glycaemic control.

It remains to be seen whether such changes can be reversed by exercise and diet interventions. While those with diabetes performed worse in all cognitive tasks tested, the differences were only significant for intellectual functioning, verbal memory and psychomotor efficiency.

Reference: 

Source: 

Topics: 

tags: 

tags development: 

tags lifestyle: 

tags problems: 

Specific hippocampal atrophy early sign of MCI & Alzheimer's

January, 2010
  • People with MCI who later developed Alzheimer's disease showed 10-30% greater brain atrophy in two specific regions.

A three-year study involving 169 people with mild cognitive impairment has found that those who later developed Alzheimer's disease showed 10-30% greater atrophy in two specific locations within the hippocampus, the cornu ammonis (CA1) and the subiculum. A second study comparing the brains of 10 cognitively normal elderly people and seven who were diagnosed with MCI between two and three years after their initial brain scan and with Alzheimer's some seven years after the initial scan, has confirmed the same pattern of hippocampal atrophy, from the CA1 to the subiculum, and then other regions of the hippocampus.

Reference: 

Apostolova, L.G. et al. In press. Subregional hippocampal atrophy predicts Alzheimer's dementia in the cognitively normal. Neurobiology of Aging, Available online 24 September 2008.

[392] Apostolova, L. G., Thompson P. M., Green A. E., Hwang K. S., Zoumalan C., Jack, Jr C. R., et al.
(2010).  3D comparison of low, intermediate, and advanced hippocampal atrophy in MCI.
Human Brain Mapping. 9999(9999), NA - NA.

Source: 

Topics: 

tags development: 

tags problems: 

Why quiet time is important for learning & memory

January, 2010

As well as during sleep, it now appears that restful periods while you are awake are also times when consolidation can occur.

It is now well established that memories are consolidated during sleep. Now a new study has found that restful periods while you are awake are also times when consolidation can occur. The imaging study revealed that during resting (allowed to think about anything), there was correlated activity between the hippocampus and part of the lateral occipital complex. This activity was associated with improved memory for the previous experience. Moreover, the degree of activity correlated with how well it was remembered. You can watch a 4 ½ minute video where the researchers explain their study at http://www.cell.com/neuron/abstract/S0896-6273%2810%2900006-1

Reference: 

Tambini, A., Ketz, N. & Davach, L. 2010. Enhanced Brain Correlations during Rest Are Related to Memory for Recent Experiences. Neuron, 65 (2), 280-290.

Source: 

Topics: 

tags lifestyle: 

tags memworks: 

Sense of direction may be innate

July, 2010
  • A finding that navigational and spatial neurons are already tuned in newborn rats lends weight to the theory that a pre-wired spatial framework may provide a conceptual framework for experience in humans.

A rat study reveals that, for rats at least, an understanding of place and a sense of direction appears within two weeks of being born, seemingly independently of any experience of the world. The directional signal, which allows the animal to know which way it is facing, is already at adult levels as soon as it can be measured in newborn rats. Sense of place is also present early, but improves with age. Representations of distance appear a few days later. These processes depend on specialized cells in the hippocampus, which in humans plays a crucial role in long-term memory for events as well as spatial navigation. The findings fit in with the theory that a pre-wired spatial framework may provide a conceptual framework for experience.

Reference: 

Source: 

Topics: 

tags: 

tags memworks: 

Memory replay not as simple as thought

March, 2010
  • Several reports have come out in recent years on how recent events replay in the hippocampus, a process thought to be crucial for creating long-term memories. Now a rat study suggests that these replays are not merely echoes of past events, but may include possible events that never happened.

Several reports have come out in recent years on how recent events replay in the hippocampus, a process thought to be crucial for creating long-term memories. Now a rat study suggests that these replays are not merely echoes of past events, but a dynamic process aimed at improving decision-making. Rather than being solely replays of recent or frequent paths through the maze, the replays were often paths that the rats had rarely taken or, in some cases, had never taken, as if the rats were trying to build maps to help them make better navigation decisions.

Reference: 

Source: 

Topics: 

tags: 

tags memworks: 

Repeated anesthesia can affect children's ability to learn

March, 2010

A rodent study provides more support for the idea that repeated anaesthesia in children can lead to memory impairment.

Supporting the idea that repeated anaesthesia in children can lead to memory impairment, a rodent study has revealed that repeated anaesthesia wiped out a large portion of the stem cells in the hippocampus. This was associated with impaired memory in young animals, which worsened as they got older. The effect did not occur in adult animals. A similar effect has also been found with radiotherapy, and animal studies have found physical activity after radiotherapy results in a greater number of new stem cells that partly replace those that have been lost.

Reference: 

Source: 

Topics: 

tags: 

tags development: 

Why older adults remember the good times better

March, 2010

An imaging study has found differences in brain activity that explain why older adults are better at remembering positive events.

An imaging study reveals why older adults are better at remembering positive events. The study, involving young adults (ages 19-31) and older adults (ages 61-80) being shown a series of photographs with positive and negative themes, found that while there was no difference in brain activity patterns between the age groups for the negative photos, there were age differences for the positive photos. In older adult brains, but not the younger, two emotion-processing regions (the ventromedial prefrontal cortex and the amygdala) strongly influenced the memory-encoding hippocampus.

Reference: 

Source: 

Topics: 

tags development: 

tags memworks: 

tags problems: 

Memory of emotions persist beyond memory of the event for memory-impaired

April, 2010

A study involving severe amnesiacs has found that induced feelings of happiness or sadness persist long after the memory of the event. The findings challenge the idea that by minimizing a specific memory of past trauma, associated sadness will also decrease, and also point to the need for care in dealing with those with impaired memory — don’t assume that any induced emotion will vanish as quickly as the memory of it.

A study involving five patients with severe amnesia due to damage in the hippocampus, resulting in a condition comparable to Alzheimer's, has found that memory tests given 5-10 minutes after sad and happy film clips showed little (if any) memory of the details, but the generated emotion lasted for 20 to 30 minutes afterward. Interestingly, normal controls also felt happy for about the same length of time, but the impact of sad scenes was shorter. The findings challenge the idea that by minimizing a specific memory of past trauma, associated sadness will also decrease. Indeed, it may be that forgetting the details of unhappy events prolongs the effects. The findings also point to the need for care in dealing with those with impaired memory — don’t assume that any induced emotion will vanish as quickly as their memory of it.

Reference: 

[471] Feinstein, J. S., Duff M. C., & Tranel D.
(2010).  Sustained experience of emotion after loss of memory in patients with amnesia.
Proceedings of the National Academy of Sciences. 107(17), 7674 - 7679.

Source: 

Topics: 

tags: 

tags memworks: 

Pages

Subscribe to RSS - hippocampus
Error | About memory

Error

The website encountered an unexpected error. Please try again later.