Memories

New discoveries on depression

depressed woman

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During depression, the brain becomes less plastic and adaptable, and thus less able to perform certain tasks, like storing memories. Researchers at the Swedish medical university Karolinska Institutet have now traced the brain’s lower plasticity to reduced functionality in its support cells, and believe that learning more about these cells can pave the way for radical new therapies for depression. “We were able to cure memory dysfunction in ‘depressed’ rats by giving them doses of D-serine,” says Mia Lindskog, biologist and Assistant Professor at Karolinska Institutet’s Department of Neuroscience.

Dr Lindskog and her team used FSL rats, which are rats that have been specially bred with a disposition for ‘depression’. The rats were first put through two tests to confirm that they had the symptoms that are also characteristic of human depression. In the first, the rats’ memories were checked by repeatedly being exposed to different objects; in the second, the team assessed their level of apathy by releasing them in a container of water and observing whether they merely stayed floating in the container or immediately tried to climb out (non of the rats had to stay in the water for more than five minutes). In both cases the FSL rats’ results were compared with normal laboratory rats, and memory disorders and apathy could be confirmed.

The researchers then injected the rats with D-serine. This substance improved their memories but had no effect on the apathy. “We have shown that there are two symptoms here that can be influenced independently of one another, which means they could be treated in tandem in patients with depression,” says Dr Lindskog. The researchers also studied the synaptic activity in the hippocampus of the rats, a part of the brain which plays an important part in the memory. [continue reading…]

Emotions and memories

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A University of Leicester psychologist has been involved in new research with Cornell University professors which has shown that emotions, particularly those provoked by negative events, can trigger inaccurate memories – and the effect is worse, not better, when the witness is an adult rather than a young child.

In an international collaboration of researchers, Dr Robyn Holliday, Senior Lecturer in Psychology at the University of Leicester, and professors from the United States collected data from 7 and 11 year old children and young adults.

The findings have recently been published in the peer-reviewed Journal of Experimental Child Psychology, 107, 137-154. Curious? Continue reading

Older adults remember the good times

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istockphoto

Despite the aches and pains that occur in old age, many older adults maintain a positive outlook, remembering the positive experiences from their past. A new study, reported in the April 2010 issue of Elsevier’s Cortex (http://www.elsevier.com/locate/cortex), reveals that older adults’ ability to remember the past through a positive lens is linked to the way in which the brain processes emotional content. In the older adult brain, there are strong connections between those regions that process emotions and those known to be important for successful formation of memories, particularly when processing positive information. [continue reading…]

Forming lasting memories

Researchers at the Swedish medical university Karolinska Institutet have discovered a mechanism that controls the brain’s ability to create lasting memories. In experiments on genetically manipulated mice, they were able to switch on and off the animals’ ability to form lasting memories by adding a substance to their drinking water. The findings, which are published in the scientific journal PNAS, are of potential significance to the future treatment of Alzheimer’s and stroke. [continue reading…]