Jun/090
Viva la nap consolidates long-term memory
Want to submit your memory to a restorative care? The winning recipe does not contain phosphorus or supplements, but surely a more healthy and pleasant nap. Ninety minutes of sleep during the day, shows a study published in Nature Neuroscience, promote the consolidation of long-term memory, or to that form of permanent memory destined to disappear never to fade or only after many years.
So far the good news of the clearance of the afternoon naps. But the Israeli researchers in the Center for Brain and Behavior Research at the University of Haifa have also prepared a cold shower. In practice with their research are trying to unravel the mechanisms underlying memory consolidation induced by sleep, and play them back artificially.
The learning of a task may be considered as two distinct phases, the performance improvement that occurs during the execution of the task is to refine the next linked to processes of memory consolidation, i.e. the transformation of the memory of a given experience into something more solid and durable.
One can distinguish two different forms of this type of memory: the memory of the “what” (e.g. what happened today) and the memory of “how” (e.g. how to do something, like driving etc…) In the early stages post-learning processes underlying the consolidation of experience, can be disturbed in various ways, from interfering chemical, physical or electrical (interference behavioral retrograde), which may act but only within a time window limited to 5 -6 hours after the training phase.
The processes of memory consolidation, for their part involving the expression of genes and the synthesis of proteins that lead to alterations in synapses (synaptic consolidation). Study participants were initially instructed to learning a motor sequence, to be carried out with the thumb and forefinger of the non dominant hand (finger sequence task). One group was made to sleep for 90 minutes after the session of learning, but others remained awake.
The group that had lunch break, the evening ran perfectly the motor performance learned in the morning, unlike the other group. After a night of sleep, however, both groups showed the same level of performance of the motor task. This experiment therefore shows that the afternoon sleep memory consolidation produces a much more rapid and effective.
In a second experiment was evaluated instead’s influence on the mechanisms of sleep interference. Participants in the experiment were subjected to the usual seat of learning of a motor task, half of them followed by 90 minutes of sleep, the other by a period of wakefulness.
This second experiment demonstrates for the first time that the afternoon sleep protects the memory of “how” of the interference and facilitates consolidation. Are not yet known, however, the mechanisms by which sleep can produce these effects. Until then we will be able to reproduce artificially continue to enjoy the benefits of an afternoon nap. With’s excellent excuse to strengthen our memory of how.
Feb/090
Fatal familial insomnia. An Italian would be the first man died for “insomnia”
It narrated in the book of the researcher TDMax the story of the first patient with Fatal Familiar Insomnia (FFI, insomnia Fatal familial) a rare genetic disease that prevents those who are carriers of sleeping up to take him to death. In the book “The Family That Could not Sleep” the author tells the story of an Italian doctor who died in 1765 which would be the first carrier of the genetic mutation that generates the disease (the so-called patient zero) and reconstructs the path through the generations of this man until the 80s.
It was thanks to a descendant of this first patient, who died just in the ’80s, it was possible to investigate more thoroughly the cause’s fatal familial insomnia. In fact this man has bravely chosen to donate his body to science because they had conducted the necessary investigations. Post-mortem analysis of brain structures has been possible to show that the pathological process of FFI is the rupture caused by a genetic mutation, the protein in the brain, which, accumulating, end up destroying the neurons. As stated Michael Geschwind, University of San Francisco, the damage is localized mainly at the level of the thalamus, a brain structure involved in regulating the sleep-wake rhythm.
The disease, described for the first time in Italy and R. Medori E. Lugaresi Institute of Neurology, University of Bologna, which would be affected forty families around the world, is hereditary and has a sudden onset and late unfortunately almost always around forty years when often they have already had children, who have a 50% chance of developing it. It characterized by a persistent insomnia, nightmares and even hallucinations, which are accompanied by autonomic disturbances and engines. This is actually a true dementia, caused by a pathological process similar to the so-called mad cow disease (BSE) that leads to death within a little over a year.