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A lot of research has been done to determine whether short-term memory works better in the morning or afternoon. In a study, 16-18-year-olds (sixth form students of Battersea park school) were administered to take part in a word test to assess their short-term memory. Results of this were analyzed. Null Hypothesis: learning in the morning is more effective Alternative hypothesis: learning in the afternoon is more effective. Introduction To learn new things, to store experiences and to adapt to new circumstances – these characteristics of the brain enable us the daily survival .
This special flexibility of the brain is reached through constant making and breaking contact between nerve cells. Whenever we learn something, the connections between nerve cells, (synapses) change. At this point, the Axon of a nerve cell and the Dendrite of the neighbouring cell meet. The centre for brain research of the medical University of Vienna is currently involved in two researches that contribute to the clarification of the processes in memory. They had tested the article (of researchers at the Harvard Medical School), which is called a key experiment.
It was found that a Micro RNA and the accompanying messenger RNA exist at the contact point of synapses. What are Micro- and messenger RNA? It is a different form of the Ribonucleic acid. As a messenger RNA (mRNA), one is already more familiar with for a long time: It functions as a messenger, transports a message of the DNA – often, but not always from a gene – out of the cell nucleus into the cytoplasm. There the message is translated often, but not always into a protein.
One knows micro RNAs for the least in time: They consist only of 21 bases respectively, and they are not translated into proteins. They rather check an mRNA in that they cause or prevent that the mRNA is translated into a protein. So they are regulators. For example just at a synapse, as long as there a micro RNA on a certain mRNA, it is not translated into a protein. If the micro RNA falls away, the protein emerges – and the synapse changes its form and also the signal forwarding. In other words we can say that the nerve cell learned something. In the journal of Cell Biology (172, p.
221) – Kiebler describes a second factor that is necessary, with a synapse function: Staufen 2: That is a protein that is responsible for the carrying of mRNA along the cell skeleton to the synapse. It brings RNAs to where they are needed. Neurons which are missing the protein Staufen2 have less synapses, and the signal transmission between them is disturbed. “An important notice on that, is that Staufen 2 for the education of functioning Synapses is crucial”, says Kiebler ( researcher). If what we have learned is forgotten, long-term connections become out of contact of the connection points.
German Neurobiologist worked on the correlation between the outgrowing of the connections of cells, the so-called “thorns” and the building of functioning synapses. In order to be able to follow the outgrowing of thorns, the cells in the near surrounding area of the stimuli were observed using a high resolution two-Photon-microscope. An electron microscope was used in order to review whether the variations in the nerve cells actually led to the origin of new synapses. Within few minutes after the current impulse, the encouraged nerve cells opened the gate to a new discovery.
These thin thorns do not grow spontaneously (as they thought), but rather grow towards possible contact partners. Within the first eight hours no piece of information can be exchanged between the newly emerged cell contacts. Not until the following hours it is decides whether a connection remains exist or disappears. For sure, those contacts, that are still available after 24 hours, have fully functioning synapses which can transfer information and have a good chance to exist after several days. Then the reconstruction in the brain is locked evidently. Which parts of the brain remember which type of memory?