Allgemeines
Gehirn
und Gedächtnis
vera
Eine wichtige Fähigkeit unseres Gehirns ist das Gedächtnis.
Drei "Speicher" ermöglichen uns die Verwaltung unzähliger
Informationen. Dabei unterscheidet die Wissenschaft in Ultrakurzzeit-,
Kurzzeit- und Langzeitgedächtnis. Das Ultrakurzzeitgedächtnis
behält ins Gehirn gelangende Informationen durchschnittlich
nur 15 bis 20 Sekunden - danach löscht es sie wieder.
Informationen, die wichtig erscheinen, dringen ins Kurzzeitgedächtnis
vor. Es hat eine Kapazität von etwa 24 Stunden. Danach löscht
es entweder die vorläufig abgespeicherten Informationen oder
leitet sie an das Langzeitgedächtnis weiter. Dort wird alles
gespeichert, was unser Gehirn für besonders wichtig erachtet.
Das geschieht, indem bestimmte vom Körper hergestellte Eiweißmoleküle
- die sogenannten "Gedächtnismoleküle" - sie
sozusagen stofflich verankern - ähnlich den chemischen
Prozessen, die bestimmte Bildinformationen eines Films unlöschbar
machen. Die im Langzeitgedächtnis gespeicherten Informationen
können auch nach einem längeren Zeitraum immer wieder
abgerufen werden. Durch gezieltes Training lassen sich sowohl
Kurzzeit- als auch Langzeitgedächtnis schulen.
http://www.verbrauchernews.de/gesundheit/tests/0000001315.html
Das
Gedächtnis
Werner Stangl - werner.stangl@jk.uni-linz.ac.at
Schon lange haben Forscher nach dem Sitz des Gedächtnisses
gefahndet. Dabei kamen allerlei merkwürdige Vorstellungen
auf. In den 50er und 60er Jahren beispielsweise versuchte man,
sogenannte "Gedächtnismoleküle"
nachzuweisen. Erinnerung sollte nach dieser Theorie in Form
verschiedenster Eiweißstoffe im Gehirn existieren. Einer der
Anhänger dieser Richtung, der Neurophysiologe James
McConnell, stellt einige recht ausgefallene Experimente
an: Er brachte Plattwürmern bei, Licht zu meiden. Taten sie
es, so zerkleinerte McConnell sie in einem Mixer und verfütterte
sie an Artgenossen, die dann angeblich auch das Licht mieden.
Die New York Times titelte daraufhin: "Verspeisen Sie
Ihren Professor".
http://paedpsych.jk.uni-linz.ac.at/ARBEITSBLAETTER/GEDAECHTNIS/default.html
Informationen
zum Thema Kurzzeitgedächtnis
http://www.psychologie.uni-bonn.de/allgm/projekte/dfg_arb/weit_inf.htm
Gedächtnistricks:
Ohne Mühe mehr behalten
Bruno Klumpp - bruno.klumpp@t-online.de
Ein gutes Gedächtnis ist nicht nur Sache des Trainings,
sondern vielmehr der Methode. Mit simplen Tricks lassen sich
erstaunliche Ergebnisse erzielen.
http://www.methode.de/dm/my/dmme001.htm
Molecular
mechanism for learning and memory is identified
Megan Fellman - fellman@northwestern.edu
Past research has shown that a growth-associated protein,
called GAP-43, that is found in neurons and no other organ of
the body, is required for the growth of nerve cell processes
during the brain's early development and later during neuronal
regeneration. What was not known was whether or not GAP-43
could alter axonal growth and synaptic change, elements
crucial to learning and memory.
Now, a research
team led by Aryeh Routtenberg, professor of psychology,
neurobiology and physiology, has demonstrated that GAP-43,
when overexpressed in a phosphorylatable form, enhances
learning and memory in the mammalian brain. The findings could
provide a novel target for new drugs to combat memory loss and
learning disorders.
http://www.eurekalert.org/pub_releases/2000-06/NU-Mmfl-1806100.php
NYU
neuroscientists find long-term memories are surprisingly
unstable and impermanent
Josh Plaut - josh.plaut@nyu.edu
Neuroscientists at NYU's Center for Neural Science have
discovered evidence that contradicts entrenched psychological
and neurobiological models of memory. Karim Nader, Glenn E.
Schafe and Joseph E. LeDoux have revealed that the storage and
retrieval of long-term memories of fearful experiences are
surprisingly unstable. Nader and colleagues found that
long-term memories become labile (that is, chemically unstable)
every time they are retrieved. In this labile state, long-term
memories can be easily altered or disrupted. Furthermore, the
researchers found that once a long-term memory is retrieved,
it cannot be stored without the synthesis of new proteins.
http://www.eurekalert.org/pub_releases/2000-08/NYU-Nnfl-1508100.php
Memory
mechanism found at nerve cell connections in the brain
Scott Turner - Scott_Turner@Brown.edu
Scientists have identified a novel mechanism behind the
decrease in strength of synapses in the brain, a process that
leads to the creation of memories and their long-term storage.
The finding suggests that experience or activity in the
mammalian brain can regulate individual synapses, said lead
investigator Kimberly Huber, a post-doctoral researcher at
Brown.
"The study
shows that synaptic depression actually relies on the
manufacture of proteins at the synapses," she said.
"This is the first demonstration in mammals that when
synapses change, the modification depends on new proteins
created specifically at the site."
http://www.eurekalert.org/pub_releases/2000-05/BU-Mmfa-1805100.php
Psychologist
challenges basic assumptions of human memory theory
Art Glenberg - glenberg@facstaff.wisc.edu
Glenberg is an expert on the nuances of human memory, one of
the most intriguing, but hard to understand, mysteries of the
mind. More recently, Glenberg has been refining a
controversial theory about memory and language that questions
some basic assumptions of his field.
Glenberg's
opening salvo came in 1997, when his paper was published in
the journal Behavioral and Brain Sciences called "What
Memory is For." It suggested psychologists drop the
widely accepted view that human memory works like computer
memory, which stores abstract symbols designed to be
reproduced with verbatim accuracy.
Instead,
Glenberg argued that human memory is a direct result of
action: Of how the body moves and responds to its
environment. Memory exists to help us walk, talk, run, drive a
car, answer the phone, and all of the myriad tasks of getting
along in the world. Because
these memories are designed to facilitate action, rather than
verbatim reproduction, human recall is rarely totally accurate.
http://www.eurekalert.org/pub_releases/1999-12/UoW-Pcba-051299.php
Gene
found responsible for social amnesia
Lilli Kim - llkim@emory.edu
What if you could find your way home, but couldn't recognize
anyone when you got there?
Reporting in
the July issue of Nature Genetics, scientists at the Center
for Behavioral Neuroscience at the Yerkes Primate Center have
discovered in mouse studies that the oxytocin gene is
necessary for forming social memories -- allowing you to
recognize an individual you've seen before.
The gene has no
apparent influence on spatial or other types of memory. The
study demonstrates that social memory has a neural basis
distinct from other forms of memory, and someday could provide
a therapeutic target for a variety of psychiatric illnesses.
http://www.eurekalert.org/pub_releases/2000-06/EUHS-Gfrf-1806100.php
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