Scientists Erase Memories in Rat Brains

[MOODY BLUE]

Scientists Erase Memories in Rat Brains
By Charles Q. Choi
Special to LiveScience
posted: 24 August 2006
04:58 pm ET


Scientists have for the first time erased long-term memories in rats and also directly seen how the brain is changed by learning.



The research points to potential human benefits.



These findings could prove key "to understanding how memories can be augmented, for example in diseases that affect memory, like Alzheimer's," said neuroscientist Mark Bear at the Picower Institute for Learning and Memory at MIT.



The research could also help treat pain that does not go away, "like neuropathic pain, where people have a moderately severe injury, typically to the hands or feet, and instead of going away in a couple of hours just perpetuates," neurologist and molecular biologist Todd Sacktor at the State University of New York Downstate Medical Center in Brooklyn said in a phone interview.



The investigators separately examined the hippocampus, a structure critical for memory. Three decades ago, scientists discovered the existence of persistent increases in the strength of the connections, or synapses, linking brain cells in the hippocampus. This mechanism is largely believed to help in memory formation.



Remarkably, however, until now there was no evidence confirming a link between learning and this synaptic strengthening. One major problem was that these changes in the hippocampus during learning are few and far between.



"It was getting fairly embarrassing to the field that it had yet to be directly observed," Bear told LiveScience.



Sacktor and his colleagues found they could erase long-term memories in rats by suppressing this synaptic strengthening.



"This is the first time we can show you can erase long-term memories this way," Sacktor said.



Sacktor and his collaborators worked on rats trained to avoid a shock zone on a rotating platform. If they received an injection of a chemical dubbed ZIP into the hippocampus one day to one month after they learned to keep away from the shock zone, they no longer shunned it.



"It doesn't have an effect on short-term memory, and afterward they can continue to store long-term memories," Sacktor said.



Bear and his colleagues experimented in rats trained to avoid a shock zone in a darkened area of a box. Using an electrode array that enabled Bear and his collaborators to listen in on many places in the hippocampus at the same time, they eavesdropped on the hard-to-detect synaptic strengthening take place.



"This same process might be hijacked in psychiatric diseases, such as anxiety disorders and even depression," Bear said. "What is cool is that we know how to reverse some of the changes we measure after learning, which suggests the possibility of new treatments."



Both research teams reported their findings in the Aug. 25 issue of the journal Science.

http://www.livescience.com/humanbiology ... erase.html

[doctorwho]

Goed nieuws geen eindeloze sessies meer voor traumaverwerking.

[sjun]

Het doet me denken aan een lobotomie zonder incisie... Zijn er al neveneffecten van de betreffende toepassing gemeten?

[Sado]

Transhumanism: here we come!

[doctorwho]

Geen lobotomie dat is wel zeer invasief.

Herinneringen ontstaan als zenuwcellen in een netwerk hun onderlinge verbindingen, de synapsen versterken. In geval van het kortetermijngeheugen duurt dit effect maar een paar minuten of uren. Voor langetermijnherinneringen worden de synapsen permanent versterkt. Het is dus feitelijk hard of in dit geval wetware die de ervaring opslaat.

Om een herinnering te kunnen uitwissen moeten we eerst weten hoe deze in de hersenen gecodeerd wordt. Herinneringen worden niet in een zenuwcel opgeslagen maar zoals boven vermeld in de verbindingen tussen zenuwcellen. In de loop der tijd kunnen deze verbindingen verzwakken, versterken of geheel verdwijnen.

Als we een manier kunnen vinden om te voorkomen dat na een traumatische gebeurenis de herinnering te consolideren verdwijnen traumatische herinneringen na verloop van tijd. Medicijnen zouden de zogenaamde extinctietherpie kunnen versnellen. Bij deze behandeling moeten patienten pijnlijke ervaringen herhaaldelijk weer oproepen in een veilige situatie om de hersenen er a.h.w. ertoe over te halen de herinnering te laten verflauwen.

Hierover staat een artikel in scientific american special psyche. Helaas niet digitaal een geen zin/tijd veel typwerk dus dit is een zeer beknopte synopsis.