Researchers at Johns Hopkins have figured out how one particular protein contributes to long-term memory and helps the brain remember things longer than an hour or two. The findings are reported in two papers in the Nov. 9 issue of Neuron.

The protein, called Arc, has been implicated in memory-linked behaviors ranging from song learning in birds to rodents being aware of 3-D space. In people, Arc may be one culprit behind certain long-term memory-based behaviors like drug addiction, the researchers say.

"We think Arc controls how brain cells learn and associate behaviors and remember them over a long period of time," says Paul F. Worley, M.D., professor of neuroscience and neurology at Hopkins and director of both studies. "For example, the person who quits smoking can wean himself from cravings at home, at work or outside. But if you put him in a bar with a drink in his hand, his brain remembers that former association and suddenly the craving returns. These types of long-term associations are memories wired in your brain."

Years ago, Worley and his colleagues, studying laboratory rats, found that their brains made lots of Arc protein while the animals were awake and active. In fact, it has been long known that stimulating individual nerve cells - by an act as simple as exploring new environs, for example - causes the cells to make more Arc protein almost immediately. "Arc is an instant and reliable readout for active cells in the brain," says Worley. But although scientists knew that active cells were making copious amounts of Arc, no one knew exactly what Arc was doing in those cells until now.

To figure out what Arc was doing, the Hopkins team looked for what other proteins Arc "plays" with. Using Arc protein as bait, they went on a molecular fishing expedition in a pond filled with other proteins normally found in the brain and hooked two known to be involved in transporting materials into and out of cells.

"Moving things in and out of cells is critical for normal brain cell function. We were extremely excited that Arc might somehow be involved in this transport because it links transport to memory formation," says Worley. "This brings us one step closer to understanding how the brain saves memories."

According to Worley, memories form when nerve cells connect and "talk" to other nerve cells. It's thought that the stronger these connections are, the stronger the memory.

Like the childhood game called Telephone, where one person taps her neighbor and whispers a message that is passed on in similar fashion to the next person in line, nerve cells connect and "talk" to each other by relaying messages - usually by passing small chemicals - from cell to cell.

When nerve cells connect with each other in the brain, one cell releases chemicals into the space between it and its neighbor. The neighboring cell has protein receptors on its surface that capture the released chemicals. The cell that captures these chemicals then swallows up the receptor-chemical complexes, removing the receptors from the cell's surface. The more receptors present, according to Worley, the stronger the connection between the two cells. New receptors constantly replace the swallowed-up ones.

The two proteins that came out of the Arc fishing expedition - known as dynamin and endophilin - previously were known to be critical for this swallowing action. And, it turns out that Arc controls these two proteins and therefore controls how often cells swallow receptors from their surfaces.

When the researchers altered Arc so that it was unable to bind these two proteins, cells were unable to "swallow" and wound up with more receptors than normal on their surfaces. Adding more Arc to cells caused the opposite to happen; the cells hyperactively swallowed up too many receptors, leaving few at the surface.

Unfortunately, it's possible to over-excite a cell to death, says Worley, and if the excitation controls come off, the strength of long-term memory is altered.

So what does Arc's control over brain cell receptors mean for our ability to remember where we put the car keys? "We know that animals lacking Arc live only in the here and now. They learn fine in the short term, but tomorrow they will need to relearn everything," says Worley. And in the case of long-term memories that are better forgotten, such as that cigarette craving while sitting in a bar, a better understanding of how these memories form promises hope that there might be a way in the future to forget them entirely.

Researchers were supported by grants from the National Institute of Mental Health, the National Institute of Deafness and Other Communication Disorders, the Howard Hughes Medical Institute and the Human Frontier Science Program Organization.

Authors of the two papers are Shoaib Chowdhury, Jason Shepherd, Gavin Rumbaugh, Hiroyuki Okuno, Gregory Lyford, Jing Wu, Richard Huganir and Worley of Hopkins; Ronald Petralia of National Institute on Deafness and Other Communication Disorders at the National Institutes of Health; and Niels Plath and Dietmar Kuhl of Freie Universitat Berlin in Germany.

Source: Johns Hopkins Medical Institutions

Saya paling senang (baca: tertantang) kalo soal urusan mengingat.

Yang paling sering saya coba sih adalah dengan cara terus mengulang sampe berapa kali. (Katanya short memory cuma bertahan 8 detik ya? Jadi ulang setiap 7 detik).

Yang nggak kalah pentingnya adalah: dengan mencamkan dalam hati bahwa hal ini penting untuk diingat/dihapal. Dengan cara ini biasanya lebih efektif. (Cara ini saya praktikin untuk ngeset jam berapa mau bangun. Yaitu dengan cara bergumam dan meyakinkan diri sendiri: "Gue harus bangun jam 05.00". Besoknya kita akan bangun jam 5).

Selamat mencoba.

bicara masalah memory, emang susah susah gampang. anggap aja gini (diluar teori ya, malas ngikut ngikut teori, berdasarkan experience aja, guru juga kok).jadi, gini kita manusia punya kapasitas memori beda beda, kadang ada yang gampang cepat inget sesuatu kadang pelupa. kadang saking udah penuhnya memori dikepala kita harus delete or kita trush spam kali ye. ibaratnya mp4 saya beli ada yang 4giga, muat 1000 songs. trus saya beli lagi yang 30Giga, kapasitas  7500 songs and bisa download video lagi.nah ada yg cuma suffle, engga ada displaynya sama sekali 512MB (saya kayak tukang jualan elektronic aja nin). nah jadi bayangin di manusia. kalau orang pinter mungkin bisa 60Giga kayak laptop saya ini, tp kalau yg engga pinter kayak saya mungkin cm 1Giga doang kali ye. kalau memori udah full ya udah kgk bs nampung yang lain lagi. tp biasanya kalau untuk dimanusia masalah memorinya full or kagak biasanya berdasarkan pengalaman yang dialami. kalau hidupnya monoton situ situ aja, ya memorinya engga full full, tapi kalau banyak yang diliat and dirasa , walaupun umurnya masih separoh dari manusia yg hidupnya monoton, angap aja umur 60taon life monoton dibandingkan ama yg masih 30ton tp uda banyak pengalamannya , ya mungkin yg 30taon itu dengan kapasitas memori 30Giga tapi diumurnya yg segitu udah full dibandingkan dengan si kakek dgn kapasitas memori 2Giga tapi engga full full (persoalan pikun lain lagi masalahnya ya, itu cuma masalah karatan aja bang,di amplas juga bisa ingat lagi, hehe) . so persoalannya ente liat aja teori teori yg ada , tp ane anjurin all, everything kita bawa kembali pada pengalaman kita. cari dari  empiriknya aja.

Penjelasan dari prietea saya rasa belum bisa menjelaskan dalam bentuk apa ingatan itu disimpan, tapi lebih tepatnya bagaimana proses belajar dan mengingat itu terjadi. Memang dalam proses belajar akan terbentuk jalur2 neuronal baru melalui pembentukan sinaps2. Hal ini sesuai dengan definisi belajar/mengingat yaitu perubahan kemampuan penghantaran melalui sinaps oleh sebab impuls2 sebelumnya.
Tapi sejatinya, data mengenai sesuatu yang kita ingat itu ada di otak dalam bentuk apa?apakah bisa dipindahkan?disentuh?diraba?
Kalau cuma "sekadar" jalur atau sirkuit neuronal, tentu bisa diciptakan mesin yang bisa baca pikiran orang seperti halnya anda membaca sirkuit elektronika..sirkuit yang sama persis tentu memiliki fungsi yang sama atau ingatan tentang sesuatu yang sama.

dalam bentuk impul2 listrik, yg diterjemahkan dngn cara yg berbeda2 tergantung proses pembelajaran dan faktor genetik. misalnya bau, saat qta masih bayi qta gak dapat membedakan bau yg sedap dan yg tak sedap, tetapi ibu qta(lingkungan) mengajari qta bahwa bau yg ini tak enak dan bau yg lainnya enak. memori ini dibawa terus sapai dewasa sehingga bila sebuah molekul bau harum (dngn spesifikasi tertentu) menyentuh bulu2 dalam hidung qta, kemudian sel saraf menyalurkan listrik keotak bagian tertentu, dalam proses pembelajaran qta mengenali molekul ini sebagai bau harum, ato dngn kata lain otak qta menerjemahkannya melalui proses pembelajaran sebagai bau harum.

mungkin dalam bentuk rangkaian peptida tertentu?

ampun deh mas hendi jangan galak2 napa? saya cuma mencoba menjawab sebisa mungkin
nih yg aku dapet dari buku jendela iptek kehidupan oleh dorling kindersley
"sel2 saraf ato neuran seperti kawat listrik yg terbentang di seluruh tubuh seekor binatang. Mereka tidak mengalirkan aliran listrik, tetapi impuls listrik sesaat. sel saraf tertentu memiliki serabut ramping yg panjang yg disebut akson dan sejumlah serabut lain yg lebih pendek yg berhubungan dngn saraf2 lain. saraf secara teratur memompa sodium keluar melalui membran. Hal ini menyebabkan ketidak seimbangan listrik dimembran , yg disebut potensi terpendam. jika saraf dirangsang, sodium masuk kembali melalui membrandan potensi terpendam ini runtuh. ini menimbulkan reaksi beruntun, impuls listrik menjalar sepanjang akson ketika tiba diakhir akson, impuls lalu merangsang sel saraf lain"

nyambung gak. klo masalah penyimpanan dalam bentuk apa mungkin dalam bentuk aliran2 sel2 otak tertentu. kan bagian otak tertentu, memiliki fungsi tertentu. jadi klo jalur yg dilewati A menimbulkan efek tertentu. jalur B efeknya beda lagi.

semoga bisa menjawab, tapi klo salah jangan marah ya (jadi takut gua ama mas hendi)

ya udah lah, yg penting sama2 belajar. tapi saya masih belum mengerti pertanyaan mas hendi mungkin bisa dipertegas, biar saya juga bisa belajar, masalah otak memang masalah penting, termasuk masalah hakikat.

kayaknya di kompeter juga gak ada zat khusus yg digunakan untuk menyimpan memori. adanya kapasitor tapi semua zat yg digunakan untuk menyimpan ya sama aja. klo misalnya dianalogikan prosesor = otak, kapasitor=neuron, sofware=pembelajaran, trus tegangan listrik = sodium. bisa dibilang listrik pada komputer ato sodium pada manusia merupakan memori itu sendiri kali ya.