Memory Molecule Identified 97
Reader Ostracus informs us of research led by Michael Ehlers of Duke University that has identified a molecule, myosin Vb (five-b), that seems to be a critical component in the formation of memory. "A major puzzle for neurobiologists is how the brain can modify one... synapse at a time in a brain cell and not affect the thousands of other connections nearby. Plasticity, the ability of the brain to precisely rearrange the connections between its nerve cells, is the framework for learning and forming memories ... The discovery of a molecule that moves new receptors to the synapse so that the neuron... can respond more strongly helps to explain several observations about [brain] plasticity ... [The researchers] found that the myosin Vb molecule in hippocampal neurons responded to a flow of calcium ions from the synaptic space by popping up and into action. One end of the myosin is attached to meshlike actin filaments so it can 'walk' to the end of the nerve cells where receptors are. On its other end, it tows an endosome, a packet that contains new receptors. 'These endosomes are like little memories waiting to happen,' Ehlers said."
Problems with the headline (Score:5, Informative)
I'm not sure they can call this a "memory molecule" so much as a "molecule responsible for changing the receptors at the synapse to make a memory." The molecule itself is not what memories are actually made of, which is what I would think of. The changed activity of the neuron is more akin to that. And it's also not specific to memories. The process of myosin Vb bringing endosomes to the surface is not unique to neurons, that's been known for a while (http://www.ncbi.nlm.nih.gov/pubmed/11408590).
That said, it's really interesting that they've identified this, as it not only tells you how the change is made, but also tells you the stimulus to change it.
Re:Applications and deeper questions (Score:2, Informative)
The calcium (Ca2+) signal is just due to a very temporary Ca2+ influx into the cell. The Ca2+ stems from the extracellular fluid and from intracellular Ca2+ stores. After excitation, Ca2+ gets immediately pumped out of the cytosol. None gets used up. (This is only half the truth: Some Ca2+ signals are lasting for minutes to hours.)
It does. Calcium signaling is essential not only for muscle action, but also for nerve cell signaling (and many other cell types use Ca2+ signaling, too).
Anterograde amnesia is usually induced by drugs (AFAIK the mechanism how that works is completely unknown) or by traumatic brain injury to regions responsible for memory formation, i. e., damage to the medial temporal lobe and especially the hippocampus. Concerning the drugs (benzodiazepines), they target GABAA receptors, thereby inhibiting neuronal signaling. That is, they have indeed some influence on Ca2+ signaling, too, but they also influence action potentials induced by Na+/K+ signaling ... saying anterograde amnesia is caused by lack of Ca2+ is a little far stretched.
The main reason you should specifically care about your diet containing enough Ca2+ is that Na+ and Cl- and most other minerals are abundant (concerning Na+: far too abundant) in almost any food we eat. Therefore, you will almost never suffer from lack of Na+, but lack of the more rare Ca2+. (Lack of Na+ would be very detrimental to neuronal action and to your health, too: In a desert you lose very much NaCl and therefore you have to uptake large amounts of salt--and of course even more water ...)
Re:Sound rough (Score:3, Informative)
Wikipedia is your friend :)
It appears actin is part of filaments which are a rather important part of the contractile system, which is the system that gets your muscle cells to contract (which makes you muscles move). I have not a clue what an M line is. ATP is an important chemical that your cells internally use for energy. Why one would force feed someone ATP is beyond me (AFAIK it does not do anything special when ingested).
It appears MillionthMonkey is boosting his strength while Anonymous Coward is boosting his memory -> MM kicks AC's ass. (or something like that)
I used to be good at biology :(