Organelles in parallel
نویسنده
چکیده
Learn more when your neighbors do S ynaptic neighbors help each other learn, according to Christopher Harvey and Karel Svoboda (HHMI, Chevy Chase, MD). Learning and memory, which require a strengthening of synaptic connections known as long-term potentiation (LTP), have traditionally been thought to be synapse specifi c, with one synapse unable to infl uence LTP induction in even its closest neighbors. But computational modeling has suggested that this kind of infl uence could allow individual neurons to store more information. To test whether brains exploit this theoretical advantage, the authors stimulated individual dendritic spines with the neurotransmitter glutamate. Next, a weaker stimulus was applied to nearby spines. This weak stimulus is too low to trigger LTP on its own, but it caused robust potentiation when following the stronger stimulus. “It made it easier for [synapses] to learn in the future if their neighbors had learned something in the past,” Harvey says. But too far in the past, or too distant a neighbor, didn’t help: the subthreshold stimulus had to occur within 10 min and 10 μm of the fi rst. The two synapses also had to be on the same branch, suggesting that the bolstering signal probably travels intracellularly from spine to spine. So far, the group has no leads on this roaming internal signal. The authors suggest that such “clustered plasticity” may link memories that are laid down in close succession on the same dendritic branch. Whether this neighbor effect increases storage capacity remains to be seen.
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عنوان ژورنال:
- The Journal of Cell Biology
دوره 180 شماره
صفحات -
تاریخ انتشار 2008