WC Archive

Despite all of the breakthroughs in biology over recent years, the functioning of the human brain retains significant mysteries. Chief among these is how memory functions: just how does the mind record events, feelings, ideas in a way which allows later recall? Neuroscientists at MIT's Whitehead Institute for Biomedical Research think they've figured out how memories are stored -- but, surprisingly, the mechanism for storage turns out to be prions, the class of proteins considered responsible for neurodegenerative diseases such as mad cow.

Central to a protein's function is its shape, and most proteins maintain only one shape throughout their lifetime. Prions, on the other hand, are proteins that can suddenly alter their shape, or misfold. But more than just misfolding themselves, they influence other proteins of the same type to do the same. In all known cases, the proteins in these misfolded clusters cease their normal function and either die or are deadly to the cell – and ultimately to the organism.

For this reason, Kausik Si, a postdoc in Kandel's lab, was surprised to find that a protein related to maintaining long-term memory contained certain distinct prion signatures. The protein, CPEB, resides in central-nervous-system synapses, the junctions that connect neurons in the brain. Memories are contained within that intricate network of approximately 1 trillion neurons and their synapses. With experience and learning, new junctions form and others are strengthened. CPEB synthesizes proteins that strengthen such synapses as memories are formed, enabling the synapses to retain those memories over long periods.

This is one of those discoveries that has the potential to open up incredible new vistas. At minimum, better understanding of the role that properly-functioning prions play in biology can help us figure out ways to block or repair badly-behaving prions. Similarly, figuring out the mechanisms of memory could lead us towards cures for memory-attacking diseases such as Alzheimers (which, in its most severe forms, displays symptoms similar to the effects of CJD, the human form of mad cow). Finally, this moves us further on the path towards unlocking deep brain physiology and really figuring out how the brain and mind work.