Experience-dependent regulation of CaMKII activity within single visual cortex synapses in vivo

The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 12/2011; 108(52):21241-6. DOI: 10.1073/pnas.1108261109
Source: PubMed


Unbalanced visual input during development induces persistent alterations in the function and structure of visual cortical neurons. The molecular mechanisms that drive activity-dependent changes await direct visualization of underlying signals at individual synapses in vivo. By using a genetically engineered Förster resonance energy transfer (FRET) probe for the detection of CaMKII activity, and two-photon imaging of single synapses within identified functional domains, we have revealed unexpected and differential mechanisms in specific subsets of synapses in vivo. Brief monocular deprivation leads to activation of CaMKII in most synapses of layer 2/3 pyramidal cells within deprived eye domains, despite reduced visual drive, but not in nondeprived eye domains. Synapses that are eliminated in deprived eye domains have low basal CaMKII activity, implying a protective role for activated CaMKII against synapse elimination.

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    • "Förster resonance energy transfer (FRET) is a sensitive method to determine if two fluorophores are within a small distance of each other. Sensor molecules, such as CaMKII (a major player in LTP) [82-85], and actin (a major synaptic structural protein) [78,86], were engineered to visualize the synaptic engram using FRET. "
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