Monday, August 29, 2011

Functional mapping of single spines in cortical neurons in vivo

Hey, in vivo means while living, so following this they can map individual neuron synapses. This is absolutely necessary for researchers to figure out exactly what occurs in neuroplasticity and neurogenesis. I know I shouldn't presume to tell the medical gods what to do and where to go but they are lost as far as stroke rehabilitation is concerned.
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10193.html
The individual functional properties and spatial arrangement of afferent synaptic inputs on dendrites have a critical role in the processing of information by neurons in the mammalian brain1, 2, 3, 4. Although recent work has identified visually-evoked local dendritic calcium signals in the rodent visual cortex5, sensory-evoked signalling on the level of dendritic spines, corresponding to individual afferent excitatory synapses, remains unexplored6. Here we used a new variant of high-resolution two-photon imaging7 to detect sensory-evoked calcium transients in single dendritic spines of mouse cortical neurons in vivo. Calcium signals evoked by sound stimulation required the activation of NMDA (N-methyl-D-aspartate) receptors. Active spines are widely distributed on basal and apical dendrites and pure-tone stimulation at different frequencies revealed both narrowly and widely tuned spines. Notably, spines tuned for different frequencies were highly interspersed on the same dendrites: even neighbouring spines were mostly tuned to different frequencies. Thus, our results demonstrate that NMDA-receptor-dependent single-spine synaptic inputs to the same dendrite are highly heterogeneous. Furthermore, our study opens the way for in vivo mapping of functionally defined afferent sensory inputs with single-synapse resolution.

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