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. 2007 Jul 11;2(7):e604. doi: 10.1371/journal.pone.0000604

Figure 4. Temporal kinetics of ERK activation in synaptic and somatic compartments after visual stimulation.

Figure 4

Histograms in A and B show the percentage of pERK-positive synaptic profiles (A, postsynaptic; B, presynaptic) out of the total number of synapses that were randomly sampled. (A) ERK activation in postsynaptic profiles was significantly elevated after 2.5 minutes of visual activity, remained stable for 15 minutes and returned to baseline/DR conditions after 40 minutes. (B) A similar temporal profile of ERK activation was observed in presynaptic profiles. Histogram in C show the percentage of pERK-positive synapses showing immunogold labelling simultaneously in the pre- and post-synaptic profile. (D,E) Confocal images of pERK immunofluorescence in layers II/III of the visual cortex of rats that were dark reared for three days and sacrificed in the dark (D) or after 2.5 min of light exposure (E). Note that light exposure causes a dramatic increase in the number of pERK-immunopositive neurons. (F) Quantitative analysis revealing that light exposure causes an almost three-fold increase in the number of pERK-positive neurons in the cortex of light exposed animals compared with DR rats. Data in G are partially re-plotted from [1]. The histograms show the time course of light-induced ERK activation in the cell soma and nuclei of visual cortical pyramidal neurons. One-way ANOVA; *** = p<0.01; ** = p<0.02 ; * = p<0.05; n = 3 rats for each experimental group.