For the benefit of readers, we have included the sex and age of each mouse in Figure 4 figure supplement 1 and Figure 4 figure supplement 2. Heterogeneity of SPREADs vs. basal ERK activity: we compared the basal ERK activities between mice with frequent SPREAD (#102, 107, 112, and 115) and mice with infrequent SPREAD (#113, 114, and 120).
It is important to note that despite the frequent spread of NPEV among study participants, there was no evidence of poliovirus transmission from participant A to other children at the orphanage, as type 1 poliovirus isolates from other children were genetically distinct from her isolates.
For example, while mice #102, #107, #112, #115, and #117 showed frequent SPREADs and cell divisions, mice #113, #114, and #120 showed much less SPREADs and cell divisions.
(A and B ) Left panels show frequencies of SPREADs (blue) and cell divisions (red) during periods with frequent SPREADs (A ) and less frequent SPREADs (B ).
Such slow potential changes of clustered, highly frequent spreading depolarizations are shown in Fig. 3B.
Furthermore, we counted cell divisions by visual inspection of time lapse images and found that cell divisions were also more abundantly observed in the periods with frequent SPREADs than those with less frequent SPREADs.
DOI: http://dx.doi.org/10.7554/eLife.05178.013 10.7554/eLiFigure78.014 figure 4—figure supplement 2. Steady-state backskin with frequent SPREADs and cell divisions.
Notably, the period with frequent SPREADs and cell divisions was also observed in the backskin, indicating that SPREAD is not limited to the ear skin.
The authors find that mice with frequent SPREADs also have more frequent cell division, but these events do not appear to have a definable temporal relationship.
These findings thus suggest that highly frequent spreading depolarizations with depression of spontaneous activity in the AC-electrocorticography led to fusion of depression periods in the AC-EEG between subsequent spreading depolarizations.
Mice with frequent SPREADs (mice #102, #107, #112, #115, and #117) showed higher basal ERK activity than those with infrequent SPREADs (mice #113, #114, and #120); however, the difference was not statistically significant.
