Figure 4: Blocking the waves in the auditory nucleus alters the pattern of wave activity in the VPM and triggers an enlargement of the barrel-field in S1.
From: Prenatal thalamic waves regulate cortical area size prior to sensory processing
(a) Maximum projection of a Ca2+ wave (yellow) at the level of the MGv in an E16.5 control (upper panel, inset post hoc in situ hybridization of the auditory thalamic marker Crabp2) and in a MGvKir (lower panel) littermate. No waves are observed in the territory were Kir2.1 is overexpressed (mCherry). Raster plot of individual cells activity recorded during 10 min in the MGv of control (upper panel) and MGvKir (lower panel) mice. The Ca2+ transient labelled by the open arrow in the control reflects a Ca2+ wave. (b) Maximum projections of Ca2+ waves (yellow) propagating between the dLGN and VPM in an E16.5 control mouse (upper panels) and in a MGvKir littermate (lower panels). Additional waves (red arrows) remain restricted to the VPM in the MGvKir mouse (blue contours). (c) Upper panel shows the quantification of Ca2+ waves that propagate between dLGN–VPM in the control (n=6) and MGvKir (n=11) mice showing no significant change (dLGN–VPM: 0.20±0.04 waves per minute control; 0.21±0.04 waves per minute MGvKir, P=0.84). Lower panel shows the significant increase of de novo waves in the VPM in the MGvKir mouse (VPM: 0.20±0.04 waves per minute control; 0.34±0.04 waves per minute MGvKir, *P=0.028; Two-tailed Student’s t-test). (d) vGlut2-immunostaining in tangential sections of the PMBSF in the S1 of P7 control (n=11) and MGvKir mice (n=12). Quantification of the PMBSF area in P7 MGvKir mice relative to the controls (**P=0.007; Two-tailed Student’s t-test). (e) Maximum projections of Ca2+ waves in the embBE mouse at E17. Waves propagating between the dLGN and VPM (yellow) and de novo VPM waves (blue). (f) Quantification of the frequency of waves in the VPM in the embBE mouse (VPM: 0.16±0.03 waves per minute control; 0.29±0.03 waves per minute embBE, *P=0.019; Two-tailed Student’s t-test). Graphs represent mean±s.e.m. Scale bars, 200 μm in a,b,e,f, and 300 μm in d.
