the top right panel of Fig. \[fig:map\_all\] through the brightness distribution of the $J=3/2-1/2$ $F=1/2-1/2$ component, whose rest frequency is 113499.644 MHz. For this map, the synthesized beam is $0{\mbox{\rlap{.}$''$}}85\times0{\mbox{\rlap{.}$''$}}74$ and the rms per 3 km s$^{-1}$ channel is 1.0 mJy beam$^{-1}$.

**C$_4$H and C$_3$N.** The radicals C$_4$H and C$_3$N have four and three, respectively, rotational transitions (each consisting of a spin-rotation doublet) within the frequency range 84.0-115.5 GHz. The brightness distributions of the individual lines of the two species are discussed in Appendix \[sec:map\_trans\]. In Fig. \[fig:map\_all\] we show the emission map of a selected line of each of these radicals to illustrate their spatial distributions in IRC+10216. The maps of C$_4$H and C$_3$N in Fig. \[fig:map\_all\] have a similar angular resolution, $1{\mbox{\rlap{.}$''$}}14\times0{\mbox{\rlap{.}$''$}}98$ and $1{\mbox{\rlap{.}$''$}}10\times0{\mbox{\rlap{.}$''$}}92$, respectively, and sensitivity, with rms levels per 3 km s$^{-1}$ channel of 1.3 and 0.7 mJy beam$^{-1}$, respectively.

**HC$_3$N and HC$_5$N.** The cyanopolyynes HC$_3$N and HC$_5$N have several rotational transitions within the frequency range covered, three in the case of HC$_3$N and up to 12 for HC$_5$N. A detailed discussion on the brightness distributions of the individual lines of the two molecules is also presented in Appendix \[sec:map\_trans\]. In Fig. \[fig:map\_all\], the spatial distributions 