  We present a study of sub-pc scale radio structure of the radio galaxy 3C
84/NGC 1275 based on the Very Long Baseline Array (VLBA) data at 43 GHz. We
discover a limb-brightening in the "restarted" jet associated with the 2005
radio outburst. In the 1990s, the jet structure was ridge-brightening rather
than limb-brightening, despite the observations being done with similar angular
resolution. This indicates that the transverse jet structure has changed
recently. This change in the morphology shows an interesting agreement with the
$\gamma$-ray flux increase, i.e., the $\gamma$-ray flux in 1990s was at least
seven times lower than the current one. One plausible explanation for the
limb-brightening is the velocity structure of the jet in the context of the
stratified jet, which is a successful scenario to explain the $\gamma$-ray
emission in some active galactic nuclei (AGNs). If this is the case, the change
in apparent transverse structure might be caused by the change in the
transverse velocity structure. We argue the possibility that the transition
from ridge-brightening to limb-brightening is related to the $\gamma$-ray time
variability on the timescale of decades. We also discuss the collimation
profile of the jet.
