$\begin {array} {1 1} (1)\;increases \: by\: 29.5\: mV & \quad (2)\;decreases \: by\: 29.5\: mV \\ (3)\;increases\: by\: 59.0\: mV & \quad (4)\;decreases\: by \: 59.0\: mV\end {array}$