Perishing with convulsive twitch after electrical discharge (6)
I believe the answer is:
arctic
'perishing' is the definition.
(I've seen this before)
'convulsive twitch after electrical discharge' is the wordplay.
'convulsive twitch' becomes 'tic' (nervous tic).
'after' is a charade indicator (letters next to each other).
'electrical discharge' becomes 'arc' (I've seen this before).
'tic' put after 'arc' is 'ARCTIC'.
'with' is the link.
(Other definitions for arctic that I've seen before include "Relating to northern polar regions" , "Extremely cold" , "It's cold at the top" , "-- Circle; -- fox" , "Northern ocean" .)