Related Clues:

• Involuntary jerk, e.g
• Little bit of personality
• Sort of movement some solicitor set up
• Knee-jerk response to, for example, dropping a mop
• With 50 and 55 Across, the ''central'' theme
• Wrinkling one's nose, perhaps
• What the odd letters in "twitch" spell
• Syllable before 'Tac' or '-tac-toe'
• Little jerk not quite recalling quote
• First of three game X's
• Idiosyncratic twitch
• Muse tends to confuse — it's inevitable
• Check mark*
• Antichrist hides nervous twitch
• Muscle convulsion