Related Clues:

• Noodle nugget
• Mental impression
• Inventor's specialty
• Original thought
• Plan not yet on paper
• Think-tank output
• [Oh ... my ... Lord!]
• What's on your mind
• It can come to a head
• Start of a brilliant scheme
• Shocked response
• Problem solver, perhaps
• Cortex product
• "What's the big __?"
• Reason to shout 'Eureka!'