Cortical probe

A cortical probe was a type of medical instrument.

In 2373, The Doctor asked Kes to hand him a cortical probe to study the axonal amplifier on the corpse of a Borg drone. 

In 2375, The Doctor and the holographic Doctor Crell Moset used a cortical probe to administer a neurostatic shock to a cytoplasmic lifeform that had attached itself to B'Elanna Torres.