(covers information from several alternate timelines)
The cerebral cortex is the part of the brain involved in many higher level tasks such as language, memory, and consciousness. The cerebral cortex includes the parietal lobes, the occipital lobe, the frontal lobe, and the temporal lobes.
A burst of seventy millivolts will burn out the cerebral cortex of a normal humanoid brain. This, however, can be cheated with an injection of an inoprovaline drug, which provides additional resistance against such excessive electro-stimulation. (DS9: "Life Support")
When Deanna Troi temporarily lost her empathic sense due to the influence of two-dimensional lifeforms, a pattern of unresponsive neural cells in her cerebral cortex and cerebellum was recorded. (TNG: "The Loss")
After being accused of espionage by Admiral Strickler and Lieutenant Lasca in an alternate reality, Harry Kim denied it and suggested they run a microcellular scan of his cerebral cortex to prove his memory had not been altered. (VOY: "Non Sequitur")
Seven of Nine's cerebral cortex underwent severe stress in 2375, when a malfunctioning Borg vinculum caused numerous neural patterns from assimilated individuals to overwhelm her mind. (VOY: "Infinite Regress")