A hypothalamic series is a medical examination.

In 2370, Dr. Beverly Crusher ordered a hypothalamic series to be run to Deanna Troi, whose body temperaure had dropped several degress below normal. In reality, she was suffering from the initial stages of Barclay's Protomorphosis Syndrome. (TNG: "Genesis")

In an alternate timeline in 2373, Linnis Paris ran a hypothalamic scan on Kes to determine the reason for decreases in her body temperature. (VOY: "Before and After")