The thyroid, a gland located at the front of the neck, regulates cell metabolism by interacting with the brain. When the brain senses that thyroid hormone levels are low, it produces TRH, or Thyrotropin Releasing Hormones, and TSH, Thyroid Stimulating Hormones. TRH and TSH stimulate the thyroid to release more hormones. If this brain-thyroid interaction goes awry, the thyroid can become enlarged. Watch this video for the full scoop on the thyroid-brain connection!