Brain. Coloured composite 3-D magnetic resonance imaging (MRI) scan of a human brain, seen from the front. The ventricles (purple) circulate the cerebrospinal fluid (CSF), which cushions the brain. The two lateral ventricles lie either side of the mid-line of the brain, one in each cerebral hemisphere. They communicate with the fourth ventricle (bottom centre). Beneath the lateral ventricles lie the sensory-processing thalami (yellow) and the hypothalamus (green, centre), which controls emotion and body temperature and releases chemicals that regulate hormone release from the pituitary gland (green, above fourth ventricle).