Correlation of regional cerebral blood flow and change of plasma sodium concentration during genesis and satiation of thirst

Positron emission tomography studies were conducted during genesis of moder ate thirst by rapid i.v. infusion of hypertonic saline (0.51 M) and after s atiation of thirst by drinking water. The correlation of regional cerebral blood flow with the change in the plasma Na concentration showed a signific ant group of cerebral activations in the anterior cingulate region and also a site in the middle temporal gyrus and in the periaqueductal gray. Strong est deactivations occurred in the parahippocampal and frontal gyri. The dat a are consistent with an important role of the anterior cingulate in the ge nesis of thirst.