Similarly, the cleaved circulating form of the exercise-induced membrane protein fibronectin type III domain containing 5—FNDC5 (also known as irisin), released in the bloodstream following voluntary regular exercise, attenuates age-related cognitive dysfunction [30], and the cognitive impairment after genetic deletion of FNDC5 in knockout mice can be rescued by irisin delivery directly into the dentate gyrus [31]. Here, FNDC5 is linked to Cognitive impairment.