Mirror neurons: a definition. Description: Professor Christian Keysers explains that mirror neurons in the premotor cortex respond when we perform an action and also when we see someone else perform that action. This is similar to empathy. Transcript: Mirror neurons are a set of neurons that we discovered in the premotor cortex of the monkey.
lectin. [ 1 lekâ²tin] 2  a protein in seeds and other parts of certain plants that binds with glycoproteins and glycolipids on the surface of animal cells, causing agglutination. Some lectins agglutinate erythrocytes in specific blood groups, and others stimulate the production of T lymphocytes.
Medical Definition of LEPTIN. : a peptide hormone that is produced by fat cells and plays a role in body weight regulation by acting on the hypothalamus to suppress appetite and burn fat stored in adipose tissue.ADVERTISEMENT. Greek leptos slender + English 1-in.eptin. noun lepÂ·tin \Ëlep-tÉn\. : a peptide hormone that is produced by fat cells and plays a role in body weight regulation by acting on the hypothalamus to suppress appetite and burn fat stored in adipose tissue. Britannica.com: Encyclopedia article about leptin.