TY - RPRT TI - Hypothalamic motivational systems: fixed or plastic neural circuits? AU - E S Valenstein AU - V C Cox AU - J W Kakolewski PY - 1969 DO - 10.1126/science.163.3871.1084 UR - https://pubmed.ncbi.nlm.nih.gov/5764877/ ID - 5764877 ER -