Behavioral and Brain Sciences

Short Communication

Brain energetics and evolution

Paul Bach-y-Rita a1 and Gaetano L. Aiello a2
a1 Department of Rehabilitation Medicine and Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706; Facultad de Medicina, Universidad Autónoma del Estado de Morelos, Cuernavaca,
a2 Dipartimento di Scienze Fisiche e Astronomiche, Via Archirafi n. 36, Palermo,


The human brain does not use more energy than the smaller brains of animals of comparable corporal weight. Uniquely, human functions localized largely in parts of the human brain that show greatest size increase over other animals may be mediated primarily by nonsynaptic neurotransmission, with reduced energy cost per kilogram of brain. This may affect the energetic constraints on evolution.