Clinical Neuropsychology is the discipline that investigates the interrelations of the human brain with thinking and behavior on the basis of the variations in brain function produced by injury or disease. That such injury caused mental impairment must have been apparent even to primitive man who resorted to trephining in an attempt to alleviate its pernicious effects. Interestingly, emphasis was placed not only on the brain substance itself but also on the fluids, which it enclosed, ie, the ventricles. Early Greek physicians (eg, Nemesius ca. 400 A.D.) placed sensation and perception in the lateral ventricles, reasoning in the third ventricle, and memory in the fourth ventricle. This ventricular concept accorded well with the doctrine of the circulation of animal spirits. Moreover, it provided a structural basis for a dynamic process wherein sensations were integrated into perceptions in the lateral ventricles, moved to the third ventricle to be reflected upon, and consolidated as memories in the fourth ventricle. In the absence of better alternatives, “ventricular” theory survived for a remarkably long time. It was displaced definitively by “brain substance” concepts only in the 17th and 18th centuries. It is also worth recalling that Aristotle, the greatest natural scientist of the ancient world, maintained that the heart was the seat of thinking and emotion, assigning the brain only the function of cooling the heat generated by the heart. His conclusions were based on sound empirical study. He noted that the exposed brain of animals was cold to the touch and that poking the brain surface did not elicit movements or signs of feeling. In contrast, the heart was warm and active; it accelerated during excitement and was slower during periods of calm. Aristotle’s cardiocentric concept of the seat of mental life had many supporters during the Middle Ages, the Renaissance, and even as late as the 17th century. That it was widely accepted is reflected in our language today. We still “learn by heart”; we offer “heartfelt sympathy”; and we “lose our heart” when we fall in love.