This review presents an account of the observations made in clinical and experimental investigations and in neuroimaging studies, on the brain structures and circuits in which the neural mechanisms for memory, affective functions and conscious experience are thought to operate. It is important, indeed necessary, we believe, that the study of the higher brain func tions be introduced by a brief account of the evolution of the philosophical thinking and scientific researches on cognition. The intuition that sensations and intelligence reside in the brain goes back to the Egyptians, in particular the Edwin Smith papyrus, probably dated between 2500 and 3000 b. c. , where the term "brain" appears for the first time and where there is a description of its coverings (meninges) and circumvolutions (Walsh 1994). The philosophical debate on brain and mind made its appearance in ancient l Greece and in subsequent centuries developed among the philosophers. The flow of sensations, the process of thinking, and the site of reason were localized in the brain, according to Alcmaeon of Croton (sixth to fifth centuries b. c. ) and subsequently Lattanzio, Alexander of Tralles, Democritus, Anaxagoras, and particularly Hip pocrates (460-377 b. c. ), who placed the soul, envisaged as a mental function, in the brain. Plato (427-347 b. c. ) believed that the brain provided the sensory experiences (hearing, sight, smell) and that from these were generated thinking and memory, and the act of thinking produced the truth or "episteme. " The formulation of the problem changes radically with Aristotle (384-322 b. c. ), who believed that the heart, and not the brain, was the site of passions, feelings, intelligence, and thought (Gross 1995). 1 Introduction.- 2 Memory.- 2.1 Introduction.- 2.2 Remembering and Forgetting.- 2.3 Types of Memory and Their Neural Correlates.- 2.3.3 Episodic Memory.- 2.3.4 Semantic Memory.- 2.4 Amnesia.- 2.5 Cellular Basis of Memory.- 2.6 Concluding Remarks.- 3 Affective Functions (Emotion, Mood, Feeling).- 3.1 Introduction.- 3.2 Functional Anatomy of Affective Disturbances.- 3.3 Magnetic Resonance Spectroscopy.- 3.4 Flow and Metabolism Related to the Clinical Picture.- 3.5 Structural Cerebral Alterations.- 3.6 Emotional States Induced in Normal Subjects.- 3.7 Concluding Remarks.- 4 Conscious Experience.- 4.1 Introduction.- 4.2 Neural Systems Involved in Conscious Experience.- 4.3 Bistable Percepts: Binocular Rivalry.- 4.4 Unconscious Perception and Covert Cognitive Functions.- 4.5 Impairment or Loss of Conscious Functions in Humans.- 4.6 Hypotheses on the Neural Activity of Consciousness.- 4.7 The Dynamic Core Hypothesis and the Reentrant Networks.- 4.8 Concluding Remarks.- 5 Conclusion.- 6 Summary.- 6.1 Introduction.- 6.2 Memory.- 6.3 Affective Functions.- 6.4 Conscious Experience.- 6.5 Conclusion.- References.
