CHAPTER 6 Computations in Memory Systems in the Brain Edmund T. Rolls Department of Experimental Psychology, University of Oxford, Oxford OXl 3UD, United Kingdom; www.cns.ox.ac.uk I. INTRODUCTION This chapter describes memory systems in the brain based on closely linked neurobiological and computational approaches. The neurobiological approaches include evidence from brain lesions, which show the type of memory for which each of the brain systems considered is necessary, and analysis of neuronal activity in each of these systems to show what information is represented in them and the changes that take place during learning. Much of the neuro- biology considered is from nonhuman primates as well as humans, because the operation of some of the brain systems involved in memory and the systems connected to them have undergone great development in primates. Some such brain systems include those in the temporal lobe, which develops massively in primates for vision and which sends inputs to the hippocampus via highly developed parahippocampal regions, and the prefrontal cortex. Many memory systems in primates receive outputs from the primate inferior temporal visual cortex, and understanding the perceptual representations in this of objects and how they are appropriate as inputs to different memory systems helps to provide a coherent way to understand the different memory systems in the brain (see Rolls and Deco, 2002, which provides a more extensive treatment of the brain architectures used for perception and memory). The computational Neurobiology of Learning and Memory, Second Edition Copyright © 2007 by Elsevier Inc. All rights reserved. 191