Book 50

The prefrontal cortex makes up almost a quarter of the human brain, and it expanded dramatically during primate evolution. The Neurobiology of the Prefrontal Cortex presents a new theory about its fundamental function. In this important new book, the authors argue that primate-specific parts of the prefrontal cortex evolved to reduce errors in foraging choices, so that particular ancestors of modern humans could overcome periodic food shortages. These developments
laid the foundation for working out problems in our imagination, which resulted in the insights that allow humans to avoid errors entirely, at least at times.

In the book, the authors detail which parts of the prefrontal cortex evolved exclusively in primates, how its connections explain why the prefrontal cortex alone can perform its function, and why other parts of the brain cannot do what the prefrontal cortex does. Based on an analysis of its evolutionary history, the book uses evidence from lesion, imaging, and cell-recording experiments to argue that the primate prefrontal cortex generates goals from a current behavioural context and that it
can do so on the basis of single events. As a result, the prefrontal cortex uses the attentive control of behaviour to augment an older general-purpose learning system, one that evolved very early in the history of animals. This older system learns slowly and cumulatively over many experiences based on
reinforcement. The authors argue that a new learning system evolved in primates at a particular time and place in their history, that it did so to decrease the errors inherent in the older learning system, and that severe volatility of food resources provided the driving force for these developments.

Written by two leading brain scientists, The Neurobiology of the Prefrontal Cortex is an important contribution to our understanding of the evolution and functioning of the human brain.

Current theories about human memory have been shaped by clinical observations and animal experiments. This doctrine holds that the medial temporal lobe subserves one memory system for explicit or declarative memories, while the basal ganglia subserves a separate memory system for implicit or procedural memories, including habits. Cortical areas outside the medial temporal lobe are said to function in perception, motor control, attention, or other aspects of executive function, but not in memory.

'The Evolution of Memory Systems' advances dramatically different ideas on all counts. It proposes that several memory systems arose during evolution and that they did so for the same general reason: to transcend problems and exploit opportunities encountered by specific ancestors at particular times and places in the distant past.

Instead of classifying cortical areas in terms of mutually exclusive perception, executive, or memory functions, the authors show that all cortical areas contribute to memory and that they do so in their own ways-using specialized neural representations. The book also presents a proposal on the evolution of explicit memory. According to this idea, explicit (declarative) memory depends on interactions between a phylogenetically ancient navigation system and a representational system that evolved in humans to represent one's self and others. As a result, people embed representations of themselves into the events they experience and the facts they learn, which leads to the perception of participating in events and knowing facts.

'The Evolution of Memory Systems' is an important new work for students and researchers in neuroscience, psychology, and biology.