Memory is a central feature of minds. Memories are elements used in the construction of maps and schemas, models of what is going on out there. These schemas are incorporated into realtime processors that track events as they happen. They allow us to recognize things and events, make decision such as safe or not safe, and match needs with opportunities for gratification.

Innate patterns within the mind are the deepest form of memory that is transmitted by DNA and built into the structure of the brain. Phylogenic memory is procedural, the form of the mind. Individual experience is the content that is added to and modifies the underlying form. A reasonable memory model would distribute the long term storage of acquired memory in different regions of the neocortex. Every topic discussed in this book is in part a discussion of memory in its many forms. In this chapter we will review the some of the ideas that are current in the neuroscience of memory.

In the evaluation of intelligence, we have recognized that there are underlying general functions that determine how smart a person is. Intelligence is based on memory and, in a functional sense, intelligence can be appreciated as a collection of abilities that lead to successful interactions with the world. The term “cognition” can be roughly translated as thinking and knowing and the neocortex can be considered the ultimate processor of cognition. Every student of psychology knows that specialized regions of the neocortex handle different sensory or input modalities. Phillips and Singer [i] suggest: "… cognitive sub-systems are distinguished from each other just in terms of the information on which they operate, but it is also likely that some cognitive functions require special information processing capabilities. These include: episodic memory and working memory; intentional representation, i.e. processes that distinguish between representation and referent; and the creative aspects of language and long-range strategic planning…in contrast to skills, episodic memories cannot be acquired in the absence of the hippocampus, and may require special computational capabilities.”

Information coming in from sense organs is encoded into patterns of electrochemical activity in the brain. The brain monitors events in real-time and a selected sample of events are stored briefly in a working or short-term memory. This memory capability gives humans a flow of consciousness and provides a sense of continuity between previous and current experiences. Some of the events registered in short-term. working memory are transferred to intermediate storage with the option of inclusion in long-term memory. If the record of an experience is reinforced by repetition, a permanent or long-tem memory (LTM) may be established. Even well-learned implicit memory will fade unless reinforced by recall exercises and repeated practice.  Advanced skills require daily practice to maintain a high level of performance.

Human Brain in Health and Disease

Intelligence and Learning

The flow of information through a human brain is prodigious and memory is selective. We could not possibly remember everything. Selective retention of the most relevant information and frequent editing and pruning of LTM is the secret to sanity and cognitive success. We rely on external devices that expand our ability to store and access information. Increasingly, we store information in photographic images, books, newspapers, journals, paper files, microfilm, tapes, CDs computer hard drives and other storage devices.  The most compact and versatile information is stored digitally in random access format on hard drives and CDs. This information can be accessed by humans with computers and other devices and is distributed worldwide on the internet.  Human memory storage is  limited so that access to externally stored and easily accessed information is a powerful addition to our cognitive abilities.

Four levels of human memory function can be identified during the course of a lifetime. Peak performance is reached early and may be preserved during senescence by rare individuals. Most humans' suffer from memory decline and are considered age-appropriate if their performance remains within the range of same-age peers. In the USA, the average performance for 30-year-olds on the Wechsler Memory Scale is 31; and the "normal" average performance for 70-year-olds is 15.  Some aging humans decline more than their same-age peers without experiencing a major disruption of daily living activities and can be described as senescent with a mild cognitive impairment. Others deteriorate more severely and memory impairment interferes with daily living activities.