Memory is a central component of the brain mechanisms that leads to consciousness. (Edelman; Universe of Consciousness, 93)

Memory is the key element in consciousness. (Edelman; Bright Air, 167)

Memory is a central functionality that brings together learning, understanding, and consciousness. (Ratey; User's Guide to Brain, 185)

Memories are groups of neurons that fire together in the same pattern  each time they are activated.  The links between individual neurons, which bind them into a single memory, are formed through a process called long-term potentiation (LTP). (Carter; Mapping the Mind, 176)

A basic requirement for memory formation is intact perception. (Corkin; Permanent Present Tense, 96)


Link to — Bayesian Inference in Brain Functionality

Research Study — Strengthening Synaptic Connections by NMDA for Long-Term Potentiation (LTP)

Research Study — Shared Neural Ensemble links Distinct Contextual Memories

Research Study — Memory Formation and Recall via Competition between Engrams

Link to — Memories Retrieved

Link to — Death of H.M.


Memory Is Mediated by Synaptic Plasticity

Neural signals follow a pathways pattern corresponding to the most efficacious synapses established by genetics and prior experience. The signal pattern activates a widespread but sparse memory trace that most closely conforms to a synaptic efficacy pattern established by prior neural activity. The neural network’s billions of synaptic efficacies, molded by biochemical plasticity in the short term and protein synthesis in the long term, mediate a neural mechanism for the synaptic efficacy distribution representing a person’s individuality and memory.


Research Study — Dendritic Branches— a Basic Unit for Synaptic Plasticity and Information Storage

Research Study — NMDA Receptor Ion Channel Crystal Structure

Research study — NMDAR Receptor Structure


 All Memory Is Associative

Memories are necessarily associative and never identical. (Edelman; Wider than the Sky, 53)

By the associative property of memory, neural assemblies aggregate via the laws of Gestalts into the sparse but widespread neural assemblies of the dynamic core of consciousness.

The operation of association involves the linkage of information with other information. (Anderson; Associative Networks, 102)

Throughout the cerebral cortex, association becomes the essence of sensation, perception, and memory. (Fuster; Cortex and Mind, 8)

The key ingredient in the cortical globalization process is the ability of the oscillatory mechanisms to recruit anatomically distant cortical neurons into temporal coalitions. (Buzsáki; Rhythms of the Brain, 185)

Association is the most natural form of neural network computation. (Anderson; Associative Networks, 102)

The ability of autoassociative systems to reconstruct missing or noisy parts of the learned patterns. (Anderson; Associative Networks, 105)

The enormous associative capabilities of the dynamic core are ideal to link or hierarchically organize a series of preexisting unconscious routines into a particular sequence. Pianist deliberately links separate arpeggio passages. (Edelman; Universe of Consciousness, 187)

Marr (1971) proposed a theory for how the hippocampus could function as an associative memory. From this proposal have followed many extensions, usually focusing on the role of the CA3 recurrent collaterals. (Burgess; Hippocampus Spatial Models, 469)

Associative functionality of memory is likely implemented via overlap in memory traces,   synaptic plasticity,   the associative functionality of hippocampus,   the interconnectivity of cortical interneurons with the dendritic fields of principal neurons, the ongoing thalamocortical signals of the dynamic core of consciousness, and other processes.


Link to — Associative Memory, Gestalt, Dendrite Tree


Research Study — Hippocampal Place-Cell Episodic Memory Context Basis for Recollectionspatial coding of the hippocampal place-cell system is part of a more general engine of episodic memory in which items become associated with their spatiotemporal contexts, and retrieval of items    reinstates those contexts    to help cue other context-appropriate memories.


 Amnesic Patient HM

On Tuesday, August 25, 1953, neurosurgeon William Beecher Scoville operated on patient Henry Gustave Molaison at Hartford Hospital in Hartford, Connecticut in an effort to control his epileptic seizures, which were occurring daily in spite of massive medication. (Corkin; Permanent Present Tense, 20)

It is important to keep in mind that amnesic patient HM, who had his hippocampuses removed, retained his memory functionality for short-term memory and his remote long-term memory, but could not form new long-term memories. He could form new procedural memory but retained no knowledge of the learning process.

Diagram —Taxonomy of Mammalian Memory Systems

Diagram — Major Memory Systems in the Brain


Declarative Memory

Declarative memory includes Episodic Memory and Semantic Memory.

Two types of declarative memory -- semantic and episodic. (Gazzaniga; Human, 303)

Declarative memory is what most people think of as memory. Declarative memories can be consciously recalled and discussed. There are two kinds: Episodic, Semantic. Episodic memories are all the specific events you have experienced and remembered, and also your associations with people in which you can recall the specific occasion. Semantic memory is all the facts learned in school, ideas learned, mathematical procedures, general recollection of “grandma’s house,” etc.

Link to — Perception and Memory

Link to — Autobiographical Memory


  Distinction between "episodic memory" events tied to specific time and place, as contrasted with "semantic memory" for knowledge that is time- and event-independent. (Eichenbaum; Neuroscience of Memory, 121)

 Link to — Episodic Memory

 Link to — Semantic Memory


 What we normally refer to as the memory of an object is the composite memory of the sensory and motor activities related to the interaction between the organism and the object. (Damasio; Self Comes to Mind, 133)

Memory is not a single entity but is composed of different systems.  Only one of these systems is accessible to awareness, the declarative memory system. (Squire & Kandel; Memory, 159)

We perceive what we remember as well as remember what we perceive. (Fuster; Cortex and Mind, 84)

Long-Term and Short-Term Memory

Functionally, cognitive psychologists make a demarcation between Long-Term Memory and Short-Term Memory.

One of the outstanding challenges to any general brain theory is to explain the structural basis of long- and short-term memory. (Edelman; Neural Darwinism, 204)


Link to — Declarative Memory


Procedural Memory

Procedural memory includes motor skills, cognitive skill learning, simple classical conditioning, priming, habituation, sensitization, perceptual after-effects and other cognitive operations improved by experience. (Squire; Memory and Brain, 164, 170)

Motor cortex, supplementary motor cortex, and neostriatum and may be the structures that store the skill-based information and long-term memory that allow the smooth execution of skill movements. (Squire & Kandel; Memory, 178)

Link to —  Procedural Memory


Emotional Memory

Link to —  Emotional Memory



Link to — Memory — Recent Research


    Return to — Perception, Memory, Consciousness

    Link to — Consciousness Subject Outline

    Further discussion — Covington Theory of Consciousness