Memory

Paul Broca : From Phrenology to Localization

Paul Broca 1861

Association Cortices

Three association areas—the prefrontal, parietal temporal occipital, and limbic—are involved in cognitive behavior planning, thinking, feeling, perception, speech, learning, memory, emotion, and skilled movements.

Cortical mapping of the language areas in the left cerebral cortex during neurosurgery

Penfield on one occasion electrical stimulation of the temporal lobes produced what he called an experiential response —a coherent recollection of an earlier experienceBut all of the patients Penfield studied had epileptic seizure foci in the temporal lobe, and the sites most effective in eliciting experiential responses were near those foci

The medial temporal lobe and memory storage

More convincing evidence that the temporal lobes are important in memory emerged in the mid 1950s from the study of patients who had undergone bilateral removal of the hippocampus and neighboring regions in the temporal lobe as treatment for epilepsy (Brenda Milner)

The Distinction Between Explicit and Implicit Memory

Priming

Multi-store (Atkinson-Shiffrin memory model 1968)

Sensory Memory

Short Term Memory

The Percentage of Information Maintained in the Short-Term Store Over 18 Seconds (Fernald, 1997, p. 237).

The working memory model (Baddeley and Hitch 1974)

Working Memory Is a Short-Term Memory Required for Both the Encoding and Recall of Explicit Knowledge

Consolidation of Memory

Rehearsal Enhances the Transference of Short-Term Memory into Long-Term Memory

New Memories Are Codified During Consolidation

Similar types of information are pulled from the memory

storage bins and used to help process the new information.

The new and old are compared for similarities and

differences, and part of the storage process is to store the

information about these similarities and differences, rather

than to store the new information unprocessed.

Thus, during consolidation, the new memories are not

stored randomly in the brain but are stored in direct

association with other memories of the same type.

This is necessary if one is to be able to “search” the

memory store at a later date to find the required information.

How Much Information Can We Remember?

Structural Changes Occur in Synapses During the Development of Long-Term Memory

1. Increase in vesicle release sites

for secretion of transmitter

substance.

2. Increase in number of transmitter

vesicles released.

3. Increase in number of

presynaptic terminals.

4. Changes in structures of the

dendritic spines that permit

transmission of stronger signals.

Long Term Memory

Characteristics of Long-Term Memory

Hippocampus is the seat of Consolidation

The anatomical organization of the hippocampal formation.

The role of the hippocampus in memory

The Long-Term Storage of Information

Explicit Memory Is Stored in Association Cortices

Semantic (Factual) Knowledge Is Stored in a Distributed Fashion in the Neocortex

Episodic (Autobiographical) Knowledge About Time and Place Seems to Involve the Prefrontal Cortex

Source amnesia. : the ability to associate a piece of information with the time and place it was acquired is at the core of how accurately we remember the individual episodes of our lives, a deficit in source information interferes dramatically with the accuracy of recall of episodic knowledge

Implicit Memory Is Stored in Perceptual, Motor, and Emotional Circuits

Certain Forms of Implicit Memory Involve the Cerebellum

Emotional Memory stored in Amygdale

Memory  Aging and Brain Size

Forgetting

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