Skip to main content Accessibility help
×
Home
Hostname: page-component-684899dbb8-mhx7p Total loading time: 1.096 Render date: 2022-05-18T01:38:03.692Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "useRatesEcommerce": false, "useNewApi": true }

21 - Mechanisms of memory and amnestic syndromes

from PART II - DISORDERS OF HIGHER FUNCTION

Published online by Cambridge University Press:  05 August 2016

John D.E. Gabrieli
Affiliation:
Department of Psychology, Stanford University, Palo Alto, CA, USA
Silvia A. Bunge
Affiliation:
Department of Psychology, Stanford University, Palo Alto, CA, USA
Arthur K. Asbury
Affiliation:
University of Pennsylvania School of Medicine
Guy M. McKhann
Affiliation:
The Johns Hopkins University School of Medicine
W. Ian McDonald
Affiliation:
University College London
Peter J. Goadsby
Affiliation:
University College London
Justin C. McArthur
Affiliation:
The Johns Hopkins University School of Medicine
Get access

Summary

Memory comprises the recording, retention and retrieval of knowledge. All that we know, except for what is genetically predetermined, is acquired through experience. Such knowledge includes the events we remember, the facts we know, and the skills we master. Memory is not a unitary faculty, but rather an ensemble of multiple forms of learning that differ in their uses, their operating characteristics, and the neural networks that mediate their processing (Gabrieli, 1998). A memory system may be defined as a particular neural network that mediates a specific form of mnemonic processing. Neurological and psychiatric diseases result in characteristic mnemonic deficits that reflect which memory systems are injured by a particular disease.

Levels of analysis: cells and systems

Learning and memory reflect experience-induced plasticity in the brain. An experience leaves a memory trace composed of an enduring alteration in the cellular organization of the brain called an engram. Experience-induced plasticity can be examined at many levels of analysis, including molecular events at the cellular and synaptic level, reorganization of local neuronal circuits, and large-scale alterations in the functional neural architecture of memory systems.

Cellular mechanisms of memory

Little is known about neural plasticity in the human brain, but findings from in vitro and invertebrate models offer suggestions about the cellular bases of human memory. Studies of the marine snail Aplysia have revealed links between learning and alterations in neurotransmitter release. Aplysia have a gill withdrawal reflex that is triggered when the gill is touched by a rod. Repeated stimulation leads to habituation such that the gills are no longer withdrawn in response to the rod. Short-term habituation has been linked to decreased presynaptic transmitter release. Repeated stimulation with a highly noxious stimulus, such as an electric shock, can lead to sensitization, an intensification of the withdrawal response. Short-term sensitization involves increased neurotransmitter release from a facilitating interneuron (Kandel & Schwartz, 1982). Modulation of neurotransmitter release may underlie short-term changes in functional connectivity between neurons.

Long-term memory processes, in contrast, require messenger RNA and protein synthesis (Davis & Squire, 1984) to establish structural changes in synaptic connectivity as a record of experience.

Type
Chapter
Information
Diseases of the Nervous System
Clinical Neuroscience and Therapeutic Principles
, pp. 301 - 316
Publisher: Cambridge University Press
Print publication year: 2002

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×