Page 350 - Color_Atlas_of_Physiology_5th_Ed._-_A._Despopoulos_2003

A. Storage of information in the brain (explicit memory)
Information Sensory 10 bits/s Forgotten
due to fading
9
organs
Sensory memory
Storage time < 1 s

Verbalization
Unverbalized
Short-term memory Intermediate 20bits/s Forgotten: Consciousness, Memory, Language
“Overwritten”
with new
storage
information
?
Primary memory
Üben
7 bits
Storage time: seconds to minutes
Frequent Secondary memory
Long-term memory Very large capacity Disremembered due Plate 12.14
repetition
Very large capacity
Minutes to years
Tertiary memory
to disturbance (inter-
ference) by previous
Lifetime storage
Recall time (access) Fast or later knowledge Slow Fast

Amnesia (memory loss). Retrograde amnesia the main center of speech in right-handed in-
(loss of memories of past events) is character- dividuals (“dominant” hemisphere, large
ized by the loss of primary memory and (tem- planum temporale), whereas the right hemi-
porary) difficulty in recalling information from sphere is dominant in 30–40% of all left-hand-
the secondary memory due to various causes ers. The non-dominant hemisphere is impor-
(concussion, electroshock, etc.). Anterograde tant for word recognition, sentence melody,
amnesia (inability to form new memories) is and numerous nonverbal capacities (e.g.,
characterized by the inability to transfer new music, spatial thinking, face recognition).
information from the primary memory to the This can be illustrated using the example of patients
secondary memory (Korsakoff’s syndrome). in whom the two hemispheres are surgically discon-
Language is a mode of communication used nected due to conditions such as otherwise un-
(1) to receive information through visual and treatable, severe epilepsy. If such a split-brain
aural channels (and through tactile channels in patient touches an object with the right hand (re-
the blind) and (2) to transmit information in ported to the left hemisphere), he can name the ob-
written and spoken form (see also p. 370). Lan- ject. If, however, he touches the object with the left
guage is also needed to form and verbalize hand (right hemisphere), he cannot name the object
concepts and strategies based on consciously but can point to a picture of it. Since complete sepa-
ration of the two hemispheres also causes many
processed sensory input. Memories can there- other severe disturbances, this type of surgery is
fore be stored efficiently. The centers for for- used only in patients with otherwise unmanageable,
mation and processing of concepts and lan- extremely severe seizures.
guage are unevenly distributed in the cerebral 337
hemispheres. The left hemisphere is usually
Despopoulos, Color Atlas of Physiology © 2003 Thieme
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