for education only

1. Memory
A specific cognitive function, the storage and
retrieval of information
新光醫院 R2 黃彥瑜
103-05-08

2. Introduction
• Limbic system
• Regulate autonomic and endocrine function, particularly in
response to emotional stimuli
• Set the level of arousal and dreaming
• Motivation and addiction
• Olfactory system
• Appetite and eating behaviors
• Sexual behavior
• Memory and learning

3. History
• Broca, 1878: le grand lobe limbique
• Papez circuit, 1937: took as emotional feeling and expression
• Kluver-Bucy syndrome (in bilateral temporal lobectomy…):
amnesia, docility, dietary changes/hyperphagia,
hyperorality, hypersexuality, visual agnosia,
hypermetamorphosis
• MacLean, 1952: limbic system, extensively including
parahippocampus, entorhinal cortex…

4. • Hippocampus for Emotion → Memory
• LeDoux, 1986: Amygdala for Emotion
• Fear, rage, aggression
• Emotional reactions accompanied by autonomic reactions

5. • Pessoa, 2008
• 'affective' and 'cognitive' brain ?
• Amygdala in the domain of emotion
• Lateral prefrontal cortex in the case of cognition
• Complex cognitive–emotional behaviors have their basis in dynamic
coalitions of networks of brain areas, none of which should be
conceptualized as specifically affective or cognitive.

6. Neuroanatomy
• Consisted of archicortex, paleocortex and neocortex
• Components of the limbic systems: no universal agreement
on the total list of the structures
• Cortical regions (limbic lobe): surrounding cortex including
insular cortex, orbital frontal cortex, subcallosal gyrus, cingulate
gyrus, parahippocampal gyrus
• Hippocampal formation
• Subcortical portions: olfactory bulb, hypothalamus, amygdala,
septal nuclei, thalamic nuclei

7. Papez circuit
• Hippocampus
• Fornix
• Mamillary body
• Mammillothalamic tract
• Anterior nucleus of the
thalamus
• Thalamocingulate tract
• Cingulate gyrus
• Parahippocampal gyrus
• Hippocampus

8. Hippocampus
• Hippocampus proper (Ammon’s horn, cornu
Ammonis)
• CA1, CA2, CA3, (CA4)
• Dentate gyrus (fascia dentata)

9. • The functions associated with the limbic system,
such as instinctual and affective behavior, motivation, and drive, as
well as learning and memory should not be thought of as
preserve of the limbic system alone
• These functions depend on an intact
cooperation of the limbic system with many
other areas of the brain

10. Connectionstootherareasofthebrain
• Papez circuit
• Entorhinal afferent fibers
• “Gateway” to hippocampus
• Septal, hypothalamus afferent fibers
• Afferent fibers from brainstem
• Commissural afferent fibers
• Connect the two hippocampi with each other
• The major efferent bundle of the hippocampal formation:
fimbria, fornix
• Autonomic nervous system can travel through the
hypothalamus and the medial dorsal nucleus of the thalamus
to reach the orbitofrontal cortex
• Amygdala, mammillary bodies……

11. • The following fiber pathways are particularly important for
(declarative) memory:
• Projections from the hippocampus by the way of the fornix
• To the septal nuclei
• To the mamillary bodies (Papez circuit)
• Projections from the amygdala to the dorsomedial nuclear of
thalamus and onward to the orbitofrontal cortex
-Duu’sTopical Diagnosis in Neurology-
?

12. 記憶如何形成?
• “Grandmother cell”
• Jennifer Aniston cell
• Visual invariance
• Concept cells
• 18000 neurons/each concept
• Interpretation: 非回憶起事物
所需的細胞,而是把事物置入意
識以便形成新的連結和記憶所
需的細胞
• Sparse vs. Ddistributed

13. Long-term potentiation
http://www.youtube.com/watch?v=vso9jgfpI_c

14. Bloodsupply of hippocampus
• The PCA directly and
by its branches
ontributes much more
to the blood supply of
the hippocampal
formation than the
anterior choroidal
artery (AChA).

16. Stages of memory
• Encoding or registration: receiving, processing and
combining of received information
• Consolidation
• Storage: creation of a permanent record of the
encoded information
• Retrieval, recall or recollection: calling back the stored
information in response to some cue for use in a
process or activity

17. Where do they work
• According to an early positron emission tomography (PET)
study, several brain regions show consistent activation in
normal subjects during memory testing.
• A model for the functions of these areas in memory are as
follows:
• Prefrontal cortex: retrieval activation and attention
• Hippocampi: conscious recollection
• Cingulate cortex: activation of memory and selection of a
specific response
• Posterior midline regions: visual imagery
• Parietal cortex: spatial awareness
• Cerebellum: voluntary self-initiated retrieval
• Lateralization: left for word semantic memory, right for
nonverbal memory

18. • Medial temporal cortex activates more during new learning
tasks than during previously trained and practiced memory
tasks
• Overlearned memories gradually become less dependent on the
hippocampus.
• The amygdala appears necessary for affective aspects of
memory items, such as recall of fear associated with a specific
stimulus
• Amygdala is not essential for episodic memory but crucial for
recall of emotional contexts of specific events and the reactions
of fear or pleasure

19. Afilinganalogyof episodicmemory
• Frontal lobes: filing clerk, deciding
what memories to file or retrieve
• Medial temporal lobes: recent
memory filing cabinet, memories
consolidated
• Diffuse cortical regions: remote
memory file cabinet

20. Stages of memory
• Encoding or registration: receiving, processing and
combining of received information
• Consolidation
• Storage: creation of a permanent record of the
encoded information
• Retrieval, recall or recollection: calling back the stored
information in response to some cue for use in a
process or activity
Frontal lobe
Prefrontal lobe
Hippocampus
Hippocampus
(Papez circuit)
Hippocampus
Diffuse cortex
Frontal/Prefrontal lobe
Hippocampus
Diffuse cortex

21. Typesof memory
• Primary vs. Secondary memory
• Short-term vs. Long-term memory
• Explicit vs. Implicit memory

22. Classifiedby time
• Working memory, immediate memory span
• A subject can keep in conscious awareness without active
memorization
• Seven digits
• Supraspan numbers or reverse digit span require active memory
processing
• Disorders of attention and very focal lesions of the superior
frontal neocortex (Brodmann areas 8 and 9) affect immediate
memory

23. • Recent memory
• The ability to register and recall specific items after a delay of
minutes or hours
• 3 objects recall test, questions about morning breakfast
• Remote memory
• Recall of famous figures or events, knowledge

24. SMA

25. • Episodic memory: the memory of autobiographical events that can be
explicitly stated
• Semantic memory: the memory of meanings, understandings, and
other concept-based knowledge, and underlies the conscious
recollection of factual information and general knowledge about the
world
• Procedural memory: memory for the performance of particular types
of action
• Classical conditioning: an unconditioned stimulus becomes associated
with a reward or punishment given when the conditioned stimulus is
presented
• Probabilistic classification learning: predicting the weather from a
combination of cues that are regularly associated with sunny or rainy
weather
• Priming: a prior encounter with a particular item changes how one
responds to the current item, even unconsciously
• Perceptual priming: modality specific based on different sensory cortex
• Conceptual priming: “school" relates to "student“

26. Memorydisorders:amnesticsyndrome

27. Korsakoffsyndrome
• Chronic alcoholic patients who develop thiamine deficiency
• Acute:Wernicke’s encephalopathy
• Symptoms:
• Dementia especially amnesia, anterograde and retrograde
• Confabulation, anosognosia, apthy
• MRI: tectal plate, periaqueductal area, mammilary bodies,
dorsomedial thalamic nuclei, hypothalamus

28. Posttraumaticamnesia
• Diffuse brain pathology, in particular rotational forces giving
rise to diffuse axonal injury
• Transient or persisting amnesia, anterograde or retrograde
• Islands of memory
• Memory is commonly the last cognitive function to show
improvement, usually expected 1-3 months after the injury
• Coexisting psychogenic disorders: posttraumatic stress
disorder

29. Herpes simplexencephalitis
• Bilateral temporal lobe encephalitis is pathognomonic
• Symptoms: signs of meningitis/encephalitis, seizures

30. Transientglobal amnesia
• Acute loss of memory, usually recover spontaneously within
12-24 hours
• Middle aged or elderly, men
• Symptoms: repetitive questioning (short term memory,
mainly anterograde), disorientation, no other neurologic
signs
• Etiology: may be ischemic (subtle transient intense DWI
signal seen within the hippocampus)
• Need to differential with vascular events and seizures

31. Transientepilepticamnesia
• Brief episodes of memory loss (1h or less) and multiple
attacks may suggests epilepsy
• May be residual deficits between each attacks, other signs of
seizures (automatism, postictal confusion)
• Anterograde amnesia or memory gaps
• Standard EEG and CT are often normal

32. Vasculardisorders
• Thalamic infarction
• Hemorrhage or infarction of the septal nuclei
• SAH following rupture of an aneurysm: ACA or PCA
• Lesions of the splenium of the corpus callosum, either
traumatic or ischemic, which commonly also involve the
immediately underlying commissure of the fornices

33. Alzheimerdisease
• Neurodegenerative disease
• The most common disease that affects the episodic memory
system: the hippocampus and other medial temporal lobe
structures are damaged first
• Affect episodic memory mainly
• Distortions of memory
• Ribot’s law: ability to learn new information is most impaired
(anterograde amnesia), recent learned information cannot be
retrieved (retrograde amnesia), remotely learned information
is spared

34. Thanks for attention
• Reference:
• Duu’sTopical Diagnosis in Neurology
• Bradley’s Neurology in Clinical Practice
• Microsurgical anatomy of the hippocampal
arteries (J Neurosurg 79:256-265, 1993)
• The limbic system (Indian J Psychiatry. 2007 Apr-
Jun; 49(2): 132–139.)
• Disorders of memory (Brain (2002), 125,
2152±2190)
• Memory: Clinical Disorders - Boston University
Students
• 科學人 NO.134
• http://www.dartmouth.edu/~rswenson/NeuroSc
i/chapter_9.html
• http://bml.ym.edu.tw/bmlab/Pathway.html
• http://en.wikipedia.org/wiki/Memory