LECTURE 19: ANATOMICAL

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LECTURE 19 ANATOMICAL FUNCTIONAL
ORGANIZATION OF LEARNING MEMORY
REQUIRED READING Kandel text, Chapter 62
LEARNING The process through which an organism
acquires knowledge of the world MEMORY The
process through which knowledge is encoded,
stored, and retrieved Two Types of
Memory EXPLICIT MEMORY Factual knowledge of
people, places, things, and events, along with
concepts derived from this knowledge Explicit
(declarative) memory is recalled by conscious
effort, and can involve assembly and association
of many pieces of information in different
modalities IMPLICIT MEMORY Acquired
information on how to perform skills and on
associations between stimuli and
responses Implicit (nondeclarative) memory is
recalled unconsciously. Different regions of
the brain are responsible for staged acquisition
and storage of different types of memory
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ANATOMY OF CEREBRAL BRAIN
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ANATOMY OF HIPPOCAMPAL FORMATION
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ANATOMY OF PRIMARY SENSORY AND ASSOCIATIVE
CORTICES
Each primary sensory cortex (visual, somatic,
auditory) first projects to unimodal association
areas, which extract more complex information
from the sense. Unimodal association areas
project to multimodal association areas, that
integrate information from more than one sensory
modality. POSTERIOR ASSOCIATION AREA
perception of place, construction of
language LIMBIC ASSOCIATION AREA memory
storage, emotions ANTERIOR ASSOCIATION AREA
long-term planning, judgment, heart of our
identity?
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HIPPOCAMPAL FORMATION CRITICAL FOR ACQUISITION OF
EXPLICIT MEMORY
Damage to or surgical removal of hippocampal
formation has severe and very specific
consequences
Memories established before lesion ---------gt
NORMAL New short-term (up to a few minutes)
memories -------------gt NORMAL Creation of new
long-term explicit memories ---------------gt
IMPAIRED Development of new long-lasting
implicit memory ----------------gt NORMAL
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HIPPOCAMPAL FORMATION DAMAGE DOES NOT IMPAIR
FORMING NEW IMPLICIT MEMORY
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INDIVIDUAL SIDES OF HIPPOCAMPUS ARE HIGHLY
ACTIVE DURING LEARNING OR RECALLING DIRECTIONS
OR WORDS
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EXPLICIT MEMORY IS STORED IN ASSOCIATION CORTICES

• Explicit memories can be subdivided into two
  categories
• Semantic (factual) knowledge objects, facts,
  concepts, word definition, spoken fluency
• Episodic knowledge . Events
• Semantic knowledge is a rich and upgradable set
  of associations
• the word or picture of an elephant invokes a
  repertoire of stored information
• (size, sound it makes, where its from, its
  appearance in circuses)
• Different types of memory and different
  components of the same memory are stored in
  various associative cortex areas that are linked
  together to allow their combined retrieval
• Certain focal lesions in associative cortex
  regions fragment a memory, destroying specific
  components

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SELECTIVE VISUAL AGNOSIAS AFFECT MEMORY OF OBJECT
FORM OR OBJECT NAME
Lesion to posterior parietal cortex ASSOCIATI
VE AGNOSIA Lesion to occipital associative
cortex APPERCEPTIVE AGNOSIA
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MEMORIES OF ANIMALS AND OBJECTS ARE STORED IN
DISTINCT CORTICAL DOMAINS
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EPISODIC MEMORY STORED IN FRONTAL ASSOCIATION
CORTICAL REGIONS
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MULTIPLE CATEGORIES OF IMPLICIT MEMORY
Sensitization and habituation are forms of
non-associative implicit memory EXAMPLES Startle
response to a sudden loud noise upon repetition
(habituation) Withdrawl from tactile stimulus is
stronger following pinch to same area
(sensitization) THESE IMPLICIT MEMORIES ARE
STORED IN SPINAL REFLEX PATHWAYS
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MULTIPLE CATEGORIES OF IMPLICIT MEMORY
Classical and operant conditioning are forms of
associative implicit memory CLASSICAL
CONDITIONING Mild conditioning stimulus (CS) is
followed after fixed interval by a
strong favorable or unfavorable unconditioned
stimulus (US). Repetition elicits learned
behavior, where CS elicits a conditioned response
(CR) in the absence of US. CS causes
anticipation of US. Not all types of pairing
between a CS and US lead to a CR. A taste CS
paired with poison nausea US leads to food
aversion CR, BUT taste CS paired with electric
shock US DOES NOT induce a CR. OPERANT
CONDITIONING When a seemingly random behavior is
followied by a favorable stimulus, organism
learns to repeat the behavior in order to obtain
repeat of favorable stimulus. Although operant
behavior and stimulus do have an underlying
purposeful relationship, operant conditioning is
a more automatic learning that doesnt require
understanding. Therefore, operant conditioning
much less applicable to high intelligence
animals. BOTH TYPES OF CONDITIONING EXTINGUISH
IF SEVERAL REPETITIONS OF CS OR OPERANT BEHAVIOR
DO NOT YIELD ANTICIPATED STIMULUS
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CONDITIONED RESPONSE MEMORIES STORED IN SENSORY
MOTOR CIRCUITS WHICH INCLUDE CEREBELLUM OR
AMYGDALA
When an unconditioned response is motor and
non-emotional, a specific region of the
cerebellum is used for learning/storing the
conditioned response Conditioned Eyeblink
Response Auditory CS pairing to
air-puff-(US)-induced eyeblink leads to eyeblink
CR following CS. The region of cerebellum
controlling CR is DIFFERENT from region
controlling US-induced blink. When an
unconditioned response has a strong emotional
component, the amygdala is used for
learning/storing the conditioned
response Freezing Fear Response Amygdala is
required to learn association between CS and
electric shock US, which produces the freezing
fear response.
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NEXT LECTURE LEARNING MEMORY, Part
II READING Kandel text, Chapter 63