WHO AM I

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WHO AM I?
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St. Augustine

• Memory is multifaceted and not unitary.
• The repository of your own past and identity.
• The most important biological force in the human
  experience.

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St. Augustine

• Our memory allows us to change our behaviour
  because memory contains a record of our past
  history and can be replayed and analysed, it is
  the only force through which we can grow and
  change as individuals.

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WHO AM I?

• The organization of memory in the mammalian brain
  and the neural systems that mediate multiple
  kinds of memory must play a pivotal role in our
  thoughts, emotions, choices, actions, and even
  our personalities.

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WHO AM I?

• These complex neural circuits in our brain not
  only contain remnants of our past that are the
  basis of personal identity but also exert an
  enormous influence on individual behaviour.
• These brain systems, to a large extent, determine
  who we are and how we behave in particular
  situations.

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TWO THEORIES

• INTERACTING MEMORY SYSTEMS THEORY (IMST).
• GDE FACTORS.

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IMST

• Multiple learning and memory systems.
• Hippocampus.
• Amygdala.
• Dorsal striatum.

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IMST

• Parallel information processing systems.
• Acquire information simultaneously and in
  parallel.
• Each system is specifically designed to represent
  different relationships among the elements of a
  learning situation.

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IMST

• Interactions.
• Although they process information independently
  the systems can interact cooperatively or
  competitively to produce or influence behaviour.

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GDE FACTORS

• Normal and abnormal manifestations of behaviour
  are determined, to a large extent, by some
  complex set of interactions between an
  individuals genetic make-up developmental
  events during pre- and post-natal time periods
  and accumulated experience throughout the
  lifespan.

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GDE FACTORS
Genes
Development
Experience
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GDE FACTORS

• These factors can have major effects on the
  organization of the brain.
• These changes could affect overall relationships
  between each learning and memory system
  (balance).
• These changes could also affect the relationships
  of memory systems to the rest of the brain.

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GDE FACTORS

• Within the normal range of variability,
  alterations in the balance between these
  memory/behavioural systems can lead to individual
  personality, affective style, choices, actions.

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GDE FACTORS
Nucleus Accumbens
Prefrontal Cortex
Brainstem nuclei
Other Neural Systems
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GDE FACTORS

• A normal individual would have a balance between
  these systems that when activated result in
  relatively normal patterns of behaviour in a wide
  range of situations.

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GDE FACTORS

• Can also lead to certain strengths and
  weaknesses.
• Mathematics, athletics, music, social
  interactions, etc.

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GDE FACTORS

• A logical extension of this view is that there
  can also be changes in the balance of these
  systems that lead to abnormal manifestations of
  behaviour including the major psychiatric
  disorders such as schizophrenia, drug abuse, and
  the mood disorders.

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GDE FACTORS

• Alterations in the balance between memory systems
  could also produce abnormal talents as in the
  case of savants and others who display unusual
  abilities (Luria, 1968 Sacks, 1970).

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GDE FACTORS

• In the next section, I will provide an example of
  the influence of a single prenatal developmental
  event on the organization of interactive memory
  systems.

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Developmental perturbations

• Prenatal exposure to moderate levels of ethanol
  on adult cognition

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FETAL ALCOHOL SYNDROME (FAS)

• PROFOUND PHYSICAL AND NEURAL ABNORMALITIES IN
  OFFSPRING EXPOSED TO HIGH LEVELS OF ETHANOL IN
  UTERO.

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MODERATE EXPOSURE

• THE NUMBER OF CHILDREN EXPOSED TO MODERATE LEVELS
  OF ETHANOL MAY BE 10-20 TIMES HIGHER.

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INSTITUTE OF MEDICINE (IOM)

• RECOMMENDED EXPANDING THE CLASSIFICATION OF
  PRENATAL ALCOHOL EFFECTS TO INCLUDE A NEW
  CATEGORY CALLED ALCOHOL-RELATED
  NEURODEVELOPMENTAL DISORDERS (ARND).

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SYMPTOMS

• LEARNING DIFFICULTIES IN SCHOOL.
• POOR CAPACITY FOR ABSTRACTION.
• PROBLEMS IN MEMORY, ATTENTION, OR JUDGEMENT.

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ARND

• MODERATE ETHANOL EXPOSURE IN UTERO MAY CAUSE
  COGNITIVE DEFICITS IN CHILDREN WHICH MAY NOT
  BECOME APPARENT UNTIL THE CHILD IS CHALLENGED
  DURING ADVANCED EDUCATIONAL YEARS.

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ANIMAL MODEL

• INTEGRITY OF NEURONAL COMMUNICATION IN THE
  HIPPOCAMPUS.
• INTEGRITY OF BRAIN RECEPTORS NECESSARY FOR
  LEARNING AND MEMORY.
• INTEGRITY OF HIPPOCAMPAL-BASED BEHAVIORS.

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METHOD

• ETHANOL EXPOSURE
• 5 ALCOHOLBIOSERVE LIQUID DIET.
• PAIR FEDISOCALORICALLY EQUIVALENT DIET.
• AD-LIBPURINA RAT CHOW.

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METHOD

• BEHAVIOR
• WATER TASK.
• NEUROCHEMICAL
• NMDA RECEPTOR ASSAYS.

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METHOD

• ELECTROPHYSIOLOGY
• LTP INDUCED IN PERFORANT PATH? DENTATE GYRUS
  SYNAPSES.

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SUMMARY OF NEUROBIOLOGICAL CHANGES

• Neurobiochemical changes only found in
  hippocampus.
• Ability for neurons in hippocampus to change
  based on new experiences altered.

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BEHAVIOR
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COMPETITION
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Developmental perturbations

• The implications of this series of experiments
  should not be underestimated.
• They show that complex behavioural patterns in
  adulthood can be permanently altered by a single
  prenatal event.

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Developmental perturbations

• These types of events can fundamentally alter the
  overall organization of memory in the mammalian
  brain and can lead to abnormal behavioural
  patterns in adulthood.