THE DOGMA OF AN AGING BRAIN

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Transcript THE DOGMA OF AN AGING BRAIN

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THE AMAZING FACTS OF
AGING
HISTORICAL AND CURRENT
DOGMA OF THE AGING BRAIN
Historical
perspective
• Accelerated rate of brain shrinkage after age 50.
• Loss of 100,000 neurons in the cortex per day.
• Irreversible process of brain dysfunction.
Current
perspective
• Insignificant loss of neurons.
• Neuronal atrophy and loss of synaptic connections.
• Evidence of brain plasticity.
ANATOMICAL CHANGES IN THE
AGING BRAIN
Structure
Regional function
Basal ganglia
A collection of nuclei lying deep into
the brain.
Involves in the regulation of voluntary
movement
Subarachnoid
space
CSF containing compartment
surrounding the cerebrum.
Involves in CSF reabsorption.
Hippocampus
A component of the limbic system
Involves in learning & memory
Ventricles
Compartment in either side of the
cerebral hemispheres.
Involves in CSF production.
White Matter
Collection of myelinated nerve fibres
forming the deep brain.
Involves in information transmission.
ANATOMICAL CHANGES IN
THE BASAL GANGLIA
Function Neuronal clusters responsible for initiating and integrating movements.
Changes Becomes bright in appearance due to iron accumulation
ANATOMICAL CHANGES IN
THE SUBARACHNOID SPACE
Function Contains CSF to provide mechanical protection for the brain.
Changes Increase in size due to brain shrinkage
ANATOMICAL CHANGES IN
THE VENTRICLES
Function Production of CSF for mechanical protection.
Changes Increase in size due brain shrinkage.
ANATOMICAL CHANGES IN
THE HIPPOCAMPUS
Function Development of Learning and Memory
Changes Reduction in size due to cell loss in the structure.
ANATOMICAL CHANGES IN
THE WHITE MATTER
Function Communication channel for information processing.
Changes Reduction in size due to neuronal atrophy.
CONGITIVE CHANGES IN
AGING: INTELLIGENCE
Fluid Intelligence – Ability to think and reason.
Crystallized Intelligence – Ability to apply skill and knowledge.
Aged-related change: Decline in fluid intelligence
CONGITIVE CHANGES IN AGING:
MENTAL PROCESSING
Decline in attentional ability
Working memory
Aged-related change: Decline in mental processing via reduction of
attentional ability and decline in ability in forming working memory
CONGITIVE CHANGES IN
AGING: LONG-TERM MEMORY
Explicit memory – Retention of previously acquired skills & reflexes.
Implicit memory – Conscious memory of facts & events.
Aged-related change: Decline in explicit memory