Development of Intelligence
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The document discusses various aspects of neurodevelopment, including cell proliferation, migration, synaptogenesis, and neuronal pruning. It emphasizes the role of growth cones and neurotrophic factors in neuronal development and the impact of environmental factors on brain structure and function. Additionally, it covers the development of the prefrontal cortex and neuroplasticity, along with considerations for autism spectrum disorder and its heterogeneous nature.
Development of Intelligence
- 3. Proliferation Generation of new cells Cognitive Development
- 4. Migration: slow movement to the “right place” Only a soma and immature axon at this point undifferentiated at start of migration. But, differentiation begins as neurons migrate. They develop neurotransmitter making ability, action potential
- 5. Migration Radial glial cells act as guide wires for the migration of neurons Migrating cells are immature, lacking dendrites Cells that are done migrating align themselves with others cells and form structures
- 6. Growth Cones: tips of axons on migrating, immature neurons Growth cones crawl forward as they elaborate the axons training behind them. Their extension is controlled by chemical cues in their outside environment that ultimately direct them toward their appropriate targets. Chemoattractants Vs Chemorepellants
- 7. Axon Growth/Synaptogenesis Once migration is complete and structures have formed (aggregation), axons and dendrites begin to grow to their “mature” size/shape. Axons (with growth cones on end) and dendrites form a synapse with other neurons or tissue (e.g. muscle) Growth cones and chemo-attractants are critical for this.
- 8. Synaptogenesis • Formation of new synapses • Depends on the presence of glial cells – especially astrocytes • Chemical signal exchange between pre- and postsynaptic neurons is needed
- 9. Neuronal pruning Between 40-75% neurons made, will die after migration – death is normal and necessary !! Neurons die due to failure to compete for chemicals provided by targets Neurotrophins promote growth and survival guide axons stimulate synaptogenesis
- 10. Release and uptake of neurotrophic factors Neurons receiving insufficient neurotropic factor die Axonal processes complete for limited neurotrophic factor Synaptic rearrangment
- 12. Postnatal Cerebral Development Human – Synaptogenesis – Increased dendritic branches – Myelination (prefrontal cortex continues into adolescence)
- 13. Early Studies of Experience and Brain Development • Early visual deprivation – fewer synapses and dendritic spines in visual cortex – deficits in depth and pattern vision • “Enriched” environment – thicker cortices – greater dendritic development – more synapses per neuron
- 14. Brain Development and Self Organization Gene ….. Environment
- 16. Symbolization and Mapping of the World Categorization
- 17. Perceptual and Conceptual clustering
- 19. Attention Perception • Perceptual Integration • Perceptual Comparison • Attention role Consciousness
- 20. Modulation A common approach to understanding neuronal processing is to reduce complexity by defining subunits and infer their functional role by selectively modulating them. • Neural Darwinism • LTP/LTD Developmental periods Specialized Neurons
- 22. Phylogenetic and Epigenetic Evolution of the Brain 4Brain damage before modulation Chomsky theory
- 24. Where is your Prefrontal Cortex ? The prefrontal lobe is the last to fully develop
- 25. Development of the Prefrontal Cortex • Believed to underlie age-related changes in cognitive function, judgment, decision-making • Prefrontal cortex plays a role in working memory, planning and carrying out sequences of actions, and inhibiting inappropriate responses
- 26. Neuroplasticity in Adults ? • Mature Brain changes and adapts • Neurogenesis (birth of new neurons) – seen only in olfactory bulb and hippocampus of adult mammals Intelligence; Innate or adaptive
- 27. Autism • 3 core symptoms: – Reduced ability to communicate – Reduced capacity for social interaction – Preoccupation with a single subject or activity • Heterogeneous – level of brain damage and dysfunction varies (Autism Spectrum Disorder) – Probably no single cause
- 28. Autistic Brain • The brain does not make the same connections in the same ways as other people • The brain is wired differently
- 29. Modulation and Autistic Brain