Lecture 6 Slides - Brain Development(1)

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• Course: Biological Psychology (4PSYC003W)

• Focus: The development of the brain and its biological psychology aspects.

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Lecture Overview

• Main Objectives:

  1. Examine pre-natal and post-natal nervous system development processes.

  2. Consider the environmental impacts on nervous system growth and development through learning and experience.

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Gastrulation

• Process:

  • Transition from blastula (a hollow structure of undifferentiated cells) to gastrula (a multi-layered structure).

  • Gastrulation leads to the formation of different tissue types in the body.

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Neurulation

• Development Stages:

  • Neural plate folds to create the neural tube, which will develop into the central nervous system (CNS).

  • Transition from gastrula to neurula at around 17-22 days of development.

• Key Structures:

  • Notochord and neural plate play significant roles in neurulation.

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Embryonic Brain Structure

• Three main divisions of embryonic brain:

  • Prosencephalon (Forebrain)

  • Mesencephalon (Midbrain)

  • Rhombencephalon (Hindbrain)

• Additional structures include:

  • Telencephalon, Diencephalon, Metencephalon, Myelencephalon, Spinal cord.

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Brain Development Timeline

• Developmental timeframe:

  • Major brain structures observable at 3 weeks, 7 weeks, and 11 weeks.

• Assessments:

  • Identification of cranial nerves and spinal cord development.

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Main Processes of Neuronal Development

• Key processes include:

  • Proliferation: Neuron and glial cell production.

  • Differentiation: Specialization of cells (neurons and glia).

  • Migration: Neurons moving to appropriate locations.

  • Synaptogenesis: Formation of synapses.

  • Myelination: Production of myelin sheaths for neuron insulation.

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Proliferation

• Definition: Early production of neurons and glial cells.

  • Originates from cells lining brain ventricles.

  • Stem cells can continue to divide, while others migrate or remain in situ.

• Cell Potency Levels:

  • Totipotent, Pluripotent, Multipotent, Oligopotent, Unipotent.

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Differentiation

• Process:

  • Transition from unspecialized embryonic cells to specialized cells like neurons or glia, starting around 4 weeks.

• Factors Affecting Differentiation:

  • Intra- and extra-cellular influences.

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Migration

• Neuronal Movement:

  • Neurons made in the brain center migrate to specific brain areas.

  • Guided by specialized glial cells and chemical signals.

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Developmental Risks of Neuronal Migration

• Research Finding:

  • DCDC2 gene polymorphism linked to dyslexia (Meng et al., 2005).

  • Disruption in neuronal migration processes impacting reading capability.

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Synaptogenesis

• Definition:

  • Formation of synapses between neurons, occurring throughout life.

• Dependence:

  • Successful synapse formation relies on Neural Growth Factor (NGF), a crucial neurotrophin.

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Apoptosis

• Definition:

  • Programmed cell death to eliminate excess or unfitting neurons.

• Triggers:

  • Axons not receiving neurotrophins undergo apoptosis.

• Function of NGF:

  • Acts to prevent apoptosis in neurons.

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Myelination

• Role of Glial Cells:

  • Oligodendrocytes in the CNS and Schwann cells in the PNS responsible for myelination.

• Timing:

  • Most myelination occurs postnatally and varies by neuron type.

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Synaptic Pruning and Brain Reorganization

• Brain Plasticity:

  • The adult brain can reorganize in response to learning and experience.

• Impact of Learning:

  • Learning promotes dendritic growth and synaptic restructuring.

• Environmental Influence:

  • Enriched environments enhance cortical growth and dendritic branching.

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Mental Maps and Brain Development

• Study Reference:

  • Maguire et al. (2000) demonstrates hippocampal volume changes relative to experience (e.g., taxi driving).

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Musical Training and Brain Development

• Findings:

  • Extensive practice improves brain structure related to specific skills.

  • MRI results show significant structural differences in professional musicians.

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Study of Romanian Orphans

• Observations:

  • Active brain regions in orphans versus typical development.

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References

• Various studies and articles relevant to brain development, neuronal processes, and their effects on behavior and learning.