5 Infancy Physical Development Brain

5 Infancy – Physical Development

  • Source: Santrock, 19th ed. Chapter 4

Key Areas of Focus

  1. Physical Growth and Development

    • Patterns of Growth, Brain, Sleep & Nutrition

  2. Motor Development

  3. Sensory and Perceptual Development

Physical Growth and Development: Patterns of Growth

  • Description of head size as a fraction of total body length at various ages.

Physical Growth and Development: Brain

Mapping the Brain I

  • Key Features:

    • Two hemispheres

    • Four lobes:

      • Frontal

      • Parietal

      • Occipital

      • Temporal

    • Lobes are interconnected and function collaboratively.

Mapping the Brain II

Differences Between Cerebellum and Cerebrum

  • Cerebellum:

    • Appears as a separate structure beneath the cerebrum.

    • Controls coordination, precision, and timing of movements.

  • Cerebrum:

    • Largest part of the brain, comprising the cerebral cortex.

    • Involved in voluntary movement, intelligence, and memory.

Mapping the Brain III

  • Cerebellum:

    • Second largest brain part, consists of 2 hemispheres + medial vermis.

    • Motor functions and coordination.

  • Cerebrum:

    • Contains two hemispheres and 4 lobes (temporal, parietal, occipital, frontal).

    • Influences voluntary movements, intelligence, and higher cognitive functions.

Physical Growth and Development: Brain Development Process

  • Brain development starts from the bottom up, involving various functional levels:

    • Primitive functions such as heart rate and blood pressure regulation evolve first.

    • Complex abilities like abstract thought develop later.

Physical Growth and Development: Structure and Function of the Brain I

  • Key Brain Structures:

    • Brainstem: Basic reflexes fully developed at birth.

    • Thalamus: Sensory relay station functions develop post-birth.

    • Cerebellum: Involved in motor functions, grows and reorganizes over time.

    • Hippocampus: Key for memory formation.

    • Cerebral Cortex: Governs higher cognitive functions.

Physical Growth and Development: Structure and Function of the Brain II

  • Functions of Each Lobe:

    • Frontal Lobe: Voluntary movements, thinking, personality, purpose.

    • Occipital Lobe: Vision processing.

    • Temporal Lobe: Hearing, language processing, memory.

    • Parietal Lobe: Spatial location, attention, and motor control.

Physical Growth and Development: Changes in Neurons

  • Neuron Functionality:

    • Myelination: Development of myelin sheath around axons.

    • Neuronal connectivity increases creating new pathways.

    • Used connections strengthen; unused ones are “pruned.”

    • Blooming and pruning times vary by brain region, influenced by genetics and environment.

Physical Growth and Development: Neurons and their Structure

  • Neuron Components:

    • Dendrites: Receive information from other neurons.

    • Axons: Transmit information away from the cell body.

    • Myelin Sheath: Covers axons for faster transmission.

    • Terminal Buttons: End branches of axons.

Physical Growth and Development: Impact of Environment

Early Experience and Brain Function

  • Deprivation Effects:

    • Unresponsive environments (e.g., Romanian orphanages) lead to depressed brain activity.

    • Some effects are reversible through flexible and resilient brain mechanisms.

    • Example: Michael Rehbein's case post-left hemisphere removal.

Stress Types and Brain Impact

  • Positive Stress: Short, moderate stress good for development.

  • Tolerable Stress: Occasional stress offering recovery time.

  • Toxic Stress: Chronic and harmful impacts on the brain, leading to lasting damage.

Physical Growth and Development: Deprivation and Brain Imaging

  • PET Scans:

    • Compare brain activity of typically developing children against institutionalized orphans.

    • Higher activity levels are shown in typically developing children's scans, indicated by warmer colors (red, yellow).

Physical Growth and Development: Brain Plasticity

  • Michael Rehbein Case Study:

    • Demonstrated brain plasticity with language function shifting to the right hemisphere post surgery.

    • Right hemisphere compensates for left hemisphere loss but less efficiently.

Physical Growth and Development: Brain Injury and Measurement Tools

  • Shaken Baby Syndrome:

    • Causes brain swelling and hemorrhaging; significant implications for infants.

  • Brain Activity Measurement Tools:

    • Electroencephalogram (EEG)

    • Functional near-infrared spectroscopy (fNRIS)

    • Magnetoencephalography (MEG)

  • Optional Resource:

    • "The Secret Life of the Brain" video available on eLearning.