Make your own free website on Tripod.com

Psychology of Human Growth and Development
Home
cognitive development part 2
Psychosocial development
Development of emotions
Depression
Language development
Cognitive development part 1
Perceptual development part 2
Memory
Development of attachment
Introduction
Nature versus nature
Introduction to developmental theories
Prenatal development and chromosomal abnormalities
Prenatal development and teratogens
Brain development
Motor development
Physical growth
Perceptual development

Lecture 6

Development of the brain

Brain growth

 

Brain size increases as existing neurons grow and the connections between them proliferate in number.

 

Structure of the brain

 

1. Central core

 

  • Medulla
  • Cerebellum
  • Thalamus 
  • hypothalamus

 

2. limbic system

 

  •  Hippocampus

 

3. cerebral hemispheres (known together as cerebrum)

 

  • Outer layer: cerebral cortex

 

        Inside of cerebrum beneath the cortex

      Composed mostly of myelinated axons and appears white

 

  • Structure of the cerebrum
  • contains following attributes:

      speech

      self-awareness

      sensory perception

      motor abilities

      memory

 

 

        Brain Hemispheres

 

Hemispheres divided by the corpus callosum

  • Band of nerve fibers that connects the two hemispheres

 

Differences between the hemispheres

  • Hemispheres are anatomically different and control different functions
  • Each side of the brain tends to specialize in certain perceptual and cognitive tasks.
  • E.g.: studies of people who have suffered brain damage to one part of brain give us important information about the function in which each hemisphere normally specializes

 

Exceptions to specialization

  • Great deal of cross-wiring between hemispheres
  • Hemispheres may differ in their specialization but they integrate their activities all the time.
  • When one half suffers damage the other half may take over

 

 

 

Neurons and synapses

 

Function of neurons

 

Neurons send and receive messages (neural impulses) throughout brain and nervous system.

 

Neural migration

 

  • Guided my neurochemical process neurons move to a variety of places in the brain
  • Ensures that all parts of the brain are served by a sufficient number of neurons

 

Synapse

 

Importance of synapses

Crucial to survival and learning

Help brain to receive input from the environment before and after birth

 

  • Neuronal death
  • Synaptic pruning

 

      Timing of synaptic pruning

 

Motor area:

      As baby moves from reflexive behaviour to voluntary control over movements the motor area of the brain develops most rapidly

 

Visual cortex

      Number of synapses per neuron multiplied 6 times in first two years of life.

      First 4 to 12 months number of connections rises to 150% those of adult brain

      Proliferation enhances baby’s visual capacity – skilled at focusing on objects at different distances

 

Prefrontal cortex

      Doesn’t peak until first year

 

Brain’s plasticity

 

 

  • Responsiveness of the brain’s neural structures and functions to input from the environment.
  • Brain size and function can be modified by experience

 

Plasticity and ageing

        The finding backs up theories which suggest that the "plasticity" or flexibility of the cells in the adult brain is far less than in the brain of a child.

        certain areas of the brain at least, this "plasticity" appeared to persist even into adulthood.

 

ageing brain


Ageing of the brain leads to impairments in:

  • cognitive:
    • Attention
    • working memory,
    • learning and memory retrieval, and
    • language,
    • visuospatial function,
  • motor skills,
    • sensori-motor

brain disorders

 

  • Cerebral atrophy
  • Cerebellar Degeneration

brain injuries

  • Traumatic brain injury
  • Closed Head Injury

 

TPS102