The Brain and Reflex Behavior

Brain Development

• Brain goes through extensive growth from conception to birth and after birth, through infancy and later.
• Brain goes from 25 percent of its adult weight at birth to 75 percent by the second birthday.
• Brain areas do not mature uniformly.
• Brain grows from the “bottom –up”
• Brain imaging technology is used to learn about the brain’s development.
  • MEG, EEG, fMRI, fNIRS.

Building the Brain

• Brain stem: the most primitive part of the brain and controls basic survival functions such as breathing, heart rate, and sleep.
• Cerebellum: located at the top of the brain stem and receives information from the sensory systems, spinal cord, and other parts of the brain to coordinate balance and voluntary movement.
• Cerebrum or cerebral cortex: accounts for about two-thirds of the brain’s mass and handles the higher functions of thought and action

Structures of the Brain

• The cerebral cortex is divided into two hemispheres:
  • Left hemisphere: right-side motor function; language centers (for right-handed people)
  • Right hemisphere: left-side motor function; humor and emotional tone
  • Connected by the corpus callosum
  • Some functions are lateralized, but most need both sides

The Brain

• Scientists distinguish four lobes in each hemisphere that usually work together.
• Frontal lobes: involved in voluntary movement, thinking, personality, emotion, memory, sustained attention, and intentionality or purpose.
• Occipital lobes: function in vision.
• Temporal lobes: have an active role in hearing, language processing, and memory.
• Parietal lobes: important in spatial location, maintaining attention, and motor control.