The biological supercomputer? (The Brain A-level notes)

The human brain:

• Brain is part of the CNS-information processed and coordinated response results.
• Spinal chord (CNS) contains grey matter; made up of neurone cell bodies, and white matter; made up of nerve fibres. 
• Brain has 3 distinct areas: forebrain (olfactory lobes+cerebral hemispheres), midbrain (optic lobes) and hindbrain (cerebellum+medulla).
• In vertebrate embryos: anterior end of tube swells and folds back on itself forming a brain. 
• Cerebral cortex folded back over the entire brain. 
• Human brain contains around one hundred thousand million neurones, each synaspsed to 10,000 other neurones-complex. 

Cerebral hemispheres: 

• Higher functions of brain; learning, feeling emotions, thought.
• Grey matter-nerve cell bodies, dendrites and synapses. 
• Deeply folded to give larger surface area. 
• Corpus callosum: band of axons (white matter) connecting hemispheres. 
• Frontal lobe: emotion, reasoning, personality. Idea+association development. Contains primary motor cortex involved in control of body movements via motor neurones in spinal chord. 
• Temporal lobe: auditory information, memory. 
• Occipital lobe: visual information (input from optic nerves). 
• Parietal lobe: varied functions; recognition, calculation, movement, sensation, spatial orientation. 

Other areas of the brain:

• Hypothalamus: coordinates autonomic nervous system, thermoregulation, monitors chemistry of blood (hormones from pituitary glands) and basic feelings; hunger, aggression, reproduction. 
• Cerebellum: coordinates smooth muscle movements, uses info from muscles+ears for balance.
• Medulla oblongata: primitive, contains reflex centres controlling heart rate, peristalsis etc. Maintains basic life responses even if higher areas destroyed. 

Animal studies:

• Removing/damaging areas of the brain (cerebral hemispheres) of an animal to observe effect on behaviour. 
• Implanting electrodes and artificially stimulating areas of the brain to see behaviour change.
• Normal behaviour compared with post mortem changes to brain. 
• Anthropomorphism is a problem.