• The word consciousness refers to a state when a person is conscious or unconscious.   
• The term is also used to indicate a sense of conscious experience, or awareness of something 
• Consciousness involves short-term memory
• Fully conscious humans have a sense of self, which requires relatively long-term memory

Consciousness varies in level:

•  with coma and deep anesthesia on one extreme
•  alert wakefulness on the other, and
• sleep in between 

There are also altered states of consciousness:

•  including hypnosis, including therapeutic and experimental hypnosis
•  trances (sef-inflicted or natural)
•  meditative states, including yoga, chi, raiki, and others

We will consider three components of consciousness:

• awareness
• attention 
• sense of self 

 Sleep and Dreaming

• The fact that species with higher metabolic rates typically spend more time in sleep supports the hypothesis that sleep is restorative
• Support for this idea comes from the observation that species with higher metabolic rates typically spend more time in sleep
• A less obvious explanation is the adaptive hypothesis. According to this view, the amount of sleep an animal engages in depends on the availability of food and on safety considerations
• According to the activation-synthesis hypothesis, during  REM sleep  the forebrain integrates neural activity generated by the brain stem with information stored in memory 
• In other words, the brain uses information from memory to impose meaning on nonsensical random input.

Watch Video: Sleep and Consciousness