Consciousness

Definitions:

consciousness - a person's subjective experience of the world and the mind

circadian rhythm - a naturally occurring 24-hour cycle

REM sleep - a stage of sleep characterized by rapid eye movements and a high level of brain activity

Preservation Theory of Sleep - this states that sleep is evolutionary and adaptive, allowing species to preserve their energy and be protected from predators

Repair and Restoration Theory of Sleep - this states that the adaptive function of sleep allows species to recover from the excesses of the day

Information Consolidation Theory of Sleep - this states that during REM sleep, the brain undergoes changes which include the coordination and making of connections of neural pathways, which affects the cognitive/learning function of a species


Learning Objectives:


Compare and contrast the different perspectives on the function of sleep
All three theories consider sleep as an adaptive approach, each with a different adaptive function.
The Preservation Theory and Repair and Restoration Theory is physically involved, both covering species' physical preservation. 
The Preservation Theory basically states that prey species sleep at the same time as predator species to reduce the chances of being harmed, allowing for species preservation. This, in turn, preserves energy that can be devoted to mating or gathering food.
The Repair and Restoration Theory of Sleep focuses around bodily repair, where the body is able to recover from the excesses of the day.
The Information Consolidation Theory of Sleep has a cognitive focus, where the brain undergoes implicit learning during REM sleep. This, of course, is an adaptive function, since learned traits generally help with species preservation.


Identify good sleep-related practices
Sleep early!
Get lots of sleep!
Avoid caffeine, nicotine, alcohol, and other drugs!
Don't eat a large meal right before bed, but also, don't sleep on an empty stomach! (eat some wholegrain carbohydrates and a little bit of protein, like a glass of milk with a banana, or a slice of toast with some cheese or a slice of turkey on top)
Exercise regularly! (but not too late in the evening)
Sleep in a consistent pattern!
Eat in a consistent pattern!
Eat nutritious food and a well-balanced diet!


Identify different functions of REM and slow-wave sleep
REM sleep helps the body recover psychologically, while slow-wave sleep helps the body recover physically. A lack of REM sleep will render you aggressive and forgetful the next day, while a lack of slow-wave sleep will leave you sluggish and hypersensitive to muscle and bone pain the following day.


Compare/contrast REM and slow-wave sleep
When undergoing both REM and slow-wave sleep, you are essentially asleep; however, you are in different 'levels' of sleep.
You are much more easily awoken in REM sleep than in slow-wave sleep. REM sleep is characterized by rapid eye movements and a high level of brain activity, and with the Information Consolidation Theory of Sleep, it is the time when the brain undergoes changes which include the coordination and making of neural pathways, which affects the cognitive/learning function of a species. In addition, this is when you are most likely to be dreaming. On an EEG (electroencephalogram), REM sleep is characterized by sawtooth waves similar to beta waves, which are the waves the brain emits when one is awake.
In slow-wave sleep, however, during stages 3 and 4 of sleep, delta waves are read on an EEG.


Identify the functions served by different brain regions in sleep
The suprachiasmic nucleus regulates the circadian rhythm, and after approximately 12 hours, one cycles from wakefulness to drowsiness, and vice versa. Note that adolescents undergo a phase shift which disrupts the regular circadian rhythm, and that they require more sleep than adults and children.
When you dream, the amygdala, visual association areas, motor cortex, and the brain stem are activated, while the prefrontal cortex is deactivated.
The amygdala activation explains the jarring emotions one can have in a dream.
The visual association areas being activated explains the vivid images formed in a dream.
The activation of the motor cortex explains the rapid eye movement in REM sleep, and the reason people generally do not act out their dreams are due to spinal neurons running through the brain stem inhibiting the expression of this motor activation.
The prefrontal cortex's deactivation explains the randomness in events during dreaming, since it is responsible for planning.


Thought Question:


Q: James is sleepy most of the time. To counteract his sleepiness, he drinks coffee all morning during lectures and eats candy bars during labs. Because he is in class/lab all day and has a part time job in the evening, he never gets to exercise until after 11 p.m. Explain to James why he is probably sleepy all the time and give him some advice on how he might improve his wakefulness.


A: James could first of all try to change his schedule to let him sleep in or add a few breaks to eat something more filling. Also, he should not drink coffee and eat just candy bars, as that causes his body to crash after a few hours, and that in turn causes his feelings of fatigue. He should quit his part time job if possible in order to sleep earlier. If possible, he should try exercising in the morning. Furthermore, he should sleep in a consistent pattern.