Communicates information about environmental lighting to the rest of the body. Controls circadian rhythms; secretes melatonin: the release peaks at midnight and we sleep better when it is released; exposure to light during the night reduces melatonin production and release.
When we are exposed to light, it stimulates a neural pathway from the retina to the hypothalamus. This is where the SCN is located, which sends signals to other parts of the brain that control hormones, body temperature, and other processes that play a part in whether we feel sleepy or awake.
Not related to any other problems but are problems in themselves. No known cause, so most likely to be caused by bad sleeping habits such as staying up late.
When you dream, your ego's defences are lowered, so repressed wishes can reach your conscious awareness. Repressed wishes and memories are distorted in our dreams. The more unpleasant the wish or memory, the more distorted it becomes.
Criticism of Freud's theory - It is difficult to test
Its concepts are not objective enough and dreams cannot be easily verified. A big part of the theory relies on the unconscious mind, but this can't be asked about/observed.
Criticism of Freud's theory - Cultural and historical bias
Freud's themes, especially how dreams were interpreted, my have been influenced by the culture at the time. E.g. in Freud's time society was very strict about sex, so the idea of repressing lust and desire made sense. However today people have more liberal attitudes to sex, but this doesn't mean that the manifest content of dreams are very different.
Freud used the pseudonym 'Wolfman' to protect the patient's identity. Later revealed to be Sergei Pankejeff: a man in his 20s from a wealthy Russian family. In 1906 his sister killed herself and in 1907 his father killed himself, leading to Pankejeff's own depression.
The unconscious mind can have a significant effect on behaviour. It illustrates the process of repression, where traumatic events are pushed into the unconscious mind as a safety mechanism. However, it also shows that repressed memories can find their way back into the conscious mind through dreams that people have and then recall.
It is not reliable to bass a theory of dreams, which is supposed to apply to all, on the case of one person. It might be that other people don't use dreams as a way of symbolising traumatic experiences.
Wolfman criticisms - The Wolfman may only represent people with mental health problems.
Even if we accept that we can make some generalisations based on the Wolfman's experiences, they may not apply to people with good psychological health. Everybody dreams, but not everybody has traumatic life histories or mental health issues.
What does the theory day happens in our brains, which causes dreams?
Neuronal activity increases in the pons and random brain waves are generated. These waves travel up to the cerebral cortex in areas that would normally interpret sensory information, e.g. occipital lobe, limbic system. The information is treated as real sensory information. Through interpreting the stimulation, synthesis occurs; using stored memories to make sense of the information.