Examine altered states of consciousness and their causes. What are the cultural influences of hallucinogens?
Hallucinations & Perceptual Disturbances
Hallucinations are considered 'altered states of consciousnesses, altered perception from the individual's norm.
Hallucinations can occur in any sensory modality and are usually a product in a normal, healthy brain (usual balance of neurotransmitters etc).
Exception to this is Schizophrenia.
For schizophrenics hallucinations are usually auditory, there is also a reduction in the left frontal cortex, many scientists believe that changes in dopamine levels in the brain may account for the experiences of a schizophrenic.
People with schizophrenia also have difficulty in discerning internal and external sources of simulation (for example studies have revealed that a schizophrenic can tickle themselves).
Frith monitored brain activity when the patient was hearing voices with a PET scan. This revealed that the same area of the brain was activated as a third party/external voice. The 'words' the schizophrenic hears are therefore interpreted as hearing another person.
Changes in the brain's 'normal' balance of brain chemicals can result in perceptual disturbances and distortion (hallucinations).
The brain has evolved the 'blood brain barrier', so that when we eat ...