| Popis: |
This chapter reviews basic types of hallucinations that occur in neurological illness, drug-induced states, psychiatric disorders, and normal states of consciousness. A conceptual model of hallucinations first described by Benson and Gorman is reviewed. This model assumes that most hallucinations are one of two types: ‘release’ hallucinations that arise from deprivation of normal sensory input, and ‘ictal’ hallucinations that arise from activation of groups of neurons. Although this model provides a good starting point, it has limitations that are considered on the basis of a review of research pertaining to four types of hallucinations: (I) phantom limb phenomena, (II) amphetamine-induced hallucinations, (III) complex hallucinations elicited by intracerebral stimulation, and (IV) auditory hallucinations of spoken speech. Studies of these hallucinations highlight the need for more comprehensive explanatory models that consider dynamical interactions between multiple brain regions as well as neuroplastic alterations at synaptic and molecular levels. |
