Comparing Hallucinations in Schizophrenics and Sufferers of Charles Bonnet Syndrome :: Biology Essays Research Papers

A Comparative Look at Hallucinations in Schizophrenics and Sufferers of Charles hood Syndrome, and Their Corresponding Reality Discrimination Abilities Hallucinations argon defined as sensory(a) perceptions in the absence of externally generated stimuli (6). They are not to be unlogical with illusions in which actual external objects are perceived but misinterpreted by the individual (6). Hallucinations tail take many forms including visual, auditory, olfactory and tactile, but for this composing we de grapheme focus primarily on the visual type. Visual hallucinations can befall in a number of different situations, cardinal of which we will discuss here Charles Bonnet syndrome and schizophrenia. These two conditions are unique in the ca drops and effects of the hallucinations resulting from each, and in the types of people in whom they occur. A most provoke distinction is that Charles Bonnet patients are aware of their hallucinations while schizophrenics are not. In the next sections I will present a description of the hallucinations that occur in each condition, and some hypothesized causes of these. I will conclude with an blast to discover why there exists an awareness of hallucinations in one that is disappear in the other. Charles Bonnet syndrome is the onset of hallucinations in psychologically healthy individuals who suffer become either visually-impaired, or completely blind. There are two main theories as to the cause of these hallucinations. The first and most popular is that they are release hallucinations that result from the, removal of normal visual afferent foreplay to association cortex (7). This is supported by experiments involving direct stimulation of the secular lobe, and fMRIs taken during hallucination events. These studies found that in the absence of visual input, action mechanism was present in a particular visual area of the read/write head and that the resulting hallucination would be a type of image normally perceive d by that area. For instance, a assailable who hallucinated in color showed activity in the color center of the fusiform gyrus while a subject who hallucinated fences and brickwork showed activity in the collateral sulcus which responds to visual textures. (4) These areas normally respond to exterior visual input, but in this case there was none. It is possible consequently that these areas are activated in the absence of inhibition caused by away(p) visual input. This would be something like the phenomenon of the chicken that runs around in circles at once its head has been severed. The other theory is that hallucinations in visually-impaired individuals occur as part of a filling in process that is already in use by our brains.