A hypothetical model for the mediation of * complex visual hallucinations, proposed in or shortly before 2004 by the British scientists Daniel Collerton, Elaine Perry, and Ian McK-eith. The PAD model is based on the observation that complex visual hallucinations are *perceptive hallucinations, i.e. that they consist of hallucinated objects or scenes which appear to be integrated into the hallucinator's extracorporeal environment. To explain this state ofaffairs, Collerton et al. point to a combination of impaired atten-tional binding, poor sensory activation of a correct proto-object, and a relatively intact ability to create a scene representation. They suggest that these three factors are prerequisites for the mediation of a hallucinatory image, as well as for its fusion with a regular sense perception. According to these authors, the neurobiological correlates of this process may well consist of disturbances -possibly of a cholinergic nature - in the neuronal system connecting the lateral frontal cortex and the ventral visual stream.
References
Collerton, D., Perry, E., McKeith, I. (2005). Why people see things that are not there: A novel perception and attention deficit model for recurrent complex visual hallucinations. Behavioural and Brain Sciences, 28, 737-794.
Dictionary of Hallucinations. J.D. Blom. 2010.