ForeFront Parkinson's Disease Research Clinic, Brain and Mind Centre, School of Medical Sciences, University of Sydney, 100 Mallett Street, Camperdown, NSW 2050, Australia.
2 papers in the library · 143 citations · publishing 2022-2023
Eight distinct models of complex visual hallucinations have been proposed since 2000, each based on different views of brain organization. Researchers from each model group have now agreed on an integrated Visual Hallucination Framework that aligns with current theories of both real and hallucinatory vision. The Framework identifies cognitive systems involved in hallucinations and enables systematic investigation of how hallucination experiences relate to changes in underlying cognitive structures. The episodic nature of hallucinations points to separate factors for their onset, persistence, and end, suggesting a complex relationship between temporary states and long-term traits of hallucination risk. The Framework also suggests new research directions and potential treatments for distressing hallucinations.
Serotonin in the brain can be understood as an extension of the gut's serotonergic system, which controls digestion. Central serotonin activity mimics a digestion/satiety circuit, where low serotonergic tone facilitates cognitive automaticity and higher tone helps identify flexible solutions when initial responses fail. This perspective explains serotonin's roles in reward processing, exploration, and psychedelic experiences, and clarifies links between serotonergic dysfunction and psychiatric symptoms.