Exploring the links between functional activation and hallucination proneness

Abstract

Hallucinations are often associated with alterations in brain activation, particularly in language-related and sensory processing areas. Existing models suggest different frameworks for understanding the relationship between brain activation and hallucination proneness, yet practical evidence supporting these models remains limited. This study investigates the neural correlates of hallucination proneness in healthy individuals through functional MRI (fMRI) tasks focusing on both auditory and visual processing, including voice and text comprehension, face recognition, and audio-visual stimuli. Participants, primarily university students, completed Launay-Slade Hallucination Scale–Modified (LSHS-M) measures, including auditory (LSHS-A) and visual (LSHS-V) subscales, while undergoing fMRI scans. Correlations were examined between hallucination proneness scores and brain activation in task-relevant and task-irrelevant regions. Although no significant correlations were found between hallucination scores and activation in task-relevant areas, positive correlations emerged in language-related regions during visual tasks, suggesting increased engagement in task-irrelevant areas. These results point to an inhibition deficit in individuals with higher hallucination proneness, supporting theories of reduced cognitive control. Furthermore, lateralization indices showed no significant correlation with hallucination scores, challenging assumptions about the continuum hypothesis in non-clinical populations. Taken together, these findings highlight the complexity of the neural mechanisms underlying hallucination proneness. While the study provides partial support for inhibition-based theories, the largely null results highlight the need for sensitive tasks, robust statistical controls, and broader populations to fully elucidate the neurobiological basis of hallucination proneness.