A neural basis for distinguishing imagination from reality
Year: 2024
Type: preprint
Abstract: Humans use similar brain systems to both imagine and perceive. While the re-use of brain systems specialised for sensory perception for offline simulation is an efficient use of resources, it also leads to a potential for confusions between imagination and reality. It remains unknown how human observers classify perceptual signals as reflecting external reality, as opposed to internal simulation or imagination. Here we show that judgments of reality are underpinned by a latent variable that encodes the combined strength of sensory signals generated by either imagery or perception. We use functional magnetic resonance imagining to reveal that this latent variable is tracked by the activity of bilateral fusiform gyrus and predicts confusions between imagery and perception on a trial-by-trial basis. We further characterise interactions between fusiform gyrus and a network of prefrontal regions encoding binary judgments of reality, in line with higher-order theories of reality monitoring. Our results demonstrate that a key mechanism through which the brain distinguishes imagination from reality is by monitoring fluctuations in the activity of mid-level sensory cortex. These findings increase our understanding of failures of reality testing such as hallucinations and lay the foundations for characterising a generalised reality monitoring system in the human brain.
Authors: Nadine Dijkstra, Peter Kok, Stephen M Fleming
Language: English
Subfield: Experimental and Cognitive Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W4404424186