PNAS nexus
December 1, 2024
Emilia Fló, Laouen Belloli, Álvaro Cabana et al.
10 citations
Directing attention toward the body's internal signals (interoception) versus external sounds (exteroception) produces distinct brain activity patterns. Exteroceptive attention flattened overall brain wave power, while interoceptive attention reduced brain signal complexity, increased frontal connectivity and theta oscillations, and modulated the heartbeat-evoked potential (HEP). Classifiers using HEP features correctly identified the attentional state in 17 of 20 healthy participants; power spectral density features classified all 20. In five brain-injured patients, one with unresponsive wakefulness syndrome and one with locked-in syndrome showed willful modulation of the HEP, suggesting they could follow commands. These findings highlight how attention shapes sensory processing and may aid diagnosis in disorders of consciousness.
PNAS nexus
April 1, 2025
Katie Zhou, David de Wied, Robin L Carhart-Harris et al.
9 citations
Delusional ideation decreased one month after a planned psychedelic experience, while magical thinking showed no change. Over 30% of participants reported hallucinogen persisting perception disorder (HPPD)-type effects at four weeks, though fewer than 1% found them distressing. Younger age, female gender, a history of psychiatric diagnosis, and baseline trait absorption predicted HPPD-like effects. Lifetime psychedelic use at baseline correlated positively with both magical thinking and delusional ideation, suggesting these traits may correlate with psychedelic use rather than being caused by it.
PNAS nexus
February 1, 2024
Benjy Barnett, Lau M Andersen, Stephen M Fleming et al.
7 citations
Perceptual vividness—the intensity of conscious experience—varies across different experiences, but how the brain registers this variation is unclear. In other psychological domains like number or reward, magnitude is represented independently of sensory features. Reanalyzing existing magnetoencephalography and functional MRI data from two studies that quantified vividness via subjective awareness and visibility ratings, evidence emerged for content-invariant neural signatures of vividness distributed across visual, parietal, and frontal cortices. These findings suggest that neural correlates of subjective vividness may share properties with magnitude codes in other cognitive domains.