TY - JOUR

T1 - 43. Decoding Spontaneous Thoughts From Brain Resting-State fMRI: Toward Understanding Rumination

AU - Dekker, Ronald

AU - Nakamura, Aaron T.

AU - Lins, Amanda M.

AU - Bammel, Moritz

AU - Huys, Quentin

AU - Schuck, Nicolas W.

AU - Cai, Ming Bo

N1 - Abstract Supplement

PY - 2025/5/1

Y1 - 2025/5/1

N2 - BackgroundRumination, an aberrant form of spontaneous thoughts, is a common symptom of major depressive disorder and anxiety disorders. Developing non-intrusive tools to study the content and dynamics of spontaneous thoughts is likely to be helpful for understanding rumination. We developed a novel approach to decode spontaneous thoughts using functional magnetic resonance imaging (fMRI) data during resting state.MethodsfMRI data of 20 healthy participants (8 females, mean age 31.2, SD=10.1) were acquired during two tasks: free spontaneous thoughts (resting state for 3-5 minutes) followed by prompted verbal report of immediate thoughts, watching the movie Forrest Gump. Shared response modeling (functional alignment) was used to map whole-brain activity of all participants to a low dimensional space in which neural signals are synchronized during movie watching. Topic modeling based on a large language model identified 9 major topics among reported thoughts. Neural activity patterns in the low-dimensional space corresponding to the same topic in the 10 seconds before prompts were averaged across participants. Cross-validated decoding accuracy of thought topics was evaluated based on the cosine similarities between neural patterns of left-out participants and the average patterns of each topic from other participants.

AB - BackgroundRumination, an aberrant form of spontaneous thoughts, is a common symptom of major depressive disorder and anxiety disorders. Developing non-intrusive tools to study the content and dynamics of spontaneous thoughts is likely to be helpful for understanding rumination. We developed a novel approach to decode spontaneous thoughts using functional magnetic resonance imaging (fMRI) data during resting state.MethodsfMRI data of 20 healthy participants (8 females, mean age 31.2, SD=10.1) were acquired during two tasks: free spontaneous thoughts (resting state for 3-5 minutes) followed by prompted verbal report of immediate thoughts, watching the movie Forrest Gump. Shared response modeling (functional alignment) was used to map whole-brain activity of all participants to a low dimensional space in which neural signals are synchronized during movie watching. Topic modeling based on a large language model identified 9 major topics among reported thoughts. Neural activity patterns in the low-dimensional space corresponding to the same topic in the 10 seconds before prompts were averaged across participants. Cross-validated decoding accuracy of thought topics was evaluated based on the cosine similarities between neural patterns of left-out participants and the average patterns of each topic from other participants.

KW - Psychology

KW - Mind-Wandering

KW - Deep Learning Technology

KW - Rumination

KW - Machine learning-based neutral decoding

KW - resting state fMRI

U2 - 10.1016/j.biopsych.2025.02.280

DO - 10.1016/j.biopsych.2025.02.280

M3 - Conference abstract in journal

VL - 97

SP - S112-S113

JO - Biological Psychiatry

JF - Biological Psychiatry

SN - 0006-3223

IS - 9, Supplement

ER -