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Christian Gaser

3 papers in the library · 9 citations · publishing 2022-2025

Papers

Preliminary evidence of links between ayahuasca use and the corpus callosum.

Frontiers in psychiatry January 1, 2022 Otto Simonsson, José Carlos Bouso, Florian Kurth et al. 6 citations

The corpus callosum, a brain structure connecting the two hemispheres, was thicker in the isthmus region among 22 ayahuasca users compared to 22 matched controls. A positive correlation was observed between callosal thickness in the rostral body and the number of past ayahuasca sessions, though neither finding survived correction for multiple comparisons. No brain region was thicker in controls than in ayahuasca users, and no region was negatively linked to ayahuasca use. This provides preliminary evidence of an association between ayahuasca use and callosal structure, but replication with larger samples and longitudinal designs is needed.

Cortical thickness of the posterior cingulate cortex is associated with the ketamine-induced altered sense of self: An ultra-high field MRI study.

Journal of psychiatric research April 1, 2024 Lena Vera Danyeli, Zümrüt Duygu Sen, Lejla Colic et al. 3 citations

In healthy men, a thinner posterior cingulate cortex (PCC) is linked to a stronger feeling of disembodiment after a low dose of ketamine, a drug that can rapidly relieve depression. The study measured cortical thickness in two brain regions—the PCC and the pregenual anterior cingulate cortex (pgACC)—and found that only PCC thickness correlated with the altered sense of self (disembodiment). No such link appeared for the pgACC. These results suggest the PCC plays a key role in ketamine's effects on self-experience, a feature shared with other fast-acting antidepressants that also produce psychedelic-like effects.

Impact of meditation on brain age derived from multimodal neuroimaging in experts and older adults from a randomized trial

Scientific Reports October 28, 2025 Sacha Haudry, Natacha Lambert, Christian Gaser et al.

Older adults with more than 20 years of meditation experience have a younger predicted brain age compared to cognitively unimpaired older adults without such expertise, as measured by a machine learning model trained on brain structure and metabolism data. The difference in brain age was linked to total meditation hours, mental imagery, and prosocialness. However, an 18-month meditation training program did not produce a significant effect on brain age, suggesting that long-term, sustained practice may be necessary to support healthy brain aging.