Neural Plasticity
January 1, 2016
Chuan-Chih Yang, Alfonso Barrós‐loscertales, Daniel Pinazo et al.
284 citations
Forty days of mindfulness meditation training in 13 novice meditators altered functional connectivity in brain networks linked to self-referential thought and emotion regulation. During meditation, internal consistency increased in the precuneus and temporoparietal junction but decreased in frontal regions, and connectivity between the dorsal anterior cingulate cortex and anterior insula was reduced. After training, resting-state connectivity between the pregenual anterior cingulate and dorsomedial prefrontal cortex decreased. Participants also reported significantly reduced depression and anxiety scores. These results suggest that meditation may produce antidepressant effects through neuroplastic changes in brain networks underlying affective disorders.
European Neuropsychopharmacology
March 26, 2016
Marta Valle, Ana Maqueda, Mireia Rabella et al.
175 citations
Ayahuasca, a psychoactive Amazonian tea, contains DMT and other compounds. In a double-blind, placebo-controlled study with 12 experienced users, ayahuasca reduced brain oscillations in delta, theta, and alpha frequency bands. The intensity of visual imagery correlated inversely with alpha-band current density in parietal and occipital cortex. Pretreatment with the 5-HT2A antagonist ketanserin blocked these neurophysiological changes, weakened the correlation between alpha activity and visual effects, and reduced subjective intensity. These results indicate that activation of the 5-HT2A receptor is central to ayahuasca's neurophysiological and visual effects in humans, despite the tea's chemical complexity.
Molecular Psychiatry
March 31, 2015
Jordi Riba, Marta Valle, Frederic Sampedro et al.
41 citations
Chronic cannabis users, even after a period of abstinence, are more prone to false memories—mistaking events that never occurred for real ones. Using functional magnetic resonance imaging, the study found that abstinent cannabis users showed reduced brain activity in areas critical for memory processing, including the lateral and medial temporal lobe, as well as in parietal and frontal regions involved in attention and monitoring. Cannabis consumption was inversely correlated with medial temporal lobe activity, indicating a specific detriment to episodic memory. These results suggest long-lasting impairments in memory and cognitive control mechanisms that support reality monitoring.