Scientific Reports
August 2, 2013
Fábio V. Caixeta, Alianda Maira Cornélio, Robson Scheffer-Teixeira et al.
134 citations
Blocking NMDA receptors with ketamine alters how different brain rhythms interact in the hippocampus, a region critical for memory and attention. In awake rats, ketamine (25, 50, and 75 mg/kg) increased fast brain oscillations (gamma and high-frequency oscillations) across all layers of the CA1-dentate axis, while changes in slower theta waves depended on location. Ketamine also increased phase coherence of fast oscillations across hippocampal layers. The coupling between theta waves and fast oscillations changed in a dose-dependent way: theta-high-frequency coupling increased at all doses, but theta-gamma coupling increased only at the lowest dose and was disrupted at the highest dose. These findings indicate that NMDA receptor blockade disrupts neural coordination patterns linked to cognitive functions impaired in schizophrenia.
ACS Pharmacology & Translational Science
April 9, 2021
Joaquín González, Matías Cavelli, Santiago Castro-Zaballa et al.
26 citations
Ibogaine, a psychedelic alkaloid with anti-addictive potential, produces vivid, dream-like experiences while awake. Analyzing intracranial electroencephalograms in rats, ibogaine-induced wakefulness showed gamma oscillations with greater power than control levels but reduced coherence and complexity. This gamma activity profile resembled that of natural REM sleep, providing biological evidence linking the psychedelic state to REM sleep and advancing understanding of ibogaine's oneirogenic effects.
Scientific Reports
May 17, 2024
Annie C. Souza, Bryan C. Souza, Arthur França et al.
7 citations
The psychedelic 5-MeO-DMT alters brain activity in rats by increasing delta waves and decreasing theta waves in the hippocampus, changes that are not explained by movement. It also reduces slow and mid gamma power and disrupts theta phase modulation. The overall brain state resembles patterns seen during slow-wave sleep and REM sleep, suggesting that the drug's effects involve mixing waking behavior with sleep-like neural oscillations.
Scientific Reports
May 25, 2025
Jurij Brankačk, Yevgenij Yanovsky, Adriano B. L. Tort et al.
6 citations
Slow oscillations in the brain’s parietal cortex during urethane anesthesia differ fundamentally from those during natural non-REM sleep in mice, despite appearing similar on the surface. Differences are evident in the local field potential, the underlying current sources, and the modulation of unit activity. The data show that slow network oscillations in natural sleep and anesthesia are generated by different mechanisms, challenging the assumption that anesthesia reliably models sleep-related brain activity. This work highlights that phenomenological similarities can mask distinct neural processes, with implications for using anesthesia as a model for sleep and consciousness studies.
bioRxiv (Cold Spring Harbor Laboratory)
June 29, 2020
Joaquín González, Matías Cavelli, Santiago Castro-Zaballa et al.
5 citations
preprint
Ibogaine, a psychedelic alkaloid with anti-addictive properties, produces a waking state that shares brain-wave traits with REM sleep. In rats, ibogaine increased gamma oscillation power in the brain but made those oscillations less coherent and less complex than normal waking levels. This pattern mirrors REM sleep features within the gamma frequency band, providing biological evidence for the long-standing hypothesis that ibogaine induces a dream-like state while awake—a phenomenon called oneirogenesis. The findings offer an empirical basis for understanding how ibogaine's unique subjective effects may contribute to its anti-addictive potential.
Behavioural Brain Research
January 5, 2025
Santiago Castro-Zaballa, Joaquín González, Matías Cavelli et al.
4 citations
In cats, high-frequency oscillations (HFO, >100 Hz) in the brain's electrical activity are linked to breathing during wakefulness but not during sleep. A sub-anesthetic dose of ketamine increases the power of these HFO, and they remain tied to the inhalation phase of respiration. The enhanced HFO appear to originate in the olfactory bulb and travel to the prefrontal cortex. Blocking the nostrils reduces the ketamine-enhanced HFO in both regions. Auditory stimulation does not affect these oscillations. The findings suggest that ketamine's enhancement of respiration-coupled HFO may disrupt cortical information processing, potentially contributing to its neuropsychiatric effects.
Scientific Reports
July 14, 2024
Annie C. Souza, Bryan C. Souza, Arthur França et al.
1 citation
No Summary
bioRxiv (Cold Spring Harbor Laboratory)
June 5, 2023
Annie Da Costa Souza, Bryan Da Costa Souza, Arthur França et al.
preprint
The psychedelic 5-MeO-DMT increases delta power and decreases theta power in the hippocampus of freely moving rats, effects not explained by changes in locomotion. It also dose-dependently reduces slow and mid gamma power and theta phase modulation. The overall spectral profile of awake behavior after 5-MeO-DMT resembles electrophysiological states seen during slow-wave sleep and REM sleep. These findings suggest that classical psychedelics may integrate waking behaviors with sleep-like neural activity patterns.