Measuring acute effects of subanesthetic ketamine on cerebrovascular hemodynamics in humans using TD-fNIRS.
Adelaida Castillo, Julien Dubois, Ryan M Field, Frank Fishburn, Andrew Gundran, Wilson C Ho, Sami Jawhar, Julian Kates-Harbeck, Zahra M Aghajan, Naomi Miller, Katherine L Perdue, Jake Phillips, Wesley C Ryan, Mahdi Shafiei, Felix Scholkmann, Moriah Taylor
Scientific reports July 19, 2023 DOI: 10.1038/s41598-023-38258-8 via PubMed
Summary
AI-generated from the abstractKetamine administration in healthy participants caused an altered state of consciousness and changes in systemic physiology, including increased pulse rate and electrodermal activity. The drug led to a brain-wide reduction in the fractional amplitude of low frequency fluctuations and decreased global brain connectivity in the prefrontal region. Preliminary evidence suggests that a combination of neural and physiological metrics may predict subjective mystical experiences and reductions in depressive symptoms. The study demonstrates the successful use of fNIRS neuroimaging to measure physiological effects of ketamine in a clinical setting, representing a step toward larger clinical fNIRS studies of psychedelics.
Study at a glance
| Characteristics | Single-blind, placebo-controlled study with a non-randomized design Peer reviewed |
|---|---|
| Sample size | 15 |
| Population | Healthy participants (8 females, 7 males, age 32.4 ± 7.5 years) |
| Interventions | Ketamine Placebo (saline) |
| Dose | 0.75 mg/kg |
| Citations | 19 |
| Key finding | Ketamine caused a brain-wide reduction in fractional amplitude of low frequency fluctuations and decreased global brain connectivity in the prefrontal region, along with altered consciousness and physiological changes. |
Abstract
Quantifying neural activity in natural conditions (i.e. conditions comparable to the standard clinical patient experience) during the administration of psychedelics may further our scientific understanding of the effects and mechanisms of action. This data may facilitate the discovery of novel biomarkers enabling more personalized treatments and improved patient outcomes. In this single-blind, placebo-controlled study with a non-randomized design, we use time-domain functional near-infrared spectroscopy (TD-fNIRS) to measure acute brain dynamics after intramuscular subanesthetic ketamine (0.75 mg/kg) and placebo (saline) administration in healthy participants (n = 15, 8 females, 7 males, age 32.4 ± 7.5 years) in a clinical setting. We found that the ketamine administration caused an altered state of consciousness and changes in systemic physiology (e.g. increase in pulse rate and electrodermal activity). Furthermore, ketamine led to a brain-wide reduction in the fractional amplitude of low frequency fluctuations, and a decrease in the global brain connectivity of the prefrontal region. Lastly, we provide preliminary evidence that a combination of neural and physiological metrics may serve as predictors of subjective mystical experiences and reductions in depressive symptomatology. Overall, our study demonstrated the successful application of fNIRS neuroimaging to study the physiological effects of the psychoactive substance ketamine in humans, and can be regarded as an important step toward larger scale clinical fNIRS studies that can quantify the impact of psychedelics on the brain in standard clinical settings.