Neuroimage
May 1, 2020
Matthew I Banks, Bryan M Krause, Christopher M Endemann et al.
78 citations
Disruption of cortical connectivity likely contributes to loss of consciousness during sleep and general anesthesia, but the degree of overlap in mechanisms is unclear. Using intracranial recordings from five adult neurosurgical patients, alpha-band connectivity (measured by weighted phase lag index) was compared across natural sleep stages and propofol anesthesia. In wake states, alpha-band connectivity within the temporal lobe was dominant, a pattern largely unchanged in light sleep (N1, REM) and sedated states. Transitions into states of reduced consciousness (deep sleep N2/N3 and anesthesia-induced unresponsiveness) showed dramatic shifts, with dominant connections moving to prefrontal cortex. The findings suggest common mechanisms of loss of consciousness in sleep and anesthesia.
Translational Psychiatry
September 12, 2024
Christopher R. Nicholas, Matthew I Banks, Richard C Lennertz et al.
10 citations
Psilocybin, a serotonergic psychedelic, can relieve symptoms in several psychiatric disorders and improve well-being, but it was unclear whether these benefits arise during the acute experience or depend on later memory of it. In 8 healthy participants, psilocybin (25 mg) was co-administered with the amnestic benzodiazepine midazolam at a dose that allowed a conscious psychedelic experience while partially impairing memory for it. Higher midazolam doses and greater memory impairment tended to associate with lower salience, insight, and well-being from psilocybin. These results suggest memory plays a role in therapeutically relevant behavioral effects of psilocybin.
Psychedelic medicine (New Rochelle, N.Y.)
September 1, 2024
Zarmeen Zahid, Ziyad W. Sultan, Bryan M Krause et al.
5 citations
In mice, the serotonergic psychedelic DOI, but not ketamine, enhanced neural plasticity and metaplasticity in the hippocampus 24 hours after a single dose. Brain slices from DOI-treated animals showed stronger synaptic responses and short-term potentiation compared to saline-treated controls, with evidence that these effects involve a presynaptic mechanism. Ketamine did not produce similar changes. These findings suggest that the therapeutic benefits of serotonergic psychedelics may be supported by a window of heightened neural plasticity, whereas ketamine's effects may rely on different mechanisms.
bioRxiv (Cold Spring Harbor Laboratory)
June 13, 2024
Christopher R. Nicholas, Matthew I. Banks, Richard C Lennertz et al.
3 citations
preprint
Co-administering the amnestic benzodiazepine midazolam with psilocybin in 8 healthy participants partially impaired memory for the psychedelic experience while still allowing a conscious experience to occur. The degree of memory impairment was inversely associated with salience, insight, and well-being induced by psilocybin. These results suggest that memory of the acute psychedelic experience contributes to therapeutically relevant behavioral effects. Because midazolam blocks memory by blocking cortical neural plasticity, it may also help evaluate how the pro-neuroplastic properties of psychedelics contribute to their therapeutic activity.
bioRxiv (Cold Spring Harbor Laboratory)
July 29, 2025
May Kung Sutherland, Christopher R. Nicholas, Richard C Lennertz et al.
preprint
Psilocybin, a serotonergic psychedelic, induces neural plasticity and alters consciousness, while midazolam, a benzodiazepine, blunts plasticity and causes sedation and amnesia. In an open-label pilot study, 25 mg of oral psilocybin was given alongside intravenous midazolam at doses that allowed a full psychedelic experience but reduced memory of it. EEG recordings showed that 15-30 minutes after dosing, when midazolam was at its target concentration, beta power increased and the spectral exponent decreased. As psilocybin's effects emerged over the next six hours, Lempel-Ziv complexity and spectral exponent increased while broadband power decreased. These findings suggest psilocybin's effects persist even with midazolam, supporting its use in mechanistic studies.
Translational Psychiatry
February 14, 2026
Michael H Sutherland, Christopher R. Nicholas, Richard C Lennertz et al.
Psilocybin, a serotonergic psychedelic, induces neural plasticity and alters consciousness, while midazolam, a benzodiazepine, blunts plasticity and induces sedation. In an open-label pilot study, 25 mg of oral psilocybin was given alongside intravenous midazolam at doses that allowed a full psychedelic experience but blunted memory. Electroencephalography (EEG) data showed that 15–30 minutes after dosing, when midazolam was at its target concentration, beta power increased and spectral exponent decreased. As psilocybin's effects emerged over the next six hours, Lempel-Ziv complexity and spectral exponent increased, while broadband power decreased, especially in delta, theta, and alpha bands. The findings suggest psilocybin's effects persist with midazolam, supporting its use in mechanistic studies.
Cerebral cortex (New York, N.Y. : 1991)
August 23, 2023
Bryan M Krause, Declan I Campbell, Christopher K Kovach et al.
Theories of consciousness propose that brain mechanisms for losing and regaining consciousness are similar regardless of cause. Using intracranial electroencephalography in neurosurgical patients during propofol anesthesia and overnight sleep, researchers found strikingly similar reorganization of cortical networks. Effective dimensionality of functional connectivity decreased during reduced consciousness (anesthesia unresponsiveness, N2 and N3 sleep), indicating lower network complexity. These changes were global, not region-specific. Brain regions became more functionally distant yet individual recording sites closer to nearest neighbors, reflecting decreased differentiation and integration. This network reorganization constitutes a common neural signature of reduced consciousness across anesthesia and sleep, providing a framework for understanding neural correlates of consciousness.