TABLE 2.

Summary of neurophysiology studies.

References	Pre-registration?	Treatment	Control	Sample size	Observed post-dosing effect	P-value	Effect size	# of studies reporting consistent findings	# of studies reporting inconsistent findings	Strengths	Limitations
Carhart-Harris et al. (12)	No	LSD in saline (75 μg/10 mL)	10 mL saline	20	Increased CBF in visual cortex associated with decreased alpha power in OC	0.029	NA	0	0	Motion correction took place for analyses of neuroimaging data making it robust	Not performed as a double blind RCT. Performance of neuroimaging techniques at separate times.
					Decreased alpha power associated with hallucinations	<0.05	NA	2	0
Muthukumaraswamy et al. (89)	No	Psilocybin in saline (2 mg/10 mL)	Saline	15	Reduction in oscillatory power in delta, gamma, alpha, beta, and theta bands	<0.05	NA	3	0	Robust statistical analyses of measures. Vast neuroimaging data collected	Low generalizability to population of those that have no experience using psychedelic drugs. Removal of MEG data due to head movement. Small sample size.
Murray et al. (87)	No	Two LSD sessions (13 μg and 26 μg)	Water	22	Reduction in oscillatory power in delta, gamma, alpha, beta, and theta in MPC, PCC, TPC	<0.05	NA	3	0	Blinded study with participants acting as their own controls. Robust EEG data collected	Affected brain structures were inferred from the location in which the extra cranial electrodes were located. Small sample size.
Riba et al. (86)	No	Two doses of Ayahausca (0.6 mg DMT Kg–1, 0.85 mg DMT Kg–1)	Water	18	Decreased absolute power of theta, delta, alpha, and beta	<0.05	NA	3	0	Blinding and placebo control were used while participants acted as their own controls.	Small sample size
Kometer et al. (88)	No	Placebo with ketanserin 50 mg, and placebo with psilocybin (215 μg/kg)	Placebo	17	Decrease in alpha power in POC after pretreatment with placebo	<0.01	NA	1	0	Blinding and placebo control were used while participants acted as their own controls. Validated measures used such as SCID	Small sample size

This table highlights the main studies into psilocybin-assisted therapy and neurophysiological outcomes reviewed. Brain regions are signified by their abbreviations; CBF, cerebral blood flow; PC, posterior cingulate cortex; MPC, medial prefrontal cortex; TPC, tempo parietal cortex; POC, parieto-occipital cortex; OC, occipital cortex. The column titled “# of studies reporting effect” refers to the number of studies reviewed which reported findings that are consistent with the post-dosing effect observed in each main neurophysiology study included in the table. Similarly, the column “# of studies reporting contrary” refers to the number of studies reviewed which report findings that are contradictory to the effect observed in each main neurophysiology study. NA signifies information pertaining to effect sizes is unavailable.