Lebedeva · Bulletin of experimental biology and medicine 2018 · Placebo-controlled trial · n=24

Effects of Semax on the Default Mode Network of the Brain.

Cited 6 times in the scientific literature.

Level 3 - non-randomized controlled study

Controlled trial comparing Semax to placebo; randomization is not explicitly specified in the abstract.

PubMed 30225715 · doi:10.1007/s10517-018-4234-3 · record verified 2026-08-27

What was done

Resting-state functional magnetic resonance imaging (rs-fMRI) was used to evaluate default mode network (DMN) topography in 24 healthy volunteers (11 men, 13 women, mean age 43.9 ± 9.5 years). Participants were administered intranasal 1% Semax (n = 14) or placebo (n = 10). Brain imaging was performed at three time points: immediately prior to administration, and at 5 and 20 minutes post-administration.

What was found

Participants receiving Semax exhibited a greater volume of the rostral subcomponent (medial frontal cortex) of the default mode network compared to the placebo group. The abstract did not report exact numerical effect sizes, variances, or p-values.

Why it matters

This study provides preliminary human neuroimaging evidence that intranasally administered Semax alters the functional connectivity and spatial topography of resting-state brain networks involved in default mode processing.

Limits

The study had a very small sample size (n = 24 total, with only 10 placebo controls), short observation window (up to 20 minutes post-dose), and the abstract lacks quantitative statistical values, blinding details, and explicit confirmation of randomization. Functional connectivity changes were not correlated with cognitive or behavioral outcomes.

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