Multistable perception—where sensory ambiguity causes spontaneous alternations between two or more perceptual interpretations—occurs across many animal species. This review covers research on visual perceptual rivalry in insects, fish, reptiles, and primates, highlighting binocular rivalry and the Necker cube as examples. Common behavioral indicators of perceptual alternation appear across species. The comparative approach offers insights into how brains suppress conflicting sensory signals and generate shifts in perceptual dominance, suggesting that ambiguous sensation is a fundamental problem that has shaped brain evolution.
Benchtop NMR spectroscopy at 60 MHz can distinguish seven members of the 2C-X series of new psychoactive substances (2C-B, 2C-C, 2C-D, 2C-E, 2C-P, 2C-T2, and 2C-T7) based on their proton NMR spectra. The molecular structural relationships among these compounds are reflected in their spectral patterns, supporting the use of portable benchtop NMR instruments for forensic drug identification.
A structural approach to studying consciousness maps mathematical descriptions of qualia—the qualitative aspects of conscious experience—onto mathematical structures derived from brain activity and neuronal connectivity, aiming for general mappings akin to physical laws like E=mc². This review surveys literature from psychophysics and the neuroscience of consciousness, critically examines classical models such as Shepard's pitch helix and visual color space, and explores the structure of their neuronal correlates. It extends analysis to visual similarity spaces, including face space and general image spaces, and suggests that exact experimental comparisons yield an enriched psychophysics that expands single-valued measures into richer scientific exploration.
A method for measuring MDMA content in ecstasy tablets using a compact 60 MHz benchtop NMR spectrometer was validated against UNODC guidelines. The method showed good specificity, selectivity, linearity, precision, and accuracy. Among seized tablets, the lowest MDMA free base detected was 9.35 mg in a piperazine mix, and the highest was 237.55 mg. The median MDMA amount in 2022 was 9.1% lower than pre-pandemic 2019 data but still higher than the 105 mg median reported in 2018. Within-batch variation was insignificant for one seizure but greater for another, indicating a single tablet's content may not represent the whole batch. The upward dosage trend underscores the need for ongoing monitoring and prevention interventions.