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Knopfel, T.

Publications and source records attributed to Knopfel, T..

3 recordsLinked to original sources

Psychedelic 5-HT2A agonist increases spontaneous and evoked 5-Hz oscillations in visual and retrosplenial cortex

Visual perception appears largely stable in time. However, psychophysical studies have revealed that theta waves (4-8 Hz) can modulate perception and have been linked to various cognitive states and functions. Neither the contribution of theta waves to cortical activity nor their impact during aberrant brain states have been resolved at high spatiotemporal scales. Here, using cortex-wide population voltage imaging in awake mice, we found that bouts of 5-Hz oscillations in the visual cortex are accompanied by similar oscillations in the retrosplenial cortex, occurring both spontaneously and evoked by visual stimulation. Injection of psychotropic 5-HT2AR agonist induced a significant increase in spontaneous 5-Hz oscillations, and also increased the power, occurrence probability and temporal persistence of visually evoked 5-Hz oscillations. This modulation of 5-Hz oscillations in both cortical areas indicates a strengthening of top-down control of perception, supporting an underlying mechanism of perceptual filling and visual hallucinations.

neuroscience↗

Lasting effect of psilocybin on sociability can be blocked by DNA methyltransferase inhibition

The recent renaissance in research on psychedelics such as psilocybin has highlighted their therapeutic potential including their lasting influences on brain function. Here we report that a single systemic administration of the serotonergic psychedelic psilocybin can durably promote social behaviour in the Cntnap2-knockout mouse model of autism. This effect can be blocked by pharmacological inhibition of DNA methyltransferase I, indicating an epigenetic mechanism underlying the long-lasting effect of psilocybin.

neuroscience↗

Bright near-infrared genetically encoded voltage indicator for all-optical electrophysiology

We developed genetically encoded voltage indicators (GEVIs) using bright near-infrared (NIR) fluorescent proteins from bacterial phytochromes. These new NIR GEVIs are optimized for combination of voltage imaging with simultaneous blue light optogenetic actuator activation. Iterative optimizations led to a GEVI here termed nirButterfly, which reliably reports neuronal activities including subthreshold membrane potential depolarization and hyperpolarization, as well as spontaneous spiking, or electrically- and optogenetically-evoked action potentials. This enables largely improved all-optical causal interrogations of physiology.

neuroscience↗