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Fields, C. W.

Publications and source records attributed to Fields, C. W..

2 recordsLinked to original sources

The impact of the serotonergic psychedelic DOI on active vision in freely moving mice

Psychedelics offer a unique opportunity to investigate the neural mechanisms governing both normal and altered perceptual states, yet relatively little is known about their impact on visual processing at the level of neural coding, particularly in the context of active vision. Here we examined how the serotonergic psychedelic DOI (2,5-dimethoxy-4-iodoamphetamine) influences neural activity within the visual cortex (V1) of freely moving mice engaged in naturalistic vision. Previous work has demonstrated that, under normal conditions, gaze shifts trigger a temporal sequence in V1 that encodes visual information in a coarse-to-fine sequence. Here we found that DOI had a diverse and temporally dynamic impact on response amplitudes across this sequence -- while net population-level firing was modestly suppressed, individual neurons showed large increases or decreases in their gaze shift responses. Strikingly, this bidirectional modulation was correlated with gaze-shift response latency. DOI had mixed effects on short latency, low spatial frequency preferring neurons, but became increasingly suppressive across the sequence, ultimately suppressing nearly all long latency, high spatial frequency preferring neurons. These findings demonstrate how psychedelics disrupt naturalistic visual processing and support a framework in which visual hallucinations result from an imbalance in coarse and fine input integration during active vision. HighlightsO_LIWe recorded neural activity from V1 of freely moving mice before and after administration of the psychedelic DOI. C_LIO_LIDOI had diverse effects on visual response amplitude following a gaze shift, with some neurons increasing while others decreased. C_LIO_LIThe modulation of responses was temporally dynamic, shifting across the response sequence. C_LIO_LILonger latency neurons, which preferentially encode high spatial frequency information, were more consistently suppressed C_LIO_LITogether these effects result in a disruption of population response and coarse-to-fine processing, providing potential mechanisms for altered visual perception C_LI

neuroscience↗

Psychedelic-mediated Reversal of General Anesthesia and Restoration of Brain Dynamics in Rat

Serotonergic psychedelics enhance neurophysiological complexity and the repertoire of brain states, whereas general anesthetics produce opposite effects. Serotonergic psychedelics are also known to increase wakefulness and reduce sleep time in rodents. Therefore, we hypothesized that 2,5-dimethoxy-4-iodopamphetamine (DOI), a serotonergic psychedelic, will reverse general anesthesia and restore neurophysiological conditions associated with normal wakefulness. We demonstrate that intravenous administration of DOI in rats under general anesthesia induced wakefulness despite ongoing delivery of the anesthetics, propofol or isoflurane. Behavioral arousal was accompanied by recovery of directional and non-directional high gamma (125-165Hz) functional connectivity and restoration of functional brain network structure. These behavioral and neurophysiological effects were blocked by a 5-HT2A antagonist, volinanserin. Intravenous administration of a non-psychedelic 5-HT2A agonist, lisuride, failed to restore wakefulness or brain dynamics in anesthetized rats. To our knowledge, these results provide the first evidence of psychedelic-mediated reversal of general anesthesia and concurrent restoration of brain dynamics associated with normal wakefulness.

neuroscience↗