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Mark W. Geisler

5 papers in the library · 115 citations · publishing 2014-2025

Papers

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Psilocybin’s effect on human brain synaptic plasticity

Research Square October 10, 2025 Gitte M. Knudsen, Annette Johansen, Pontus Plavén-sigray et al. preprint

Abstract Psychedelics such as psilocybin have been linked to enhanced neuroplasticity and symptom relief in affective disorders, but the neurobiological mechanisms and impact of environmen-tal context remain unclear. Here, we tested whether a single dose of psilocybin alters synap-tic density in healthy individuals and whether setting-dependent subjective experience shapes this effect. Fifteen...

The reflexive imagery task: An experimental paradigm for neuroimaging

AIMS Neuroscience 2018 Hyein Cho, Wei Dou, Zaviera Reyes et al. 7 citations

High-level cognitions can be triggered into consciousness through the presentation of external stimuli and the activation of certain action sets. These activations arise in a manner that is involuntary, systematic and nontrivial. For example, in the Reflexive Imagery Task (RIT), subjects are presented with visual objects and instructed to not think of the names of the objects. Involuntary...

Conscious contents as reflexive processes: Evidence from the habituation of high-level cognitions.

Consciousness and Cognition April 2016 Sabrina Bhangal, Allison K Allen, Mark W. Geisler et al.

Reflexes are often insuppressible, predictable, and susceptible to external control. In contrast, conscious thoughts have been regarded as whimsical, 'offline,' and shielded from external control. Recent advances suggest that conscious thoughts are more reflex-like and susceptible to external control than previously thought. In one paradigm, high-level conscious thoughts (subvocalizations) are...

DOI: 10.1016/j.concog.2016.02.012 (opens in new tab) Full text (opens in new tab) Habituation Involuntary cognitions Ironic processing Mind wandering +1

Internally generated conscious contents: interactions between sustained mental imagery and involuntary subvocalizations.

Frontiers in Psychology December 17, 2014 Hyein Cho, Christine A. Godwin, Mark W. Geisler et al.

The conscious field includes not only representations about external stimuli (e.g., percepts), but also conscious contents associated with internal states, such as action-related intentions (e.g., urges). Although understudied, the latter may provide unique insights into the nature of consciousness. To illuminate these phenomena, in a new experimental paradigm [Reflexive Imagery Task (RIT)],...

DOI: 10.3389/fpsyg.2014.01445 (opens in new tab) Full text (opens in new tab) Consciousness Mind wandering Cognitive control Mental imagery +2

The olfactory system as the gateway to the neural correlates of consciousness

Frontiers in Psychology 2014 Christina Merrick, Christine A. Godwin, Mark W. Geisler et al. 108 citations

How consciousness is generated by the nervous system remains one of the greatest mysteries in science. Investigators from diverse fields have begun to unravel this puzzle by contrasting conscious and unconscious processes. In this way, it has been revealed that the two kinds of processes differ in terms of the underlying neural events and associated cognitive mechanisms. We propose that, for...

DOI: 10.3389/fpsyg.2013.01011 (opens in new tab) Consciousness Unconscious mind Cognition Cognitive science +2