A Deep-Dream Virtual Reality Platform for Studying Altered Perceptual Phenomenology

By: Keisuke Suzuki, Warrick Roseboom, David J. Schwartzman & Anil K. Seth

In: Nature, Scientific Reports, 7

Date: 22 November 2017

Key Concepts:

  • Altered states of consciousness (ASC):
    • Qualitative alteration in the overall pattern of mental functioning.
      • The experiencer feels their consciousness is radically different from “normal”.
    • Not defined by any particular content of consciousness.
      • Covers a wide range of qualitative properties.
      • Temporal distortion, disruptions of the self, ego-dissolution, visual distortions and hallucinations.
    • Causes of ASC.
      • Psychedelic drugs (e.g., LSD, psilocybin).
      • Pathological or psychiatric conditions such as epilepsy or psychosis.
  • Difficult to distinguish:
    • The primary causes of altered phenomenology.
    • The secondary effects of other more general aspects of neurophysiology and basic sensory processing.
  • Combine virtual reality and machine learning:
    • Isolate and simulate one specific aspect of psychedelic phenomenology: visual hallucinations.
  • Deep convolutional neural networks (DCNNs).
    • Successful in object recognition.
    • Surprising similarities with primate human brain.
      • Higher and lower layers of show similar activity patterns.
  • Deep dream:
    • “Clamping” certain parts of the neural network.
      • Adjusting the input image until the network settles into a stable state.
    • Meaning, adjusting the image until it fits previously learned categories.
      • Resulting images have hallucinatory qualities.
    • Similarities to the framework of perception as a form of predictive processing.
      • Perceptual content is determined by the exchange of:
        • Top-down perceptual predictions.
        • Bottom-up perceptual prediction errors.
      • Perceptual content is the brain’s “best guess” of the causes of its sensory input.
    • Hallucinations:
      • Imbalances between top-down perceptual predictions (prior expectations or ‘beliefs’) and bottom-up sensory signals.
  • Deep dream is similar to the imposition of a strong perceptual prior on incoming sensory data.
    • Deep Dream used to produce biologically realistic visual hallucinations.
      • Feeding this images back to humans in VR.
      • Create a “Hallucination Machine”.
        • Experience is some ways qualitatively similar to psilocybin.
          • Perceptual and imagination dimensions.
          • Patterns, imagery, strange, vivid, and space.
          • Overall intensity and emotional arousal of the experience.
        • Not sufficient to induce temporal distortions.
  • Psychedelics may work by influencing [alternating] different levels of processing.
    • Increased influence of the lower levels (less categorization influence of  higher levels).
    • Increased influence of the higher levels (over-emphasis of prediction).

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