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.
- Qualitative alteration in the overall pattern of mental functioning.
- 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.
- Perceptual content is determined by the exchange of:
- Hallucinations:
- Imbalances between top-down perceptual predictions (prior expectations or ‘beliefs’) and bottom-up sensory signals.
- “Clamping” certain parts of the neural network.
- 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.
- Experience is some ways qualitatively similar to psilocybin.
- Deep Dream used to produce biologically realistic visual hallucinations.
- 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).