The role of prefrontal cortex in conscious experience
The Ghost in the Shell
Subjectivity
- How does subjective experience occur at all?
Neural Mechanisms
- What are the neural events that generate conscious experience?
Scale
- What is the scale at which conscious experience emerges from biological activity?
Function
- What is the evolutionary function of conscious experience?
Detection
- How can we detect conscious experience outside of the human mind?
5 problems
Mechanisms
- How can consciousness be generated at 20 W?
Feedforward processing
- Individual frames are processed independently
Feedforward processing
- Individual frames are processed independently
Natural environments
- Individual frames are strongly autocorrelated
Feedback
- Predictive coding compresses the input and saves energy
Feedback
- There is extensive feedback connectivity within the brain
Mechanisms
Sensory Inputs
Executive Function
Attention
Experimental Dissociation
Sensory Ambiguity
Bistable Perception
Bistable Perception
Bistable Perception
Bistable Perception
Predictive Coding
Predictive Coding
Predictive Coding
Predictive Coding
Predictive Coding
Predictive Coding
Model-based fMRI
- Prediction errors are encoded in IFC and V5/hMT+.
Model-based fMRI
- Prediction errors are encoded in IFC and V5/hMT+.
Model-based fMRI
- Prediction errors are fed forward from V5/hMT+ to IFC.
Model-based fMRI
- Perceptual content can be decoded from V5/hMT+.
Model-based fMRI
- Prediction errors are generated in suppressed V5/hMT+ voxels.
Feedforward Processing
- Suppressed voxels in V5/hMT+ encode perceptual conflict.
- IFC receives feedforward information about perceptual conflict.
Feedback processing
- Is the prefrontal representation of perceptual conflict relevant for conscious experience?
- Causal intervention: theta-burst stimulation in IFC and vertex
TMS
TMS
TMS
TMS
TMS
Hybrid model
- IFC detects and resolves perceptual conflict during bistable perception.
Summary
Thanks!
Computational Psychiatry
- Are psychotic experiences linked to alterations in the processing of perceptual conflict?
Bayesian Account of Psychosis
- Imbalance between in the precision-weighting of prior an likelihood
Bayesian Account of Psychosis
- Weak vs. strong priors: Corlett et al. (TICS 2019); Sterzer et al. (Biol. Psych. 2018)
Predictive Coding
Model simulation
Computational Psychiatry
Computational Psychiatry
Computational Psychiatry
Computational Psychiatry
Summary
Thanks!
Thanks a lot for your attention!
Bibliography
Weilnhammer, Fritsch, Chikermane, Eckert, Kathak, Stuke, Sterzer. An Active Role of Inferior Frontal Cortex in Conscious Experience. Current Biology 2021.
Weilnhammer, Lukas, Eckert, Stuke, Heinz, Sterzer. Psychotic Experiences in Schizophrenia and Sensitivity to Sensory Evidence. Schizophrenia Bulletin 2020.
Weilnhammer, Stuke, Sterzer, Schmack. Hierarchical Predictions for Perceptual Decisions. Journal of Neuroscience 2018.
Weilnhammer, Stuke, Hesselmann, Sterzer, Schmack. A Predictive Coding Account of Bistable Perception. PLOS Computational Biology 2017.
Schmack, Weilnhammer, Heinzle, Stephan, Sterzer. Learning what to See in a Changing World. Frontiers in Humans Neurocience 2016.