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Charles Bonnet syndrome: evidence for a generative model in the cortex?
David P Reichert1, Peggy Seriès, Amos J Storkey
1Institute for Adaptive and Neural Computation, University of Edinburgh, Edinburgh, United Kingdom. david_reichert@brown.edu
Plos Computational Biology
|July 23, 2013
Summary
Charles Bonnet syndrome (CBS) hallucinations may arise from the brain's internal generative model overcompensating for vision loss. A deep Boltzmann machine (DBM) computational model explains CBS features and suggests homeostatic plasticity's role.
Area of Science:
- Computational neuroscience
- Machine learning
- Neuroscience
Background:
- Theories suggest the cortex uses internal models for sensory data processing, prediction, and learning.
- Charles Bonnet syndrome (CBS), characterized by visual hallucinations after vision loss, offers insights into these internal models.
- The precise mechanisms underlying CBS and the brain's generative models remain poorly understood.
Purpose of the Study:
- To propose a computational model for Charles Bonnet syndrome (CBS) using machine learning.
- To investigate the role of generative models and homeostatic plasticity in the cortex.
- To explore the potential neural mechanisms underlying visual hallucinations in CBS.
Main Methods:
- Application of a deep Boltzmann machine (DBM), a type of probabilistic generative model and neural network.
- Modeling homeostatic regulation of neuronal activity as a potential mechanism for CBS.
- Simulating the DBM to explain features of CBS and the impact of sensory input degradation.
Main Results:
- Demonstrated that homeostatic plasticity can lead to hallucinations in CBS by overcompensating for sensory input loss.
- Showed that the DBM can account for a wide range of CBS features.
- Identified a potential role for the neuromodulator acetylcholine in CBS.
Conclusions:
- The deep Boltzmann machine provides a concrete computational model for Charles Bonnet syndrome.
- Results support the hypothesis of a generative model in the brain capable of synthesizing visual representations.
- Homeostatic plasticity is implicated as a key mechanism in the generation of hallucinations in CBS.
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