The sketchpad model. A theory of consciousness, perception, and imagery.
E Harth
Consciousness and Cognition September 1, 1995 DOI: 10.1006/ccog.1995.1042 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Theoretical or philosophical paper Peer reviewed |
|---|---|
| Keywords | Thalamic nuclei Neural pathways Neurons Humans Brain mapping Awareness Consciousness Imagination Perception Arousal Models, neurological Neural networks, computer |
| Key points | Proposes that conscious thought is a self-referential loop of neural activity rather than the information content of a fictitious set of output neurons. The model uses feedback pathways from cortical and subcortical areas to the thalamus, where primary sensory inputs are modified through hill-climbing processes that tend to optimize global responses, avoiding both the assumption of a unifying homunculus and the denial of conscious unity. |
Abstract
Subjective consciousness suggests a unity of the sensing and perceiving self that is difficult to reconcile with the multiplicity of sensory analyzers and the absence of a convergence zone in the brain. This has led--on the one hand--to the dead-end assumption of a unifying sentient homunculus and--on the other--to a denial of conscious unity. The sketchpad model presented here avoids this dilemma by viewing conscious thought as a selfreferent loop of neural activity, rather than as the information content of a fictitious set of output neurons. Use is made of the numerous neural pathways that originate at various cortical and subcortical areas and terminate in the thalamus. The model assumes that primary sensory inputs are modified by such feedback in the thalamic relay nuclei through hill-climbing processes that tend to optimize global responses.