Blindsight, the ability to respond to supraliminal visual stimuli despite extensive primary-visual (V1) damage and reports of them as unseen, is central to theories of phenomenal consciousness. However, one phenomenon has not yet been considered in any theory: Pavlovian blindsight. In this phenomenon, subjects that have such a lesion receive pairings of an initially neutral visual conditioned stimulus (CS) and an unconditioned stimulus that initially elicits a similar unconditioned response (UR). After a number of pairings, and despite the lesion, the CS comes to evoke an appropriate conditioned response that is similar to the UR. This phenomenon implies a possible role of associative learning in phenomenal consciousness. I propose a theoretical account of this phenomenon by applying an existing neural network model of conditioning to the influential two-stream hypothesis of visual organization. On this hypothesis, V1 projects to the posterior parietal (dorsal) and inferotemporal cortices (ventral). The former also receives projections from the pulvinar, which allows for a V1-independent visual control, characteristic of blindsight. Artificial neural networks were designed after this hypothesis, according to the model. A network with pulvinar and without V1 inputs could simulate Pavlovian blindsight. Implications for the role of associative learning in phenomenal consciousness are discussed.
Neuroscience and Behavior e-session
Photos by : David Rytell