Abstract This chapter presents findings indicating that psilocybin-induced visual distortions and impaired executive functioning originate in temporary disruptions of attentional mechanisms. It then revisits a predictive processing account of neural processing and argues that this lacks the resources to provide a unified model of the perceptual mechanisms underpinning psychedelic experiences...
Traditionally, philosophers have appealed to the phenomenological similarity between visual experience and visual imagery to support the hypothesis that there is significant overlap between the perceptual and imaginative domains. The current evidence, however, is inconclusive: while evidence from transcranial brain stimulation seems to support this conclusion, neurophysiological evidence from...
This chapter considers some implications of broad principles of the neural architecture and neural coding of information in the visual system. J. H Reynolds and R. Desimone suggest that attentional shrinkage of receptive fields around attended objects serves to solve the binding problem. Attention serves to optimise the veridicality of responses of cells involved in coding complex properties of...
The most central metaphysical question about phenomenal consciousness is that of what constitutes phenomenal consciousness, whereas the most central epistemic question about consciousness is that of whether science can eventually provide an explanation of the phenomenon. Many philosophers have argued that science doesn’t have the means to answer the question of what consciousness is (the...
Blindsight is a kind of residual vision found in people with lesions to V1. Subjects with blindsight typically report no visual awareness, but they are nonetheless able to make above-chance guesses about the shape, location, color and movement of visual stimuli presented to them in their blind field. A different kind of blindsight, sometimes called type 2 blindsight, is a kind of residual...
Though synesthesia research has seen a huge growth in recent decades, and tremendous progress has been made in terms of understanding the mechanism and cause of synesthesia, we are still left mostly in the dark when it comes to the mechanistic commonalities (if any) among developmental, acquired and drug-induced synesthesia. We know that many forms of synesthesia involve aberrant structural or...
David Milner and Melvyn Goodale's dissociation hypothesis is commonly taken to state that there are two functionally specialized cortical streams of visual processing originating in striate (V1) cortex: a dorsal, action-related "unconscious" stream and a ventral, perception-related "conscious" stream. As Milner and Goodale acknowledge, findings from blindsight studies suggest a more...