The taxonomy proposed by Pessoa et al. should be extended to include “pathological” completion phenomena in patients with unilateral brain damage. Patients with visual field defects (hemianopias) may “complete” whole figures, while patients with parietal lobe damage may “complete” partial figures. We argue that the former may be consistent with the brain “filling-in” information, and the latter may be consistent with the brain ignoring the absence of information.

Mechanisms of selective attention are vital for coherent perception and action. Recent advances in cognitive neuroscience have yielded key insights into the relationship between neural mechanisms of attention and eye movements, and the role of frontal and parietal brain regions as sources of attentional control. Here we explore the growing contribution of reversible neurodisruption techniques, including transcranial magnetic stimulation and microelectrode stimulation, to the cognitive neuroscience of spatial attention. These approaches permit unique causal inferences concerning the relationship between neural processes (...) and behaviour, and have revealed fundamental mechanisms of attention in the human and animal brain. We conclude by suggesting that further advances in the neuroscience of attention will be facilitated by the combination of neurodisruption techniques with established neuroimaging methods. (shrink)

Mechanisms of selective attention exert a powerful influence on visual perception. We examined whether attentional selection is necessary for generation of the vivid colours experienced by individuals with grapheme-colour synaesthesia. Twelve synaesthetes and matched controls viewed rapid serial displays of nonsense characters within which were embedded an oriented grating (T1) and a letter-prime (T2), forming a modified attentional blink (AB) task. At the end of the stream a coloured probe appeared that was either congruent or incongruent with the synaesthetic colour (...) elicited by the letter-prime. When the prime was attended, synaesthetes showed a reliable effect of prime-probe congruency. In contrast, when the prime appeared at 350 ms following T1 (during the AB), the congruency effect was eliminated. Our findings suggest that focused attention is crucial for inducing letters to elicit colours in synaesthesia. © 2009 Elsevier B.V. All rights reserved. (shrink)