Non-spatial extinction following lesions of the parietal lobe in humans (1994)

To date, the conjecture that front parietal regions serve as control sites sending signals to perceptual areas to implement attentional selection is mainly based on correlatory brain imaging data in humans. This chapter provides direct evidence that the ability to ignore salient visual distractors is contingent on a neural circuit involving both the left IPS and occipital pole. It suggests that the IPS acts to down regulate an occipital response when salient distractors have to be ignored, which in turn prevents a bottom-up orienting response to salience. The present findings also suggest that problems in suppressing irrelevant but salient stimuli, found after brain lesions may be linked to various neuroanatomical loci including the following: abnormalities in the left IPS itself, decreases in effective connectivity between the left IPS and visual cortex, or even heightened activity in the occipital pole.