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Lilach Shalev, Carmel Mevorach, Harriet Allen, Glyn Humphreys; Dissociating the cognitive mechanisms of sustained attention and response inhibition: An fMRI study using a conjunctive go/no-go task. Journal of Vision 2007;7(9):182. doi: 10.1167/7.9.182.
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© ARVO (1962-2015); The Authors (2016-present)
In many aspects of everyday life we have to sustain out attention across time to detect low probability targets, whilst concurrently we must refrain from responding to irrelevant stimuli that nevertheless have a high frequency of occurrence. Previous studies have conflated these two aspects of performance, making it difficult to distinguish the underlying neural substrates. Using an experimental procedure to separate out sustained attention and response inhibition, we fractionated the neural circuits supporting the underlying cognitive mechanisms. Event-related fMRI data were acquired during a go/no-go task where target-and distractor-frequencies were manipulated. Neural processes involved in sustaining attention were revealed by a conjoint analysis of areas activated independently for ‘go’ and no-go’ events when targets were frequent relative to when they were infrequent. This revealed reliable activations in a network of cortical and sub-cortical areas primarily in the right hemisphere. Neural processes underlying the cognitive process involved in response inhibition were shown by subtracting the activation associated with ‘no-go’ events when targets were infrequent relative to when they were frequent. This isolated activation in the right inferior parietal lobe. The proposed distinction between sustained attention and response inhibition was supported by analyses of the time course of the haemodynamic response. We propose that sustaining attention over time is accomplished by a distributed cortical and sub-cortical network which is activated throughout the task in hand, while cognitive mechanisms involved in response inhibition are associated with the right inferior parietal lobe. The work suggests that response inhibition can be decomposed, separating cognitive from motor mechanisms.
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