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The role of prestimulus activity in visual extinction.

Urner, M; Sarri, M; Grahn, J; Manly, T; Rees, G; Friston, K; (2013) The role of prestimulus activity in visual extinction. Neuropsychologia , 51 (8) pp. 1630-1637. 10.1016/j.neuropsychologia.2013.05.005. Green open access

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Abstract

Patients with visual extinction following right-hemisphere damage sometimes see and sometimes miss stimuli in the left visual field, particularly when stimuli are presented simultaneously to both visual fields. Awareness of left visual field stimuli is associated with increased activity in bilateral parietal and frontal cortex. However, it is unknown why patients see or miss these stimuli. Previous neuroimaging studies in healthy adults show that prestimulus activity biases perceptual decisions, and biases in visual perception can be attributed to fluctuations in prestimulus activity in task relevant brain regions. Here, we used functional MRI to investigate whether prestimulus activity affected perception in the context of visual extinction following stroke. We measured prestimulus activity in stimulus-responsive cortical areas during an extinction paradigm in a patient with unilateral right parietal damage and visual extinction. This allowed us to compare prestimulus activity on physically identical bilateral trials that either did or did not lead to visual extinction. We found significantly increased activity prior to stimulus presentation in two areas that were also activated by visual stimulation: the left calcarine sulcus and right occipital inferior cortex. Using dynamic causal modelling (DCM) we found that both these differences in prestimulus activity and stimulus evoked responses could be explained by enhanced effective connectivity within and between visual areas, prior to stimulus presentation. Thus, we provide evidence for the idea that differences in ongoing neural activity in visually responsive areas prior to stimulus onset affect awareness in visual extinction, and that these differences are mediated by fluctuations in extrinsic and intrinsic connectivity.

Type: Article
Title: The role of prestimulus activity in visual extinction.
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.neuropsychologia.2013.05.005
Publisher version: http://dx.doi.org/10.1016/j.neuropsychologia.2013....
Language: English
Additional information: This work is licensed under the Creative Commons Attribution License, Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/ which permits unrestricted use, distribution, and reproduction in any medium. However, you must attribute the work to the author (but not in any way that suggests that they endorse you or your use of the work).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Imaging Neuroscience
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1393930
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