The role of the angular gyrus in visual conjunction search investigated using signal detection analysis and transcranial magnetic stimulation

• Published in: Neuropsychologia Vol. 46; no. 8; pp. 2198 - 2202
• Main Authors: Muggleton, Neil G., Cowey, Alan, Walsh, Vincent
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2008; Elsevier Science
• Subjects: Adult; Analysis of Variance; Anatomical correlates of behavior; Attention - physiology; Behavioral psychophysiology; Biological and medical sciences; Brain Mapping; Conjunction search; Decision Making; Electric Stimulation; Female; Field Dependence-Independence; Functional Laterality; Fundamental and applied biological sciences. Psychology; Humans; Male; Parietal Lobe - physiology; Perception; Photic Stimulation - methods; Posterior parietal cortex; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reaction Time - physiology; Signal detection theory; Signal Detection, Psychological; Task Performance and Analysis; Transcranial magnetic stimulation; Transcranial Magnetic Stimulation - methods; Vision; Signal detection theory; Transcranial magnetic stimulation; Conjunction search; Posterior parietal cortex; Human; Angular gyrus; Theory; Central nervous system; Cognition; Psychophysics; Encephalon; Visual search; Vision; Parietal cortex; Perception; Signal detection
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2008.02.016

Transcranial magnetic stimulation (TMS) delivered over the posterior parietal cortex increases choice reaction times in visual search for a target defined by a conjunction of features. Some recent studies of visual search have taken an approach based on signal detection theory, the findings of which are not addressed by studying the disruptive effects of TMS on reaction time. Here we investigated the role of the posterior parietal cortex in visual search by applying TMS while subjects performed unspeeded feature and conjunction visual search tasks matched for level of difficulty. TMS over the right, but not the left angular gyrus (AG) in the parietal cortex, nor vertex decreased subjects’ sensitivity on the conjunction but not the feature search task, as measured by the signal detection measure, d′. Changes in bias, specifically the tendency to make false positive responses, were less clear. We consider the findings in terms of four possible explanation: binding, attentional control, spatial localisation and visuomotor co-ordinate transformations.