title: Cortical correlates of perceptual decision making during tactile spatial pattern discrimination.
abstract: Perceptual decision making involves a distributed cortical network including areas related to sensory feature extraction, decision formation, and finally signalling the decision through a motor response. Although these processing steps are supposed to occur in sequence, the seemingly instant mapping of a perceptual decision onto a motor response renders these processes almost indistinguishable. To dissociate cortical areas related to sensory decision making from areas that prepare the subsequent motor response, we performed functional magnetic resonance imaging during a tactile spatial pattern discrimination task with interleaved immediate and delayed response conditions. Decision difficulty was manipulated parametrically by adding spatial noise to the tactile patterns, resulting in a rise in decision time with increasing noise. We assumed that areas involved in making the decision should show a variation in their activation with decision time and irrespective of whether (immediate response condition) or not (delayed response condition) a motor response could be prepared in advance. To exhibit these putative decision areas, we used response time, as was obtained in the immediate response condition, as parametric predictor for the difficulty-dependent variations of blood oxygenation level-dependent (BOLD)-activity in both response conditions. BOLD activations in right (contralateral) postcentral sulcus, right intraparietal sulcus (IPS) and bilateral anterior insula (aINS) reflected this parametric modulation in both response conditions, suggesting a role of these areas in tactile decisions independent of decision-specific motor preparation. Furthermore, a multivariate pattern analysis performed on the BOLD responses in the delayed response condition for a single difficulty level independently validated IPS and aINS as decision-related areas.
authors.affiliation: MEG Center, University of Tuebingen, Tuebingen, Germany.|Institute of Medical Psychology and Behavioral Neurobiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Li Hegner
authors.affiliation: Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Tuebingen, Germany.|Werner Reichardt Centre for Integrative Neuroscience (CIN), Tuebingen, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Lindner
authors.affiliation: MEG Center, University of Tuebingen, Tuebingen, Germany.|Werner Reichardt Centre for Integrative Neuroscience (CIN), Tuebingen, Germany.|Center for Mind/Brain Sciences, University of Trento, Trento, Italy.
authors.forename: Christoph
authors.initials: C
authors.lastname: Braun
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D002560:Cerebrovascular Circulation; D003657:Decision Making / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015999:Multivariate Analysis; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010812:Physical Stimulation; D011930:Reaction Time; D012815:Signal Processing, Computer-Assisted; D013028:Space Perception; D055698:Touch Perception
chemical_list: D010100:Oxygen
keywords: BOLD; anterior insula; fMRI; human; intraparietal sulcus; multivariate decoding; posterior parietal cortex; somatosensory; tactile discrimination