title: Neural correlates of binding features within- or cross-dimensions in visual conjunction search: an fMRI study.
abstract: The fMRI technique was used to investigate the functional neuroanatomy of binding features within- or cross-dimension during visual conjunction search. Participants were asked to perform feature search (FS; e.g., search for a vertical bar among tilted bars), within-dimension search (WS; e.g., search for an upright T among non-target oriented Ts and Ls), cross-dimension search (CS; e.g., search for an orange vertical bar among blue vertical bars and orange tilted bars), and complex search combining within- and cross-dimension features (WCS; e.g., search for an orange upright T among orange leftward Ts and blue Ls). Reaction times (RTs) taken to decide whether a target was present or absent were faster in the FS than in the WS, CS, and WCS conditions, but did not differ between the latter three conditions. Neuroimaging results revealed a set of fronto-parietal regions, including frontal eye field and intraparietal sulcus, to be consistently activated in conjunction search (WS, CS, and WCS) relative to feature search, suggesting that these regions play a more prominent role in matching visual input against the target template in conjunction search. Furthermore, left occipito-temporal cortex was more activated in within-dimension conjunction search, and bilateral intraparietal sulci were more activated in cross-dimension conjunction search. This suggests that features from the same dimension are 'bound' at a higher stage of the ventral pathway by conjoining the inputs from lower-level neurons, whereas neurons along the intraparietal sulcus appear to be necessary for discerning the presence of cross-dimensional conjunctions.
authors.affiliation: Beijing Key Laboratory of Learning and Cognition and Department of Psychology, Capital Normal University, Beijing 100048, China; Center for Brain and Cognition Sciences and Department of Psychology, Peking University, Beijing 100871, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wei
authors.affiliation: Department of Psychology, LMU München, D-80802 München, Germany.
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Müller
authors.affiliation: Center for Behavioral Brain Sciences and Department of Experimental Psychology, Otto-von-Guericke-University Magdeburg, D-39016 Magdeburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pollmann
authors.affiliation: Center for Brain and Cognition Sciences and Department of Psychology, Peking University, Beijing 100871, China; Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, China. Electronic address: xz104@pku.edu.cn.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult