Our visual world is filled with clusters (or ensembles) of objects. For many visual tasks, such as attending and selecting specific objects for thoughts or actions, we need to individuate and encode distinctive features from single objects. Such object-specific processing has been the core of cognitive and neuroscientific research for the past few decades. In contrast, there are also ample occasions when our visual system extracts summary statistics from an object ensemble without representing each object in the ensemble in great detail. Such object-ensemble representation can help us rapidly segment an otherwise crowded visual scene and allow us to zoom in on specific objects of interest. Object-ensemble representation thus complements and guides object- specific processing and allows our visual system to overcome the capacity limitation of object-specific processing. Yet despite the common occurrence of object ensembles in our visual world, the cognitive and neural mechanisms underlying object-ensemble processing remains poorly understood. Using fMRI, this proposal will first identify where in the human brain object ensembles are represented, under what attentional condition this representation can be formed, and then examine the nature of the neural object ensemble representation by studying how mean and variance of ensemble features are represented. The proposed studies will be one of the first to systematically investigate how real world object ensembles are processed in the human brain. Besides furthering our understanding of the connection between brain and behavior, results of these studies will have significant impact on current cognitive and neural theories on visual object perception.
The proposed research will help us understand the various constrains and limitations in normal visual cognition. It also has significant implications for understanding the impact of brain damage on visual object perception and recognition.
|Jeong, Su Keun; Xu, Yaoda (2016) Behaviorally Relevant Abstract Object Identity Representation in the Human Parietal Cortex. J Neurosci 36:1607-19|
|Bettencourt, Katherine C; Xu, Yaoda (2016) Decoding the content of visual short-term memory under distraction in occipital and parietal areas. Nat Neurosci 19:150-7|
|Jeong, Su Keun; Xu, Yaoda (2016) The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex. J Vis 16:2|
|Zhang, Jiedong; Liu, Jia; Xu, Yaoda (2015) Neural decoding reveals impaired face configural processing in the right fusiform face area of individuals with developmental prosopagnosia. J Neurosci 35:1539-48|
|Cant, Jonathan S; Xu, Yaoda (2015) The Impact of Density and Ratio on Object-Ensemble Representation in Human Anterior-Medial Ventral Visual Cortex. Cereb Cortex 25:4226-39|
|Cant, Jonathan S; Sun, Sol Z; Xu, Yaoda (2015) Distinct cognitive mechanisms involved in the processing of single objects and object ensembles. J Vis 15:12|
|Xu, Yaoda (2014) Inferior frontal junction biases perception through neural synchrony. Trends Cogn Sci 18:447-8|
|Bettencourt, Katherine C; Xu, Yaoda (2013) The role of transverse occipital sulcus in scene perception and its relationship to object individuation in inferior intraparietal sulcus. J Cogn Neurosci 25:1711-22|
|Poltoratski, Sonia; Xu, Yaoda (2013) The association of color memory and the enumeration of multiple spatially overlapping sets. J Vis 13:|
|Jeong, Su Keun; Xu, Yaoda (2013) Neural representation of targets and distractors during object individuation and identification. J Cogn Neurosci 25:117-26|