AB057.Diagnostic information for the recognition of 3D forms in humans

Background:The perception of visual forms is crucial for effective interactions with our environment and for the recognition of visual objects.Thus,to determine the codes underlying this function is a fundamental theoretical objective in the study of the visual forms perception.The vast majority of research in the field is based on a hypothetico-deductive approach.Thus,we first begin by formulating a theory,then we make predictions and finally we conduct experimental tests.After decades of application of this approach,the field remains far from having a consensus as to the traits underlying the representation of visual form.Our goal is to determine,without theoretical a priori or any bias whatsoever,the information underlying the discrimination and recognition of 3D visual forms in normal human adults.Methods:To this end,the adaptive bubble technique developed by Wang et al.[2011]is applied on six 3D synthetic objects under varying views from one test to another.This technique is based on the presentation of stimuli that are partially revealed through Gaussian windows,the location of which is random and the number of which is established in such a way as to maintain an established performance criterion.Gradually,the experimental program uses participants’performance to determine the stimulus regions that participants use to recognize objects.The synthetic objects used in this study are unfamiliar and were generated from a program produced at C.Edward Connor’s lab,Johns Hopkins University School of Medicine.Results:The results were integrated across participants to establish regions of presented stimuli that determine the observers’ability to recognize them-i.e.,diagnostic attributes.The results will be reported in graphical form with a Z scores mapping that will be superimposed on silhouettes of the objects presented during the experiment.This mapping makes it possible to quantify the importance of the different regions on the visible surface of an object for its recognition by the participants.Conclusions:The diagnostic attributes that have been identified are the best described in terms of surface fragments.Some of these fragments are located on or near the outer edge of the stimulus while others are relatively distant.The overlap is minimal between the effective attributes for the different points of view of the same object.This suggests that the traits underlying the recognition of objects are specific to the point of view.In other words,they do not generalize through the points of view.

Visual processing of word and image in the fusiform gyrus

BACKGROUND： The role of the left midfusiform gyrus as a target for visual word processing has been a topic of discussion. Numerous studies have utilized alphabetic writing for subject matter. However, few have addressed visual processing of Chinese characters in the left midfusiform gyrus. OBJECTIVE： To verify visual processing of Chinese characters and images in the left midfusiform gyrus using functional magnetic resonance imaging. DESIGN, TIME AND SETTING： A blocked design paradigm study. Experiments were performed at the Room of Magnetic Resonance, Guangdong Provincial Second People＇s Hospital, China from May to June 2009. PARTICIPANTS： A total of eight undergraduate students were recruited from Guangzhou University of China, comprising two females and six males, aged 20-23 years. The subjects were right-handed which was determined by a Chinese standard questionnaire. None of the subjects had a history of psychoneurosis, familial disease, color blindness, or color weakness. METHODS： A total of eight undergraduates were enrolled as subjects. Picture-naming and verb generation tasks were employed through the use of functional magnetic resonance imaging. Analysis of Functional Neurolmages software was used to process the data. MAIN OUTCOME MEASURES： Visual processing of Chinese characters and images in the left midfusiform gyrus was measured. RESULTS： Picture-naming and verb generation tasks were shown to significantly activate the bilateral midfusiform gyrus. Activation occurred in the visual word form area of the left midfusiform gyrus. CONCLUSION： The left midfusiform gyrus plays a general role in visual processing of Chinese characters and images.

Form Properties of Moving Targets Bias Smooth Pursuit Target Selection in Monkeys

During natural viewing,we often recognize multiple objects,detect their motion,and select one object as the target to track.It remains to be determined how such behavior is guided by the integration of visual form and motion perception.To address this,we studied how monkeys made a choice to track moving targets with different forms by smooth pursuit eye movements in a two-target task.We found that pursuit responses were biased toward the motion direction of a target with a hole.By computing the relative weighting,we found that the target with a hole exhibited a larger weight for vector computation.The global hole feature dominated other form properties.This dominance failed to account for changes in pursuit responses to a target with different forms moving singly.These findings suggest that the integration of visual form and motion perception can reshape the competition in sensorimotor networks to guide behavioral selection.