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.

Altered electroencephalographic networks in developmental dyslexia after remedial training:a prospective case-control study

Electroencephalographic studies using graph theoretic analysis have found aberrations in functional connectivity in children with developmental dyslexia.However,how the training with visual tasks can change the functional connectivity of the semantic network in developmental dyslexia is still unclear.We looked for differences in local and global topological properties of functional networks between 21 healthy controls and 22 dyslexic children(8–9 years old)before and after training with visual tasks in this prospective case-control study.The minimum spanning tree method was used to construct the subjects’brain networks in multiple electroencephalographic frequency ranges during a visual word/pseudoword discrimination task.We found group differences in the theta,alpha,beta and gamma bands for four graph measures suggesting a more integrated network topology in dyslexics before the training compared to controls.After training,the network topology of dyslexic children had become more segregated and similar to that of the controls.In theθ,αandβ1-frequency bands,compared to the controls,the pre-training dyslexics exhibited a reduced degree and betweenness centrality of the left anterior temporal and parietal regions.The simultaneous appearance in the left hemisphere of hubs in temporal and parietal(α,β1),temporal and superior frontal cortex(θ,α),parietal and occipitotemporal cortices(β1),identified in the networks of normally developing children was not present in the brain networks of dyslexics.After training,the hub distribution for dyslexics in the theta and beta1 bands had become similar to that of the controls.In summary,our findings point to a less efficient network configuration in dyslexics compared to a more optimal global organization in the controls.This is the first study to investigate the topological organization of functional brain networks of Bulgarian dyslexic children.Approval for the study was obtained from the Ethics Committee of the Institute of Neurobiology and the Institute for Population and Human Studies,Bulgarian Academy of Sciences(approval No.02-41/12.07.2019)on March 28,2017,and the State Logopedic Center and the Ministry of Education and Science(approval No.09-69/14.03.2017)on July 12,2019.

An improved Bag-of-Words framework for remote sensing image retrieval in large-scale image databases

Due to advances in satellite and sensor technology,the number and size of Remote Sensing(RS)images continue to grow at a rapid pace.The continuous stream of sensor data from satellites poses major challenges for the retrieval of relevant information from those satellite datastreams.The Bag-of-Words(BoW)framework is a leading image search approach and has been successfully applied in a broad range of computer vision problems and hence has received much attention from the RS community.However,the recognition performance of a typical BoW framework becomes very poor when the framework is applied to application scenarios where the appearance and texture of images are very similar.In this paper,we propose a simple method to improve recognition performance of a typical BoW framework by representing images with local features extracted from base images.In addition,we propose a similarity measure for RS images by counting the number of same words assigned to images.We compare the performance of these methods with a typical BoW framework.Our experiments show that the proposed method has better recognition performance than that of the BoW and requires less storage space for saving local invariant features.

Vernier But Not Grating Acuity Contributes to an Early Stage of Visual Word Processing

The process of reading words depends heavily on efficient visual skills, including analyzing and decomposing basic visual features. Surprisingly, previous reading-related studies have almost exclusively focused on gross aspects of visual skills, while only very few have investigated the role of finer skills. The present study filled this gap and examined the relations of two finer visual skills measured by grating acuity（the ability to resolve periodic luminance variations across space） and Vernier acuity（the ability to detect/discriminate relative locations of features） to Chinese character-processing as measured by character form-matching and lexical decision tasks in skilled adult readers. The results showed that Vernier acuity was significantly correlated with performance in character form-matching but not visual symbol formmatching, while no correlation was found between grating acuity and character processing. Interestingly, we found no correlation of the two visual skills with lexical decisionperformance. These findings provide for the first time empirical evidence that the finer visual skills, particularly as reflected in Vernier acuity, may directly contribute to an early stage of hierarchical word processing.

A review of object representation based on local features

Object representation based on local features is a topical subject in the domain of image understanding and computer vision. We discuss the defects of global features in present methods and the advantages of local features in object recognition, and briefly explore state-of-the-art recognition methods using local features, especially the main approaches of local feature extraction and object representation. To clearly explain these methods, the problem of local feature extraction is divided into feature region detection, feature region description, and feature space optimization. The main components and merits of these steps are presented. Technologies for object presentation are classified into three types: vector space, sliding window, and structure relationship models. Future development trends are discussed briefly.